[amsat-bb] PSAT Doppler Science Project

Daniel Estévez daniel at destevez.net
Sun Jun 7 20:27:36 UTC 2015

El 07/06/15 a las 04:10, Robert Bruninga escribió:
> Actually, on just one pass all you can get is a line of position relative
> to the satelites track,  But on two passes, then  you can have two lines
> of position and where they intersect is the stations position.

Dear Bob,

Could you elaborate on this? If I understood correctly, position
determination by means of Doppler measurements started with project
Transit. With good knowledge of the satellite TLE and an accurate clock,
a ground station could determine its position with good precision by
measuring the Doppler curve from the beacon of the satellite over a
couple of minutes or so. Indeed, two different frequencies were used to
try and compensate for ionospheric refraction.

I think that this would work similarly and given good TLEs for PSAT and
an NTP or GPS synchronized clock, it should be possible to locate ground
stations just by measuring several of their transmissions over just one
pass. Perhaps ionospheric effects on 10m are too high for this to work
with much precision, but at least some rough estimate could be obtained
(6 digit locator would be nice).


Dani EA4GPZ.

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