GNSS接收机信号极易受外界环境遮挡而完全中断,使得接收机所输出的相位观测值产生周跳,这将引起精密单点定位(PPP)模糊度参数的重新初始化,并需要十几分钟甚至更长时间的重新收敛,限制了PPP的推广应用.针对以上问题,以星间单差PPP/INS紧组合为研究基础,借助INS短期导航精度高的优势,提出一种INS辅助的周跳修复新方法.该新方法使用星间单差相位新息与星间单差电离层残差作为周跳修复量;为提高周跳修复可靠性,新方法对周跳修复量进行了质量控制并设置了多重修复准则.两组车载组合导航实验表明:与不修复相比,周跳修复后可实现PPP瞬时重新收敛,定位精度提升至20 cm以内;但需注意,周跳修复成功率会随着GNSS信号中断时间的延长而降低.

In order to improve GNSS integrity,a new integrity monitoring method of GNSS aided by INS with considering the phase Doppler smoothing code is proposed.In this algorithm,by the use of phase Doppler smoothing code to reduce the random error,the parity vector can be obtained by using measurement derived from INS and GNSS for fault detection and isolation.The simulative results show that the integrity monitoring method of GNSS aided by INS can increase the fault detection rate,when considering the phase Doppler smoothing code the performance improvement is more significant.

GDOP is one of the important standards which measure the accuracy of a navigation positioning system. Firstly, this article discusses the shortcomings in the domestic and foreign literatures of deriving the minimum of GDOP. The existing theories of minimum of GDOP are all based on the observations of ground stations, and the deduced GDOP minimum value cannot be reached because the observable range of the receiver do not be considered. Then, the minimum GDOP is derived under the condition which the cutoff angle of satellite is greater than zero, and a method to get the minimum GDOP is proposed and the corresponding geometry between satellites is given. This new theory of minimum of GDOP is also applied to the criteria for inter-satellite link establishment in Walker-δ constellation which is proposed by the authors. The optimal structure diagram of inter-satellite link is given in terms of GDOP. Finally, computations indicate the effective and useful of this new theory of the minimum of GDOP.

The computation of minimum GDOP can't be acquired in previous researches,because receiver only receives signal when satellite is above the ground level.In this paper,the equation of GDOP minimum value was again deduced with the constraint of satellites above zero degree elevation,a method to get the minimum of GDOP was given and the user/satellite geometry was considered.Finally,computation indicated the new algorithm on the minimum of GDOP is effective and useful.

GPS/INS组合导航具备数据更新率高、抗干扰、能够提供包括姿态在内的全部导航信息等优点,因此在测绘领域得到了广泛应用。但是目前国内GPS/INS组合导航研究主要集中在单GPS接收机与INS的组合模式,针对此问题,本文研究基于伪距和多普勒观测值的DGPS/INS紧组合导航算法,给出组合导航扩展卡尔曼滤波的状态方程和量测方程。实测数据解算表明,该组合模式下的导航精度得到显著提高。

This is the paper style requirement for the Chinese Control Conference. The writers of papers should and must provide normalized electronic documents in order for readers to search and read papers conveniently. An INS-aided acquisition approach is proposed in order to solve the difficulty of GNSS signal acquisition in the high dynamic environment. It utilizes information of Doppler and pseudorange, that from INS and Ephemeris to reduce the range of carrier wave frequency, the length of the C/A code is shorten. So that the acquisition time can be reduced and the acquisition performance of high dynamic receiver can be improved. Performance analysis of INS aided GNSS signal acquisition based on motion dependence of INS, the equations of performance between INS and GNSS signal acquisition are reduced. Simulation shows that INS composed of 100(°)/h bias drift gyros and 1mg bias drift accelerometers aided can obviously reduce average acquisition time and increase Sensitivity.

Ultra-tight INS and GPS integration meets the navigation accuracy requirement under low signal-to-noise ratio and high dynamic situations by using parameters of INS to aid GPS signal acquisition and carrier tracking.With the develop- ment of BDS,It's important to do the research on ultra-tight INS/GPS/BDS integration.Herein,the decisive technologies in INS/GPS/BDS were investigated and a navigation filter algorithm was designed.The entire performance was simulated on a software receiver.Simulation result shows that the navigation accuracy of new system is similar to the ultra-tight INS and GPS integration,however,the availability of it is better.

Aiming at the problem that the navigation errors increased rapidly when the GPS signal is unavailable in the GPS/INS integrated navigation system. Firstly, the characteristics of Fixed-Interval Smoothing algorithm in post-processing was researched, and Rauch-Tung-Striebel (RTS) smoothing was adopted to process the data during GPS outage. Secondly, a Parametric Error Model (PEM) that can be used in near real-time or post-processing was developed, and the scope of applications of the model was discussed. At last, both methods were compared using the simulation data, the results showed that either of them can improve the navigation accuracy during GPS outage, and the advantages and disadvantages of the two algorithms were analyzed. © 2012 Springer-Verlag GmbH.

GNSS IF signals provide a signal source for system simulation testing.We present a software realization and simulator structure based on the mathematical models of GNSS IF simulator and considering the users' dynatnic specifications.The GNSS receiver software is used for the test of developed simulator software.Our results show that the mathematical model is valid and the implementation method is feasibility,due to its flexible structure.GALILEO and COMPASS signals can be easily realized by adding other algorithm.

Time synchronization is a crucial prerequisite for GPS/INS integrated sys- tems. In this paper, the causation of time asynchronization is analyzed in detail, and thoughts of implementing time synchronization for integrated systems are described. A sur- vey of existing time synchronization solutions is presented. It is an important reference for design of integrated navigation systems.

For the navigation constellations, there are no literatures which focus on the routing algorithm and using probability of inter-satellite link (ISL) from the perspective of autonomous orbit. In this paper, the establishment criteria, routing algorithm and the using probability of ISL in the Walker-δ constellation are analyzed for the purpose of autonomous orbit determination. Firstly, the ISL establishment criteria in Walker-δ constellation are proposed based on the characters of the ISL. Then, the routing algorithm in complete Walker-δ constellation and incomplete Walker-δ constellation is studied, and the calculation formulas for using probability are given later. Finally, in the simulation, the establishment criteria, routing algorithm and using probability are discussed in detail in a specific Walker 24/3/2 constellation. © 2012 Springer-Verlag.

In dynamic environment,it is hard to process fiber optic gyro(FOG) noise,so it becomes an important constraint factor of inertial navigation accuracy.Considering the uncertain and complicated character of FOG dynamic signal,this paper develops a new method based on the technique of generalized cross-validation to adaptively determine the threshold of every wavelet layer.This method can identify wavelet signal and noise layer automatically and determine ideal threshold of wavelet decomposition level without statistic character of signal.Experiments with simulated data series and dynamic data show that the method can solve the contradiction between suppressing noise and reserving signal in dynamic environment and improve the accuracy of FOG dynamic signal processing.

Taking GPS residuals as research object,we use three methods(Box-Jenkins method,Pandit-Wu method,triangle method) to deal with the GPS residuals,and take them for comparing.It is found that Pandit-Wu method is the best one,and triangle method is worse than the others.However,through different experiments,it is also found that triangle method can exhibit the law of non-linear variation directly,which can help us go deep into studying on the reason of non-linear variation.So it is worth for further study too.

Random drift error of laser gyro is one of the main sources of error.Kalman filter algorithm can effectively restrain the random error of laser gyro.But when the model is not accurate,the conventional Kalman filter may easily result in divergent result.Fading Kalman filter can reduce the power of historical information and increase the power of the current measurement information,which may obtain continuous smooth filtering result.The fading Kalman filter was used to estimate the optimal laser gyro drift and a good result was obtained.The result showed that the fading Kalman filter has a smaller residual standard deviation,higher filtering accuracy and stability,and the output sequence is more stable.

The research on simulation software of SINS/CNS is very important to the conceptual definition,system design and development.In this paper,a scheme of integrated SINS/CNS is proposed and a simulation software of the integrated SINS/CNS Navigation system is designed and implemented.SINS and CNS can provide corresponding attitude data.Fusing these data can estimate the error state value of integrated navigation system and correct the position of aircraft,velocity and attitude angle based on Kalman filter.The applicability of the design method is tested and analyzed.Result shows that the simulation software is feasible and useful for further studies.

The method of integrated attitude determination based on inertial navigation system and celestial navigation system is researched in this paper,the state equation and measurement equation of integrated navigation systems were established.Thus the algorithm of integrated attitude determination is designed by kalman filtering technology.By designing a typical flight route of aerocraft,its mathematical simulation was made which proved the algorithm's effectivity and showed that the CNS can effectively compensate the INS error caused by gyro drift.It's very fit for the precise attitude determination of aerocraft.

In order to evaluate the real accuracy of the geocentric coordinates determined by GPS、VLBI and SLR,we used their located on the same site.After calendar correction and eccentricity correction,we get the transformation parameters.The mean square error of difference between any two kinds of geocentric coordinates is analyzed,which can reflect the real accuracy.The results show that the accuracy of the coordinates determined by GPS and VLBI is higher than SLR,better than 1 mm.

In the paper an matching algorithm based on Monte Carlo method and mean-square-error algorithm was proposed,and was used in geomagnetic matching navigation.This algorithm extracts reference geomagnetic data from the geomagnetic map around the position indicated by INS,and disturbs geomagnetic measurements randomly for several times.Then,the reference geomagnetic data and the disturbed geomagnetic data are used by mean-square-error algorithm to give a series of matching location.And the final matching location is the mean value of these matching locations.Simulation results show that the algorithm is feasible.

On accounting of the divergence of general Kalman filter in SINS/GPS integrated navigation system.This paper introduces adaptive filter and H∞ filter.Analyzed their peculiarities.Last made simulation to prove the validity and usability of these two kinds of filter used for the SINS/GPS integrated navigation system.Thus,it is of significant in practice for filter design in integrated navigation system.

The main characteristics of MATLAB/Simulink are introduced.The simulation of strapdown inertial navigation model based on MATLAB/Simulink is designed,and the example and result about simulation are given,which show that simulation efficiency can be improved by use of MATLAB/Simulink.