samedi 7 septembre 2013

Preamble search results

Preamble search has been implemented and shows good results on data channel (1s interval detected between most of the peaks on 1ms and 4ms correlation results).

Secondary code search has also been tested on the pilot channel for verification.

Tracking of pilot channel (with Bump-Jump algorithme) is used to initiate the tacking on the data channel.

samedi 24 août 2013

Galileo tracking the 20/08/2013

Galileo tracking achieved the 20/08/2013 for PRN11, PRN19 and PRN20 and shows good results of the SDR as well as the shape of the Galileo message transmitted by the satellites :

Further update of the SDR will consist into de-interleaving and viterbi decoding of the bits, then decoding of the message will allow to get the navigation data.

dimanche 18 août 2013

Galileo PVT planned

Major milestones have been successfully passed on the development of the SDR allowing tracking of all Galileo satellites (some pictures will come soon).

Further development will allow to perform a PVT with the 4 current Galileo satellites before the end of this year !

mercredi 20 février 2013

GNSS educational content from ESA

For those who are interested into good educational content on GNSS in general here is a very good site created by ESA :

jeudi 17 janvier 2013

GNSS L1 30 seconds signal record

Here you can find a binary file of a raw signal record at L1 performed on the 4th of January 2013, it's a 30 seconds signal record :

The sampling frequency is fs = 40.96 MHz
The intermediate frequency is fi = 12.82 MHz
Data type is "int8"

lundi 7 janvier 2013

4 first Galileo satellites successful E1 acquisition

Begining this year I sampled on the 4th of January the Galileo satellites signals (all four satellites in view at 14h00 above France). The analysis of the signal is the following (the gain I set in the Front-End is a little bit too high) :

The results of my E1 acquisition software are the following and shows successful detection of PRN 11 (Galileo PFM), PRN 12 (Galileo FM2), PRN 19 (Galileo FM3) and PRN 20 (Galileo FM4) :

Hera are the acquisition results (2D plot frequency and code phase slots) around the detected pic of correlation :

PRN 11 :

PRN 12 :

PRN 19 :

PRN 20 :

And the results of the fine frequency search (only 4 channels are used) :

   | Channel         |    PRN |   Frequency                |           Doppler  |           Code Offset |         Status |
   |                   1 |        20 |           1.28219e+007 |              1908   |                  67173   |               T  |
   |                   2 |        12 |           1.28210e+007 |              1006   |                  71106   |               T  |
   |                   3 |        19 |           1.28200e+007 |                 -16   |                  17637   |               T  |
   |                   4 |        11 |           1.28183e+007 |             -1657   |                  69889   |               T  |

Creation of the blog

This blog is dedicated to the developement of a Galileo Software defined receiver.

Starting with the GPS SDR suite available in the book "A software defined GPS and Galileo Receiver : a single frequency approach (Applied and Numerical Harmonic Analysis)"

I'm currently developping a software suite in Matlab that can acquire and track Galileo signals. Using a GNSS front-end developped by the Franuhofer Institute for sampling the signal received by a tri-frequency antenna, the software process the binary file generated by this front-end.

The Matlab suite currently running for the Galileo E1BC signal acquisition, it was developped using the provided signals ICD :