Research On Compensation For System Errors Of Basic Satellite Products

Under the demonstration of satellite and post-processing of data, users usually designed the corresponding satellite and earth observation data processing method according to the requirement of the mission. Due to the specific of the mission, the acquired data is generally only concerned with the completion of the mission regardless of the application to expand in other areas. This paper explores the possibility to use non-mapping data for surveying and mapping, and make up for the lack of quantity of surveying and mapping data, improve the application effectiveness of earth observation data. However, due to the high requirement of interior accuracy for surveying and mapping, it is necessary to detect and compensate the system error which is barely concern in other areas when we use the non-mapping data. In this paper, the following topics are studied.1) Strategy about Compensation for System Errors of Basic Satellite ProductUnlike the classical compensation for system errors of rigorous sensor model (RSM). The difficulties of compensation for basic satellite product system errors is the confidentiality of the rational functional model (RFM). Users can not directly get the geometry information, such as orbit, attitude and interior elements (IO), under the process of traditional compensation for system error of RSM. Therefore, the classical compensation method of RSM cannot be used directly in the compensation for basic satellite product. From the research status at home and abroad, the compensation method of RFM is basically built in the image space or the object space based on the RFM with additional parameters model. No matter how complex the additional parameters model, its essence is the fitting or approximation for the result of the residual error, and the additional parameter modification for RFM. This paper takes the Gaofen-1 Wide Field View (WFV) sensor as an example to solve the problem. For the problem that the classical system error compensation strategy models from the result of system error, we presented RCG strategy (Recovery-Compensation-Generation) which is modeled from the reason of system error. Because the strategy models from the reason of system errors, it avoids approximation assumptions and constraints of traditional strategy.2) Robust Approach for Recovery of Rigorous Sensor Model using Rational Function ModelFor the "Recovery" process of the strategy, this paper presents a robust and linear RSM recovery method which is different from traditional method. Traditional RSM recovery method construct the virtual grid ground control points (GCPs) from RFM, and restore the RSM in accordance with the bundle adjustment method. No matter how complex the parameters of the model, its essence is principle of resection, and could not escape the iterative, nonlinear, required initial value problem. This paper proposes a novel linear method to obtain the position, attitude, and interior orientation (IO) elements of satellites based on the orientation information of the rays implied by the RFM. Instead of resection, forward intersection is used to solve for position, and an equivalent body coordinate system is introduced to overcome the strong correlation between the attitude and IO. The orientation information of the rays implied by the RFM is used to calculate the IO pixel-by-pixel. Experiments using the Ziyuan 3 (ZY3-01) panchromatic nadir (NAD) sensor show that this method can recover the exterior orientation (EO) and IO elements effectively.3) Research about Compensation Model, Calibration and Self-Calibration Method for Wide-Field-View Satellite ProductFor the "Compensation" process of the strategy, firstly, this paper constructs the system error compensation model, proposed the method of estimating the long-period variation of the exterior element errors, and demonstrates that the compensation model of linear array imagery’s IO elements is a quintic polynomial model. Then, aiming at the control point acquisition problem of wide-field-view basic satellite product, this paper proposes a system error compensation model with constraint condition, in which the converage of control data is solved by multi-scene coverage. Finally, based on the problem of high-cost and limited coverage of high-accuracy control data, this paper proposes a self-calibration method which does not depend on the ground control information, and demonstrates feasibility of the self-calibration method in the flat terrain and complex terrain, respectively.4) Analysis about the Mathematical Properties and Functional Feature of the Rational Function ModelFor the "Generation" process of the strategy, the qualitative analysis about the mathematical properties and function form of one-dimensional rational function is conducted. Then the conclusion is extended to three-dimensional form of rational function. Based on the qualitative analysis of three-dimensional rational function, this paper raises that the RFM has the possibility of fitting quantic function, and verifies the view through experiments.Finally, this paper will use the proposed strategy and method in the basic satellite products of Gaofen-1 WFV sensor, and construct an automatically compensated internet for Gaofen-1 WFV sensor. The recovery accuracy of RSM, compensated accuracy of system error, replacement accuracy of RFM, the plane accuracy and elevation accuracy of Gaofen-1 WFV sensor are performed experiments respectively to verify the correctness and effectiveness of the proposed algorithm. Experiments show that the method can meet the demand of 1:250000 scale map and topographic map updating.