Abstract: A frequency scanning radar system includes a controller for controlling a frequency generator and a signal processor arranged to determine a Doppler frequency associated with a target. The frequency generator generates three or more sets of signals, each set of signals having a different characteristic frequency and including signals transmitted at a selected rate, and the radar controller selects the rate in substantially direct proportion to the characteristic frequency, whereby to normalize the Doppler frequency determined by the signal processor, such that the normalized Doppler frequency is substantially constant in relation to variation in the carrier frequency. In a frequency modulated radar system, each set of signals includes a sequence of modulation patterns, and the radar controller modifies a given modulation pattern in dependence on the characteristic frequency of the signal being modulated.

Abstract: Electronically steered radar systems such as frequency scanning radars are particularly suitable for detecting and monitoring slow moving, ground-based targets. So-called crawler radar systems are intended for detection of targets that deliberately attempt to avoid detection by keeping low and by moving slowly. Disclosed is a radar system which includes an electronically steered antenna and a receiver arranged to process signals received from a target located at a distance from the radar system so as to identify a Doppler frequency associated with the target. The antenna stares at, rather than glides past, the target surrounding clutter. This means that the spectral spreading of static ground clutter associated with mechanical radar systems can be eliminated, overcoming one of the shortcomings of mechanical radar systems that would otherwise render a crawler radar system unsuitable for Doppler processing.

Abstract: A frequency scanning radar system includes a controller for controlling a frequency generator and a signal processor arranged to determine a Doppler frequency associated with a target. The frequency generator generates three or more sets of signals, each set of signals having a different characteristic frequency and including signals transmitted at a selected rate, and the radar controller selects the rate in substantially direct proportion to the characteristic frequency, whereby to normalize the Doppler frequency determined by the signal processor, such that the normalized Doppler frequency is substantially constant in relation to variation in the carrier frequency. In a frequency modulated radar system, each set of signals includes a sequence of modulation patterns, and the radar controller modifies a given modulation pattern in dependence on the characteristic frequency of the signal being modulated.

Abstract: A scanning radar system suitable for detecting and monitoring ground-based targets includes a frequency generator, a frequency scanning antenna, and a receiver arranged to process signals received from a target so as to identify a Doppler frequency associated with the target. The frequency generator generates sets of signals, each set having a different characteristic frequency, and includes a digital synthesiser arranged to modulate a continuous wave signal of a given characteristic frequency by a sequence of modulation patterns to generate one set of signals. The frequency scanning antenna cooperates with the frequency generator to transceive radiation over a region having an angular extent dependent on the generated frequencies.

Abstract: A frequency scanning radar system includes a frequency scanning radar controller for use in controlling a frequency generator, the frequency generator being arranged to generate a plurality of sets of signals, each set of signals having a different carrier frequency and comprising a sequence of modulation patterns, transmitted at a selected rate, wherein the radar controller is arranged to select the rate in dependence on the carrier frequency. The system also includes a signal processor arranged to derive tone data from received signals, wherein the signal processor is arranged to process the received signals at a rate dependent on the rate of transmission of the sequence of modulation patterns. Additionally, the system includes an audio system arranged to output audio data derived from signals received by the frequency scanning radar system by playback of the derived tone data at a constant rate.

Abstract: Electronically steered radar systems such as frequency scanning radars are particularly suitable for detecting and monitoring slow moving, ground-based targets. So-called crawler radar systems are intended for detection of targets that deliberately attempt to avoid detection by keeping low and by moving slowly. Disclosed is a radar system which includes an electronically steered antenna and a receiver arranged to process signals received from a target located at a distance from the radar system so as to identify a Doppler frequency associated with the target. The antenna stares at, rather than glides past, the target surrounding clutter. This means that the spectral spreading of static ground clutter associated with mechanical radar systems can be eliminated, overcoming one of the shortcomings of mechanical radar systems that would otherwise render a crawler radar system unsuitable for Doppler processing.

Abstract: A scanning radar system suitable for detecting and monitoring ground-based targets includes a frequency generator, a frequency scanning antenna, and a receiver arranged to process signals received from a target so as to identify a Doppler frequency associated with the target. The frequency generator generates sets of signals, each set having a different characteristic frequency, and includes a digital synthesiser arranged to modulate a continuous wave signal of a given characteristic frequency by a sequence of modulation patterns to generate one set of signals. The frequency scanning antenna cooperates with the frequency generator to transceive radiation over a region having an angular extent dependent on the generated frequencies.

Abstract: Embodiments of the invention are concerned with a radar system, and relates specifically to scanning radar systems that are suitable for detecting and monitoring ground-based targets.

Abstract: Embodiments of the invention are concerned with improvements to Doppler radar systems, and are suitable for use with frequency scanning radar systems. In one arrangement the improvements are embodied in a frequency scanning radar controller for use in controlling a frequency generator; the frequency generator is arranged to generate a plurality of sets of signals, each set of signals having a different characteristic frequency and comprising a plurality of signals transmitted at a selected rate, and the radar controller is arranged to select the rate in dependence on the characteristic frequency. The invention can be embodied in a pulsed radar, for which each set of signals comprises a set of pulsed signals and each pulsed signal is repeated at a selected repetition rate. The radar controller is then arranged to modify the repetition rate in dependence on the characteristic frequency of the pulsed signal.

Abstract: Embodiments of the invention are concerned with a radar system, and relates specifically to scanning radar systems that are suitable for detecting and monitoring ground-based targets.