Understanding How To Use Navagation

[+AtoZ]

I have an Extrax Legend and was using it this weekend in a vary wide open space. I had about 8 to 10 satalites at any give time and had accuracy from 1o to 20 feet. I turned WAAS off, some one said it helped. Well here is the problem I would follow th navigation screen and follow where the arrow pointed and read off the distance well I would walk 10 feet in that direction and then stop and look at the GPS again and it would be pointing in a total differant direction and have a totally differant distance. This happened mutiple times.

But the confusing thing was is why with a little change in distance would the readings change SO MUCH. I had it at one time pointing NW and distance 453 ft the next time it would point SW and say 235 ft. I would stand there holding the GPS level and wait for up to 30 sec to let it stablize but it seemed to point very irratically. Some how I finally found the general area, by the grace of GOD, and then got the same first 30 feet that way then 50 feet another way. I checked the long/lat values against the GPS values and knew I was close but the variation swings lead me to not turst the GPS very much. Maybe that is something I need to know.

 

Well thanks for the time and if you reply thanks again.

 

cheers

[+Stunod]

Unless you are moving, the GPS cannot "point" you to the waypoint. It uses it's motion to figure out which way you are facing. If you are standing still, it has no idea which way you are facing, so the arrow points erratically. Maybe this was your problem?

[+Renegade Knight]

To add a little to Stunods good summery. Once you are within 20' of the cache the GPS also has a hard time figuring out where you are relative to the cache coordinate so it will start pointing erraticly as your position relative to the cache bounces around due to the natural limit of accuracy in the GPS system.

 

In other words once you are about 40' from the cache use the pointer to estimate the cache location then walk to that point. Your GPS will normally tell you that you are within 10' when you get to the spot. Then it's time to look.

[+the hermit crabs]

I'm still a relative newbie, so I don't know if this is the best way to handle this issue, but this is what works for me: when I'm pretty close to the cache (close enough that the arrow makes those sudden 180-degree turns), I just switch from the arrow screen to the satellite one, and watch the lat/long numbers on the bottom.

 

Say, for instance, you want to go to N42 25.500, W071 36.300, and the satellite screen says that you're at N42 25.485, W071.36.310. In this case, you need to go a bit further north and a bit further east.

 

I do a rough estimate of one pace per .001 minute, so my first attempt in this case would be to walk 15 paces north and 10 paces east. (This will vary greatly depending on how big your strides are, and, in the case of the longitude, how far you are from the equator.) If it's overcast and you have no compass and have no idea where north is, just start walking in a random direction and watch to see whether your lat and long numbers are going up or down, and then re-aim yourself accordingly.

 

This works for me.

[+WeightMan]

The real key is once you get that close, put the GPSr away and start looking for places you would hide a cache. Most times that is exactly where it is. Someone else suggested looking for a place to relieve pressure on the bladder works for him.

[+writer]

I find that switching to the tracks screen improves the problem with sudden swings of coordinates. As tech support at Garmin explained, the bearing compass on the Legend doesn't do much good if you aren't going at least 2 mph because the GPS receiver isn't sampling your position enough and it basically gets confused. But the tracks keep a longer history and you can get a better sens of where you are in relationship to the cache.

[+strikeforce1]

DITTO: as to Stunod, RK, and WeightMan, you must be moving with most newer GPSr's to use the pointer. As I get colse, usually .004 away, walk slow for better accuracy. Sometimes there are mineral deposits in the area, that affect the GPSr as well. SF1

[+Go JayBee]

Tebarton,

 

Another tip: Turn off "Lock on Road"......that had me doing exactly what you described. I was on a trail that was near a road and was navigating towards the cache, got within 60 feet and wammo, all of a sudden it pointed 300 feet away in the opposite direction. Have not had that problem ever since turning off the "lock on road" or maybe it's "Follow Road". Look at your menu for the Map Screen I think.

 

Good luck,

JayBee

[+Alan2]

I believe you can set "Lock on Road" to automatically turn off if you are moving slower than a certain speed, such as when you are walking on a trail?

[+Go JayBee]

I believe you can set "Lock on Road" to automatically turn off if you are moving slower than a certain speed, such as when you are walking on a trail?

Alan,

I think you are referring to the Vista in it's ability to switch to the Electronic Compass. The Legend does not have that feature. I know because I have owned both a Legend and a Vista.

 

JayBee

Edited June 17, 2004 by Go JayBee