1.09 GHz mode-S receiver design and VHF radar antenna characterization

The design and implementation of a 1.09 GHz tuned-radio-frequency (TRF) receiver which can capture mode-S secondary surveillance radar reply frames sent by aircraft transponders is discussed in this thesis. The RF frontend of the receiver employs an RF-IC and SAW filter and detects the envelope of the input signal. The detected envelope signal is sampled and demodulated by FPGA firmware to reconstruct mode-S frames which can be retrieved via a Universal Serial Bus (USB) interface. Mode-S frame recording and decoding programs were written in C++ to extract aircraft information such as latitude, longitude, altitude, and aircraft identification number. Some decoded data has been combined with radar backscatter data collected by a VHF remote sensing radar to characterize the radiation pattern of the radar antenna arrays. The analyses confirmed that one antenna array performs according to theoretical expectation and uncovered a significant problem with another antenna array due to a coaxial cable connectivity issue.unpublishednot peer reviewe