EGNOS data reference

To get the data as it was transmited, download it from ESA PAGE

If you need a day of the year, so THIS site helps. Filter the data column (change filenames) :  cat 20sep14-10-50-31-ESA.txt | awk '{ print $9 } ' | sed ':a;N;$!ba;s/\n//g' > plain-2014-sept-20-105031.txt

On 17.th of May 2014, we started activity to get the signals from the GPS geostationary references, that could be used for a continent wide time synchronization of SIDI receivers. Calculations show, that simple antena (eg 1m dish or 50cm long helix) should have enough gain to have a good S/N ratio. We started with the famous "flak mount" upgrade, i had 2 heidenhain 15 bit absolute encoders that i got in Friedrichshafen for few German Marks many years ago lying somewhere.

15 bit HEIDENHAIN absolute encoder AZIMUTH reading

I managed to find specs and wrote the decoding and display software for ATMEGA 8. With those precize and alligned position encoders, finding sky sources was immediately like a charm. For the elevation we simply calculated degrees/tooth on the elevation wheel, precision upto 0,25 deg is easily acheived. Adjustments of the base stand to get the mount to perfect horizontal position helped a lot to be in within 1 degree accuracy.

  Setup for the measurement cosisted of 3 different antennas

3m dish, vertical polarization 30 db S/N 3m dish
1m dish, circular feed 10 db S/N feed
37 cm long helix 12 db s/N helix

 

Preamp is s53mv about 0.6dB NF, 50m of 75 ohm cable and another preamp to cover the cable losses, total gain abt 30dB. For measurement we used my home made S53MV spectrum analyzer.
Signal at 3m dish was as expected 30db above noise.

SES-5 signal on 1575

 

satellite comment position azimuth elevation
Inmarsat-3 AOR-E, at    15.5° W 218.4  30
 SES-5 (also Astra 4B and Sirius 5) Best signal, next day no signal.. not reliable 5 192.5 36.7
 ARTEMIS  no signal on 1575 21.5 169.56 36.92
 Inmarsat 4-F2 (Europe Middle East Africa) (weak signal . 15db, rightmost maximum) 25 164.79 36.32
 Astra 5B [2] no signal on 1575 31.5 156.20 34.66

 

With the 3m dish the SES-5 signal was about 30dB. We tested also 80 cm dish and 50cm Helix,

helix antenna for GNSS

that gave about 10dB signal, prommissing result. The dish feed was used for pointing only. 

Following picture shows fft SIDI output with east (helix) antenna in upper and west (3m dish) in lower part.

5E dual view recording

Next picture shows same east setup with W antenna pointed to the satellite at 15.5°West

east SAS-5 and west ant to 15.5W

Marko recorded the data on sidi an will try to crunch the numbers.

Common noise source to 2 SIDI RX each own LO and EGNOS reference