Amateurfunkverein der Hochschule Luzern
The telemetry protocols used for the telemetry downlink of Astrocast 0.1 are fully based on ECSS standards. These are the three applicable documents:
Note that the telemetry downlink is only enabled for specific passes. It is not enabled most of the time, instead the beacon is transmitted.
The following image “TelemetryProcessing” shows the steps from channel symbols to packets.
437.150MHz (same as beacon)
2FSK, deviation ±4.8Khz (i.e. 437.1452MHz and 437.1548MHz)
applied to ECSS-E-ST-50-01C:
Here is the format of the Telemetry Transfer Frame and its header with values of fixed fields (fields and their usage are fully described in ECSS-E-ST-50-03C):
The Spacecraft ID is 1 for Astrocast 0.1, it will be 2 (0b0000000010) for Astrocast 0.2. It is by checking that field that it can be known which spacecraft transmitted the data.
Links to decoders:http://www.dk3wn.info/p/?p=93224