Research And Application Of Platform For SAR Technology Verification Based On Test & Measurement Instruments

Synthetic Aperture Radar, with its characteristics of long-distance imaging capabilitywithout consideration of weathers or times, has got wide range of application. But SARsystem has been getting more and more complex as well as more costs and R&D period.To break through the key technologies, it is necessary to design a application-universalplatform for SAR technology verification, which is operated over multiple band, withbig bandwidth, multiple channels, and capabilities of flexible combination andconfiguration. The costs and period of R&D will be cut significantly by making use ofthe platform for verification of key technology, and research of microwave imagingtechnology.This thesis has been making effort in research of system design based on advancedelectronic test & measurement instruments. The system consisting of some functionalblocks, achieves radar signal generation via Arbitrary Waveform Generator and VectorRF Signal Generator, transmits and receives filed through wide-band antenna, makesdown-conversion on receiving signals to acquire IF output, samples IF signals by A/Dconverter, and makes digital I/Q demodulation to avoid phase or amplitude unbalancebetween I/Q path, that would be aroused by analog I/Q demodulation.For system control, we developed system control software under Agilent VEE (VirtualEngineering Environment), made a measurement network system by inter-connectingAWG, VSG, SA, PG, etc via measurement bus like GPIB, LXI, PXI. The softwarecommunicates with instrument to configure the system parameters, and realize datatransfer, display, analysis and storage as well as automatic configuration on someparameters.To achieve system synchronization, the instruments synthesize their inner frequency viaa common 10 MHz reference respectively. The system employs pulse generator toprovide timing trigger, and works phase-coherently among all module. To realize phase -consistency among multiple channels, we came up with a scheme that take localoscillator frequency from master channel as common reference, distributed it back tomaster and all slave channels through the paths with equal delay.With the modularized design, we can reconstruct and configure system rapidly. As anexample, we realized the BiSAR simulation, and verified the scheme of phasesynchronization based on direct-arrival reference. By arranging transmitter and receiverseparately, and analysis the phases of radar signals and synchronization signals, wefound the way to compensate the phase error in radar signals, which is aroused byincoherency between transmitting and receiving local oscillators.