gps相关外文翻译

gps相关外文翻译内容摘要：

heme for single frequency GPS data—the APRI scheme is proposed which can efficiently address the above problems. 1) The theoretic basis of constructing the APRI Scheme The WAAS can provide highprecision absolute ionospheric delay estimates when it operates properly. Meanwhile, a single frequency GPS receiver serviced by the WAAS can efficiently determine the relative variation of the ionospheric delays between two arbitrary epochs even under adverse conditions if without considering observation noises. 2) On the APRI Scheme Based on a robust recurrence procedure and an efficient bination approach between absolute ionospheric delays and ionospheric relative changes, the APRI scheme is present which is an new method of correcting ionospheric delay for single frequency GPS user. The formula of estimating the precision of the APRI scheme is given. An implementation approach of the APRI scheme is analyzed as well. The experimental results discussed above show that the APRI scheme not only retains the characteristic of high accuracy of the DIDC from the WAAS under normal ionospheric and reception conditions, but also has relatively better correction effectiveness under different abnormal conditions. The implementation of this method need not change the present basic ionospheric delay correction algorithm of the WAAS. In addition, the APRI method does not impose new demands on receiver hardware, and only requires a few improvements to receiver software. Hence it can be easily used by single frequency GPS users. 4 A new theory of monitoring the random signal —AutoCovariance Estimation of Variable Samples(ACEVS) and its application in using GPS to monitor the random ionosphere A new approach for monitoring ionospheric delays is found and developed, based on the characteristic of time series observation of GPS, an investigation of the statistical properties of the estimated autocovariance of the random ionospheric delay when changing the number of samples in the time series, the development of the related basic theory and the corresponding framework scheme, and the further research of using GPS and the above research results to study ionosphere. The concrete work is as follows: 1) Studied the AutoCovariance Estimation of Variable Samples (ACEVS) From a general mathematical aspect, the basic model of ACEVS is established. The theoretic and approximate solution formulas for ACEVS are derived based on the improvement of theory of white noise and then a test raw of the state of a random signal is established based on ACEVS。 2) Verified and modeled the possibility of using ACEVS to test the change of state of stochastic delays The possibility of using ACEVS to monitor ionosphere is verified in terms of theory. Also it is found that the statistical property of ACEVS is sensitive to the change of the random ionospheric delay, on the basis of modeling the characteristics of ACEVS using a dual frequency GPS receiver. The application conditions of using ACEVS to monitor the variation of TEC extracted by GPS data are preliminarily discussed and analyzed as well. 3) Established a preliminary framework scheme of using GPS to monitor the disturbance of random ionospheric delay. According to ACVES and all other results of the above and the characteristic of the time series observations of GPS, a preliminary framework scheme for monitoring the disturbance of random ionospheric delay using GPS is established. Although this method is proposed for real time monitoring, it can be easily applied to postprocessing of GPS data. The framework scheme based on ACVES can be used to。