【正文】 進(jìn)而系統(tǒng)性地提出了一種用于星載單頻 GPS 接收機(jī)精密測軌中電離層延遲改正的綜合方法 — APRII 方案。 1）構(gòu)建 APRI 方案的理論依據(jù) WAAS 正常運(yùn)轉(zhuǎn)和正常條件下可提供高精度的電離層延遲改正信息 (絕對量 )，而 WAAS 所服務(wù)區(qū)域內(nèi)的單頻 GPS 接收機(jī)在不利條件下也能有效提供電離層延遲變化量 (相對量 )，且在不考慮噪聲影響，可直接計(jì)算任意兩觀測歷元間的電離層變化量的近似值。通過對有關(guān)模型和方法問題的深入研究，進(jìn)一步提高了利用 GPS 提取電離層延遲信息的精度。利用 GPS 觀測數(shù)據(jù)求解電離層模型或直接計(jì)算斜距電離層延遲時，都須慎重處理儀器偏差，不應(yīng)簡單把其作為噪聲處理 。具體包括： 1）研究變樣本自協(xié)方差估計(jì) (ACEVS)理論 從一般的數(shù)學(xué)意義上建立了 ACEVS 的基本模型，并在進(jìn)一步擴(kuò)展白噪聲理論的基礎(chǔ)上，得到 了 ACEVS 估計(jì)的理論和簡化解式，即變樣本自協(xié)方差估計(jì)的統(tǒng)計(jì)模型參數(shù)估計(jì)解式，進(jìn)而建立了隨機(jī)信號擾動的診斷準(zhǔn)則。 (4) How to improve the effectiveness of correcting ionospheric delays for WAAS’s users under adverse conditions. (5) How to establish the basic theory and the corresponding framework of monitoring the stochastic ionospheric disturbance using GPS (6) How to improve the modelling ability of ionospheric delay according to its diurnal, seasonal, annual variations based on GPS。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。在以上研究的的基礎(chǔ)上，估計(jì)了利用地殼運(yùn)動觀測網(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。 外文資料譯文及原文 中文翻譯 摘要 根據(jù)當(dāng)前大地測量、地球物理、空間物理和導(dǎo)航等領(lǐng)域的科學(xué)研究和工程應(yīng)用中的若干重要 GPS 科研項(xiàng)目的需要，近年來，我們系統(tǒng)研究了電離層延遲的高精度模擬和改正方法。 2. 一種構(gòu)建大規(guī)模 (區(qū)域性和全球性 )高精度格網(wǎng)電離層模型的新方法 —— 站際分區(qū)法及其在中國的初步實(shí)現(xiàn) 在系統(tǒng)深入研究了格網(wǎng)電離層模型建立原理與方法的基礎(chǔ)上，為避免基準(zhǔn)站網(wǎng)的幾何結(jié)構(gòu)對模型精度估計(jì)的影響，充分顧及電離層延遲影響的局部特性，進(jìn)一步提高格網(wǎng)電離層模型的構(gòu)建精度，提出了一種新的格網(wǎng)電離層模型構(gòu)建方法—— 站際分區(qū)格網(wǎng)法。 5. 利用 GPS 數(shù)據(jù)精確模擬電離層延遲的新構(gòu)想 —— 電離層蝕因子法及初步實(shí)現(xiàn) 提出了 IPP點(diǎn)的電離層蝕因子及其影響因子的概念，給出了簡便的計(jì)算方法，進(jìn)而提出了一種利用 GPS 數(shù)據(jù)確定電離層延遲改正模型的新方法 —— 電離層蝕因子法。 (7) How to meet the demand of correcting the ionospheric delay of highprecision orbit determination for lowearth satellite using a single frequency GPS receiver 1 Extracting (local) ionospheric information from GPS data with highprecision The factors are systematically described and analyzed which limit the precision of using GPS data to extract ionospheric delays. The precision of determining ionospheric delay using GPS is improved based on the further research of the related models and methods. The main achievements of this work include the some aspects as follows: (1) Based on a simple model with constant number of parameters, which consists of a set of trigonometric series functions, a generalized ionospheric model is constructed whose parameters can be adjusted. Due to the property of selecting the different parameters according to the change law of ionospheric delay, the new model has better availability in the field of the related theoretic research and engineering application. The experimental results show that the model can indicate the characteristic of ionospheric actions, improves further the modeling ability of local ionosphere and may be used to correct efficiently ionospheric delay of the single frequency GPS uses serviced by DGPS. (2) Different calculating schemes are designed which are used to analyze in detail the characteristics of the effect from instrumental bias (IB) in GPS observations on determining ionospheric delays. IB is different from noise in GPS observations. The experimental results show that the effect of IB is much larger than that of the noise on estimating ionospheic delay, and IB can cause ionospheric delay measurements to include systematic errors of the order of several meters. Therefore, one must significantly take notice of IB and remove its negative effect, and should not casually consider IB as part of noise whenever GPS data are used to fit ionospheric model or to directly calculate ionospheric delay. (3) Stability of IB is studied with a refined method for separating it from ionospheric delay using multiday GPS phasesmoothed code data. The experimental results show that, by using averaging of noise w