Study On Error Analysis And Correction Method Of In-orbit Attitude Measurement For Infrared Earth Sensor Based On Infrared Focal Plane Array

Infrared earth sensor is a common attitude measurement component on satellites.Its working principle is based on the detection principle of infrared detectors.The radiation of the infrared band of the earth is converted into electrical signals through photoelectric devices,and the central coordinates of the horizon circle are calculated through signal processing,and then the attitude data of the satellite is obtained through transformation.In recent years,static array infrared earth sensors have been used more and more in medium and high orbit satellites.However,due to the influence of non-uniformity,infrared radiation and oblatenessof the earth,the detection accuracy of infrared earth sensors still needs to be improved.The image quality will be affected by the non-uniformity noise of the detector,and then the attitude error will be generated.Different from the inhomogeneity of the detector response rate in the traditional sense,the earth sensor of the satellite in orbit is affected by the inhomogeneity of temperature alternating,which will produce the attitude error with the change of temperature.In this paper,the thermal simulation of infrared detectors is carried out in detail.It is not only proved that shell radiation is the main cause of non-uniform thermal noise caused by temperature alternations,but also found that the quadric surface is similar to ellipsoid in shape.The quadric surface fitting algorithm is proposed to correct the non-uniformity of the detector.The algorithm in this paper can effectively improve the non-uniformity of the detector and improve the precision of the earth sensor.For array infrared earth sensor in orbit error problem,this paper,based on the measured data of on-orbit,first analyzes the sources of error,for the earth oblateness,the earth radiation belts and the boundary of carbon dioxide layer by simulating the non-uniformity of the infrared radiation,combining satellite trajectory,the working state of the simulation of infrared earth sensor,determined by way of analysis of error sources are mainly infrared radiation non-uniformity of the earth,and the error source is corrected.Through the earth's infrared radiation model,the radiation characteristics are simulated and analyzed,and the correction algorithm is proposed.Through the simulation,the attitude deviation of the characteristic geographical position in the satellite operation process is obtained,and the infrared earth sensor is corrected in real time in orbit.Experiments show that this algorithm can improve the precision of earth sensors effectively.