【正文】 點(diǎn)。研究發(fā)現(xiàn)，新方法可有效克服噪聲對(duì)分離儀器偏差的影響，而且儀器偏差相對(duì)穩(wěn)定并可有效進(jìn)行測段間及數(shù)日間預(yù)報(bào)。在以上研究的的基礎(chǔ)上，估計(jì)了利用地殼運(yùn)動(dòng)觀測網(wǎng)絡(luò)的基準(zhǔn)網(wǎng)建立格網(wǎng)電離層模型的精度，初步探討中國域內(nèi)擬建立的廣域差分 GPS增強(qiáng)系統(tǒng)，采用格網(wǎng)電離層模型提供電離層改正信息的可行性及有待 進(jìn)一步研究的問題。 針對(duì)這種狀況，我們通過設(shè)計(jì)能有效結(jié)合電離層延遲絕對(duì)量和相對(duì)變化量的抗差遞推過程，提出了一種可在以上不利條件下有效實(shí)時(shí)改正單頻 GPS 用戶電離層延遲的方法 — APRI 方案。 APRI方案的實(shí)施，不需改變 WAAS 原有的整體設(shè)計(jì)思想，對(duì)硬件無新的要求，只需對(duì)用戶 GPS 軟件稍加改進(jìn)，實(shí)施簡便，是 WAAS 和單 頻 GPS 用戶均可接受和易于實(shí)現(xiàn)的。 以上方法盡管是針對(duì)實(shí)時(shí)監(jiān)測要求提出的，但它完全可用于后處理情況。電離層蝕因子及其影響因子，能夠根據(jù)電離層隨周日、季節(jié)、半年和周年的變化，將適應(yīng)于不同季節(jié)的電離層延遲模型有效結(jié)合起來。初步的精度估算和試算結(jié)果表明，這種在局部區(qū)域進(jìn)行有效電離層分層的設(shè)想及給出的實(shí)施方法是可行的。 (2) How to separate the instrumental biases with the ionospheric delays in GPS observation。 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 design many practical schemes for monitoring ionosphere variation using a (static or kinematic) dual frequency GPS receiver. 5 A new method of modelling ionospheric delay using GPS data ——Ionospheric Eclipse Factor Method (IEFM) The Ionospheric Eclipse Factor (IEF) and its influence factor (IFF) of Ionospheric Pierce Point (IPP) is present and a simple method of calculating the IEF is also given. By bining the IEF and IFF with the local time t of IPP, a new method of modelling ionospheric delay using GPS data —Ionospheric Eclipse Factor Method (IEFM) is developed. The IEF and its IFF can efficiently bine the different ionospheric models for different seasons according to the diurnal, seasonal and annual variations of ionosphere. The preliminary experimental results show that the correction accuracy of the ionospheric delay modeled by IEFM is very close to that of using the ionosphere free observation to correct directly the ionospheric delay, that is, the precision of using IEFM to model ionospheric delay for single GPS users seems to has a breakthrough improvement and be similar to that of using the corresponding dual frequency GPS data to correct directly the ionospheric delays. The IEFM also suits to model the ionospheric delays for a kinematic based–single GPS receiver embeded in lowearth satellite with high rapid due to its good ability in distinguishing the daytime and nighttime of the earth ionosphere for an IPP. 6 A new strategy of correcting ionospheric delay for highprecision orbit determination for lowearth satellite using a single frequency GPS receiver the APRII scheme, ., Spacebased APR scheme Analyzed the shortings of using the previous methods to divide with high accuracy the earth ionosphere into different layers. Used GPS data to model global ionospheric TEC. Established a high precision grid ionospheric model. Discussed the possibility of finding out some local areas whose ionospheric construction and action have relatively better obvious law with respect to the other areas on a global scale. Designed a