CubeBug-1TURKSAT and Istanbul Technical University
CubeBug-1 is the first technology demonstration mission for a new CubeSat platform design (mechanics, hardware and software) intended to be released as Open Source and Open Hardware for its use in Amateur projects, University projects and research labs.
437.445 MHz FM 1k2 AFSK AX.25 1W
NORAD 39153 COSPAR designator 2013-018-D Inclination 98.035 RA of A. Node 352.361 Eccentricity 0.0018381 Argument of Perigee 18.264 Revs per day 14.77975548 Period 1h 37m 25s (97.42 min) Semi-major axis 7 014 km Perigee x Apogee 623 x 649 km BStar (drag term) 0.000267390 1/ER Mean anomaly 341.924
The source of the AX.25 packet is labeled as “CUBEB” and destination “UI”. The data portion contains a binary blob. There are mainly two beacon formats. Packets starting with FF FF F0 are the complete beacon, packets starting with FF FF F3 are a short beacon, with basic information, and a different encoding. All numbers in the packets are stored in network byte ordering (Big Endinan). Most values require a conversion formula, provided in the next table.
The short beacon is encoded a bit different. For every bit the satellite wants to transmit it actually transmits 4. So, for example, the 8 bits 0xA5 become F0F00F0F in the air (a nibble per bit). As this encoding transmits more energy with each bit, it will give us a chance to decode some basic telemetry in a worse scenario. The first three bytes (FF FF F3) identify the packet as a short telemetry beacon, the rest must be “decoded” before interpretation.