Gps for S100, S120 & 7dMii doesn't work. WFT with 40d & 7d DOES.

[DBen]

December 29, 2015

Canon's internal gps doesn't work. Gps for the S100 and S120 is sporadic at best--slow to establish, and sporadically disconnects! My new 7dMii simply doesn't work at all. Even though it shows the gps in "on", there is no indication it is working. The only constant is decreased battery charge life.

Contrast this with the EXCELLENT results utilizing the WFT (Wireless File Transmitter) with my 40d and 7d. Granted, the cameras require different WFT's for each camera. The WFT uses a usb cable to connect to a Garmin eTrex.

                   There are some valuable reasons for using this setup:

1. The Garmin gps initially starts out powered by its own batteries, but upon successfully connecting to the WFT, switches to the WFT's battery. This allows literally daylong shooting, with *zero* impact on the body's battery charge. (Contrast this with the gps-power issues noted by 7dMii users.)

1. The eTrex, as a dedicated gps, has all of the advantages of such a unit.

1. The gps is *always on*, so moving while shooting is not an issue.

CAUTION: The camera's power off selection has to be OFF. Otherwise, the timed loss of body power will cause the Garmin to disconnect from the WFT battery and switch to its own batteries, and start the ~20 second countdown to shutoff.

Despite the advantages of the 7dMii, Canon's decision to join the internal-gps-game is an unwelcome one. The cost of the WPF is a small one, when its advantages are considered, vs. the internal body’s.

Even the hassle of ensuring site-specific gps metadata is recorded, by taking a single photo with the 7d/WFT/Garmin setup, while mainly using the 7dMii's superior abilities.. (The 40d is now a backup unit, probably headed for an IR conversion.)

Canon would do well to enable connecting external gps units in future models, or--hint, hint--create a way via a firmware update (Magic Lantern, are you listening?) for the 7dMii.

Obviously, the S series can't be expected to have the same level of effectiveness. However, if Canon is going to offer gps, it *should* ensure the option *works*. As the old saw goes, "The best camera in the world is the one with you".

The S-series RAW+jpeg and other very useful abilities, are really an incredible package in--most importantly for me--a shirt pocket size unit. Consequently, it is frustrating to not have such a useful option available.

[smack53]

What type of area are you using the GPS in? Are there a lot of trees or buildings around that might block the satellite signals?

Steve M.

[Mitsubishiman]

I am a professional land surveyor and have been utilizing GPS daily since 1998, I also teach a college GPS Surveying course and I am extremely familiar with the operations and limitations of the process, I question the unit itself first, the reason is as follows:

In the simplest terms, I can go into extreme detail however unnecessary for this conversation, all GPS starts as an autonomous position, when any unit is first turned on without a differential correction the latitude and longitude is “Autonomous” which simple translation is “Approximate”,  this is accurate enough for the majority of utilization after selective availability was turned off, before that autonomous was about the size of a football field, now it can vary between 10 feet and three feet, regardless of any claim made by the manufacturer in order to obtain sub-meter accuracy you still need a differential correction applied.

Your cell phone, your car GPS will function fine even with ten foot accuracy, generally your position is within a five foot radius circle, so an application such as a map program functions fine.

Even without any differential correction applied GPS works, considering the minimum is only 4 satellites to acquire a position of minimal accuracy, of course more is better, the average GPS unit should be able to maintain a stable enough reading to work.

There is a free smartphone app called “GPS Test” that will indicate how many satellites you have and the signal strength of each one, this will allow you an independent check in the area you are trying to obtain a position.

The three common GPS signals are:

Autonomous (best accuracy after 20 minutes of “On Time”)

Float (Ambiguity unresolved) {Due to insufficient satellite coverage or poor differential correction signal}

Fixed (Ambiguity Resolved) {Requires differential correction}

If you paid for a camera with built in GPS before I would give up I would send it in and have it looked at, I find it hard to believe that Canon would advertise a unit with GPS and it would not function, even the least expensive cell phone has a relatively operational GPS, and I can get accuracy of twenty feet inside of a building with mine, so blockage even inside of what we call an “Urban Canyon” would render all automobile GPS useless.

[RobertTheFat]

---

@Mitsubishiman wrote:

I am a professional land surveyor and have been utilizing GPS daily since 1998, I also teach a college GPS Surveying course and I am extremely familiar with the operations and limitations of the process, I question the unit itself first, the reason is as follows:

In the simplest terms, I can go into extreme detail however unnecessary for this conversation, all GPS starts as an autonomous position, when any unit is first turned on without a differential correction the latitude and longitude is “Autonomous” which simple translation is “Approximate”,  this is accurate enough for the majority of utilization after selective availability was turned off, before that autonomous was about the size of a football field, now it can vary between 10 feet and three feet, regardless of any claim made by the manufacturer in order to obtain sub-meter accuracy you still need a differential correction applied.

Your cell phone, your car GPS will function fine even with ten foot accuracy, generally your position is within a five foot radius circle, so an application such as a map program functions fine.

Even without any differential correction applied GPS works, considering the minimum is only 4 satellites to acquire a position of minimal accuracy, of course more is better, the average GPS unit should be able to maintain a stable enough reading to work.

There is a free smartphone app called “GPS Test” that will indicate how many satellites you have and the signal strength of each one, this will allow you an independent check in the area you are trying to obtain a position.

The three common GPS signals are:

Autonomous (best accuracy after 20 minutes of “On Time”)

Float (Ambiguity unresolved) {Due to insufficient satellite coverage or poor differential correction signal}

Fixed (Ambiguity Resolved) {Requires differential correction}

If you paid for a camera with built in GPS before I would give up I would send it in and have it looked at, I find it hard to believe that Canon would advertise a unit with GPS and it would not function, even the least expensive cell phone has a relatively operational GPS, and I can get accuracy of twenty feet inside of a building with mine, so blockage even inside of what we call an “Urban Canyon” would render all automobile GPS useless.

---

Since the most basic assumption in using GPS is that you don't already know exactly where you are, how do you know what corrections to apply? Do you still rely on the old system of C&GS "benchmarks" that used to (and maybe still do?) appear on topo maps?

[Mitsubishiman]

Bob, the real point I was trying to make is that if the GPS appears to be not working, it has little to do with the conditions and more to do with the unit.

The C&GS benchmarks (Now NGS) on Topo Quad Maps are still in the NAD 29 Datum, although close enough for practical application there has been several iterations in horizontal control order.

As far as which correction to apply, every GPS unit has a certain amount of correction values that can be applied, dependent on the manufacturer; in most cases if they exist they are applied for you automatically.

Without any correction applied you should still be able to get a relatively accurate position, the old saying among surveyors is “I can see the point from where I am standing”

Understanding that when you first turn on GPS that is a standalone unit, it will begin to acquire satellites, and initial tracking of each one that it acquires will yield a more definitive position, the general rule of thumb is after a few minutes the position will be stable, after twenty minutes it will not get much better than it is.

The short story is when you just turned on the unit, do not expect an instantaneous precise position, even a cell phone takes a bit to be as accurate as advertised.

Regarding GPS, this link has a vast amount of information:

http://www.ngs.noaa.gov/faq.shtml