Research Of GPS Reliability Based On Quality Control

Besides the precision and cost, the reliability of GPS is another important part of the GPS product evaluation. In real application, because of the higher reliability requirement, GPS reliability theory gets more and more attention. Therefore, the research on GPS reliability has important realistic significance.Firstly, from putting forward the concept of reliability theory, the purpose, meaning and necessity of it are discussed. Then the paper introduces three baseline models and their corresponding stochastic models which are necessary in the research of reliability.Secondly, the concept of internal reliability and external reliability are put forward. Then the thesis introduces the deductive process and computation method of MDB, MDE and BNR which are indexes of internal reliability and external reliability in detail. Furthermore, some parameters selection criterions are given.Thirdly, Aiming at the characteristics of reliability forecast, this thesis presents the correlative content of GPS satellite forecasting such as GPS constellation and signal structure; GPS satellite forecasting principle; the detailed computation steps of GPS visual satellites numbers. At last, a realistic GPS satellite forecasting example is given.Eventually, as the emphasis of this dissertation, taking the area around Chengdu as an example, an experiment on GPS reliability forecast is made using GPS almanac, and internal and external reliabilities of different baseline models are computed, the relationship of DOP and MDB is also discussed. Furthermore, this thesis extends the reliability forecast from single point to region, for certain time, and the global MDB forecasting is realized.