Etrex Legend C, Geko 201, Edge 205, and Foretrex 201

Edge 205 in a waterprotecting cellphone bag.

 

Test NaviGPS Amaryllo (red) versus Garmin Edge 205 (green) both measuring at 1 trackpoint

per second. 10 min recording in static positions - grid line distance = 1m

Egde205Static.gpx      NaviGPSStatic.txt

 

Test NaviGPS Amaryllo (red) versus Garmin Edge 205 (green) both measuring at 1 trackpoint

per second. ~30 min recording in a car - grid line distance = 1km

Edge205Car.gpx         NaviGPSCar.txt

 

 

10. January 2007:

 

 

Test NaviGPS Amaryllo (green) versus Garmin Edge 205 (red) and Garmin Foretrex 201 (blue),

all units sampling at 1 trackpoint per second.

25 min recording in static positions - grid line distance = 1m

 

The grid-effect (position jumps due to low spatial numerical resolution) of the Foretrex 201,

2.39m in North-South-direction and 2.39 * cos (53.6°) = 1.42m in East-West-direction

can clearly be seen.

 

During the last minute of the tests it started to rain, data without the rain period are shown below ->

the Edge 205 started strong drifts during the rain period only,

the number of satellites shown by the NaviGPS dropped from 8 to 0

and thus no valid data were recorded anymore.

 

Navi_Static.txt   E205_Static.gpx   F201_Static.gpx

 

without rain:

 

13. January 2007:

 

Some more tests with static GPS-units, this time Garmin Foretrex with NMEA-export (every 2 seconds).

Very good receiving conditions (10-11 satellites), after 20 minutes I carried the units closer to a house to the right (East), then reception of the Foretrex and the NaviGPS stopped.

 

E205_130107.gpx   F201_130107.gpx   F201_130107_NMEA.txt   NaviGPS_130107_NMEA.txt

 

 

 

Garmin Edge 205 (green), Foretrex 201 Garmin-format (red) and NMEA output (blue)

 

                          

      Garmin Edge205 (green) and NaviGPS (blue)        Edge-data downloaded by GPSBabel (MacOSX)

 

 

28.01.2007 Test with three different units (Tilmann Heining, Kite, top to bottom):

Garmin Geko 201, Garmin Edge 205 (1sec), NaviGPS (1sec, NMEA):

Geko201     Edge205     NaviGPS

 

 

Fastest 10sec run:

Geko201 (red), Edge205 (blue), and NaviGPS (green).

Dopplerspeed (bright green) and number of satellites (blue) are also shown.

 

 

31.01.2007 Test with three different units (Tilmann Heining, Kite, top to bottom):

Garmin Geko 201, Garmin Edge 205 (1sec), NaviGPS (1sec, NMEA):

Geko201     Edge205     NaviGPS

 

Fastest 10sec run:

Geko201 (red), Edge205 (blue), and NaviGPS (green).

Dopplerspeed (bright green) and number of satellites (blue) are also shown.

 

21.04.2007 NaviGPS - 1 hour in static position (gridsize 1m)

 

20070421_095229.txt

 

20070421_110142.txt

 

 

Handheld-GPS based Speed-Measurements

PDF - last update: 1. June 2007

 

Example data Navi GT-11 binary format (Buesum 30.07.2007):

MANFRED FUCHS_001154_20070730_195457.SBN

 

Program for comparing results from different independent GPS-units:

MatchV1.1.zip

 

Example from comparing two Navi GT-11 units (13 sessions)

 

GT11 versus GT11 (18 sessions)

 

Garmin Foretrex 201 versus GT11 Doppler (21 sessions)

 

Statistical distribution of the deviations between two independent GT11 units.

The red curve represents the expected Gaussian distribution from stationary measurements without aliasing effects for 500m runs.

 

Probability distribution from integration of the measured deviations from 524 500m-runs.

It can be seen from this curve that for example after subtraction of 0.115 knots from the measured Doppler-speed, the true speed was equal or larger than this corrected speed with a probability of 99%.

 

Foretrex201 versus NaviGT11 Doppler

 

Foretrex201 corrections

 

Statistical distribution of the deviations between two independent GT31 units

of 13.158 20 sec-runs with speeds > 20knots.

The pink curve represents the best-fit Gaussian distribution.

 

Probability distribution from integration of the measured deviations of 13.158 20sec-runs.

It can be seen from this curve that for example after subtraction of 0.15 knots from the measured Doppler-speed, the true speed was equal or larger than this corrected speed with a probability of 99.9%.