To achieve high-precision terrain mapping and centimeter level surface deformation detection for the new generation of remote sensing satellites, it is necessary to improve the quality and accuracy of Earth observation remote sensing images. In addition to improving the resolution of payloads, satellite platforms also need to provide high-precision attitudes. Star sensors are high-precision satellite attitude measurement sensors, whose measurement accuracy directly determines the accuracy of satellite attitude determination. Their measurement accuracy is mainly affected by factors such as measurement noise of star sensors, installation matrix calibration errors, line of sight drift errors caused by changes in solar irradiation angles, thermal deformation of satellite structures, and optical orbit errors. Therefore, it is necessary to classify the in orbit measurement errors of star sensors, and then calculate, analyze, and correct each type of in orbit error. For this purpose, this article introduces a method for correcting in orbit measurement errors of star sensors.By adjusting detector parameters and optimizing attitude calculation methods, the random noise, noise equivalent angle, and low-frequency error of the star sensor can be reduced ; to improve the design of star sensors through simulation and experimental verification, the thermal stability ability is improved by isolating the installation of the light shield and main frame, optimizing the structural materials and design, and optimizing the optical lens adjustment method ; by calculating the sum of the Earth's revolution speed and satellite motion speed in the coordinate system measured by the star sensor, the angle of optical aberration error is obtained, and the optical aberration correction is performed on the in orbit star sensor .After optimizing the detection parameters, the accuracy of the star sensor's X direction centroid positioning increased by 19.35% and the Y direction centroid positioning accuracy increased by 48.52%. After optimization using dynamic weight algorithm, the equivalent angle of ground observation experiment noise increased by 46.27% in the X direction, 52.17% in the Y direction, and 42.87% in the Z direction . The above optimization methods are validated on the ground and solidified in the internal parameters and software of the star sensor. The star sensor can self correct during in orbit operation, output high-precision measurement data in real time, and do not require satellite attitude and orbit control backend processing. Through in orbit data verification, the random noise of the star sensor is 1.35″ with an equivalent noise angle of 0.99″ and a low-frequency error of 0.91″, which meets the requirements for attitude measurement random error and attitude measurement low-frequency error in the allocation of accuracy indicators for satellite positioning.The independent installation of the sunshade and the optimization method of the optomechanical structural material have been verified through ground simulation and thermal stability tests. It can ensure that the thermal drift effect of the star sensor's line of sight is controlled to 0.1"/℃ when the sun irradiation angle changes alternately in different environmental temperatures during orbit, and high-precision measurement data is output in real-time. The star attitude and orbit control computer can directly use it without the need for backend fitting processing. Through the analysis of four-dimensional satellite in orbit data, the thermal drift of the star sensor's line of sight pointing has been reduced from 7.35" to 1.11", meeting the requirements for thermal drift of the star sensor's line of sight pointing in the accuracy index allocation of remote sensing satellite positioning.This article provides a detailed classification of the in orbit errors of star sensors, analyzes the error sources, and corrects the errors.Firstly, after optimizing the detection parameters and dynamic weight algorithm, and verifying with ground observation and in orbit data, the random noise of the star sensor is 1.35″, which meets the requirements of the accuracy index allocation for satellite positioning in remote sensing.Secondly, through simulation and thermal stability tests, the structure and material optimization design of the main frame material, weight reduction groove, optical lens installation, and independent insulation installation of the light shield of the star sensor are verified. Analysis of in orbit data shows that the thermal drift of the star sensor's line of sight pointing is 1.11″, which is consistent with the results of ground thermal stability tests. At the same time, it meets the requirements for thermal drift of the star sensor's line of sight pointing in the allocation of accuracy indicators for remote sensing satellite positioning.Finally, through the method of correcting optical aberration, the peak value of the trend term of the angle between the optical axes of the star sensor 2a and star sensor 2b in orbit decreased from 15.92″ to 3.63″, a decrease of 12.29″.The above in orbit measurement error correction method is independently completed by star sensors and outputted in real time, without the need for satellite platform backend processing and fitting. It has great engineering application value for obtaining high-quality Earth observation remote sensing images and can meet the needs of the new generation of remote sensing satellites for high accuracy and stability.