Colin, VK5HI: ... the CP6 keplerian data being issued for CP6 is definitely incorrect. I have been using the Day227 element set for Hawksat for the last week. Have not encountered any wild frequency excursions. Today I downloaded element sets for Days 233 & 234 and compared them against Day227_Hawksat, with a “simulator” program I have. The CP6 sets show up to 3 KHz deviation at TCA, whereas the Hawksat are just a few hundred Hertz.
I have just used the Day 234 Hawksat keplerian set on the most recent pass, with excellent tracking. The AOS & LOS also align well.
SpaceTrak gives an RCS of .774 for Hawksat and .0575 for CP6, so I cannot understand how they are getting them mixed up…
Colin, you gave me a good task for this evening, hihi. I tracked CP-6 with TLE OBJ 35004 ( this was the original CP6 TLE) at 1815 UTC.
For the second pass I used the TLE OBJ 35003 (the original HAWKSAT TLE) at 1905 UTC.
You can see the deviation in the first image and a nearly constant – and correct Doppler shift correction – in the second one.
I know it’s hard to determine this exactly because all my passes are low here I Germany. The first pass was 11 deg, the second one 19 deg elevation.
So I agree with you, Colin – fine job!
Alan, ZL2BX: Yes it has seemed obvious that something changed with the TLE’s. Before I
went away in June I had no particular problem but since coming back last week I have seen up to 5kHz offsets during the pass but using the “Hawksat”
TLE’s this reduced to a few Hz with about a 500 to 600Hz difference between Com A and Com B. All very interesting!