Yet Another Cycling Forum
General Category => The Knowledge => GPS => Topic started by: giropaul on 20 August, 2020, 01:54:57 pm
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I can’t find anything on this previously, but apologies if it’s been covered.
My perception is that post a hard Brexit the UKs access to some GPS satellites may be compromised. I’ve no idea what this means.
I am aware that the current UK Government has sunk a big wedge of money into a highly dubious company that seems to not be the answer.
Given that so much depends on GPS these days, commercially and for leisure, am I wrong in fearing a calamitous result?
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It's not GPS we lose access to, it's Galileo, which is an EU system.
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It's pure Project Fear. In any case, if it's Galileo that will be the issue, who currently uses a GPS that only receives Galileo?
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There's multiple levels of GPS for different purposes.
GPS, GLONASS and Galileo all have "public" access levels that are reasonably accurate.
Which is fine if you're getting directions to drive a car between large areas on well defined routes, accurate enough if you're recording a walk, cycle or run and good enough to send a helicopter to find you if it all goes pear shaped
BUT... the public access accuracy of those systems is no where near good enough when you're pointing a £1m worth of arsenal at a battleship in the middle of the Atlantic; to avoid a very expensive splash you need considerably better accuracy.
That's what the UK is losing from Galileo due to Brexit.
Obviously GLONASS is not an acceptable alternative unless Cummings really is a Russian agent, in which case we're Donald Ducked.
Which leaves the British military forces entirely dependent on being friendly enough with the US to get better aiming accuracy than others.
The US don't give us or any other NATO member full GPS access either they keep the highest accuracy levels to themselves.
It's all part of the traditional story of British resting on their laurels (of having a smashingly good land based radio navigation system) while the Americans, Chinese and Russians produced better and trying to claim the flag on the sticker meant it was brilliant...
From a consumer level the only real issue with consumer devices using SatNav systems is when the owner deliberately offsets it by an amount known only to them (which usually means they're about to blow something up and don't want the enemy to use the same system to hit them); realistically this is only a consumer problem if you're on the Western Isles or North West Scotland during Operation Join Warrior.
If you're running around a desert with assault rifle on the other hand...
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Both GPS and Galileo (and Glonass for that matter) will continue to work just fine in the UK past Brexit.
However, the UK will be excluded from the more militarily sensitive parts of Galileo once they're no longer a EU member.
[edit]boy can that FifeingEejit type fast...
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Not just military. The higher accuracy Galileo could be useful for a variety of purposes. eg surveying work. Or automated planting or crop spraying etc.
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Not just military. The higher accuracy Galileo could be useful for a variety of purposes. eg surveying work. Or automated planting or crop spraying etc.
Reminds me of the pictures some of my mates have taken while working fields in modern tractors; they don't really need to be in the cab all the driving is done by the tractor following a route set for high accuracy sat nav.
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The military Galileo signal is encrypted, as is the military GPS signal, and one needs access to the encryption keys to use it. The EU was willing, at least in principle, to negotiate access to the keys (see para. 135 https://ec.europa.eu/info/sites/info/files/communication-annex-negotiating-directives.pdf) but it's not clear if the UK government accepted the offer.
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Also question about EGNOS. It can improve the accuracy of GPS or Galileo. EGNOS uses a network of ground stations to provide correction data, including several sites in the UK. So will they still be available?
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What's the betting that Boris comes up with a world-beating system involving church towers, Ursa Major and which side of a tree has the most moss growing on it?
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Is that the contract with Dom's mate for £99 billion or is it the one Grayling signed where they check the moss on the trees in the Sahara?
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What's the betting that Boris comes up with a world-beating system involving church towers, Ursa Major and which side of a tree has the most moss growing on it?
https://www.theguardian.com/business/2020/jul/03/uk-buys-stake-bankrupt-oneweb-satellite-rival-eu-galileo-system
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I believe the UK Govt bought that stake in Oneweb not to make it into a GPS system, but to stop it falling into Chinese hands.
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As a private individual, in the short term, no change.
J
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Indeed, it's impossible to "turn off" access to a subset of consumer grade devices. There's simply no mechanism to do that.
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Many thanks all, my fears are abated
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What's the betting that Boris comes up with a world-beating system involving church towers, Ursa Major and which side of a tree has the most moss growing on it?
I think you mean spaffing 500 million for a share of a failed satellite company.. which has satellites in low earth orbit which...errr.. dont have the high presicion clocks needed for a positioning system.
ps. I do believe that LEO satellites are useless for a positioning system, even if they have precision clocks aboard. I Cannot say that categorically though.
Cumming's wheeze was to somehow knit a GPS alike system from these LEO satellites. How - we have no idea.
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Indeed, it's impossible to "turn off" access to a subset of consumer grade devices. There's simply no mechanism to do that.
I believe that accuracy CAN be degraded during military exercises in certain areas. There are notices to mariners/airmen when this happens.
https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises
Aha - this article talks about 'jamming' - I would imagine this is a terrestrial transmitter broadcasting spoof GPS signals, which in technical terms drives your car or marine satnav loopy.
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Which leaves the British military forces entirely dependent on being friendly enough with the US to get better aiming accuracy than others.
The US don't give us or any other NATO member full GPS access either they keep the highest accuracy levels to themselves.
I was unaware of this. I thought there was just selective availability which was switched off in 1999 so currently military and civilian are the same. Also I believe as the constellation of gps satellites in the American system has been updated (some were 40 years old) the latest receivers (both military and non military) can have 30cm accuracy.
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I thought there was just selective availability which was switched off in 1999 so currently military and civilian are the same.
Anyone can receive the military signals but they are encrypted and without the encryption keys there is no way to extract the data. The keys are often updated so old keys stop working. The UK probably has access to US military GPS keys, although that access could be withdrawn. The UK was offered access to military Galileo keys as part of Brexit; I assume we would accept but I don't know where to look to determine whether the government did accept.
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I thought there was just selective availability which was switched off in 1999 so currently military and civilian are the same.
Anyone can receive the military signals but they are encrypted and without the encryption keys there is no way to extract the data. The keys are often updated so old keys stop working. The UK probably has access to US military GPS keys, although that access could be withdrawn. The UK was offered access to military Galileo keys as part of Brexit; I assume we would accept but I don't know where to look to determine whether the government did accept.
But currently there is no difference in accuracy between the two. Even when there was it could be circumvented using differential gps.
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Indeed, it's impossible to "turn off" access to a subset of consumer grade devices. There's simply no mechanism to do that.
I believe that accuracy CAN be degraded during military exercises in certain areas. There are notices to mariners/airmen when this happens.
https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises
Aha - this article talks about 'jamming' - I would imagine this is a terrestrial transmitter broadcasting spoof GPS signals, which in technical terms drives your car or marine satnav loopy.
Drifting slightly OT, but I see that the current NOTAM in force for jamming around the Epynt / Sennybridge range includes a phone number for 'emergency cease jam' - could always try calling if my Garmin goes haywire when out riding!
GNSS SIGNAL JAMMING TRIAL. GND JAMMERS LOCATED WI 3NM RADIUS PSN
520052N 0033832W (DIXIES CORNER, POWYS, WALES). ACTIVITY MAY AFFECT
ACFT WI 62NM (ALL DIRECTIONS) AND 62NM RADIUS OF SITE. EMERGENCY
CEASE JAM CONTACT 01874 635599 OR 01980 953785. DURING TRIAL GNSS
REC MAY SUFFER INTERMITTENT/TOTAL FAILURE, OR GIVE INCORRECT PSN
INFO. CREWS SHOULD BE AWARE OF THESE LIMITATIONS AND USE ALT MEANS
OF NAV. FOR INFO 01980 953785. 2020-08-0277/AS4
https://notaminfo.com/ukmap
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I'd quite like my etrex to have military grade GPS accuracy. I wonder how hard it would be - why aren't the more accurate signals made available to consumer devices?
Are they somehow more taxing to the satellite so that if millions of devices were using it, it couldn't cope.... Or is it just a security thing?
If it's the data, surely the information about exactly where I am standing isn't such a big secret... Or is it?
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I'd quite like my etrex to have military grade GPS accuracy. I wonder how hard it would be - why aren't the more accurate signals made available to consumer devices?
Are they somehow more taxing to the satellite so that if millions of devices were using it, it couldn't cope.... Or is it just a security thing?
If it's the data, surely the information about exactly where I am standing isn't such a big secret... Or is it?
It's just the data. The signal is a broadcast, so the satellite doesn't know or care who's listening.
It's a big secret because anyone who knows how to work balsa wood and an arduino could build a cruise missile around the civilian version, and the military would quite like the ability to turn that off, while still knowing where their planes and boats are.
(This is mostly 90s-era paranoia, when you mostly used GPS for navigating in the middle of nowhere. Turning civilian GPS off now would be Bad, because boffins worked out how to use it for important things like synchronising the stock market.)
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If civilian GPS were turned off now, the only people getting their Nandos from Uber Eats would be the ones who used their what3words address, and we don't want that to happen.
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The encrypted signal is not necessarily more accurate but it is less prone to spoofing, i.e. because it is encrypted it is harder for a malicious 3rd party to transmit fake signals and thus fool the receiver. GPS spoofing has been demonstrated and there are several claims that it has been used in military operations against the US, although the validity of these claims is hard to verify.
Both GPS and Galileo are continuing to develop in various ways, e.g. Galileo has plans for a High Accuracy Service (https://www.gsc-europa.eu/galileo/services).
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If civilian GPS were turned off now, the only people getting their Nandos from Uber Eats would be the ones who used their what3words address, and we don't want that to happen.
Doesn't they W3W just use GPS after the location is decoded from the 3 words ? ;)
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If civilian GPS were turned off now, the only people getting their Nandos from Uber Eats would be the ones who used their what3words address, and we don't want that to happen.
Doesn't they W3W just use GPS after the location is decoded from the 3 words ? ;)
Yes exactly , so it’d be reduced to coarse phone network location. For what three words that means it would get Tourette’s.
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Indeed, it's impossible to "turn off" access to a subset of consumer grade devices. There's simply no mechanism to do that.
I believe that accuracy CAN be degraded during military exercises in certain areas. There are notices to mariners/airmen when this happens.
https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises
Aha - this article talks about 'jamming' - I would imagine this is a terrestrial transmitter broadcasting spoof GPS signals, which in technical terms drives your car or marine satnav loopy.
Drifting slightly OT, but I see that the current NOTAM in force for jamming around the Epynt / Sennybridge range includes a phone number for 'emergency cease jam' - could always try calling if my Garmin goes haywire when out riding!
GNSS SIGNAL JAMMING TRIAL. GND JAMMERS LOCATED WI 3NM RADIUS PSN
520052N 0033832W (DIXIES CORNER, POWYS, WALES). ACTIVITY MAY AFFECT
ACFT WI 62NM (ALL DIRECTIONS) AND 62NM RADIUS OF SITE. EMERGENCY
CEASE JAM CONTACT 01874 635599 OR 01980 953785. DURING TRIAL GNSS
REC MAY SUFFER INTERMITTENT/TOTAL FAILURE, OR GIVE INCORRECT PSN
INFO. CREWS SHOULD BE AWARE OF THESE LIMITATIONS AND USE ALT MEANS
OF NAV. FOR INFO 01980 953785. 2020-08-0277/AS4
https://notaminfo.com/ukmap
Or just use glonass in the area.
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I have a waterproof cycling map of my current favourite cycling area.
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Maybe one of the side effects of brexit will be to highlight all the idiots who've forgotten or never learned how to navigate with a map.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
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Maps, both physical and mental, tell you where you are based on context. Most of the time , particularly on land, the function of a gps can be replaced with a map. A gps on its own without a map (possibly electronic) is not much use for navigation
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That.
Both maps and GPS are multifunctional tools. Maps need a little more work but have the advantage that they still work when the batteries run out or someone turns off the satellites.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Post of the day!!!
J
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Maybe one of the side effects of brexit will be to highlight all the idiots who've forgotten or never learned how to navigate with a map.
Because that's such a great bonus. Worth the loss of rights and the wholesale destruction of the country...
Certainly not something we could have achieved with changes to the geography curriculum...
J
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Maybe one of the side effects of brexit will be to highlight all the idiots who've forgotten or never learned how to navigate with a map.
Because that's such a great bonus. Worth the loss of rights and the wholesale destruction of the country...
Certainly not something we could have achieved with changes to the geography curriculum...
J
Brexit is an unmitigated self inflicted disaster.
It may have the occasional amusing side effect though.
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That.
Both maps and GPS are multifunctional tools. Maps need a little more work but have the advantage that they still work when the batteries run out or someone turns off the satellites.
The great thing about GPS is that it lets a computer know where you are in term that computers understand (alternative, clunkier, technologies are available). Which means you can use a computer to read the map for you and successfully navigate by map, even if you missed second year Geography.
And we think that's a bad thing?
Might as well complain that nobody under the age of 50 knows how to use a slide rule.
(I also note that we never seem to see a "maps are better than compasses" debate. Funny that. It's almost as if people were irrationally prejudiced against electricity.)
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A gps on its own without a map (possibly electronic) is not much use for navigation
Not true at all. Plenty out there navigating large distances using bread crumb trails on GPS.
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A gps on its own without a map (possibly electronic) is not much use for navigation
Not true at all. Plenty out there navigating large distances using bread crumb trails on GPS.
To be fair, a bread crumb trail is a map.
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
It’s not a geographical map / a map representing a geographical area, which is I’m sure what you meant above. Otherwise your statement about not being able to navigate with a gps without a map is null and void. Which it is, whichever way you paint it.
For instance I could have a gps and a set of distances and bearings, to navigate by, which you’ll now be calling a map. Indeed it is if you consider it a set of instructions to get from A to B (possibly via C-Z)
I could do the same with a compass and bearings and pacing. Still a map if defined as a set of instructions etc.
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Useful app on my phone gives me the OS map reference for current position. Resolves the group arguments about where we are on the map!
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Which means you can use a computer to read the map for you and successfully navigate by map, even if you missed second year Geography.
I can honestly say I have no idea how to read a map. I mean proper map reading with a compass and shit. And I didn't even miss second year Geography!
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
It’s not a geographical map / a map representing a geographical area, which is I’m sure what you meant above. Otherwise your statement about not being able to navigate with a gps without a map is null and void. Which it is, whichever way you paint it.
For instance I could have a gps and a set of distances and bearings, to navigate by, which you’ll now be calling a map. Indeed it is if you consider it a set of instructions to get from A to B (possibly via C-Z)
I could do the same with a compass and bearings and pacing. Still a map if defined as a set of instructions etc.
A gps and a set of bearings and a compass is more than a gps. I was saying a gps that simply gives you your Lon and lat (like the very early ones), on its own, is no good on its own for navigating. Most devices are far more than simply a gps positioning device, they include various levels of mapping and navigation. Given the choice of just a gps positioning device giving lot and lat or just a map, a map is the better option. Having both is better still.
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What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
Your stretching definitions here, but if we're playing that game...
If I was dumped in the middle of the Atlantic ocean in a boat with a GPS device that just told me my lat/lon I'd be able to navigate myself back to the UK much better than if I didn't have the GPS device.
No map required as I know the rough coordinates for the UK so all I need to do is point the boat in a vague direction that makes the GPS co-ordinates tick towards 51N,0E. That counts as a form of navigating to me.
You could even replace the GPS device with an accurate clock (at a known location) and a sextant (and with a bit of training) one would be able to do something similar.
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What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
Your stretching definitions here, but if we're playing that game...
If I was dumped in the middle of the Atlantic ocean in a boat with a GPS device that just told me my lat/lon I'd be able to navigate myself back to the UK much better than if I didn't have the GPS device.
No map required as I know the rough coordinates for the UK so all I need to do is point the boat in a vague direction that makes the GPS co-ordinates tick towards 51N,0E. That counts as a form of navigating to me.
You could even replace the GPS device with an accurate clock (at a known location) and a sextant (and with a bit of training) one would be able to do something similar.
I did say “particularly on land”
Edit: and indicated a wide ranging definition of map when I said “maps both physical and mental”
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
It’s not a geographical map / a map representing a geographical area, which is I’m sure what you meant above. Otherwise your statement about not being able to navigate with a gps without a map is null and void. Which it is, whichever way you paint it.
For instance I could have a gps and a set of distances and bearings, to navigate by, which you’ll now be calling a map. Indeed it is if you consider it a set of instructions to get from A to B (possibly via C-Z)
I could do the same with a compass and bearings and pacing. Still a map if defined as a set of instructions etc.
A gps and a set of bearings and a compass is more than a gps. I was saying a gps that simply gives you your Lon and lat (like the very early ones), on its own, is no good on its own for navigating. Most devices are far more than simply a gps positioning device, they include various levels of mapping and navigation. Given the choice of just a gps positioning device giving lot and lat or just a map, a map is the better option. Having both is better still.
Nope you can set the bearing and distance in the gps. Nothing is in addition to the gps. Perfectly good for navigating in some circumstances particularly in the mountains. In fact in some circumstances where a traditional map is useless. There are myriads ways of navigating, many not involving a map.
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I wouldn't a breadcrumb trail alone a map. It's an indication of a route but gives no context. It's like a line drawn on a map, with the map removed.
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I concur. A map (https://www.merriam-webster.com/dictionary/map) conveys information about the environment. A breadcrumb trail conveys information about a route. A correlation between that route and ground features such as roads is a human convenience, it may be common but it is not at all prescribed by the terms.
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I will be less ambiguous. Just knowing your longitude and latitude and nothing else is not sufficient not for navigation. You need other stuff. Many gos devices provide other stuff other than position.
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I will be less ambiguous. Just knowing your longitude and latitude and nothing else is not sufficient not for navigation. You need other stuff. Many gos devices provide other stuff other than position.
I don't think anyone is really disagreeing with you, you just seem to have picked a very strict definition of a GPS device which very few (given the number of mobile phones with mapping) fit within.
It's like saying: A map with just contour lines every 500m of elevation and nothing else is not sufficient for navigation (in the UK at least). You need other stuff on it. Many maps provide other stuff than just contour lines every 500m of elevation.
True, but a relatively pointless digression.
If I was dumped in the middle of the Atlantic ocean I'd rather have a device that could tell me my lat/lon than a map.
If I was dumped in the middle of Dartmoor or the Dales or the Peaks I'd rather have a good map than a device that could tell me my lat/lon.
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Maybe one of the side effects of brexit will be to highlight all the idiots who've forgotten or never learned how to navigate with a map.
Might as well complain that nobody under the age of 50 knows how to use a slide rule.
I must admit my 1st thought exactly when reading the 1st quote above was "I must dig out my old book of log tables". I could add it to my reading list, straight after the telephone directory. It's 55 years since I had to refer to logs, and I never was progressive enough to own a slide rule.
Progress = dumbing down, just two ways of saying the same thing.
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I will be less ambiguous. Just knowing your longitude and latitude and nothing else is not sufficient not for navigation. You need other stuff. Many gos devices provide other stuff other than position.
I don't think anyone is really disagreeing with you, you just seem to have picked a very strict definition of a GPS device which very few (given the number of mobile phones with mapping) fit within.
It's like saying: A map with just contour lines every 500m of elevation and nothing else is not sufficient for navigation (in the UK at least). You need other stuff on it. Many maps provide other stuff than just contour lines every 500m of elevation.
True, but a relatively pointless digression.
If I was dumped in the middle of the Atlantic ocean I'd rather have a device that could tell me my lat/lon than a map.
If I was dumped in the middle of Dartmoor or the Dales or the Peaks I'd rather have a good map than a device that could tell me my lat/lon.
Anticipating the “what use is a piece of plain blue paper” I did say on land. I would say for marine navigation the most important thing is a compass. Without that it is very difficult to even go in a straight line especially when it is cloudy.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
But neither tell you where you want to go. For that, you need a piece of paper and a pen. 👍
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I'd quite like my etrex to have military grade GPS accuracy. I wonder how hard it would be - why aren't the more accurate signals made available to consumer devices?
Are they somehow more taxing to the satellite so that if millions of devices were using it, it couldn't cope.... Or is it just a security thing?
If it's the data, surely the information about exactly where I am standing isn't such a big secret... Or is it?
It's just the data. The signal is a broadcast, so the satellite doesn't know or care who's listening.
It's a big secret because anyone who knows how to work balsa wood and an arduino could build a cruise missile around the civilian version, and the military would quite like the ability to turn that off, while still knowing where their planes and boats are.
(This is mostly 90s-era paranoia, when you mostly used GPS for navigating in the middle of nowhere. Turning civilian GPS off now would be Bad, because boffins worked out how to use it for important things like synchronising the stock market.)
I think if I was whoever's being targeted by this balsa wood Arduino based missile I'd ideally like slightly more protection than simply its GPS being slightly wrong, but still :)
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It's just the data. The signal is a broadcast, so the satellite doesn't know or care who's listening.
It's a big secret because anyone who knows how to work balsa wood and an arduino could build a cruise missile around the civilian version, and the military would quite like the ability to turn that off, while still knowing where their planes and boats are.
(This is mostly 90s-era paranoia, when you mostly used GPS for navigating in the middle of nowhere. Turning civilian GPS off now would be Bad, because boffins worked out how to use it for important things like synchronising the stock market.)
There's more to it than that. Any commercially produced approved GPS is supposed to have limits built into the device, called COCOM limits. Which basically say if you're going faster than a set speed, or higher than a set altitude, then the device turns it self off. The idea being to stop people making said Balsa cruise missiles.
The reality is that these days you can make your own gps receiver with an FPGA, or even just an SDR, which makes those limits a bit redundant. But it does raise the entry requirements for such an enterprise above the bare minimum technical competence.
J
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
But neither tell you where you want to go. For that, you need a piece of paper and a pen. 👍
And a destination!
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The reality is that these days you can make your own gps receiver with an FPGA, or even just an SDR, which makes those limits a bit redundant. But it does raise the entry requirements for such an enterprise above the bare minimum technical competence.
Can you really do it with just an FPGA though? It's the GPS receiver chips that are supposed to do some pre-processing to stop reporting location data when they detect they are above 60,000 ft ASL or moving too fast (1000mph is often quoted as the limit).
An FPGA that speaks to a GPS chip can't bypass this as it should be the chip that enforces it. Not sure about an SDR approach though, not sure how easy it is to make an SDR listen on L1 (1575.42MHz) and then write the software to decode time/almanac/ephemeris/etc stuff.
(I might get an SDR capable of receiving that frequency and experimenting...)
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It's just the data. The signal is a broadcast, so the satellite doesn't know or care who's listening.
It's a big secret because anyone who knows how to work balsa wood and an arduino could build a cruise missile around the civilian version, and the military would quite like the ability to turn that off, while still knowing where their planes and boats are.
(This is mostly 90s-era paranoia, when you mostly used GPS for navigating in the middle of nowhere. Turning civilian GPS off now would be Bad, because boffins worked out how to use it for important things like synchronising the stock market.)
There's more to it than that. Any commercially produced approved GPS is supposed to have limits built into the device, called COCOM limits. Which basically say if you're going faster than a set speed, or higher than a set altitude, then the device turns it self off. The idea being to stop people making said Balsa cruise missiles.
The reality is that these days you can make your own gps receiver with an FPGA, or even just an SDR, which makes those limits a bit redundant. But it does raise the entry requirements for such an enterprise above the bare minimum technical competence.
J
As long as your missile isn’t flying over twice the height of Everest or travelling greater than 1100 mph it’ll be fine.
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Can you really do it with just an FPGA though? It's the GPS receiver chips that are supposed to do some pre-processing to stop reporting location data when they detect they are above 60,000 ft ASL or moving too fast (1000mph is often quoted as the limit).
Yes, because you use the FPGA instead of the GPS receiver chip. There are plenty of open source implementations out there.
An FPGA that speaks to a GPS chip can't bypass this as it should be the chip that enforces it. Not sure about an SDR approach though, not sure how easy it is to make an SDR listen on L1 (1575.42MHz) and then write the software to decode time/almanac/ephemeris/etc stuff.
(I might get an SDR capable of receiving that frequency and experimenting...)
as I say, it doesn't need to talk to a GPS receiver chip, as you don't need it...
SDR's that work at that frequency are just fine. They are cheap and easy to get hold of.
J
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I will be less ambiguous. Just knowing your longitude and latitude and nothing else is not sufficient not for navigation. You need other stuff. Many gos devices provide other stuff other than position.
I don't think anyone is really disagreeing with you, you just seem to have picked a very strict definition of a GPS device which very few (given the number of mobile phones with mapping) fit within.
It's like saying: A map with just contour lines every 500m of elevation and nothing else is not sufficient for navigation (in the UK at least). You need other stuff on it. Many maps provide other stuff than just contour lines every 500m of elevation.
True, but a relatively pointless digression.
If I was dumped in the middle of the Atlantic ocean I'd rather have a device that could tell me my lat/lon than a map.
If I was dumped in the middle of Dartmoor or the Dales or the Peaks I'd rather have a good map than a device that could tell me my lat/lon.
Anticipating the “what use is a piece of plain blue paper” I did say on land. I would say for marine navigation the most important thing is a compass. Without that it is very difficult to even go in a straight line especially when it is cloudy.
Navigating on land to a geocache. Navigating on land to the Greenwich Meridian. Navigating on land to the location of a crashed WW2 plane on a featureless upland bog. Navigating on land back to a car left in a large car park. Navigating on land back to a bike parked at a large control on PBP.
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A gps on its own without a map (possibly electronic) is not much use for navigation
I Audaxed for 3 years with exactly that. The old yellow Garmin eTrex H with routes programmed with a routepoint labelled "L@T" or equivalent at each turn. No mapping at all. No breadcrumb trail. Got me 600km across Wales and back for example.
I also did the last 150km of a 200km Audax with no maps displayed on my Edge 705 after some water got into the slot that held the SD card with mapping data. All I had was the pink tracklog for the route and my current position. Took a few turns to get used to but then had no problem following it.
Just a GPS (and no other route info) would be a different prospect though.
I'd be fine with a map though, I spent years poring over them growing up and I'd be quite happy to navigate to somewhere completely new just looking at a map. Being able to look at a map and work out what you should be able to see at any point is a core skill that many people will now be missing.
Them: "We must be here."
Me: "No, we can't be there, otherwise there'd be a church up there on that ridge and there'd be a river over there. We walked past a lake a couple of minutes ago and there's a pub just up the road, of the 3 lakes in this area only one is near a pub and so I'd say we're probably here - if we walk this way for a couple of minutes we should see a junction on the left for Smith's Farm, if we don't see that then we'll stop and re-assess, otherwise we'll be going in the right direction and the footpath will be on the right after a further couple of minutes walk on that same road."
Them: "What? How can you tell that from just looking at a map?"
What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
It’s not a geographical map / a map representing a geographical area, which is I’m sure what you meant above. Otherwise your statement about not being able to navigate with a gps without a map is null and void. Which it is, whichever way you paint it.
For instance I could have a gps and a set of distances and bearings, to navigate by, which you’ll now be calling a map. Indeed it is if you consider it a set of instructions to get from A to B (possibly via C-Z)
I could do the same with a compass and bearings and pacing. Still a map if defined as a set of instructions etc.
A gps and a set of bearings and a compass is more than a gps. I was saying a gps that simply gives you your Lon and lat (like the very early ones), on its own, is no good on its own for navigating. Most devices are far more than simply a gps positioning device, they include various levels of mapping and navigation. Given the choice of just a gps positioning device giving lot and lat or just a map, a map is the better option. Having both is better still.
Nope you can set the bearing and distance in the gps. Nothing is in addition to the gps. Perfectly good for navigating in some circumstances particularly in the mountains. In fact in some circumstances where a traditional map is useless. There are myriads ways of navigating, many not involving a map.
If you are using gps to refer to the global position satellites and can be used to give you a position, no that does not give you a bearing. If you are referring to the handheld GPS receiver that has lots of other stuff in yes. Some have MP3 players too. Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
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If I’m referring to features (that have been around more than 20 years) of handheld gps than yes. There’s no way you were referring to anything other than handheld GPS in your original comment on this.
Dave you can’t try and prove a point you made by reducing handheld gps to something they are not. As Greenbank says, your reductionist rhetoric is like giving someone a map with just contours 500m apart and saying go navigate. Or having a map that doesn’t have street detail and saying go navigate to such and such a street using only the map we provide.
Simple fact is you can navigate by gps alone in a range of different circumstances and all on land. To say otherwise is not to understand GPS or navigation or both. You can navigate just using natural (or man made) features if you really wanted to.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
GPS can also tell you where you need to go as well or are you deliberately ignoring that?
Plus a map won’t always tell you where you are depending on visible landmarks and the detail and scale of the map.
So there you go Dave by your arguments you can’t navigate with a map.
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And from that people seem to think I am anti gps. Handheld gps devices are fantastic - I have owned gps devices since before they had screens and own several now. They are now sophisticated navigation devices providing much more than the position information provided by gps.
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And from that people seem to think I am anti gps. Handheld gps devices are fantastic - I have owned gps devices since before they had screens and own several now. They are now sophisticated navigation devices providing much more than the position information provided by gps.
There you go wasn’t so hard to admit your you can’t navigate by (handheld) gps alone statement was wrong. ;D
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
GPS can also tell you where you need to go as well or are you deliberately ignoring that?
Plus a map won’t always tell you where you are depending on visible landmarks and the detail and scale of the map.
So there you go Dave by your arguments you can’t navigate with a map.
If you are using GPS to mean a hand held GPS receiver like an etrex, yes it can tell you where to go using all the stuff it does in addition to receiving transmissions from GPS satellites to calculate your current lat,lon,alt and time. If you are using GPS in the strict sense that Kim appeared to be, meaning just Global Positioning System then all that does is give a position. It tells you where you are now, that is all. I was using it that second sense as I was responding to Kim.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off entirely.
Not sure if modern ones still use GPS bearings while in motion, but it could be trivially tested with a magnet.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off.
Was that back when positional accuracy was 10m or so. You would have to travel several times that to get a decent bearing.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off entirely.
Not sure if modern ones still use GPS bearings while in motion, but it could be trivially tested with a magnet.
Or standing in one place and rotating slowly.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off.
Was that back when positional accuracy was 10m or so. You would have to travel several times that to get a decent bearing.
The eTrex 20 has no compass and was released in 2015. Its GPS is a STA8088 TESEO II, I don't think there's been a significant improvement in accuracy since then? A couple of metres is typical for my eTrex 30.
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Not sure if modern ones still use GPS bearings while in motion, but it could be trivially tested with a magnet.
Or standing in one place and rotating slowly.
That shows it's got a magnetic compass, but wouldn't test whether it switches to GPS-derived bearings when moving.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off entirely.
Not sure if modern ones still use GPS bearings while in motion, but it could be trivially tested with a magnet.
I can tell you that the iPad is not using gps for orientation as I just slowly rotated with google maps open. It smoothly rotated the direction thing. It then jumped the location by about 100m. (I am indoors so poor satellite signal) but maintained the correct orientation. Just going to look for some magnets !
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I can tell you that the iPad is not using gps for orientation as I just slowly rotated with google maps open. It smoothly rotated the direction thing. It then jumped the location by about 100m. (I am indoors so poor satellite signal) but maintained the correct orientation. Just going to look for some magnets !
Yes, most smartphones and tablets have compasses (and 3-axis accelerometers) in them. That's why those chips are now so cheap.
Now try the same test in a vehicle moving at speed. Preferably not while driving it.
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Can you really do it with just an FPGA though? It's the GPS receiver chips that are supposed to do some pre-processing to stop reporting location data when they detect they are above 60,000 ft ASL or moving too fast (1000mph is often quoted as the limit).
Yes, because you use the FPGA instead of the GPS receiver chip. There are plenty of open source implementations out there.
Sorry, I was being pedantic about just an FPGA chip (and no antenna). Just an FPGA isn't enough, you need an antenna of some sort otherwise the FPGA has no signal to process. That's what I meant when I asked whether a SDR solution is enough, I guess it is.
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Anyway, what a pedantic hill to choose to die on.
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Almost all have some sort of electronic compass and various accelerometers. If it did not have a built in compass it could calculate a bearing by take two position readings maybe a few tens of metres apart, but I don’t know of any that work that way.
A few years ago compass chips were harder to come by and they all worked that way (I think they just took the bearing between the last two positions, so it could be uselessly noisy at low speed, even with a bit of low-pass filtering). Indeed, my Vista HCx would a) power down the compass and use this method to save battery when travelling above walking speed and b) had a menu option to turn the magnetic compass off.
Was that back when positional accuracy was 10m or so. You would have to travel several times that to get a decent bearing.
The eTrex 20 has no compass and was released in 2015. Its GPS is a STA8088 TESEO II, I don't think there's been a significant improvement in accuracy since then? A couple of metres is typical for my eTrex 30.
I was thinking last millennium with the 10m. I did not realise the etrex 20 had no compass. Etrex 30 did/does.
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I can tell you that the iPad is not using gps for orientation as I just slowly rotated with google maps open. It smoothly rotated the direction thing. It then jumped the location by about 100m. (I am indoors so poor satellite signal) but maintained the correct orientation. Just going to look for some magnets !
Yes, most smartphones and tablets have compasses (and 3-axis accelerometers) in them. That's why those chips are now so cheap.
Now try the same test in a vehicle moving at speed. Preferably not while driving it.
Well that was weird. Got my strong magnets (from a hard disk drive) and wafted them around my iPad. The direction showing in google maps did not change, but the position leapt a few metres as I past the magnets over.
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It can possibly tell it’s not rotating from its accelerometers.
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I’m sure it’s smart enough to filter out sudden strong magnetic fields. iPads themselves are full of strong magnets to attach the case.
The next experiment is to wave a magnet around while rotating it and see if it can still detect north.
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I’m sure it’s smart enough to filter out sudden strong magnetic fields. iPads themselves are full of strong magnets to attach the case.
The next experiment is to wave a magnet around while rotating it and see if it can still detect north.
Yes indeed. The weird bit was not just the lack of effect on the direction, more the jump in location. At first I thought it just a random jump as I am inside with poor satellite reception, but it was consistent, each time I move the magnets over.
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Anyway, what a pedantic hill to choose to die on.
My map shows it as a re-entrant.
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Rotating the iPad and wafting magnets does seem to cause a bit of confusion but not much - it seems remarkably resilient
As I am indoors the gps is going to be inaccurate jumping around. I think the device is sensible ignoring these changes until there is some other trigger from the compass or accelerometer. Even though it ignores the compass change when there is no acceleration it still prompts it to update the gps derived position
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The eTrex 20 has no compass and was released in 2015. Its GPS is a STA8088 TESEO II, I don't think there's been a significant improvement in accuracy since then? A couple of metres is typical for my eTrex 30.
The E30 turns its compass off at and above normal walking speeds, and (unlike the old Vista) it's non-negociable. It's in the documentation somewhere. The Etrex 10/20/30 were originally released in 2011, of course there've been several minor refreshes since then.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
GPS can also tell you where you need to go as well or are you deliberately ignoring that?
Plus a map won’t always tell you where you are depending on visible landmarks and the detail and scale of the map.
So there you go Dave by your arguments you can’t navigate with a map.
If you are using GPS to mean a hand held GPS receiver like an etrex, yes it can tell you where to go using all the stuff it does in addition to receiving transmissions from GPS satellites to calculate your current lat,lon,alt and time. If you are using GPS in the strict sense that Kim appeared to be, meaning just Global Positioning System then all that does is give a position. It tells you where you are now, that is all. I was using it that second sense as I was responding to Kim.
Dave I include a quote of your original statement
Maps, both physical and mental, tell you where you are based on context. Most of the time , particularly on land, the function of a gps can be replaced with a map. A gps on its own without a map (possibly electronic) is not much use for navigation
It is stretching the bounds of credibility to suggest you meant the global positioning satellite system in isolation, when you refer to "the function of a gps" and "a gps". You clearly were referring to the devices we all use and hold in our hands not a bunch of satellites in orbit. Which incidently are no use to use to anyone without a suitable handheld device when out on a bike ride or walk! Just as mapping data held on the Ordnance Survey computers is of no use to anyone unless you can access a representation of it in some way via a handheld device or paper version.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
GPS can also tell you where you need to go as well or are you deliberately ignoring that?
Plus a map won’t always tell you where you are depending on visible landmarks and the detail and scale of the map.
So there you go Dave by your arguments you can’t navigate with a map.
If you are using GPS to mean a hand held GPS receiver like an etrex, yes it can tell you where to go using all the stuff it does in addition to receiving transmissions from GPS satellites to calculate your current lat,lon,alt and time. If you are using GPS in the strict sense that Kim appeared to be, meaning just Global Positioning System then all that does is give a position. It tells you where you are now, that is all. I was using it that second sense as I was responding to Kim.
Dave I include a quote of your original statement
Maps, both physical and mental, tell you where you are based on context. Most of the time , particularly on land, the function of a gps can be replaced with a map. A gps on its own without a map (possibly electronic) is not much use for navigation
It is stretching the bounds of credibility to suggest you meant the global positioning satellite system in isolation, when you refer to "the function of a gps" and "a gps". You clearly were referring to the devices we all use and hold in our hands not a bunch of satellites in orbit. Which incidently are no use to use to anyone without a suitable handheld device when out on a bike ride or walk! Just as mapping data held on the Ordnance Survey computers is of no use to anyone unless you can access a representation of it in some way via a handheld device or paper version.
Thanks for letting me know what I meant. I can’t believe I thought it was not possible to navigate using a gps based navigation system when I do it pretty much every day, certainly every bike ride. I apologise.
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GPS tells you where you are. Maps tell you what's there. One is not a replacement for the other.
Kim said that ^
And I said that a map can tell you where you are.
GPS can also tell you where you need to go as well or are you deliberately ignoring that?
Plus a map won’t always tell you where you are depending on visible landmarks and the detail and scale of the map.
So there you go Dave by your arguments you can’t navigate with a map.
If you are using GPS to mean a hand held GPS receiver like an etrex, yes it can tell you where to go using all the stuff it does in addition to receiving transmissions from GPS satellites to calculate your current lat,lon,alt and time. If you are using GPS in the strict sense that Kim appeared to be, meaning just Global Positioning System then all that does is give a position. It tells you where you are now, that is all. I was using it that second sense as I was responding to Kim.
Dave I include a quote of your original statement
Maps, both physical and mental, tell you where you are based on context. Most of the time , particularly on land, the function of a gps can be replaced with a map. A gps on its own without a map (possibly electronic) is not much use for navigation
It is stretching the bounds of credibility to suggest you meant the global positioning satellite system in isolation, when you refer to "the function of a gps" and "a gps". You clearly were referring to the devices we all use and hold in our hands not a bunch of satellites in orbit. Which incidently are no use to use to anyone without a suitable handheld device when out on a bike ride or walk! Just as mapping data held on the Ordnance Survey computers is of no use to anyone unless you can access a representation of it in some way via a handheld device or paper version.
Thanks for letting me know what I meant. I can’t believe I thought it was not possible to navigate using a gps based navigation system when I do it pretty much every day, certainly every bike ride. I apologise.
Well all your running around claiming you didn't mean handheld GPS (in the above statement) can't be used soley for navigation, has me confused. How else are we meant to navigate by GPS, using signals received directly into a tin foil hat on our heads? What exactly did you mean by "a GPS" if not a handheld unit? ;)
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A physical or mental model of the world together with what is observed at a point in the world might be sufficient to unambiguously determine the coordinates of that point and the orientation of the observer and therefore be sufficient for navigation.
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Well all your running around claiming you didn't mean handheld GPS (in the above statement) can't be used soley for navigation, has me confused. How else are we meant to navigate by GPS, using signals received directly into a tin foil hat on our heads? What exactly did you mean by "a GPS" if not a handheld unit? ;)
He was following up from a statement I made, where I very much had a raw GPS chipset in mind as I wrote it. Sure, it's not something you'd use to navigate on your bike or whatever, but it's the sort of thing I've used as a component in some other system to provide a location, speed or (more usually) an accurate time signal. If I wanted to build a thing that could do any meaningful navigation, it would need (at a bare minimum) another set of coordinates in memory to compare to the current GPS position in order to produce some useful output.
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Which means you can use a computer to read the map for you and successfully navigate by map, even if you missed second year Geography.
I can honestly say I have no idea how to read a map. I mean proper map reading with a compass and shit. And I didn't even miss second year Geography!
But did stick around for Higher level Information Technology and Computer Science (or alternatively are a 5yr old with a TV telecommand)
Edit: Sorry for the ambiguity. I was actually replying to Kim's comment, not making a personal remark!
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What you describe is a map. A rudimentary one. A gpx unit that simply tells you your current location and nothing else on its own is no good for navigating.
Your stretching definitions here, but if we're playing that game...
If I was dumped in the middle of the Atlantic ocean in a boat with a GPS device that just told me my lat/lon I'd be able to navigate myself back to the UK much better than if I didn't have the GPS device.
No map required as I know the rough coordinates for the UK so all I need to do is point the boat in a vague direction that makes the GPS co-ordinates tick towards 51N,0E. That counts as a form of navigating to me.
You could even replace the GPS device with an accurate clock (at a known location) and a sextant (and with a bit of training) one would be able to do something similar.
Don't need map or GPS (or even compass)! Just row with the sun on your left cheek and trust your will to survive!! (and hope it rains or you could get very thirsty)
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If I’m referring to features (that have been around more than 20 years) of handheld gps than yes. There’s no way you were referring to anything other than handheld GPS in your original comment on this.
Dave you can’t try and prove a point you made by reducing handheld gps to something they are not. As Greenbank says, your reductionist rhetoric is like giving someone a map with just contours 500m apart and saying go navigate. Or having a map that doesn’t have street detail and saying go navigate to such and such a street using only the map we provide.
Simple fact is you can navigate by gps alone in a range of different circumstances and all on land. To say otherwise is not to understand GPS or navigation or both. You can navigate just using natural (or man made) features if you really wanted to.
You can navigate using just the bokel and asking the right questions - but you will need to have a description of where you want to go that he can relate to, which may bear no relation to real world features. This of course is a different view of navigation because you don't need to know where you are, only where you want to go. For most using a handheld navigation device is quicker and easier (but not half as much fun); for me who might speak more bokelish than IT this is not necesaarily the case!
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There is some evidence that mammals including humans have an ability to detect the earths magnetic field like migratory birds. If so it is very subconscious.
It has been suggested dogs rotating before lying down is mapping and there is the odd statistic that male dogs tend to orient themselves north/south when taking a dump.
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My (female) dogs always do a little twirly dance before they poo. I've never thought to check their orientation.
I'll make a spreadsheet and report back.
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If civilian GPS were turned off now, the only people getting their Nandos from Uber Eats would be the ones who used their what3words address, and we don't want that to happen.
If I could hack my what3words address to pizza here now I'd never go hungry. ;D
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There is some evidence that mammals including humans have an ability to detect the earths magnetic field like migratory birds. If so it is very subconscious.
It has been suggested dogs rotating before lying down is mapping and there is the odd statistic that male dogs tend to orient themselves north/south when taking a dump.
All important research that got people an Ig Noble award:- http://www.frontiersinzoology.com/content/10/1/80
(From https://www.improbable.com/ig-about/winners/)
I think there was also some research of satellite photos that showed that cows like to stand facing North/South more than any other direction.
(Digs): Ah, here's a starting point: https://www.newscientist.com/article/dn14590-and-on-that-farm-the-cows-face-north-says-google/
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
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If civilian GPS were turned off now, the only people getting their Nandos from Uber Eats would be the ones who used their what3words address, and we don't want that to happen.
If I could hack my what3words address to pizza here now I'd never go hungry. ;D
Or surrounded by fat people in cars , angry that you aren’t offering free pizza.
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
The result is 3D spatial coordinates and time. For the purposes of navigation the time may or may not be relevant. For other uses of GPS the time may be of more importance than the position.
Edit: though the time could be useful for sanity checking. If the results come back as “Buckingham in 2036”, something is probably awry.
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For other uses of GPS the time may be of more importance than the position.
One example: we keep time using atomic clocks and there are lots of atomic clocks around the world. The way we determine the accuracy of any given atomic clock is to compare it to lots of other atomic clocks, and one way to do that is to compare to GPS time https://www.bipm.org/en/bipm/tai/time-transfer/
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There is some evidence that mammals including humans have an ability to detect the earths magnetic field like migratory birds. If so it is very subconscious.
I dunno about subconscious. It's not difficult to detect (within 10 degrees or so) where the sun is in the sky, even on overcast days. Is this awareness 'subconscious'? I'd call it 'natural'. Match that to time of day - well some people (I speak as one) have an innate sense of time passing and time-of-day without reference to clocks, watches, phones etc. So I would say I always know where north is, give or take, during daylight, because I always know where the sun is and I always know whether it's morning, evening, noon or night (and many gradations between). And yes I suppose the total computation is at the subconscious level.
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There is some evidence that mammals including humans have an ability to detect the earths magnetic field like migratory birds. If so it is very subconscious.
I dunno about subconscious. It's not difficult to detect (within 10 degrees or so) where the sun is in the sky, even on overcast days. Is this awareness 'subconscious'? I'd call it 'natural'. Match that to time of day - well some people (I speak as one) have an innate sense of time passing and time-of-day without reference to clocks, watches, phones etc. So I would say I always know where north is, give or take, during daylight, because I always know where the sun is and I always know whether it's morning, evening, noon or night (and many gradations between). And yes I suppose the total computation is at the subconscious level.
Birds, insects and some vertebrates are detecting the magnetic field directly - it is for example disrupted by power lines. Generally it is thought humans do not have this ability but there have been some experiments suggesting it could still be present at a very low level. These experiments excluded other cues by being conducted inside with no windows. You mentioned your innate sense of time - one of the proteins involved in regulating the human body clock is sensitive to magnetic fields and is thought to be involved in how homing pigeons ‘see’ magnetic field lines.
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My (female) dogs always do a little twirly dance before they poo. I've never thought to check their orientation.
I'll make a spreadsheet and report back.
Apparently cows always piss north.
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My (female) dogs always do a little twirly dance before they poo. I've never thought to check their orientation.
I'll make a spreadsheet and report back.
Apparently cows always piss north.
I think the theory of the benefit to herd animals is that if you are all randomly aligned and you sprint off when a predator arrives you crash into each other.
Unfortunately attaching a cow, even a smallish one, to the handlebars as a navigation device could be challenging.
The other week, whilst cycling, I narrowly avoided being pissed on by a sheep.
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My (female) dogs always do a little twirly dance before they poo. I've never thought to check their orientation.
I'll make a spreadsheet and report back.
Apparently cows always piss north.
Unfortunately attaching a cow, even a smallish one, to the handlebars as a navigation device could be challenging.
Plus all the water needed for a regular bearing check.
Sent from my SM-G930F using Tapatalk
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
The result is 3D spatial coordinates and time. For the purposes of navigation the time may or may not be relevant. For other uses of GPS the time may be of more importance than the position.
Edit: though the time could be useful for sanity checking. If the results come back as “Buckingham in 2036”, something is probably awry.
The result being you can use just a gps and that data to navigate.
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
The result is 3D spatial coordinates and time. For the purposes of navigation the time may or may not be relevant. For other uses of GPS the time may be of more importance than the position.
Edit: though the time could be useful for sanity checking. If the results come back as “Buckingham in 2036”, something is probably awry.
The result being you can use just a gps and that data to navigate.
Absolutely. I completely agree a gps navigation device is all you need to navigate. I have never thought otherwise, even though my poor wording might have led you, but not others, to believe so, but I think I have explained that on several occasions.
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
The result is 3D spatial coordinates and time. For the purposes of navigation the time may or may not be relevant. For other uses of GPS the time may be of more importance than the position.
Edit: though the time could be useful for sanity checking. If the results come back as “Buckingham in 2036”, something is probably awry.
The result being you can use just a gps and that data to navigate.
Absolutely. I completely agree a gps navigation device is all you need to navigate. I have never thought otherwise, even though my poor wording might have led you, but not others, to believe so, but I think I have explained that on several occasions.
Oh come on, you can tell from the replies from others such as Greenbank that your words were clearly interpreted that way. It just everybody else got bored with your changing responses. :P
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I was sloppy in my wording.
I was trying to say ...
A single point in 3 dimensional space and time (obtained through measurement of transmission times from at least 4 satellites of GPS or one of the other GNSSs or obtained otherwise) is insufficient to define a line segment that is needed as the basis of navigation.
A point in space time, are we now time travelling as well? Giles fetch the Tardis ;D
So you’re saying if given a single coordinate , a once off , and no update if you move, then you can’t navigate? Bit like if you were given a 5m x 5m square of map, with a red dot saying you are here, that did not update as you moved?
Clearly you can still navigate by what you can see. But you’re right, the single coordinate won’t necessarily help (much), on its own, just as the tiny fixed fragment of map won’t help you navigate.
But that’s a very long way from not being to able to navigate solely with a gps and your eyes.
If you think about it, you’ll also realise there are methods of navigation that are not point to point but based on terrain and / or valley systems. So not dependent on having a line segment as the basis.
I wasn’t suggesting time travel. It is necessary to calculate the time which is why you need a minimum of 4 satellites for a decent position (3 would be sufficient for a point in 3-space). The reason for this is that the time needs to be incredibly accurate, far better than you can obtain from a normal clock because you are working out your position based on the speed of light, even a millionth of second is 300m.
Indeed time is used in the technicalities of calculating position due to the nature of how it works. But the location derived , the point coordinates, has no time dimension. It is not a point in space and time. Just a coordinate for a location on Earth.
The result is 3D spatial coordinates and time. For the purposes of navigation the time may or may not be relevant. For other uses of GPS the time may be of more importance than the position.
Edit: though the time could be useful for sanity checking. If the results come back as “Buckingham in 2036”, something is probably awry.
The result being you can use just a gps and that data to navigate.
Absolutely. I completely agree a gps navigation device is all you need to navigate. I have never thought otherwise, even though my poor wording might have led you, but not others, to believe so, but I think I have explained that on several occasions.
Oh come on, you can tell from the replies from others such as Greenbank that your words were clearly interpreted that way. It just everybody else got bored with your changing responses. :P
I am really bored with it too. Clearly I misunderstood what I was trying to say.
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More of our money gone to spivs as the UK finally realises OneWeb won’t work. Now the UK plans to ask if it can get back on the Galileo project.
https://www.theneweuropean.co.uk/top-stories/uk-goverment-could-rejoin-eu-s-galileo-system-1-6848108