Research and Engineering Center for Unmanned Vehicles

NexSTAR UAS

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21 August 2009

Goals

  • Testing 2.45 GHz Piccolo Link with Tempest electronics module

Flight Review


Irridium Test

    Operation Time: 99 mins

    The Irridium modem was set out on a table and powered from a steady source. Below is a plot of the data index vs. time of day. Over the 99 minutes of testing the connection dropped out 9 times and took around 2 minutes to reestablish.

    Results


NexSTAR-2 Flight 1

    Flight Time: 31.47 mins
    Autonomous Flight Time: 14.66 mins

    Test using the 2.45 GHz piccolo system in NexSTAR 2. The groundstation used the standard whip antenna that comes with the Piccolo system. From the RSSI and ACK ratio it is apparent that either something was interfering with our communications, or certain orientations of the aircraft blocked the signal to the ground station. These can be investigated further by placing the antenna in a location that should not be blocked by either the electronics or the Piccolo box.

    Results


NexSTAR-2 Flight 2

    Flight Time: 19.88 mins
    Autonomous Flight Time: 17.72 mins

    This test was conducted using the 13 dBi patch antenna with the ground station and manually pointing it toward the UA. The pattern was extended south until we saw significant attenuation of the signal. This might still not be caused simply by distance, as the ground station was located below the ridge line. Furthermore, it is quite apparent that the orientation of the aircraft also caused attenuation of the signal as every time the aircraft was on the southern part of the pattern the signal dropped off.

    Results




NexSTAR-2 Flight 3

    Flight Time: 14.52 mins
    Autonomous Flight Time: 12.51 mins

    This flight was conducted with the patch antenna on the ground station, and the freewave system turned on and operating. There is no significant evidence of interference, and it seems that the two systems should be able to operate at the same time. The signal on the Piccolo link was similar to that seen from the last test, with attenuation at the Southern part of the pattern.

    The plots of the control loops are also shown. Some oscillation remains in the altitude loop that probably could be eliminated. The plot of the surfaces indicates that the engine was being over-actuated and is the likely cause for the oscillations.

    Results