An Antenna Error Correction Method for Spaceborne Microwave Radiometer

Abstract

The invention relates to an antenna error correction method for a space-borne microwave radiometer, which belongs to the field of microwave remote sensing. The method of the invention provides a spaceborne microwave radiometer antenna error correction method, which can correct the calibration error and the earth brightness temperature observation error introduced by the limited antenna beam efficiency; by dividing the space region into the earth region under the satellite orbit coordinate system In the two parts of the satellite and the cold space area, under the condition of considering the influence of satellite attitude factors, the coordinates of any point in the space under the satellite orbit coordinate system and the antenna coordinate system are obtained by using the rotation matrix method, and then the corresponding points are obtained by integrating in the earth area and the cold space area respectively. The antenna beam efficiency factors for earth observation and cold space observation are used to correct the brightness temperature of earth observation and cold space calibration respectively, which improves the measurement accuracy of brightness temperature of the instrument.

Description

technical field [0001] The invention relates to a method for correcting antenna errors of a spaceborne microwave radiometer, which belongs to the field of microwave remote sensing. Background technique [0002] The spaceborne microwave radiometer performs remote sensing measurement of marine environmental parameters such as sea surface temperature, wind speed, atmospheric liquid water content and atmospheric water vapor content by passively receiving microwave radiation signals from the sea surface. The spaceborne microwave radiometer realizes the continuous scanning observation of ocean targets through the periodic rotation of the antenna. In each scanning cycle, the microwave radiometer sequentially observes the earth scene, high temperature calibration source and low temperature calibration source. The high-temperature calibration source is realized by a microwave absorber at a constant temperature under precise temperature control, and the low-temperature calibration sou...

AI Technical Summary

Problems solved by technology

[0015] From formula (3-3), it can be seen that when the spaceborne microwave radiometer is observing the earth, it is affected by the antenna beam efficiency factor, f E (α,ω) Causes the antenna to actually receive the brightness temperature T A Less than the real radiation brightness temperature of the earth scene When the spaceborne microwave radiometer performs cold-space calibration observations in each scan period, also due to the influence of the antenna beam efficiency factor, f CS (α,ω) As a result, the actual receiving brightness temperature of the antenna is greater than the nominal radiation brightness temperature of the cold air, that is, T A >T C0 , if the nominal radiation brightness temperature T of the cold air is used directly C0 Calibration will cause the calibrated brightness temperature to be lower than the real radiation brightness temperature of the scene, resulting in measurement errors

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