Focusing Bistatic FMCW SAR Signal by Range Migration Algorithm Based on Fresnel Approximation

Abstract

Frequency modulated continuous wave (FMCW) technique has recently been employed by synthetic aperture radar (SAR) to decrease the radar cost and volume. However, the operation range is limited by the direct energy leakage from the transmitting channel to receiving channel due to the operation principle of FMCW technique. Bistatic configuration is an efficient way to increase the isolation between the transmitter and receiver, which could significantly increase the radar standoff range. A bistatic FMCW SAR spectrum model is proposed by using the Fresnel approximation in this paper. This model is similar to that of a monostatic FMCW SAR spectrum, which allows the existing imaging algorithms to be used on bistatic image processing. Based on the new model and the characteristics of FMCW signal, a modified range migration algorithm (RMA) for FMCW SAR is proposed to focus the image, which requires less memory and computational load than the traditional RMA. Point-target simulation is used to verify the proposed spectral model and real data processing verified the effectiveness of the proposed RMA.

Critical Design Considerations on Continuous Frequency Modulation Localization Systems

“…Basic passive FMCW ranging systems measure the propagation time by mixing their transmit and receive sinusoidal chirp signals whose frequency linearly sweeps in time T fm along a frequency bandwidth of B fm . Mathematically, the transmit signal is modeled at a given time t as follows [6]:…”

Signal Modeling for Bistatic FMCW Radar Asynchronization and Its Effect on ISAR Images

“…또한 바이스태틱(bistatic) 구조의 FMCW 레이다 시스 템에 관한 연구가 활발히 진행되고 있다 [7]∼ [9] . 바이스태 틱 레이다는 송신기와 수신기가 서로 공간적으로 분리되 어 레이다 신호를 송, 수신하는 레이다로, 송․수신기가 서로 다른 공간에 배치되기 때문에 기존 모노스태틱 (monostatic) 대비 공간 활용도가 높으며, 관측 표적에 대 한 다양한 레이다 반사 정보를 얻을 수 있는 장점들이 있 다.…”

Research on the burst height measurement method based on the missile-borne millimeter wave detector

“…Cooper et al 4 researched the directional ranging accuracy of FMCW Doppler radar; the effectiveness was proved through simulation experiments and field tests. Li and Young 5 researched signal processing algorithms of high-altitude millimeter wave sensor synthetic aperture radar (SAR), and a Fresnel approximation-based algorithm was proposed for promoting remote ranging accuracy, the research has a certain prospect of military application. Du and Gong 6 analyzed linear frequency module continuous wave detection performance in high-frequency radar, which could measure the burst height through Doppler frequency extracting, and proposed a combined algorithm with ranging/Doppler processing technology and adaptive digital beam forming technology that can extract echo target information and suppress clutter and interference at the same time.…”