DRM signals for HF passive bistatic radar

The concept of using digital HF signals in a passive radar configuration is discussed. Ambiguity functions of these signals are presented and a comparison of the waveform's properties is made with other signals of interest in passive radar in terms of their radar parameters. The ambiguity functions show no ambiguities, approach the ideal thumbtack shape and are thus potentially very useful for passive radar applications. For 5 s integration times the signals have a processing gain in excess of 40 dB. Expected coverage is examined in terms of the signal to interference ratios expected for an array of receivers and compared to the coverage obtained using a single surveillance channel. It is concluded that to support the detection ranges of which HF is capable, a phased array surveillance receiver is required to reduce the effects of interference from the transmitter.