Help us track SIDLOC on the Ariane 6 launch!

Calling all radio amateurs!

LSF’s SIDLOC will be launched on the Ariane 6 on July 9th, 20:00-23:00 CEST, 18:00-21:00 UTC.
If you are in the flight path of the Ariane 6, your valuable help is needed to track SIDLOC at 401.5 MHz with at least 2 MHz bandwidth.

Note that SIDLOC is a low-power DSSS beaconing system, so NO transmission will be observable at the spectrum without further processing. The SIDLOC beacon is attached to the second stage of Ariane 6 and is expected to re-enter after two orbits.

Captured signal recordings can be sent to @surligas on the Community or on this thread so that they can be processed.

Your help is greatly appreciated,

Thank you in advance,

Nikoletta from the LSF Team :heart: :rocket:

cf32, cs16/wav16 ?
no doppler ?
tracking antenna required ?
temp norad/tle to track ?

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  • Center Frequency: 401.5 MHz
  • Bandwidth: 2 MHz
  • DSSS = No transmission observable
  • Don’t doppler correct
  • No tracking antenna required (if used please note)
  • cf32 preferable (cs16 is OK too)
  • TLE to be used for AOS/LOS and/or tracking purposes:
1 99997U          24191.75347222  .00000000  00000-0  50000-4 0    04
2 99997  62.0100 146.0000 0003415   0.0000  -1.1100 14.96641939    04

Please note that SIDLOC is attached on the upper stage of Ariane 6 and will be decaying ~1.5 orbits after launch together with the rocket.

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If anyone has the bandwidth to afford, higher sampling rates are quite beneficial :blush:

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I can record IQ with 3 MHz bandwidth 401.5 center, on an omnidirectional with filter and preamp, in a quite noise free location at 27 m ASL at the westcoast of the Netherlands. However, I have no clue about the exact time and I cannot see in the waterfall if the signal has appeared. After that I have no clue how to transfer about 700? GB of data to you. But for safety I start recording now, for 12 hours and if you have the idea my IQ data could be of any help you can tell met the UTC time the transmitter passed my receiver and I can start finding a way to share the data…

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For the Europe pass please approximately record on:

20:57:00 UTC - 21:15:00

cc @pe2bz

We got the SIDLOC beacon! The results exceeded all expectations!!! From an IQ file provided by @SA2KNG, we run the post analysis and the results can be found at the figure below.

The Y axis corresponds to the frequency offset in Hz and each point of the X axis is a DSSS symbol. Without any SIDLOC transmission the offset estimation is randomly spread across the minimum/maximum Doppler configured. The SIDLOC on Ariane 6 was configured beaconing for 30 seconds with 20 seconds of pause between each transmission.

As shown, during three beacons received there are pretty accurate Doppler offset estimations, with just a single estimation been significantly off. The stepping corresponds to the granularity of the system, as it is producing (for now) quantized estimations. The granularity of the offset estimation is configurable, but affects the CPU required to demodulate and decode the signal. We are still waiting for IQ recordings from stations with less SNR to evaluate the system performance and we will keep you posted!


Thanks info. I have had a recording running, I have ran "Datafile editor: in SDR Radio V3, and saved the given time as start, 18 minutes duration, 401.5 center and 3 MHz bandwidth (Either 3 or 1.5) which resulted in 13 files with 1 GB size. So at the moment I am uploading those files to my google drive and after that I am going to share the URL. I am curious if there is any results from my recording too :slight_smile: