Today sees the first flight of my tiny ARM based GPS tracker. The balloon (a 36″ Qualatex foil) was launched from Wirral Grammar School for Girls with their Astronomy Club, who were responsible for the successful WGGS1 high-altitude launch last October.
This flight is a float attempt, and can be tracked at spacenear.us with the callsign WG2. Calculations suggest the battery (a single AAA) should be good until about Friday morning.
The tracker, shown in the picture (more here), has the connector piece removed once programmed. For scale, the board is the same length as the AAA that powers it. Wire antennas were used for both GPS and downlink, and these were just soldered straight to the board. Total mass is about 12 g including the battery. Technical details of the tracker follow…
- Transmitter frequency: 434.45 MHz (nominally)
- Output power: +6 dBm (4 mW)
- Modulation: OLIVIA 8/1000 with CW pips between bursts
- Typical range: Horizon limited (300 km+)
- Power supply: 0.7 V to 2.0 V (single AAA lithium cell)
- Transmitter: SiLabs Si4060
- CPU: Freescale Kinetis KL05Z32 (ARM Cortex M0+)
- GPS: uBlox MAX7C (from HAB Supplies)