Improvement in detection with forward scattering radar

Abstract

Forward scattering radar (FSR) has advantages over traditional monostatic radar such as an enhanced radar cross section. Enhancement of the radar cross section can increase the detection range of the FSR system. This feature has renewed interest in FSR. The latest development of the FSR system for ground application does not consider a rough environment and there is no advanced signal processing technique for the detection procedure, which have delayed the deployment of FSR. Therefore, this paper analyzes a signal processing technique that extracts the Doppler signal scattered from a moving target under the influence of ground clutter, receiver noise and surrounding noise. The scattered Doppler signal is processed for target detection. Two methods, namely the use of the Hilbert transform and wavelet technique, are evaluated. Results show that target detection using a Hilbert transform is applicable only for certain conditions but target detection employing the wavelet technique is more robust against clutter and noise. An inclusive comparison of various wavelet threshold selection rules for different types of wavelet filters and levels of decomposition is conducted to study the effect on target detection with FSR. Two sets of field experiments were carried out to validate the proposed method, and target signals under the influence of large clutter were successfully detected using the proposed method with a confidence level exceeding 75%.

Joint Time-Frequency Signal Processing Scheme in Forward Scattering Radar with a Rotational Transmitter

“…If the target's Doppler frequency component due to the motion relative to the transmitter and receiver is given in Equations (7) and (8), respectively, then the total target's Doppler frequency, f d , can be calculated as follows, the detail derivation is given in Appendix A:…”

“…The Doppler shift will be zero for a stationary target. In most of the publications on FSR, this Doppler shift can be used for target detection, moving target selection, speed determination and trajectory reconstruction [5][6][7][8][9][10][11][12][13][14][15]. The higher the target effective target speed, the higher the Doppler shift in the received signal.…”

“…The receiver will be triggered upon receiving a sufficient direct signal from the transmitter, and it is assumed within the transmitter antenna main lobe. Equations (1)- (8), which were dedicated to a fixed Tx-Rx pair and moving target crossing the baseline, need to be modified based on the new FSR layout. If an object exists, the two signals present at the input of the receiver are now:…”

“…The FSR used the fixed transmitter-receiver pair, and the target flew crossing the baseline between the FSR systems. Later, FSR was tested for ground target detection and classification, but still used a fixed transmitter-receiver pair [7][8][9]. Signal processing and signal modeling of FSR are explained in [10].…”

Analysis on Target Detection and Classification in LTE Based Passive Forward Scattering Radar

“…Alternatively, this paper proves that by having hybrid operation between the FSR technique and conventional passive radar is beneficial due to: (i) a simple FS receiver circuit; (ii) significant improvement in radar cross section (RCS) at the forward scatter main lobe (FSML); (iii) passive FSR does not require direct signal from the base station and (iv) target detection scheme based on signal envelope is straight forward without complicated signal pre-processing step. Furthermore, the classification capability in passive FSR increases the effectiveness of the system [1,12]. The interesting feature in passive FSR, which is the sharp rise of the FS RCS, can increase the sensitivity of the system, making it robust to “Stealth” technology.…”