Beam position design method of inclined geosynchronous orbit synthetic aperture radar

Abstract

The invention relates to a beam position design method of an inclined geosynchronous orbit synthetic aperture radar, which belongs to the technical field of the synthetic aperture radar, and is characterized in that: by satisfying coherent accumulation time required by system indexes, a range of latitude argument run by a satellite platform is calculated, then influence of earth rotation is considered according to a relative geometric relation between the satellite platform and a target, and information of an echo window of a surveying and mapping zone can be precisely calculated; and then a valid pulse recurrence frequency (PRF) range is calculated according to a substar echo and launching pulse blocking, and a zebra map is drawn. Working parameters are designed within the valid PRF range, the PRF is preferentially selected to satisfy the requirement of the system performance and to complete the beam position design of the geosynchronous orbit synthetic aperture radar (GEO SAR), a minimal slope distance and echo window information of the surveying and mapping zone of the GEO SAR can be more precisely calculated, and the method is particularly suitable for the beam position designof satellite-mounted SAR platforms of an elliptic orbit which cannot ignore omit the earth rotation.

Description

technical field [0001] The invention relates to a wave position design method of an inclined geosynchronous orbit synthetic aperture radar, belonging to the technical field of synthetic aperture radar. Background technique [0002] Synthetic Aperture Radar (SAR) is an all-weather, all-weather high-resolution microwave remote sensing imaging radar that can be installed on aircraft, satellites, spacecraft and other flying platforms. It has unique advantages in environmental monitoring, ocean observation, resource exploration, crop yield estimation, surveying and mapping, and military applications, and can play a role that other remote sensing methods are difficult to play. [0003] The wave position design of spaceborne SAR is an important aspect of the overall design of spaceborne SAR. It is mainly to design the working parameters such as pulse repetition frequency from different perspectives to meet the system performance indicators. Wave position design includes beam param...

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Problems solved by technology

However, in GEO SAR, the orbital altitude is high, and the earth’s rotation is seriously affected. When zero-Doppler control is not performed, the equivalent squint effect is serious, and the distance migration is very large within a synthetic aperture time. When calculating the echo opening time and echo The impact of the equivalent squint effect on the slant distance information of the surveying zone must be considered in the window information; and the coherent accumulation time of GEO SAR is long, and the coherent accumulation time is different for different system resolutions or at different orbital positions. Calculate the coherent accumulation time based on the position, beam center viewing angle, and resolution requirements of the system

The traditional wave position design method is based on the front-view mode of LEO SAR, which does not consider the impact of distance migration caused by the equivalent squint effect, and does not consider the requirements of different coherent accumulation times, which will cause the real echo to be affected by the transmitted Blocking of pulse or sub-satellite point echo

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