diff --git a/GPS-Sim.md b/GPS-Sim.md index 116fd45..667ef83 100644 --- a/GPS-Sim.md +++ b/GPS-Sim.md @@ -3,7 +3,7 @@ This app allows you to broadcast GPS baseband signal data streams. ## Generator You can use [gps-sdr-sim](https://github.com/osqzss/gps-sdr-sim) to generate data for this app. -`gps-sdr-sim -e RINEX_NAVIGATION_FILE -l LAT,LONG,HEIGHT -o SOMENAME.C8` +`gps-sdr-sim -e RINEX_NAVIGATION_FILE -l LAT,LONG,HEIGHT -b 8 -o SOMENAME.C8` That will create `SOMENAME.C8`, but note that you also need to specify its sample rate and frequency in another file, as explained below. @@ -18,10 +18,20 @@ center_frequency=1575420000 ``` This file should use the same filename as the .C8 file but with .TXT extension. It contains the sample rate and center frequency for the .C8 file. Copy the files to your PortaPack MicroSD and open the .C8 file in the GPS Sim app. -## Example +## Example 1 +Create a rather small polygon with a path in KML format (i.e. a path you might want to simulate to walk). You can use Google Earth or another solution like https://www.doogal.co.uk/polylines.php. Load that file in the free [SatGen NMEA simulator](https://www.labsat.co.uk/index.php/en/free-gps-nmea-simulator-software). In the generator, change the frequency to 10 Hz and export the NMEA. + +`gps-sdr-sim.exe -e brdc1180.20n -g NMEA.txt -b 8 -o TESTGPS.C8` + +You also need to create `TESTGPS.TXT` as specified above. + + +## Example 2 +> **NOTE:** The website nmeagen may add timestamps to the output. That might be problematic for the simulation + We can create a realistic movement using a NMEA GGA stream generator like https://nmeagen.org/. In this website create several multi point lines with the positions you want. Download the NMEA file clicking "Generate NMEA file". -`gps-sdr-sim.exe -e brdc3540.14n -g OUTPUT.nmea -d DURATION -o MYGPSWALK.C8` +`gps-sdr-sim.exe -e brdc3540.14n -g OUTPUT.nmea -b 8 -d DURATION -o MYGPSWALK.C8` You also need to create `MYGPSWALK.TXT` as specified above.