Today, December 19th 2014, researchers from NavSAS group acquired and tracked the signal transmitted by the Galileo FOC-FM1 (PRN 18, COSPAR ID 2014-050A and NORAD ID 40128). This satellite is the fifth Galileo navigation satellite launched, one of two left in the wrong orbit by a Soyuz rocket on 22 August. The satellite was recently put into a more circular orbit than before by the European Space Agency (the full story is available on the ESA Navigation Launching Galileo website).
Signal elaboration was performed using N-GENE fully software receiver with a SiGe USB front-end. N-GENE is a GPS/Galileo single frequency fully SW real-time receiver, running on a general purpose processor (standard PC based on an Intel x86 processor). N-GENE was totally developed by NavSAS researchers. It is able to process in real-time the GPS L1 and Galileo E1 signals, as well as to demodulate the differential corrections broadcast on the same frequency by the EGNOS system.
N-Gene is a test-bed that allows to master the whole receiving chain and to test innovative algorithms implementing them in a ‘real receiver’. The flexibility due to software implementation allows
- to add custom logs
- to implement and test new algorithms
- to support new signals and services
The received navigation message indicates the satellite as currently "unhealthy". Following, there are some plots showing some preliminary acquisition and tracking results.
This first figure shows the result of the acquisition procedure over the Galileo PRN 18: the correlation peak clearly visible in the figure indicates the presence of the signal.
The following figure reports the state of the tracking regarding the synchronization of the despreading code reached through a DLL tracking loop.
This final figure exhibits a scattering diagram demonstrating the synchronization of the phase carrier of Galileo PRN 18, also the presence of the navigation message bit transitions can be noticed.