Antenna error correction method of space-borne microwave radiometer

Abstract

The invention relates to an antenna error correction method of a space-borne microwave radiometer, and belongs to the field of microwave remote sensing. According to the antenna error correction method of the space-borne microwave radiometer provided in the invention, the calibration error and the earth brightness temperature observation error introduced by the limited antenna beam efficiency canbe corrected; a space area is divided into two parts including an earth area and a cold air area in a satellite orbit coordinate system; in a condition that the satellite attitude factor influence isconsidered, the coordinate of the arbitrary point in the space in the antenna coordinate system under the satellite orbit coordinate system can be obtained by utilization of a rotation matrix method;then, integration is separately carried out in the earth area and the cold air area, so that antenna beam efficiency factors corresponding to the earth observation and the cold air area are obtained;the earth observation brightness temperature and the cold air calibration brightness temperature are separately corrected; and thus, the brightness temperature measurement precision of an instrument is improved.

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 space-borne 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 space-borne microwave radiometer realizes the continuous scanning observation of ocean targets through the periodic rotation of the antenna. In each scanning cycle, the microwave radiometer observes the earth scene, high-temperature calibration source and low-temperature calibration source sequentially. The high-temperature calibration source is realized by a microwave absorber at a constant temperature under precise temperature control, and the low-temperature calibration s...

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 Smaller than the real radiant 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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