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Fox-1 Satellites to Offer Slow-Speed Telemetry During Normal Transponder Operation

09/04/2014

The Fox-1 series of CubeSats will be capable of transmitting continuous telemetry during normal transponder operation, while contacts are taking place. The satellites will feature slow-speed (200 bps) telemetry data that accompany transponder audio or voice ID activity. The slow-speed data are contained in the audio spectrum below 300 Hz. Using DSP techniques, high-pass filtering is applied to the uplink signal and voice IDs, low-pass filtering is applied to the telemetry audio generated by the IHU (internal housekeeping unit), and the combined audio is sent via the downlink as voice and data signals. Forward error correction added to the downlink stream will accommodate data recovery during fades of up to 250 ms.

The slow-speed data on Fox-1A will contain four payload types: Current telemetry readings, high telemetry readings, low telemetry readings, and Vanderbilt University radiation experiment telemetry. The payloads will be transmitted in a scheduled rotation that delivers one payload, or frame, about every 5 seconds. This means that current telemetry is received once every 15 seconds, experiment telemetry about twice every 15 seconds, and high or low telemetry once a minute — alternating minutes between high and low.

The telemetry will contain many satellite health and operational values, including readings such as solar panel output, battery voltages, temperatures from various areas of the satellite, IHU performance, and the Penn State University MEMS gyro experiment data.

AMSAT plans to provide free software for decoding and displaying both slow and high speed telemetry from the Fox-1 series of satellites, as they get closer to launch. The software will be similar to the user software that was provided for ARISSat-1.

Fox-1A will be an easy-to-operate, FM transponder satellite with operating characteristics similar to those of AMSAT OSCAR-51. The satellite has been designed so that when the battery fails, the transponder can continue to operate when the satellite is in sunlight, and the FM transponder will be able to operate without relying on the IHU. It will have a downlink on 145.980 MHz and uplink on 435.180 MHz (FM).

AMSAT currently is raising funds to cover the costs of the launch contract and additional materials to build and launch Fox-1C. Its fundraising goal is $125,000 to cover these expenses over the next 12 months. Donate via the AMSAT webpage, by calling (888) 322-6728 or by mail to AMSAT, 10605 Concord St, Kensington, MD 20895. Donations marked specifically for Fox-1C are welcome via PayPal. AMSAT is also raising funds via a “crowd sourcing” campaign on fundrazr.com. — Thanks to AMSAT News Service

 



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