Why Different Coordinates For Two Different Gps Units

[+Fuzzywhip]

I did a test today between my old Magellan 2000 and my new Magellan eXplorist 100.

 

(Side note: I found that my 2000 was not giving correct coords so I bought a new 100. I have been very happy with the accuracy of the 100).

 

While geocaching today, I tested my two units. After finding Auto box CGRWVM, I sat down on a nearby rock and got a firm sat lock on both units. Both units were exposed to the same direction, angle relative to the ground, and using the same datum WGS84.

 

The eXplorist 100 had 10 satellites and gave N49-31.783 W119-37.106 (very accurate reading)

 

The old 2000 had 5 satallites and gave N49-32.01 W119-37.22 (by my calculations, over 800 feet off)

 

Since this was a side-by-side test, and if all GPS units should at least give 30M resolution (yes, I know the 2000 does not have WAAS as it was built in 1995), shouldn't the reading be close?

 

I don't expect perfect readings as the 2000 is over 10 years old, and technology has vastly improved.

 

Comparing other caches I have worked has shown the 2000 to be 100 to 200 feet off.

 

Comments? Suggestions? Solutions?

[+Sputnik 57]

My best guess is that the 2000 is set to a datum other than WGS84. I'd check that out first. The 2000 seems to be limited to two decimal minutes, so its accuracy is limited to about 60 feet in any event (pre-turn off of Selective Availability). It does look to be degrees minutes and seconds, but I would check that too.

[+Woodbutcher68]

I've done the same thing with my 315 (4 years old) and my Platinum (had it 3 weeks) and they're almost exactly the same every time. The Platinum usually locks on 2 more satellites than the 315.