低轨卫星编队星载GPS相对定轨理论及应用

发布时间：2018-05-31 13:42

本文选题：卫星编队 + GPS　；参考：《武汉大学》2014年博士论文

【摘要】：随着GPS定位、定轨技术的发展和精度的提高,利用星载GPS对低轨卫星进行相对定轨已经成为一种有效的方式,可以达到cm级乃至mm级的相对定轨精度。同地面GPS一样,星载GPS也受到相位中心延迟、电离层延迟等误差的影响,也要通过解算整周模糊度提高定轨精度。同时,由于星载GPS星座变换迅速,卫星间共视卫星较地面站少,因而数据处理过程更为复杂。本文的主要研究内容和创新点如下： 1.针对星载GPS观测数据的特点,详细分析了GRACE星载GPS的可视性、DOP值及C/No等信息,利用切比雪夫多项式对轨道和钟差进行了拟合,并利用伪距相位组合法、电离层残差法、M-W组合法对星载GPS观测数据进行了粗差和周跳探测。 2.研究了星载GPS卫星和接收机天线相位中心延迟(PCO)和变化(PCV),比较了不同改正方式下的卫星PCO,将IGS发布的卫星PCV改正值由天底角14°扩展到15°,将NGS提供的接收机PCV校准值由高度角80°扩展到90°,分析了GFZ改正值的使用和坐标转换方法,以及相位中心改正对GRACE相对定轨的影响。研究表明：使用IGS绝对模型进行卫星天线相位中心改正,并使用GFZ产品进行星载接收机天线相位中心改正时结果最优。 3.提出了一种适用于星载单频GPS的改进的电离层改正模型及其近似算法。分析了星载GPS的单层模型投影函数,并计算了不同单层高度下的值。计算了500km单层高度下GRACE卫星对应的穿刺点轨迹。利用改进的Klobuchar模型和比例因子来得到GRACE卫星轨道以上电离层部分的延迟量,并利用双频观测值进行了验证。研究表明,对GRACE卫星而言,单层高度需从350km调整到500km；改进的Klobuchar算法中,地心角和倾斜因子的近似形式精度足够；试验数据中,改进的Klobuchar算法可以改正大于80%的电离层延迟。 4.探讨了星载GPS电离层延迟及接收机硬件延迟的计算方法和影响。低轨卫星只受到其轨道高度以上电离层部分的影响,这一影响可以通过地面以上电离层的延迟乘上一个比例因子来得到。本文利用双频观测值和GIM、Klobuchar模型或改进的Klobuchar模型间的相关性计算出比例因子和接收机硬件延迟,并利用GRACE星载GPS数据进行了验证。结果表明,比例因子与接收机高度、视线方向TEC值以及采用的电离层改正方法等因素有关,本文采用的数据中,利用双频观测值和GIM的相互关系求得的比例因子和接收机硬件延迟比较规律,而Klobuchar方法则与TEC值密切相关,但都可以提高相对定轨的精度。 5.探讨了星载GPS相对定轨初值的确定、浮点解的求解、模糊度的固定等问题。分别采用适用于星载GPS的宽巷法和LAMBDA方法进行模糊度固定,并对解算结果进行了分析。本文采用的数据中,采用平均取整法固定宽巷模糊度时,GRACE A和B模糊度固定的成功率都在60%以上；利用电离层模型固定宽巷模糊度时,成功率约70.2%。采用LAMBDA法时,模糊度固定后,解的精度大大提高。 6.分析了GRACE卫星搭载的KBR系统的基本原理和观测模型,并与GPS双差模型比较,得到GPS/KBR联合解算的模型,并给出一种利用信噪比(SNR)和载噪比(C/N0)确定KBR单位权标准差的方法。基于双差GPS、GPS/KBR观测方程,首先利用双向卡尔曼滤波求得GRACE双星相对定轨结果,然后利用一般LAMBDA法、附加KBR星间距离约束的LAMBDA法解算整周模糊度,继而求得固定解。研究结果表明,KBR可以作为一个新的观测值类型,与GPS一起解算时可以提高定轨精度,KBR星间约束有利于固定更多的模糊度,试验数据中,GPS/KBR联合解算精度优于3cm (RMS)。
[Abstract]:With the development of GPS positioning, the development of orbit determination technology and the improvement of precision, it has become an effective way to make the relative orbit determination of the low orbit satellite using the spaceborne GPS, which can reach the relative orbit determination precision of the cm level and the mm level. As with the ground GPS, the spaceborne GPS is also affected by the phase center delay, the ionospheric delay and other errors. The ambiguity resolution improves the orbit determination accuracy. At the same time, due to the rapid transformation of satellite GPS constellation, the satellite to satellite is less than the ground station, so the data processing is more complicated.
The main contents and innovations of this paper are as follows:
1. according to the characteristics of spaceborne GPS observation data, the visibility, DOP value and C/No information of GRACE spaceborne GPS are analyzed in detail. The orbit and clock difference are fitted by Chebyshev polynomial, and the pseudo distance phase combination method, the ionospheric residual method and the M-W combination method are used to detect the rough and circumferential jump of the spaceborne GPS observation data.
2. the phase center delay (PCO) and change (PCV) of spaceborne GPS satellite and receiver antenna are studied. The satellite PCO under different corrections is compared. The PCV correction value issued by IGS is extended from 14 degrees to 15 degrees, and the PCV calibration value provided by NGS is extended from 80 degrees to 90 degrees, and the use of the GFZ correction value and the coordinate conversion are analyzed. The method, and the correction of the phase center correction on the relative orbit determination of GRACE. The study shows that the IGS absolute model is used to correct the phase center of the satellite antenna, and the result is optimal when the phase center of the spaceborne receiver antenna is corrected by using the GFZ product.
3. an improved ionospheric correction model and its approximate algorithm for spaceborne single frequency GPS are proposed. The single layer model projection function of the spaceborne GPS is analyzed, and the values at different single layer heights are calculated. The trajectory of the puncture point corresponding to the GRACE satellite at the 500km single layer height is calculated. The modified Klobuchar model and the proportional factor are used to obtain the G. The delay of the ionosphere above the RACE satellite orbit is verified by two frequency observations. The study shows that, for the GRACE satellite, the single layer height needs to be adjusted from 350km to 500km; in the improved Klobuchar algorithm, the approximate form accuracy of the core angle and the inclination factor is sufficient; in the experimental data, the improved Klobuchar algorithm can be corrected. The ionosphere delay greater than 80%.
4. the calculation method and influence of the spaceborne GPS ionospheric delay and the receiver hardware delay are discussed. The low orbit satellite is only affected by the ionosphere part of its orbit height. This effect can be obtained by multiplying a proportional factor by the delay of the ionosphere above the ground. This paper uses the dual frequency observation value and the GIM, Klobuchar model or improvement. The correlation between the Klobuchar models and the receiver hardware delay are calculated and verified with the GRACE borne GPS data. The results show that the ratio factor is related to the height of the receiver, the TEC value of the line of sight and the method of the ionospheric correction. In this paper, the two frequency observations and the GIM are used in the data collected in this paper. The relationship between the proportional factor and the receiver hardware delay is obtained, while the Klobuchar method is closely related to the TEC value. However, the accuracy of relative orbit determination can be improved.
5. the problems of determining the initial value of the spaceborne GPS relative fixed orbit, solving the floating point solution and fixing the fuzzy degree are discussed. The fuzzy degree is fixed with the wide lane method and the LAMBDA method applied to the spaceborne GPS, and the results are analyzed. In the data adopted in this paper, the fuzzy degree of GRACE A and B is used to fix the ambiguity of the wide lane, and the fuzzy degree of the A and the B. The fixed success rate is more than 60%. When using the ionosphere model to fix the width of the wide lane, the success rate is about 70.2%. LAMBDA method. The accuracy of the solution is greatly improved after the fuzzy degree is fixed.
6. analysis the basic principle and observation model of the KBR system carried by GRACE satellite, and compare with the GPS double difference model, get the GPS/KBR joint calculation model, and give a method to determine the standard deviation of KBR unit weight by the signal to noise ratio (SNR) and the carrier noise ratio (C/N0). Based on the double difference GPS, the GPS/KBR observation equation, first use the bidirectional Calman filter to obtain the method. GRACE binary star relative orbit determination results, then using the general LAMBDA method, additional KBR INTERSTAR distance constraint LAMBDA method to solve the integer ambiguity, and then get the fixed solution. The results show that KBR can be a new type of observation value, and the solution calculation with GPS can improve the precision of the orbit, KBR INTERSTAR constraint is beneficial to fixed more fuzziness. The accuracy of GPS/KBR combined calculation is better than that of 3cm (RMS).
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P228.4

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