Performance Indications of a Novel Chaotic - Signal Fm - Cw Radar for Multi - User Applications

Emerging requirements for several radar applications call for highly-specialised signal processing algorithms displaying good multi-user capability. The theoretical basis of the implicit sampling averaging algorithm implemented in the radar receiver and its use for time delay determination has been described by Szajnowski [3]. The CSR utilises chaotic or truly random continuous binary waveforms obtained as a result of Implicit Sampling of an analogue random waveform at zero level. Such a waveform is then utilised for modulation in the transmitter. The implicit averaging operation of the received chaotic signal z(t), conditioned on zero crossings of the transmitted reference signal v(t) generates the conditional Implicit Average ) ( ˆ v z τ μ (also called the characteristic waveform or ‘S-curve’ for its visual similarity). The principle of the Implicit Sampling Averaging operation is shown diagrammatically in Fig.1. This paper presents some results of tests and measurements from an experimental Chaotic-Signal Radar (CSR) test bed where a novel, yet simple, signalprocessing algorithm, called Implicit Sampling Averaging, Szajnowski, [1], has been implemented. The CSR has a very large processing gain and hence provides high resistance to external noise and interference. Furthermore, it is also highly resistant to mutual interference from similar systems, since the random or chaotic-signal generator in each system produces a unique signal. As an initial verification of the theory, a standard 77GHz FM-CW radar receiver was specially adapted to facilitate the novel CSR scheme. A digitising oscilloscope was used as a signal processor for reconstructing and visualising the characteristic bipolar waveform (so-called ‘S-curve’) indicating obstacle position. First results agree well with theory and stimulate further development of this new approach. Transmitted chaotic signal v(t) Tw