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Beta Testing of Radio Direction Finding in GPSSppc

See GPSSppc user Guide for latest on Direction Finding - June 2010.

Updated 0900 Saturday 10th February 2007


Direction Finding

This is the "DF in GPSSppc" page, set up to help those beta testing this new capability.
Have you visited the GPSS on Pocket PC page ?

These words from Robin are from the GPSSppc beta testing page:

from Robin on 9th February: I've just uploaded new v3a gpssppc.exe which starts to add Radio Direction Finding capability into GPSSppc. This rather specialized capability has been in the full Windows version of GPSS for years, and has often been pioneered by the Radio Amatuers, or "hams", who use it in their "foxhunting" hobby, explained on the page above. If you already have the required experience and hardware to help test this new capability, you may wish to contact me, and join people like David in Nottingham,UK and Anton in Indonesia, help us test DF in GPSSppc.

DF.NME file for offline test with [>] replay

DF.NME replay with XP Before starting to make changes in GPSSppc, to recognize the %090/8 type DF bearing message, I used the full Windows GPSS to help test an edited version of NEWTRIP.NME, named DF.NME, which includes DF bearings onto a target lamp post opposite my house.

You may want to download and test this file with the full Windows GPSS.
You can download DF.NME from DF.NME

DF.NME should start:
etc, etc

GPSS Ctrl-A REPLAY should work OK on it.

If you replace the Pocket PC NEWTRIP.NME by this DF.NME it should behave much as the original copy within the Pocket PC baseline - showing my walk from the front of my house.

Radio Direction Finding on Pocket PC On the right you see a screen shot from the emulator running v3a of GPSSppc. I replaced NEWTRIP.NME in the GPSS folder by DF.NME. After starting GPSSppc I tapped on the menu icon to select the replay page and tapped on the [>] replay button. I continued tapping the menu icon until only the menu icon was shown. I then watched the replay which seemed to process the %090/8 type messages as they should.

v3a does not yet do more than extract the relative bearing from the %090/8 message, add car heading (based on GPS movement) to get an absolute bearing, then draw white lines on the map. There is not yet any triangulation of intersecting lines, or any of the filtering logic within the full Windows GPSS.

v3a should handle %090/8 type messages from a NME file or on either of the possible two COM ports.

Do you see that the pattern of lines are different in these two pictures ? I think this is not a problem with GPSSppc, but with GPSS. The NEWTRIP.NME/DF.NME GPS data was recorded at low, walking speed, and the car heading (course) information within the data was not accurate. GPSSppc has logic to calculate heading at low speed from the changes in position, instead of the course in the NMEA data. Maybe I should put the same logic into GPSS :-)