diff --git a/GPS-Sim.md b/GPS-Sim.md index 29f73a8..60c9ace 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 BBD_NNNN.C8` +`gps-sdr-sim -e RINEX_NAVIGATION_FILE -l LAT,LONG,HEIGHT -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. @@ -16,15 +16,14 @@ Create `SOMENAME.TXT` with: sample_rate=2600000 center_frequency=1575420000 ``` - -Copy to your PortaPack MicroSD and open the file from the GPS Sim app. +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 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` -You also need to create `MYGPSWALK.TXT` as specified above, using the same filename as the .C8 file but with .TXT extension. This file contains the sample rate and center frequency. +You also need to create `MYGPSWALK.TXT` as specified above. ## Compatibility Depending on several factors, results may vary. A modern device will use several sources and methods to validate the current position, so spoofing positions may not be possible in all situations. To improve your chances to receive simulated GPS data, try: