Can ADS-B provide position information for Search and Rescue?

On Saturday, February 18, 2017 at 11:13:58 AM UTC-8, Sarah wrote:
In that case, either Powerflarm or something like the cheaper $300 TRX-1000 would be able to receive 1090es and feed a common FLARM compatible glider display. Beware though - you would not receive air-air UAT data directly.

No. Unfortunately this is not correct.

The PowerFLARM does not understand how to process a TIS-B (or ADS-R) message.

Ah, too bad. I did not know TIS-B messages are not properly decoded by Powerflarm. PF must then only correctly parse air-air 1090es squawks. Thanks for the clarification.

On a related question, if someone were to connect an uncertified GPS source to a 1090es transponder, with the intention of appearing on others PF displays.... how often would the transponder send this data? Only when interrogated (ie never, out of Radar coverage/TCAS ping range) or often, for each GPS position string? If the latter, this may have power consumption implications.

ADS-B Out data is always sent about once per second (well assuming you have it turned on and its working OK). The data sent from even a Mode-S interrtogation is different from the ADS-B 1090ES data.

The Power consumption implication on broadcast are insignificant. The issue of adding GPS to say a current Trig transponder is the power consumption of the GPS itself. Some certified GPS units can have relatively high power consumption. Transponders are being interrogated all the time, by SSR, TCAS and TCAD systems. All that stuff can add to power consumption but the interrogation rates there can be orders of magnitude higher than the ~1/second ADS-B Output.

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