Everything space & RF. Amateur radio operator (EA4GPZ / M0HXM). PhD in Mathematics from Univ. Autónoma de Madrid. he/him
Daniel Estévez
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New blog post: An update about Tianwen-2 telemetry. This is a quick update about Tianwen-2 telemetry decoding. First, I've figured out the format of the timestamps included in AOS frames. I explain what was confusing me yesterday.
I showed that the loop coefficients for an order 2 loop with supercritical damping and phase/phase-rate update have explicit formulas that are obtained by solving a cubic equation. Now I treat the rate-only update case, showing that it leads to a degree 6 equation.
We think a Tianwen-2 manoever happened early 7 June, as expected. With the Bochum telescope (@amsat-dl.org) and the Dwingeloo telescope, we observe that a) Tianwen-2 is close to the asteroid on the sky and b) the change in the line-of-sight velocity (Doppler) now almost matches that of the asteroid.
Tianwen-2 at #Asteroid (469219) Kamoʻoalewa now transmitting at High Data Rate!! Receiving with the 20m #Bochum antenna on X-Band.
Just a quick update on Tianwen-2. We saw several events before LOS- At 23:06:10 UTC the data rate was reduced, probably in preparation for some trajectory maneuvers.
New blog post: PLL coefficients for rate-only feedback. A couple years ago I wrote a post that extends a paper of Stephens and Thomas where they model PLLs in discrete time rather than transforming a continuous-time design.
New blog post: Decoding Tianwen-2. I analyze the telemetry decoded from recent @radiotelescoop.bsky.social recordings of Tianwen-2. Compared to Tianwen-1, there is not much in the telemetry. There are not that many fields and most are mainly static. Read more: destevez.net/2026/05/deco...
