Comparison of a Garmin 12XL and a Garmin eTrex Venture

Track Logging - Test Course

The large yellow centered, blue outlined marks are common reference points.  The reference points are an average of about 8 marks by both the Venture and the 12XL. The patterns were walked with either no delays or a delay of some number of seconds at the turning points.  The delay is approximate...  counted 1 thousand 1, 1 thousand 2, etc.  The walking speed is about 3 to 3.8 miles per hour.  Both of the GPSR's were hand held in front of me, a bit below shoulder level and generally not too close. Both GPSR's were set to "Auto" record and the Venture was set to "Least Often".  The distance from "MS2" to "MS8" is about 125 ft.  The test location was a large empty parking lot with a very good view of the sky in all directions (except where I block the satellites).

The point "MS1" was the starting point where more than 30 seconds was spent between walking the routes.  The GPSR's received about 5 minutes (or more) of data before the tests started.  The firmware version for the 12XL is 4.58 and the Venture is version 2.26.
 
Diamond Pattern

1 to 2, 6, 8, to 1


Garmin 12XL

Aug. 18, 2001, 12:19 to 12:35 UTC
Blue: No delay
Dark Green: 6 second delay
Red: 12 second delay
Yellow: 18 second delay
Navy: No delay
EPE or Accuracy: about 13 to 14 ft.
Number of Satellites: 7 to 8

Garmin eTrex Venture

Aug. 18, 2001, 12:19 to 12:35 UTC
Black: No delay
Light Green: 6 second delay
Purple: 12 second delay
Gray: 18 second delay
Blue: No delay
EPE or Accuracy: 6 to 10 ft.
Number of Satellites: 8 to 9
WAAS: Received (1 more sat. than 12XL)
Garmin 12XL

Sept. 22, 2001, 10:34 to 10:42 UTC
Blue: No delay
Dark Green: 6 second delay
Red: 12 second delay
EPE or Accuracy: 15 ft.
Number of Satellites: 8 to 9
Garmin eTrex Venture

Sept. 22, 2001, 10:34 to 10:42 UTC
Black: No delay
Light Green: 6 second delay
Purple: 12 second delay
EPE or Accuracy: 6 to 7 ft.
Number of Satellites: 9 to 10
WAAS: Received (1 more sat. than 12XL)
Complex Pattern

1 to 2, 3, 4, 5, 6, 7, 4, 8, to 1


Garmin 12XL

Sept. 22, 2001, 10:43 to 11:03 UTC
Blue: No delay
Dark Green: 6 second delay
Red: 12 second delay
EPE or Accuracy: 15 ft.
Number of Satellites: 8 to 9

Garmin eTrex Venture

Sept. 22, 2001, 10:43 to 11:03 UTC
Black: No delay
Light Green: 6 second delay
Purple: 12 second delay
EPE or Accuracy: 6 to 7 ft.
Number of Satellites: 9 to 10
WAAS: Received (1 more sat. than 12XL)
Garmin 12XL

Sept. 26, 2001, 11:35 to 11:52 UTC
Blue: No delay
Dark Green: 6 second delay
Red: 12 second delay
EPE or Accuracy: 12 ft. first two, 13 ft. last one
Number of Satellites: 10
Garmin eTrex Venture

Sept. 26, 2001, 11:35 to 11:52 UTC
Black: No delay
Light Green: 6 second delay
Purple: 12 second delay
EPE or Accuracy: mostly 6, 5 to 9 ft. on first two 
about 13 ft. last time (purple)
Number of Satellites: 11
WAAS: Received (1 more sat. than 12XL) 
Most of the time
Garmin 12XL and eTrex Venture

Red: First track 12XL
Dark Green: Second track 12XL
Purple: First track Venture
Light Green: Second track Venture
EPE on 12XL:
EPE on Venture:
Num. of Sats. on 12XL:
Num. of Sats. on Venture:
Garmin 12XL and eTrex Venture
Sept. 22, 2001, 7:00 to 7:40
Red: First track 12XL
Purple: First track Venture
EPE on 12XL:  11 ft. EPE on Venture:  9 to 15 ft.
Num. of Sats. on 12XL:  9 to 10
Num. of Sats. on Venture: 10 to 11


Sept. 25, 11:45 to 12:03
Dark Green: First track 12XL
Light Green: First track Venture
Blue: Second track 12XL
Black: Second track Venture
EPE on 12XL: EPE on Venture:
Num. of Sats. on 12XL:
Num. of Sats. on Venture:
 
Comments:
  • An external antenna was not used with the 12XL in these tests.
  • The primary purpose of this exercise was to show the purpose of delaying when there is a change in direction when using the 12XL.
  • One item I noticed at the beginning of a test was that the Venture and the 12XL were different by about 20 plus meters in the northing coordinate (UTM).  This was shortly after they where turned on.  Over a period of about three minutes, I watched the value in the Venture slowly approach that of the 12XL.  The value given by the 12XL remained about the same.  This might have been caused by the 12XL having a more recent almanac in storage.  I don't remember if the 12XL had been more recently turned on and obtained a lock subsequent to the Venture being ON.

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    Copyright © 2001, 2002 Dan Anderson. All rights reserved.