Undersökning av OFDM för radartillämpningar

Robin Bengtsson () och Emil Bergman ()

Sammanfattning

The merging of communication and sensing in the same transmission chain has become an increasingly relevant prospect as it allows for better coordination between users at the same time as it more effectively utilize the available frequency bands which are becoming increasingly crowded. OFDM radars is one way to combine the two by applying the common modulation scheme to a radar, thus opening up the possibility to extract radar data from a communication transmission. This thesis will present the design, implementation and proof of concept verification of an OFDM radar platform constructed from commercially available antennas, low cost Software Defined Radios (SDRs) and open-source software. The presented platform uses two Yagi-Uda antennas, each connected to an SDR, one for transmission and one for reception, each with its own host computer that handle signal generation and signal processing after the measurements have been recorded. Previous work has investigated, often by use of simulations, the difference in performance between a typical FMCW radar and an OFDM based radar. Since similar performance is achievable this thesis aims to contribute by comparing the performance effect of sending a chirp-like Zadoff-Chu signal and a communication-like signal with random data over the OFDM channel in terms of people and vehicle detection. The comparison is carried out experimentally in two different outdoor environments where each test is recorded both by sending a chirp-like signal and a communication-like signal and the results suggests that there is no apparent difference between the two in regards to detecting persons or vehicles at short range, using the given setup which notably utilizes automatic gain control.

Handledare: Fredrik Tufvesson (EIT) och Michiel Sandra (EIT)
Examinator: Ove Edfors (EIT)