GPS 60CSx problem

[Peakbagr]

My GPS60CSx seems to be experiencing a problem. The last few hikes it seems to be taking an excessively long time to find satellites when I turn it on. Until this began, my usual process it to turn it on at the trailhead and it usually found the birds and went 3D shortly after tuning on.
I first notices that it was taking longer a month ago. Yesterday it took 3 or more minutes for satellite lock. Today we were back out and I turned it on and off 3x over 10-12 minutes and then as I scolled to set a track log, it had lock at about 450'. It then acted funny for about a half hour before settling in for the day.

Getting back home a few min ago, I turned it on, powered by the USB cable and in my office, it found satellite lock in about a min or a little longer.

Any ideas a to what might be going on. It gets used a lot, but not abused.
I really don't want to sent it off to Garmin unless I have to.

Thanks,

Alan

 

[DougPaul]

My GPS60CSx seems to be experiencing a problem. The last few hikes it seems to be taking an excessively long time to find satellites when I turn it on. Until this began, my usual process it to turn it on at the trailhead and it usually found the birds and went 3D shortly after tuning on.
I first notices that it was taking longer a month ago. Yesterday it took 3 or more minutes for satellite lock. Today we were back out and I turned it on and off 3x over 10-12 minutes and then as I scolled to set a track log, it had lock at about 450'. It then acted funny for about a half hour before settling in for the day.

Getting back home a few min ago, I turned it on, powered by the USB cable and in my office, it found satellite lock in about a min or a little longer.

Any ideas a to what might be going on. It gets used a lot, but not abused.
I really don't want to sent it off to Garmin unless I have to.

Are you moving right after you turn it on? That can slow the time-to-lock for the 60csx considerably. Best way to cold start is to remain stationary in a good location with the antenna oriented properly (ie pointed upward)--this should give you a lock within a minute or so. Once you have a lock, you can move off.

Another trick is to turn it on in the car in transit (or anywhere within an hour of so of departing the trailhead. This will pre-record the ephemeri (ephemerises?) and give you a hot start. (BTW, the 60csx does not use the almanac and thus does not have a warm start.)

You could always call or email Garmin support--they have a pretty good reputation.

Doug

 

[MichaelJ]

Have you tried the Web Updater software from the Garmin web site to make sure you have the latest version of the firmware?

 

[DougPaul]

Have you tried the Web Updater software from the Garmin web site to make sure you have the latest version of the firmware?

A number of people have had problems with the web updater. I recommend that you simply download the update and install it manually.

In this case, as long as the OP has had the same software during the observed slowdown, it should not be a factor. Also, the GPS chipset software is probably the critical software and it hasn't been updated since Nov 2006.

Latest GPS chipset, v2.90, Nov 27, 2006
GPSChipsetTypeG_290.exe

Latest Unit software, v3.30, Mar 26, 2007
GPSMAP60CSx_330.exe

Doug

 

[Peakbagr]

I usually start the GPS and leave it antenna up on the dashboard, leaning against the windshield. Sometimes, on the hood of the car.
Its just that all of a sudden, the start up lasts a long time. I never move it while its booting.

Took the batteries out and reseated the memory card and relocked it in place. I'll see if that makes a difference.

 

[Peakbagr]

Problems solved

Thanks for suggestions here, and the extensive advice offered by Capn Caper and Doug Paul.

I put the unit out in the backyard where it had a 360 degree view of the sky and left it on for 4 hours.
I then have been scrupulous about turning the GPS off inside or any place where the unit can't see the full sky.

By following the suggestions given, the GPS acquires satellite lock quickly at the start of a hike. The side benefit is the accuracy. Before following these steps, my accuracy as recorded on the unit was generally in the 70' to 90' range during hikes. Good looks at the sky or not. Its now back in the 20' and under range under heavy canopy, and in the 10' range where there is a good look at the birds.
Thanks everybody for all the excellent advice. In addition to the thank you's, I posting the followup for anyone who may experience these kinds of problems with your units.

I am so impressed with the 60CSx that if I had the money, I'd buy a 2nd one just as a backup. I think its that good.

 

[DougPaul]

I put the unit out in the backyard where it had a 360 degree view of the sky and left it on for 4 hours.
I then have been scrupulous about turning the GPS off inside or any place where the unit can't see the full sky.

My guess is that turning the GPS off wherever you have a poor skyview doesn't matter.

The key steps for the 60CSx (and 76CSx) are:
* 1. acquire (lock on to) 4 or more satellites (the signal strength bars will be hollow). This takes only a few seconds under good receiving conditions.
* 2. receive data from the satellites to obtain the ephemeris (orbital parameters) for 4 or more satellites (takes ~30 sec under good receiving condiitons). Each satellite transmits its own ephemeris. Once a valid ephemeris has been received, the signal bar will be solid.

Note 1: if you are moving during (2), portions of the ephemeris transmission may be blocked (by trees etc) and phase (2) can take much longer.
Note 2: If you have the unit operating with a good fix, turn it off, and turn it back on before too long, it will already have valid ephemerdes and can provide a fix very quickly. An ephemeris is only valid for a few hours.
Note 3: The above sequence is only for certain GPSes--many others also include the use of almanac (coarse orbital information) to help them acquire the satellites. The SIRFstarIII GPS chipset (used in the 60CSx) does not require the use of the almanac.
Note 4: The GPS, it will attempt to continuously update the ephemerdes (and almanac if relevent) as you use it as well as download the ephemeris of any new satellites that come into view.

For example, when I take a walk with GPS from my house, I turn the unit on in my living room, leave the unit stationary, and get a fix within a minute or two. I can then go walk with it. (No need to turn it off for any reason.) In contrast, if the unit has been off for a day or so (ie no valid ephemerdes) and I just start walking (or driving), it will take much longer to get a fix.

By following the suggestions given, the GPS acquires satellite lock quickly at the start of a hike. The side benefit is the accuracy. Before following these steps, my accuracy as recorded on the unit was generally in the 70' to 90' range during hikes. Good looks at the sky or not. Its now back in the 20' and under range under heavy canopy, and in the 10' range where there is a good look at the birds.

Those accuracy numbers are rather fluffy--they assume a perfect skyview and neglect some major (frequently the dominant) sources of error--multipath, diffraction, and reflection--so if they took everything into account, the numbers would frequently be much bigger. And they typically mean that there is a 95% chance the error is the displayed figure or less. So the GPS can claim a 10ft error and still be off by miles... (I've seen it happen on the first fix or two after turning a GPS on or during momentary bad signal conditions. One bad point can make the maximum speed number meaningless...)

I am so impressed with the 60CSx that if I had the money, I'd buy a 2nd one just as a backup. I think its that good.

I agree--it is an impressive little beast. I had a 60CS (a pretty good unit) and bought my 60CSx as a result of the bakeoff comparisons.

Doug

 

[Peakbagr]

Doug,

I certainly can't dispute the technical nature of your reply, or your knowledge of the little beaties.
All I know is that the GPS was taking 5 to 10 min to get lock from a stationary position at trailheads and sometimes longer.
And it would never be under 50' or 60' on the GPS accuracy, all day, on hikes or walks.

And after Capn Caper told me to do what I did, it now gets lock quickly and my all day accuracy is mid to low teens, in the woods, with light canopy, with heavy canopy, and in the open.

I have no idea which of the things I was asked to try worked, but there was an immediate, sudden, and drastic improvement to all of the previous benchmarks. Can't explain it, but I'm a happy camper again.

 

[DougPaul]

Doug,

I certainly can't dispute the technical nature of your reply, or your knowledge of the little beaties.
All I know is that the GPS was taking 5 to 10 min to get lock from a stationary position at trailheads and sometimes longer.
And it would never be under 50' or 60' on the GPS accuracy, all day, on hikes or walks.

And after Capn Caper told me to do what I did, it now gets lock quickly and my all day accuracy is mid to low teens, in the woods, with light canopy, with heavy canopy, and in the open.

I have no idea which of the things I was asked to try worked, but there was an immediate, sudden, and drastic improvement to all of the previous benchmarks. Can't explain it, but I'm a happy camper again.

GPSes are complicated beasts that remember info from previous uses and I have heard of units that have required resets to recover from pathological states. An obvious piece of remembered info is the satellite orbits (almanac (apparently not used by the 60CSx) and the ephemeris). My understanding is that a 60CSx will still lock on to the satellites quickly with a bad remembered ephemeris and the bad ephemeris will be rapidly (~30sec in good receiving conditions) replaced with a new one. I have never heard of a 60CSx exhibiting the symptoms that you described. (There are also multiple ways of implementing many of the functions in a GPS and the pathological states would depend on these details. Naturally, the manufacturers are not in the habit of releasing info on these details...)

My guess would be that the several hour run with a good skyview cleared some pathogical state or data.

BTW, in this case, the accuracy numbers were most likely just a symptom of the problem. As stated earlier, the the accuracy numbers are still just fluffy estimates*. The only way to accurately determine the accuracy of a consumer GPS is to compare the indicated location to an accurately surveyed location. (Technically, the accuracy is a 30-day average, so to be fully accurate, you would have to accumulate statistics for 30 days... In GPS-bakeoff #2, I made some 12hr data runs.)

* The accuracy estimate (technical name: EPE=estimated position error) can be viewed as a lower bound on the true accuracy. Thus if the indicated accuracy is poor, then the GPS accuracy is poor. But if the accuracy number is good, you cannot trust the GPS accuracy to be good. That said, I'd rather have a small EPE rather than a large EPE.

Anyhoo, whatever the cause, I'm glad to hear that it is fixed.

Doug

 

[Mohamed Ellozy]

I then have been scrupulous about turning the GPS off inside or any place where the unit can't see the full sky.

Interesting, that is exactly the opposite of what I do!!!

Before almost every trip I spend some time looking through my collection of tracks and waypoints and loading whatever seems appropriate on my GPSr. During that time it is on, and sitting on my desk. One or two hours later I am on the trail, and almost always get a fix between the time I take my pack out of the car, switch the GPSr on, then fool around with last minute nonsense.

When I had a more primitive unit I used a suggestion from Docross: I had (and still have) a lighter adapter in my car, so I would plug the GPSr in as soon as I got in my car, and keep it on for the duration of the trip. At that time I also used an external antenna; I still have it but never use it as the inconvenience of the wires cannot be justified with a unit that does not really need any help.

 

[DougPaul]

I then have been scrupulous about turning the GPS off inside or any place where the unit can't see the full sky.

IMO, this is completely unnecessary. In fact any GPS that gets into trouble any time it cannot see a full sky is useless.

Interesting, that is exactly the opposite of what I do!!!

I'm with Mohamed here...

Doug

 

[MichaelJ]

I'm also with Mohamed, with the exception that I do turn the GPS off, with the unit on, while it's on my desk being futzed with pre-hike (hit "menu" on the sky/satellite page). That just saves battery.

However, if you want to really, really just not get a fix at all ... turn it off, transport it 160 miles or so, then turn it back on while still in the moving car. The change of location combined with not standing still can make it almost impossible to get a fix, while stopping the car for barely a minute will allow it to lock on fully.

 

[DougPaul]

However, if you want to really, really just not get a fix at all ... turn it off, transport it 160 miles or so, then turn it back on while still in the moving car. The change of location combined with not standing still can make it almost impossible to get a fix, while stopping the car for barely a minute will allow it to lock on fully.

This appears to be a quirk with the 60CSx/76CSx*. My 60CS (which does not use the SIRFstarIII GPS chipset) is better at obtaining an initial lock while in motion than is my 60CSx, but once the initial lock is obtained my 60CSx is better at holding it through poor receiving conditions. The 60CSx is also better and faster at obtaining a cold-start lock under poor receiving conditions when the GPSes are stationary.

* I do not know whether this is a quirk with the SIRFstarIII GPS chipset used by the 60CSx or a quirk with how the 60CSx uses it. Garmin has announced some new high sensitivity models and there are rumors that they are based upon a MediaTek Chipset. I don't know if they will also exhibit this quirk.

Doug