Last year, we tested and improved the OCAP protocol primarily with paragliders. By late autumn / winter, development had progressed to the point where we wanted to carry out tests at higher speeds with motorized aircraft.
Motorized test flights require good visibility and a high level of pilot awareness. We were unable to carry out any tests in November and December due to poor weather conditions. The conditions did not allow the first test flights until January. This blog post shows an initial evaluation of a test flight carried out in mid-January by our partner MSW Aviation (https://mswaviation.com/).
Two motorized aircraft were used:
- HB-RDN, a North American AT-16 Harvard IIB U-323 formerly used by the Swiss Air Force, and
- HB-YLA, a Votec 351 from MSW Aviation.
The OCAP test firmware was installed on modified XC Tracer Maxx II devices and detailed information about the flight was recorded on the SD card.
The following two screen recordings show a OCAP simulator replay of two different test flights.
You can see the simulation time in seconds (sim_time) at the top left of each recording. The recording is accelerated by a factor of about 30 (1 minute is compressed to 2 seconds). The color of the two flight paths indicates the alarm level generated by the OCAP algorithm, from level 1 (yellow) to level 3 (red, critical). The algorithm uses our proposed extension of the ADS-L protocol which was presented in an earlier blog post, to include curvature information in the data packets.
The thin blue dashed lines that you can see are the path predictions of each airplane, calculated by the OCAP algorithm. The algorithm calucuates the alarm level based on the distance between the aircraft along these predicted paths.
The test results confirm that the protocol works as expected even at higher velocities.
We will perform additional tests and discuss with the pilots whether and how the alarm levels need to be optimized.
Many thanks to our test pilots and all our supporters!
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