Geocaching Instability

[+Pokaroo]

Why did my text not get included...

 

Here it is again...

 

I love my new Colorado 300. I have read about accuracy and getting different waypoint locations when returning to the same spot. In the Geocaching mode I have found a interesting quirk and wondered if anybody else has ran into this. I am assuming you can geocache with the Compass turn off. But often times when I approach the area of a Cache my Colorado seems to jump all over the placle (WAAS ENabled). When this happens I have found that if I turn my compass on and calibrate it it settles down the GPS and the direction and distance stabilizes nicely. It is then VERY accurate. Other tmes when I seem to have a problem getting a good fix on a cache I just calibrate the compass and it solves the problem. Anyone else run into this or have any great insight as to why this hapens?

[+Prime Suspect]

Why did my text not get included...

 

Here it is again...

 

I love my new Colorado 300. I have read about accuracy and getting different waypoint locations when returning to the same spot. In the Geocaching mode I have found a interesting quirk and wondered if anybody else has ran into this. I am assuming you can geocache with the Compass turn off. But often times when I approach the area of a Cache my Colorado seems to jump all over the placle (WAAS ENabled). When this happens I have found that if I turn my compass on and calibrate it it settles down the GPS and the direction and distance stabilizes nicely. It is then VERY accurate. Other tmes when I seem to have a problem getting a good fix on a cache I just calibrate the compass and it solves the problem. Anyone else run into this or have any great insight as to why this hapens?

It's probably because you're standing in one spot for a bit while you're calibrating the compass, instead of running around chasing the arrow. Once you're inside the error zone, stop trying to find an exact GZ, and start looking for the cache.

[+twolpert]

I generally agree with Prime Suspect. You are most likely getting better results because you allowed the unit to settle. But there are other considerations related to the compass.

 

Remember that the pointer shows the difference between the direction you are travelling and the direction you should be travelling to reach the cache. If the compass is off, your direction of travel is based exclusively on data from the GPSr. If you are, in fact, standing still, the GPSr has no idea which way you are facing so the pointer (if visible at all) is completely unreliable. With the compass on and calibrated, when you are stopped or travelling at low speed, the unit will use the compass data to determine your direction of travel (or the direction you are facing if stopped). Even with the compass on and calibrated, the unit will use satellite information if you are travelling at higher speeds.

 

In challenging reception conditions, the whole situation is complicated by the behavior of high-sensitivity receivers like the Colorado. These units are subject to multi-path effects under heavy tree cover, near reflective obstructions like steep hills or cliffs, and so forth. These effects result in abrupt shifts in apparent position. Sometimes, these shifts can be quite large (50 or 60 feet) and virtually instantaneous -- meaning that the unit perceives a high rate of travel for a brief time. This can cause the unit to switch unpredictably between the compass and satellite data for your heading. This means that you sometimes observe a spinning pointer even when standing still with the compass on and calibrated.

 

Bottom line: The compass can be helpful in some cases. But because of multi-path effects, many cachers choose to leave the compass off and rely on their eyeballs once they get near the cache location.

[+Pokaroo]

This was very helpful and I appreciate the time you took to explain this. Multi-path effect is totally new to me and really makes sense of what I have been expereiencing. Perhaps I have been too keen on getting the exact GZ when in effect the accuray of the coordinaters may be determined by the cache hiders GPS. Now I have a much better understanding and can act accordingly. Thanks very much. John