Synchronization Aspects And Imaging Algorithms Of Bistatic SAR

Bistatic Synthetic Aperture Radar (BSAR), in which the transmitter and receiverare on separate platforms, is a kind of SAR system. It, as opposed to monostatic SAR,offers more degrees of freedom in geometric configuration, more image content,better anti-jamming and counter vulerability, and has potentials in SAR interferometry(INSAR) and ground moving targets indication (GMTI), which has prosperous futurein civil and military field. Synchronization aspects and bistatic SAR imagingalgorithms are key techniques in bistatic SAR system. In this dissertation, bistaticsystem performance, time synchronization, phase synchronization and variousimaging algorithms are investigated in detail. The main contributions and innovationsinclude:1. System performances of general bistatic synthetic aperture Radar systems,includes range characters, Doppler characters, spatial resolutions, and ambiguities,are analyzed. Particularly, three typical bistatic configurations, i.e. along trackmode, cross track mode and forward looking mode, are investigated in detail.2. Bistatic SAR time synchronization schemes are investigated. An indirect timesynchronization method, which uses the GPS timing signal to slave the localoscillators, is proposed. And the synchronization precision is analyzed. GPSCommon View and carrier phase methods are firstly introduced for bistatic timesynchronization. Methods of two-way single-frequency and one-waydual-frequency pseudo-random codes timing synchronization are suggested forbistatic autonomous timing synchronization. Their performances are illustrated.3. Phase synchronization methods of bistatic SAR are investigated at length. Indirect phase synchronization of bistatic SAR using two high stable oscillators is studied.And the effects of oscillators phase noise on bistatic SAR image are analyzed. Adirect phase synchronization schemes in terms of one-way and two-way carrierphase lock techniques are put forwad, which reduces the requirement for oscillatorstability.4. Range-Doppler (R-D) algorithm of along-track mode bistatic SAR areinvestigated. Range-Doppler algorithm is exploited in along-track mode bistaticSAR, which resolves the sidelook bistatic data successfully. Furthermore, squintmode bistatic SAR data is processed using second range compression (SRC). It isillustrated that the two algrothms is widely applicable by computer simulation.5. Chirp Scaling (CS) algorithm of along-track mode bistatic SAR are investigated.In terms of the range history and its Taylor expansion approximation. CSalgorithm and Extended CS algorithm are introduced into bistatic SAR imageformation with sidelook and small squint angle mode. Furthermore, a equivalentmonostatic SAR range mode is proposed which has less errors than Talyorexpansion with larger squint angle. Then bistatic SAR images with large squintangles are gotten by common Nonlinear CS algorithm.