GPSMAP62ST problem

[+badger10]

A buddy of mine has a GPSMAP62ST and he is having a problem with the compass and tracks. He is out doing caches (no wires, canyons, buildings etc) and when he stops the compass goes erratic. It will show the cache 30 feet to the East and then 70 feet to the West. He has turned on the tracks function while staying still and the tracks show him going all over the place. He says the compass is calibrated. He is fairly new to caching and he wants me to check his gps out. I have a GPSMAP62s and have not had a problem. Any ideas what could be wrong. I thought maybe he has some settings wrong but he will get the gps to me in a couple of days to check it out.

Ray

[+Cacheoholic]

How often does he calibrate the compass? The compass needs to be calibrated at every battery change since the batteries affect compass calibration.

[+wifireman]

Calibrate the compass and also make sure they have the latest software update. I know from reading the past updates that they were having problematic issues with the compass jumping around and believe the latest had a fix for that.

[+badger10]

He said he had the latest update and he had calibrated the compass. That is the first thing I asked him. I wonder if the routing or profile settings would cause any problems?

[+Team Periwinkle]

It will show the cache 30 feet to the East and then 70 feet to the West.

 

Hmmm...the arrow pointing to the cache has nothing to do with the compass. The arrow pointing to the cache (or any waypoint) is the bearing and distance calculated by the GPS using the two known positions: the cache and the receiver (GPSr). If the GPSr gets erratic reception (due to poor GPS signal), then the position of the GPSr will 'jump' around, and therefore the calculated distance and bearing to the cache will change.

 

He has turned on the tracks function while staying still and the tracks show him going all over the place.

 

And same thing here - tracks have nothing to do with the compass. The tracks feature shows the cululative position solutions of the GPSr over time. If the GPSr gets erratic reception (due to poor GPS signal), then the position of the GPSr will 'jump' around, and the track will show erroneous positions.

 

So now that we know we don't have a problem with the compass (or, perhaps rather, the symptoms described above do not have anything to do with the compass), it is a possible problem with the GPSr, but to verify, I recommend the following:

 

1) stand in a wide open field or parking lot, where you can visually see all the way around 360 degrees to the horizon without signifigant obstructions.

2) Turn on the GPSr and let it acquire satellites and wait for a long time to let the position calcuation resolve itself. then wait more just to be sure you're getting locked onto all the satellites.

3) Look at the satellites screen to see how many and how strong a signal you are getting. Record that information.

4) Record the track and determine the radius / diameter of the position drift circle.

 

There will be some expected wandering of the position solution even in the middle of the field with a clear view of the sky. Somebody probably knows what that diameter should be...

 

Dave

[+kwcahart]

Go to "settup", heading, and make sure it is set to "bearing, small needle". Or something like that, I don't have it right in front of me. If the setting is on "CDI" it will really be crazy looking for a cache.

[+Hynr]

A buddy of mine has a GPSMAP62ST and he is having a problem with the compass and tracks. He is out doing caches (no wires, canyons, buildings etc) and when he stops the compass goes erratic. It will show the cache 30 feet to the East and then 70 feet to the West. He has turned on the tracks function while staying still and the tracks show him going all over the place. He says the compass is calibrated. He is fairly new to caching and he wants me to check his gps out. I have a GPSMAP62s and have not had a problem. Any ideas what could be wrong. I thought maybe he has some settings wrong but he will get the gps to me in a couple of days to check it out.

Ray

You might suggest to your friend to look at page 15 of the manual and direct his attention to the bullet "Compass" in the section that refers to "Compass Setup Options". If this setting is causing the unit to use what Garmin calls "GPS compass" (which is an emulation which only works when the GPSr is moving) at the time when he is standing still, then the pointer will bounce. The ideal condition is for him to have the compass calibrated, turned ON, and to have it active whenever the overall motion is less than a typical walking pace.