Research On Index System And Assessment Programme Of Gravitational Field Model

With the development of high-precision long-endurance inertial navigation systems, inertial element's accuracy has been greatly improved. Compared with the errors caused by inertial devices, the errors caused by gravity disturbance are roughly equivalent or greater. So gravity disturbance has become one of the most important error sources. We need to use the gravitational field model to compensate for INS. Only considered the spherical harmonics model amounted to over a hundred different kinds since 1966. In such a diverse selection of models, we need to study on availability analysis and evaluation method of gravitational field model.The gravitational field model's evaluation indexes have been researched in this paper, meanwhile, an evaluation system has been established, an assessment programme has been put forward, and the graphical user interface of the evaluation system has been completed.This paper has analysed the concept of gravity disturbance, studied the effects of gravity disturbance on high-precision inertial navigation system. The modeling methods of gravitational field have been researched, and the formula about spherical harmonics model has been derived.In the study of evaluation indexes, the text has analysed three aspects of higher-order spherical harmonic gravity field model, such as complexity, real-time performance and accuracy. From the computational complexity and space complexity measure the models' complexity requirements. From the index W and communication time measure the models' real-time index whether can achieve the requirement of INS. From the internal and external to analysis the accuracy index in order to determine the model's availability. Then established a four-level evaluation system based on complexity, real-time performance and accuracy indexes, proposed two kinds of evaluation methods, applied the multi-index weighted fuzzy evaluation method to establish an assessment program, and completed the GUI design.To verify the accuracy of the assessment program, simulation experiment has been designed. We selected EGM2008(2190) and EGM2008(360) to evaluate in the Northeast Plain region and the Tibetan Plateau region. Thus illustrate the rationality of the proposed method.