GAL-OSNMA-SIM

GAL-OSNMA-SIM generates GALILEO baseband signal data streams (E1B/E1C). The baseband signal can be converted to RF using software-defined radio (SDR) platforms, such as HackRF. This projet has been inspired from GPS-SDR-SIM. Many thanks to Takuji Ebinuma

Configure the project

By default, the software is linked with the library libhackrf. You can disable this option by undefined HACKRFLINKED in include/constant.h

Building the project

A makefile is provided with the project. The makefile support Windows, Linux and MacOS. Edit the file Makefile and modify the path according to your setup.

$ make all

OSNMA test vectors files

The gal-osnma-sim software has been tested using the official ICD test vectors from the Receiver Guidelines for the Test Phase v1.1 available here.

The test vectors must be reformatted using, for instance, the python script reformat_test_vector.py available with the project OSNMAlib. Thanks Algafix.

Generating the GALILEO OSNMA signal file

The software has been designed to generate on the fly the I/Q samples and send them to the HackRF. The multithreading implementation allows a realtime signal generation on a PC equiped with a processor such as Intel® Core:tm:i7. Nevertheless, you can also generate I/Q file and replay it later on your SDR device.

Our test setup:

graph LR
A(PC) --> B(HackRF)
B --> C(att. 30dB)
C --> D(GNSS Rx)

Notes: An external TCXO Clock Oscillator Module (0.5PPM) is installed on our HackRF.

You don't need additional files than the test vectors. The ephemeris are extracted from the navigation messages. You have to set the location of the simulation (latitude,Longitude ,altitude).

Specify at least -v <testvector>
Usage:
  -v <testvector>  Test vector file
  -l <location>    Lat,Lon,Alt (default 48.8435155,2.4297700,60)
  -o <output>      I/Q sampling data file (default: osnma.bin)
  -s <frequency>   Sampling frequency [Hz] (default: 2600000)
  -b <iq_bits>     I/Q data format [8/16] (default: 8)
  -k               HackRF transfer
  -d <duration>    Scenario duration [s] (default : 0 -> whole scenario duration)
  -h help

The signal generation date/time is the same as the test vector scenario

> ./gal-osnma-sim -l 48.8435155,2.4297700,60 -t ./tv/configuration_A/13_DEC_2020_GST_09_00_01_fixed.csv -k

Transmitting the samples

HackRF:

The output data have to be 8-bit signed I/Q samples.

> ./gal-osnma-sim -l 48.8435155,2.4297700,60 -t ./tv/configuration_A/13_DEC_2020_GST_09_00_01_fixed.csv

You can use hackrf_transfer tool in the HackRF host software.

> hackrf_transfer -t osnma.bin -f 1575420000 -s 2600000 -a 1 -x 0

galileoz/gal-osnma-sim