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Mission Tracking Feedback / Re: S-NET tracking
« Last post by Yarragadee on April 15, 2018, 07:39:54 AM »
Dear All,

The details on the two passes we have got returns on so far:

Doy 103/1600
Sic: 6207
CPF: DLR6031
Timebias +40mS
X-track: ~0 mdeg
Returns: 96
Comments: Returns steady in range window @ 40mS. Return strength similar to
technosat and faded out during pca period.

DOY 104/1605
Sic: 6207
CPF: DLR6031
Timebias -30mS
X-track: ~0 mdeg
Returns: 167/64 ( two segments)
Comments: Returns steady.

Now I will see if I can attach the excel spreadsheet of the O-C's - Randall
Mission Tracking Feedback / Re: S-NET tracking
« Last post by jsteinborn on April 10, 2018, 02:59:27 PM »
Dear all,

We got a glimpse of S-NET 4 tonight!

Sadly we were unable to record a relevant number of data points.

We saw the target swooshing through the screen with a time bias setting of -170 to -200 ms.
The real time bias must be less than -200 ms.

Mission Tracking Feedback / S-NET tracking
« Last post by Matt Wilkinson on April 06, 2018, 03:15:05 PM »
The 4 S-NET ( satellites were launched on February 01, 2018.  They have been difficult targets up to now. At Herstmonceux, we've had a number of unsuccessful attempts. And i think they have not been tracked by any station in the ILRS network.

However, next week (11th April) we expect to begin to see passes that are partially sunlit and so we will hopefully stand a better chance of getting some returns. This must also be true for other stations.

We will focus on S-NET4 as suggested in the recent ilrs-sta mail (

Please use this space below to comment on your S-NET attempts, successes and failures over the coming weeks. Good luck!
Mission Tracking Feedback / Re: COMPASS-MS1/MS2 predictions
« Last post by jsteinborn on March 16, 2018, 12:55:21 PM »
I've also added Compass-M3 for comparison.

Best Jens
Mission Tracking Feedback / Re: COMPASS-MS1/MS2 predictions
« Last post by jsteinborn on March 16, 2018, 12:48:27 PM »
As a test I've just added both targets to the service front-page.

Please keep in mind that we are using NP, which means there is not much data for a good estimation and also the arc may be very short.

If there is interest we can try to extend the computation backend to take full rate CRDs as input, which would help a lot for such targets.

Mission Tracking Feedback / Re: COMPASS-MS1/MS2 predictions
« Last post by Rob Sherwood on March 12, 2018, 02:43:42 PM »
Dear all, Randall,

Toshi forwarded the original post to Zhang, who replied to say that the MS1/2 (I assume all 3rd generation Beidou) predictions are done at a different institute and he would pass on the information. He did also say though that they have raised this several times before. As you say Randall, it may well be that they are more difficult to do good cpfs for because they aren't officially active yet, so the quantity of ground station data will be less. But surely this makes them poor candidates for highest priority in the LARGE campaign? Unless someone is going to use the SLR to improve the predictions, but I don't know if this is happening? Can we be explicit in saying to the mission people that the ILRS performance on their satellites (even in LARGE campaign) is currently limited by prediction quality and this is seriously impacting the work they can do with the final data set?

Best regards,

Mission Tracking Feedback / Re: COMPASS-MS1/MS2 predictions
« Last post by Yarragadee on March 12, 2018, 05:47:10 AM »
Thanks for bringing this up Jose - lets hope we can get some answers.
Compass IS2 also suffers from the poor prediction quality, so that means none of the new Beidou3 type satellites have good cpfs.
According to the latest constellation status I can find , these newer sats are still not available for users. Maybe they are still relying on TLEs rather than radio data for the cpfs?
At least since the LARGE campaign began, the cpfs seem to be provided a bit more regularly and we find that the timebiases stay under a second for one or two days usually. The x-track and range biases also start out smallish.
As you say very difficult daytime targets due to the x-track/range bias. If they were only out in timebias they would be fairly easy since they are nice and "loud".

- Randall.

Mission Tracking Feedback / COMPASS-MS1/MS2 predictions
« Last post by jose_sgf on March 08, 2018, 02:56:47 PM »
The predictions for COMPASS-MS1 and COMPASS-MS2 have been consistently poor since the start of their laser tracking operations. This is strange, for the COMPASS-M3 predictions are of the regular good quality we expect for this kind of satellite.

We are talking about time biases of seconds, plus up to hundreds of milliarcseconds cross-track offsets. This makes daytime tracking simply impossible, and requires substantial additional time and effort to obtain returns during night time operations.

COMPASS-MS1 has been recently included in the high priority list of the LARGE campaign. The intensive tracking requirements for this campaign are obviously harder to fulfill if the predictions are sub-standard. Two questions come to mind: 1) Why are predictions so poor for these objects? 2) When should we expect them to improve?

In the interim, perhaps it would be useful to include COMPASS-MS1 in the time bias prediction service run by Potsdam?

In-Sky Safety / Re: FLARM
« Last post by Matt Wilkinson on January 11, 2018, 11:43:50 AM »
Thanks Franz.  That seems nice and easy if it is integrated in to your ADS-B receiver. 

We're covered for ADS-B aircraft but not the gliders and small aircraft that FLARM is intended for. We rely on the observer.

I found a community page here with a lot of guidance for setting something up:

And there is a live map here, but i guess it depends on the available network of receivers for its coverage:
In-Sky Safety / Re: FLARM
« Last post by franzkoidl on January 10, 2018, 10:29:20 AM »

At the Graz station we are using a TRX-1500 ADS-B Receiver which includes a FLARM System.

The data stream gives us the position of ADS-B equipped aircrafts as well as those with FLARM.

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