Predicting Number Of Satellites Overhead

[+BigWhiteTruck]

I have seen my GPS tracking as many as 10 satellites at once. Sometimes only 3. Is there any way to predict when you will have more satellites to get a more accurate signal?

For example, I wouldn't try to place a cache with only 3 satellites if I knew I could wait 6 hours and have 7 or 8.

[+PDOP's]

Trimble's Planning Software It's freeware too

[+Butano]

I seem to always have a few more than 3 and sometimes as many as 12, fairly often too. Here is a link to Trimble's web site for their Trimble Planning Software. It is pretty slick software and will do exactly this (as well as some other cool stuff).

 

Guess PDOP'S beat me to it

Edited November 9, 2004 by Butano

[+Prime Suspect]

I have seen my GPS tracking as many as 10 satellites at once.  Sometimes only 3.  Is there any way to predict when you will have more satellites to get a more accurate signal?

For example, I wouldn't try to place a cache with only 3 satellites if I knew I could wait 6 hours and have 7 or 8.

The number is less important than their position. Five SVs grouped closely overhead will not be as good as three SVs spaced far apart, 45 degrees off the horizon.

Edited November 9, 2004 by Prime Suspect

[bug and snake]

The number is less important than their position. Five SVs grouped closely overhead will not be as good as three SVs spaced far apart, 45 degrees off the horizon.

It's a better bet to have more then three for 3D accuracy but that is absolutely right. Geometry, geometry, geometry.

The Trimble offering will help you here too. I use GPS to make my living and we use that software all the time. It's the best.

The OP makes a wonderful and IMPORTANT point as regards when to place a hide. The difference between 'where it is now' and 'where it was then' can be significant in the hiding phase.

[MMACH 5]

This site shows a 3-D globe with all of the satellites' positions. If you click on the sats themselves, you'll see their name and path. It probably doesn't do much for prediction, but I thought it was pretty cool.

Notice many of the GPS satellites are the ones way out on the perimeter in a semi-vertical orbit. I thought that was interesting, (they're the ones above and below the poles, all alone).

Realtime sat positions

[pepperblues]

How do I use the numbers for the satallites on my GPS,

to know the names listed at the 3D site?

pepperblues

[MMACH 5]

I'm not sure how they correspond. I just found the site, myself. I'll do some research and see what I can find out.