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Ultra-Wideband Antenna Technology
Published in James D. Taylor, Introduction to Ultra-Wideband Radar Systems, 2020
P. R. Foster, J. Doss Halsey, Malek G. M. Hussain
This composite waveform distortion measure for an antenna pattern is indicative of system performance for a system using a correlating receiver. In a communications system, the connection between spatial distribution of correlatable energy and system performance is straightforward. In a radar system, this distorted waveform must first be reflected off a target and received back at the source or, in the case of bistatic radar, at another location. Reflection off a complex scatterer adds another level of distortion to the temporal behavior of the signal. Reception by another (or the same) array adds one further level of complexity. Receive beamforming can be accomplished in several ways. The signals from all receive elements of an array can be coherently added either before or after the correlation process. The receive array can be electronically steered synchronous with or independent of the transmit array. The receive array beamforming process proceeds as the inverse of the transmit array process; however, it is important to keep in mind the strong waveform dependence of the process. In radar applications, the return signal scattered from a target situated off-boresight is a distorted composite of the waveform sent by each radiator. It is this scattered waveform which is processed by the receive array. Thus, it cannot be generally assumed that antenna behavior is reciprocal on transmit and receive as is customary in frequency domain antenna theory.
Radar Equations
Published in Habibur Rahman, Fundamental Principles of Radar, 2019
A bistatic radar is one in which the transmit and receive antennas are separated by a considerable distance as shown in Figure 3.3, and the separation must be comparable with the target distance. The bistatic RCS must now be stated as a bistatic value σb, which measures the ability of the real target to scatter energy incident from the direction of the transmitter into the direction of the receiver. The bistatic angle, denoted by β, largely determines the size of the bistatic RCS: for a small angle bistatic RCS is similar to monostatic RCS, and for a large bistatic angle approaching 180° the bistatic RCS is determined by σb=4πAe2λ2.
Bistatic Radar Polarimetry Theory
Published in James D. Taylor, Ultra-wideband Radar Technology, 2018
Anne-Laure Germond, Eric Pottier, Joseph Saillard
For our discussion, monostatic radars have the transmitter and receiver located at the same place. Bistatic radars have large distances between the transmitter and the receiver relative to the transmitter-target and target-receiver ranges.22 The geometry of a monostatic configuration and bistatic configurations are illustrated in Figures 14.1 and 14.2. The bistatic radar system has some advantages, because the wide separation of the receiver and transmitter eliminates any coupling.
Performance Improvement of Bistatic Baseline Detection
Published in IETE Journal of Research, 2023
Xueli Sheng, Dian Lu, Yingsong Li, Mengfei Mu, Jinghan Sun
In recent years, multistatic detection [1] has been a hotspot in underwater acoustic engineering research and mainly focuses on underwater target detection. As is known to all, the bistatic working mode is the most typical system among multistatic detection. A bistatic radar is one in which the receiver is physically separated from the transmitter, so the echo signal does not travel over the same path as the transmitted signal; meanwhile, the transmitted signal travels over another path directly to the receiver, regarded as the direct blast [2,3]. Several important issues should also be addressed, such as reverberation [4,5], scattering [6,7], ambient noise, etc. Owing to the proposed issues above, detecting the weak target appears to be much more complicated. Besides, limited by the bearing-resolution performance of DOA estimation algorithms, there always exists a blind zone around the bistatic baseline [8,9]. Therefore, realizing the DOA estimation of the weak target interfered by the direct blast in the mainlobe, is of great significance for reducing blind zone and expanding detection coverage area in multistatic detection.