University of Oklahoma Aug 28, 2008
ADS-B radar Flight test: Aug 27, 2008
Radar Innovations Laboratory, University of Oklahoma
Figure 1 flight test configurations
The ADS-B radar sensor provided by IAI was used in the flight test of late afternoon, Aug 27, 2008. The Cessna 210 carrying two pilots (John and Kevin) flied over the top of NWC building according to the 3 re-defined flight paths. The flight height is 1000 ft above ground and flight speed is 50-60 mph (tend to maintain 50 mph when approaching radar). Total actual flight time is about 20 min (left airspace at ~6:30 PM to avoid weather balloon launching).
For all flight paths, the four ‘I’ channels from the TCAS antenna are sampled using DSO 8500 at 100 Msps. Total time durations for each sampling is 30-40 secs. The transmit antenna has the fixed elevation angle of 60° pointing to the sky (allowing the aircraft passing through the transmit antenna beam) and the receive TCAS array antenna is placed horizontally next to the transmit antenna. Special care is taken to enhance the isolation between the transmit and receive antenna, by adding an large size aluminum plate in between. See the video file and the readme file in the data folder for more detailed descriptions of the recorded data.
In the recorded video (wmv file), the first 5 min is about the system setup and test preparation. Also, the transmitter trigger signal during the first path 1 and path 2 flights has some problems so the data for them are discarded. After the trigger signal is fixed, the actualdata recording starts from the E-W path 3, and then the path 1 and 2 are repeated.
Overall, the flight test run smoothly and important sensor data from all 4 TCAS channels are obtained. To analyze the data, start from the readme file in the data folder and check with the associated flight path figures. In the next stage, we can discuss how to add phase coding in IAI’s ADS-B transmitter and possible onboard GPS carried by aircraft to get accurate true trajectory data.