GPS sometimes is half a world off

I love the new 7D Mk II, but the GPS will sometimes indicate that I am in China or Russia. I live in NJ and have been shooting in NJ. Interestingly, this can happen 'within' a set of photos, suddenly moving from NJ to the other side of the world, and a few dozen frames later, back to NJ. Any ideas? Any suggestions? Thanks.

A GPS receiver is line of sight (Generally speaking)....If you are indoors or in an area where tall buildings cause reflections, there can be problems. The GPS antenna in the camera has to have an unobstructed line(BLUE SKY) of sight from the receiver to the satellite. I am going to guess that your problem occurs when you do not have a clear view of the sky. The minimum number of satellites the receiver has to see is three.

On another note the fact that we can now get a GPS receiver integrated in a consumer camera is a sign of the technology we have at our finger tips. I remember when a single channel GPS receiver was a 8 foot rack of electronics, and you needed three racks to get your position.

Regards,

110yd

What I find interesting is that the GPS in my iPhone 5S works just fine when it is in my pocket when I am inside my automobile. Or in my living room. Or in my basement. Or in my windowless office in a reinforced poured-concrete building.

The GPS on the 7DII should be a lot more convenient that the GPS tagging software app that I used to use, but I am thinking about going back to the phone app because it was much more reliable.

I'm just curious, if you look at the GPS coordinates, are they very similar with the only difference being that the ones from NJ have a longitude with W or - and the ones in Russia/China have an E or +?
For example, the NJ coordinates look like: 40.5931° N, 74.6047° W and the Russia/China coordinates look like: 40.5931° N, 74.6047° E.

pknight wrote in post #17545978
What I find interesting is that the GPS in my iPhone 5S works just fine when it is in my pocket when I am inside my automobile. Or in my living room. Or in my basement. Or in my windowless office in a reinforced poured-concrete building.

99.9% of the time my iPhone 6 Plus also works just fine. Last month while visiting the New York International Auto Show at the Jacob Javits Center, my phone thought I was in VA one minute and Chicago the next.

Your smartphones aren't totally reliant on the GPS satellites, they can also use local phone transmitters and WiFi points to help determine location when the satellite signal is unreliable.

I had remarked about an image gps posted some time ago. Here's the link: https://photography-on-the.net …showthread.php?​p=17385724
#6919 by Alex was shot in South America but gps lookup says China. If memory serves, 180 degrees off..E V W.

Good luck,

Paul

The cell phone base stations have GPS receivers in them. The precise time from the GPS system is used for the network backbone so that the timing is synchronized.

110yd

hollis_f wrote in post #17545993
Your smartphones aren't totally reliant on the GPS satellites, they can also use local phone transmitters and WiFi points to help determine location when the satellite signal is unreliable.

The bottom line is that a phone app will work better than the camera GPS. If you are interested in geotagging you photos, there would seem to be no reason to rely on the camera.

Review the thread at https://photography-on-the.net …showthread.php?​p=16036514. What you are experiencing is probably normal although there are some workarounds once you understand how the GPS system works.

John from PA wrote in post #17546168
Review the thread at https://photography-on-the.net …showthread.php?​p=16036514. What you are experiencing is probably normal although there are some workarounds once you understand how the GPS system works.

I'm sure it is normal. It just isn't good enough.

I agree that the programming shouldn't be that bad. I would find it unacceptable.

Seems like a programming problem. 1/2 the world away, most of the satellites wouldn't be in view and the ephemeris data for the satellites would be messed up. The GPS in the 7D2 mostly seems to work fine for me but I wish there were an option to either store the last good fix or not fill in location data when it can't get a fix. It currently just sores the last fix, fine when in a building but not so good in a vehicle.

As I recall there are two possible positions for every GPS coordinate. That was why early-on aircraft had to set the initial GPS position to start tracking from. I don't know if that is still required or not. Current GPS systems remember the last stopping point so they don't have to be initialized at each start up. Unless of course you moved half a world away while the unit was off. Then initialization is still required. They do have to acquire three satellite lock-on at each start up. Location is based on timing between the signals from each satellite.

So why isn't the camera remembering the previous GPS coordinate and picking up which side of the earth you are on. I can't say. The modern system used in these cameras self initializes. But I don't know what criteria it accesses. Yes GPS is line of sight to the satellites but the satellites are in motion so you don't usually know the line. Which could be close to the horizon. It needs to lock-on and have a clear shot to three satellites to be accurate. Indoors, clouds, tunnels, even camera bags etc. do interfere with GPS signals. And any of these can cause erroneous readings. What is really strange is loosing the location in the middle of a series of shots.

If the problem persists you might want to have a discussion with Canon service. You may be getting some sort of power disruption to the GPS unit inside the camera.

Mike

The GPS coordinate system is a cartesian system, centered at the center of earth. Thus there's only one possible position for each coordinate. The map datum used will make the projection on the earth's surface different, but not around half the world.
When using under-determined solutions, there may be alternate positions that are mathematically possible, but they are usually moving at unrealistic speeds or at unrealistic elevations (space travel), so they are pretty easy to detect.
Today's GPS receivers are always multi-channel (twelve or so) and normally runs with over-determined solutions. Thus they rarely get confused because of loosing contact with a satellite or two.

Still, I've had a Garmin eTrex Vista travelling across the North Sea at about 250000 km/h for half a minute or so, until it suddenly locked up and restarted, so everything can go wrong.