應用於超視距雷達/汽車雷達之調頻連續波信號處理

Abstract

近年來，調頻連續波(frequency modulated continuous wave; FMCW)信號處理在目標物偵測之應用上日漸普及，許多雷達系統均採納此技術，但調頻連續波信號在實際環境下面臨許多問題。在本論文中，吾人將調頻連續波信號處理應用於超視距雷達與汽車雷達。在超視距雷達之環境中，吾人面臨可使用的連續頻寬不足、海雜波(sea clutter)干擾的問題；連續頻寬不足使得系統無法達到要求的距離解析度，而海雜波將影響目標物的偵測。在汽車雷達之環境中，吾人面臨目標物移動速度太快造成取樣數(snapshot)不足的問題；取樣數不足使得系統無法建立相關矩陣(correlation matrix)進行角度估計。為了解決這些問題，吾人針對超視距雷達提出多載波之調頻連續波收發機，此收發機可有效地利用剩餘的頻帶偵測目標物以及對抗海雜波；針對汽車雷達提出基於相位比較法(phase-comparison)之低複雜度最大似然(maximum likelihood; ML)角度估計器，此估計器利用單一取樣數即能良好地運作。吾人藉由電腦模擬驗證所提方法可良好運作在超視距雷達與汽車雷達之環境。

In recent years, frequency modulated continuous wave (FMCW) signal processing technique becomes a popular technique in target estimation. However, in practice, environments limit the performance of radar systems. In this thesis, we focus on the FMCW signal processing with applications to over-the-horizon (OTH) and automotive radars. In OTH radars, a continuum bandwidth for achieving the desired range resolution is difficult to find and the sea clutter phenomena will dominate the detection performance of radar systems. In automotive radars, only a small number of snapshots are available for direction-of-arrival (DOA) estimation in high mobility scenarios. To tackle these problems, we propose a multi-frequency FMCW transceiver for OTH radars and a low complexity single-snapshot maximum likelihood (ML) DOA estimator based on the phase-comparison technique for automotive radars. Finally, computer simulation results are included to confirm the effectiveness of the proposed method.