Entwicklung und Untersuchung eines Radars mit stochastischer Wellenform

The research goal of this thesis is the evaluation of stochastic waveforms regarding radar imaging systems. Due to the uncorrelated nature of successive radar pulses, stochastic waveforms allow a high pulse sampling rate without generating range ambiguities. This leads to a higher resolution in synthetic aperture radar imaging systems, than using conventional, repeating waveforms.
First, the thesis gives an overview of previous work in this area, especially the signal-theoretic description, occurring effects and their filtering by means of algorithms used so far. Special attention is paid to the masking effect occurring with stochastic waveforms. Due to the highly variant power density spectrum of the waveform, the cross-correlation products of the matched filter of strong targets mask the target response of weaker targets. This effect is described in terms of signal theoretical aspects. Further, possible solutions are shown, which include CLEAN algorithms and mismatched filters reducing the self-interference.
In the thesis a new filter is proposed for pulse compression that corresponds to a Wiener deconvolution filter. This filter reduces the masking effect that occurs with stochastic waveforms without increasing the computational effort compared to a classic matched filter. After a derivation of the filter, this filter is compared in the course of the work with the previously existing and used filter. In addition, other scene reconstruction methods will be investigated.
To validate the filters examined in this thesis, a radar transmitter is developed, that uses thermal noise as the transmitting waveform. This transmitter is integrated in a portable case. In conjunction with the four-channel radar receiver HITCHHIKER developed at the Centre for Sensor Systems, this transmitter system forms an experimental radar system.
Using this radar system, the algorithms can be compared under different conditions and applications. This includes Range-Doppler target tracking, multi-channel DOA estimation, synthetic aperture radar and inverse synthetic aperture radar. From indoor experiments to outdoor experiments, from stationary targets to moving targets such as road vehicles or ships, a wide range of operating conditions and possibilities is covered by experiments using this system.