- 學位論文
基於FM廣播被動相列雷達系統之整合空時訊號處理技術
Integrated Spatial-Temporal Signal Processing Techniques for FM-Based Passive Radar with Antenna Array
摘要
在FM被動雷達系統中，接收機在目標通道中不僅會接收到來自於目標的回波訊號，也會接收到來自於FM發射機的直達波訊號而影響偵測性能。針對抑制DPI和多路徑干擾的問題，吾人利用波束成形的方法，設計其相對應之空間濾波器。經由波束成形器的抑制後，更進一步地在時域下，對其殘存的DPI做估計/消除處理。在此研究中，本論文提出了在單/多態雷達網的佈建下引入線性/環形雙極天線陣列，發展結合空域零點放置(Null Placement)波束成型器(Beamformer)。首先吾人應用雙域空時訊號處理(spatial-temporal processing, STP)去抑制直接路徑干擾(Direct Path Interference, DPI)。接著，吾人運用STP研發一個限制波束的單脈波比幅法(constrained-beam amplitude monopulse, CBAM)，在單一位置及單一站臺被動雷達(single-site single-station passive radar, S4PR)的場景下，來估測該飛機目標物的到達方向。研究結果顯出結合STP-CBAM技術有許多優點，例如估測來向的精準度高，複雜度低，以及易於以硬體實現的可行性。最後使用電腦模擬完整STP的DPI抑制性能，以及结合CBAM來向估測機制的準確度及目標定位性能，其大量的模擬结果顯示，基於FM廣播被動相列雷達系統之整合空時訊號處理技術可以顯著提升DPI消除和目標偵測/追踪的性能。
並列摘要
In frequency modulation (FM) passive radar system, the receiver will not only receive the echo signal from the target, but also receive the direct wave signal from the FM transmitter, and it will affect the target detection performance. In order to suppress the direct-path (and multipath) interference, spatial notch filtering is first designed in term of beamforming with null placement. Under angular uncertainty, the residual DPI can be further estimated and cancelled by time-domain adaptive filtering scheme. In this study, we employ the uniform linear array or uniform circular dipole array for spatial-domain beamforming with null placement under the bistatic/multistatic scenario. First, we use the dual-domain spatial-temporal processing (STP) for suppressing the direct path interference (DPI). To estimate the direction of arrival (DoA) of aircraft targets using a single-site single-station passive radar (S4PR) with STP, a constrained-beam amplitude monopulse (CBAM) technique is then developed. It is shown that the combined STP-CBAM technique has many merits, such as high bearing estimation accuracy, low computational complexity, and feasibility for hardware realization. Finally, the performance of the complete STP combined with CBAM bearing estimation scheme is validated using computer simulation. Extensive simulation results show that the integrated spatial-temporal signal processing techniques for FM-based passive radar with antenna array can significantly improve the DPI cancellation performance and the target detection/tracking performance.