Clutter Cancellation and Long Time Integration for GNSS-Based Passive Bistatic Radar

Abstract

Clutter cancellation and long time integration are two vital steps for global navigation satellite system (GNSS)-based bistatic radar target detection. The former eliminates the influence of direct and multipath signals on the target detection performance, and the latter improves the radar detection range. In this paper, the extensive cancellation algorithm (ECA), which projects the surveillance channel signal in the subspace orthogonal to the clutter subspace, is first applied in GNSS-based bistatic radar. As a result, the clutter has been removed from the surveillance channel effectively. For long time integration, a modified version of the Fourier transform (FT), called long-time integration Fourier transform (LIFT), is proposed to obtain a high coherent processing gain. Relative acceleration (RA) is defined to describe the Doppler variation results from the motion of the target and long integration time. With the estimated RA, the Doppler frequency shift compensation is carried out in the LIFT. This method achieves a better and robust detection performance when comparing with the traditional coherent integration method. The simulation results demonstrate the effectiveness and advantages of the proposed processing method.

Maritime Targets Velocity Estimation in Space-Based Passive Multistatic Radar Using Long Integration Times

“…From (12) we observe as the bound is composed by two terms. The former is the CRLB concerning the conventional approach exploiting Doppler information only to recover the target velocity (provided that 𝐹 𝑥,𝑓 is an invertible matrix), while the latter takes into account the impact on the performance of the exploitation of the Doppler-rate measurements (i.e., of the performance improvement as it will be shown in the next sub-section).…”

“…Over the last few years, several methods for extending considerably the integration time in GNSS-based passive radar have been proposed. These could be fully coherent [11] [12] or hybrid (i.e., multi-frame) [8] [13] [14]. In both the cases, most of the approaches implement a target motion compensation (TMC) procedure driven by hypothesized Doppler-rates: such information is therefore provided as detection output along with the bistatic range and Doppler shifts.…”

Target Detection and DOA Estimation for Passive Bistatic Radar in the Presence of Residual Interference

“…In order to estimate target DOA, it is necessary to detect the target first in PBR. However, unlike the traditional active radar, the weak target echo in PBR is usually embedded in the background of strong direct and multipath interferences (DMI) due to the bistatic and continuous wave transmitting and receiving system [26]. Therefore, in the traditional target detection and DOA estimation method of PBR, the clutter cancellation method should be first used to suppress DMI.…”

“…In the traditional PBR based on FM and analog TV, which adopt the frequency division multiple access (FDMA) technique, the interferences mainly include the DMI from the base station that is used as the IoO (BS-IoO) [7,22]. At present, many clutter cancellation methods [26] have been proposed, such as least mean square (LMS) [27], extended cancellation algorithm (ECA) [28], sub-carrier domain algorithm [29,30], etc. These methods have been proved to be effective in suppressing DMI from BS-IoO [26,31].…”

SNR Enhancement of Back Scattering Signals for Bistatic Radar Based on BeiDou GEO Satellites

“…For example, to study the deformation applications based on BeiDou system (BDS) inclined geosynchronous orbit (IGSO) satellites, a dedicated transponder with amplifier is constructed to simulate the displacement device which can generate strong reflected signals [11], but the drawback of this method is the need of supply power to the transponder. Moreover, some signal processing methods are presented, for example, the long accumulation time method based on the short-time Fourier transform (STFT) and the Keystone transform are used to correct the range cell migration [12], but this method is only effective for signals with high radial velocity and relatively high bandwidth; also, fractional Fourier transform (FrFT) is employed for long time integration [13]. Although simulation results prove its validity, multiple targets in close range will lead to errors in the results in actual measurement.…”