【摘要】：完備性是指系統(tǒng)在導(dǎo)航系統(tǒng)有任何故障或誤差超限不能應(yīng)用于導(dǎo)航和定位服務(wù)時(shí)向用戶發(fā)送警告信息的能力。本文通過理論分析和實(shí)驗(yàn)驗(yàn)證質(zhì)量控制和完備性問題,保證實(shí)時(shí)網(wǎng)絡(luò)RTK的成功運(yùn)行。由于電離層變化非常復(fù)雜,并且難于建模,電離層延遲是影響網(wǎng)絡(luò)RTK定位的主要無差源。使用NRTK系統(tǒng)可以對電離層誤差的大部分(低階項(xiàng))進(jìn)行建模和消除。然而,在太陽或地磁風(fēng)暴或電離層擾動期間,存在較大的電離層殘差,影響了相位模糊度的確定和網(wǎng)絡(luò)RTK的性能。因此,完備性需要通過電離層完備性監(jiān)測來監(jiān)測和控制電離層殘余無差,以保證流動站定位的可靠性和可用性。網(wǎng)絡(luò)RTK的電離層完備性監(jiān)測包括以下四方面。第一,估計(jì)和分析電離層延遲;第二,構(gòu)建了電離層插值模型;第三,計(jì)算電離層殘差完備性監(jiān)測指標(biāo)(IRIM);第四,計(jì)算電離層殘插值不確定度(IRIU)。本文實(shí)驗(yàn)采用了廣東省CORS站2015年9月11日和9月22日兩天的兩個(gè)子網(wǎng)數(shù)據(jù),采樣間隔1秒。基線長度對模糊度的正確固定有重要的影響。基線長度越短,雙差的殘余誤差越小。通常雙差電離層延遲在分米到厘米級別,當(dāng)基線的長度較長時(shí),它會變大。因此,雙差電離層延遲在很大程度上取決于基線長度。由于電離層活動的特點(diǎn)及其在空間中的彌散特性,利用區(qū)域誤差模型預(yù)測流動站處的改正數(shù)是一種常用方法。在這些模型中,Wanninger(1995)提出的線性插值法(LIM)是典型的且最常用的獲取流動站誤差預(yù)測值的插值方法。對不同時(shí)段和測站網(wǎng)的電離層改正殘差的分析表明了改正精度的變化及其對電離層條件的依賴性。的雙差電離層延遲真值和雙差電離層殘差會受太陽輻射的影響,特別是在下午和傍晚時(shí),雙差電離層延遲及其殘差會很大。電離層活動的變化取決于太陽輻射量。由于電離層殘差的線性部分通常已經(jīng)通過插值方法剔除,殘留在網(wǎng)中的主要是非線性部分,該部分無法通過插值來建模。因此,電離層的線性度可以為網(wǎng)內(nèi)的電離層插值誤差和電離層殘余誤差提供一個(gè)好的估值。在計(jì)算得到了基線的雙差電離層延遲并建立了插值模型后,可以利用電離層殘余完備性監(jiān)測(IRIM)和電離層殘余完備性不確定性(IRIU)來監(jiān)測剩余殘差。完備性監(jiān)測指標(biāo)IRIM和IRIU的對應(yīng)值與電離層殘差的變化相似。IRIM和IRIU都反映了電離層殘差的情況。
[Abstract]:Completeness refers to the ability of the system to send warning information to the user when there is any fault in the navigation system or when the error exceeds the limit and cannot be applied to the navigation and positioning service. In this paper, the quality control and completeness problem are verified by theoretical analysis and experiment to ensure the successful operation of RTK in real time network. Because of the complexity of ionospheric variation and the difficulty in modeling, ionospheric delay is the main non-differential source of network RTK location. Most of the ionospheric errors (low order terms) can be modeled and eliminated by using NRTK system. However, during solar or geomagnetic storms or ionospheric disturbances, there are large ionospheric residuals, which affect the determination of phase ambiguity and the performance of network RTK. Therefore, the completeness needs to monitor and control the ionospheric residual error through ionospheric completeness monitoring to ensure the reliability and availability of mobile station location. The ionospheric completeness monitoring of the network RTK consists of the following four aspects. First, estimate and analyze ionospheric delay; second, construct ionospheric interpolation model; third, calculate ionospheric residual completeness monitoring index (IRIM); fourth, calculate ionospheric residual interpolation uncertainty (IRIU). In this paper, two subnet data from CORS station in Guangdong province, September 11, 2015, and September 22, 2015, are used. The sampling interval is 1 second. Baseline length has an important effect on the correct fixation of ambiguity. The shorter the baseline length, the smaller the residual error of double difference. Usually the double-difference ionospheric delay is in the decimeter to centimeter level, when the baseline length is longer, it will become larger. Therefore, the double difference ionospheric delay depends to a large extent on the baseline length. Because of the characteristics of ionospheric activity and its dispersion in space, it is a common method to predict the corrections at mobile stations by using the regional error model. In these models, (LIM), a linear interpolation method proposed by Wanninger (1995), is a typical and most commonly used interpolation method to obtain the error prediction value of mobile station. The analysis of ionospheric correction residuals in different periods and stations shows the variation of correction accuracy and its dependence on ionospheric conditions. The true values of the double difference ionospheric delay and the double difference ionospheric residuals will be affected by solar radiation, especially in the afternoon and evening, the double difference ionospheric delay and its residuals will be very large. Changes in ionospheric activity depend on the amount of solar radiation. Because the linear part of the ionospheric residuals is usually eliminated by interpolation, the residual part in the network is mainly nonlinear, which cannot be modeled by interpolation. Therefore, the ionospheric linearity can provide a good estimate for the ionospheric interpolation error and the ionospheric residual error in the network. After the double difference ionospheric delay of the baseline is calculated and the interpolation model is established, the residual (IRIM) can be monitored by using the ionospheric residual completeness and the ionospheric residual completeness uncertainty (IRIU) can be used to monitor the residual error. The corresponding values of IRIM and IRIU are similar to the variation of ionospheric residuals. IRIM and IRIU both reflect the ionospheric residuals.
【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：P228.4;P352.7

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