21 August 2009
- Testing 2.45 GHz Piccolo Link with Tempest electronics module
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.
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.
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.
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.