Table of Content

05 May 2011, Volume 40 Issue Sup.

Previous Issue    Next Issue

学术论文

Method of Network RTK Based on Undifferenced Observation Corrections and its Functional Realization in Cross-CORS Service

2011, 40(Sup.):  1-5. 

Asbtract ( )   HTML   PDF (1520KB) ( )  

Related Articles | Metrics

Method of Network RTK based on undifferenced observation corrections allows clients to gain rapid and precise positioning service in undifferenced processing mode equivalent to Network RTK by providing error corrections of each satellite. Compared with current Network RTK, the new method could efficiently solve problems of ambiguity re-initialization caused by selected main reference stations change under circumstances of cross reference sub-networks within the same CORS network, or even cross different CORS networks, thus providing continuous and reliable positioning results for clients during observing session, as well as seamless link of Cross-CORS service. In addition, based on the characteristics of realizing Network RTK technology under the undifferenced processing mode, this new method makes the unification of regional Network RTK and wide-area undifferenced precise positioning technology possible. Through serial analysis of a practical example, this paper testifies the consistency in positioning accuracy, and initializing time of this new method and the current Network RTK, together with the efficiency of this method to provide seamless link of different reference sub-network and Cross-CORS service.

Research and Simulation of Orbit Determination for Geostationary Satellite Based on GNSS

2011, 40(Sup.):  6-10. 

Asbtract ( )   HTML   PDF (1411KB) ( )  

Related Articles | Metrics

Abstract: As the limitations of ground orbit system, this paper presents a method of orbit determination of GEO satellite based on GNSS, and designs an orbit determination of GEO satellite software. Combination of orbit determination of GEO satellite characteristics and construction of GNSS, the satellite visibility algorithms and inter-satellite observation model are discussed, integral Filter method is proposed to determine the orbit of geostationary satellite to make use of the advantage of orbit integral and Kalman filter method. Simulation results show that orbit determination of GEO satellite based on GNSS can increase the satellite observations and improve the accuracy of orbit determination. Finally, the paper develops a space-based orbit determination of GEO satellite simulation platform with STK, MATLAB and Visual C++. The outcomes of this paper will provide theoretical reference and ideal simulation tool for the application of Compass on orbit determination of GEO satellite.

（增刊）Assessment of Radio Frequency Compatibility between Compass and GPS

2011, 40(Sup.):  11-18. 

Asbtract ( )   HTML   PDF (3283KB) ( )  

Related Articles | Metrics

Compatibility becomes a matter of concern in GNSS field for many countries as multiple systems like GPS, GLONASS, Galileo and Compass are all in service. In December 2010, China launched the seventh Compass Phase II satellite, and the nation plans to make it provide global service before 2020. Since Compass's signal structures are similar to and its frequencies are close to GPS, it certainly causes the interference problem. This paper analyzes the important parameters for compatibility which are spectral separation coefficient, code tracking spectral sensitivity coefficient, and effective carrier-power-to-noise density ratio. Meanwhile, the effect of code length, code-chip rate and navigation data rate onto compatibility computation is assessed. Then, a modified compatibility assessment model with good balance of computation efficiency and accuracy is suggested. The simulations of Compass and GPS signals on all navigation bands are accomplished. In these simulations, frequency distribution, signal structure definition, transmission power and bandwidth, antenna gain, elevation angle, Doppler offset, atmospheric loss and receiver’s parameters are considered. The result of simulation shows that GPS induces more interference onto Compass than that Compass induces onto GPS when full Compass constellations are deployed in 2020.

A New Strategy of Rapid Orbit Recovery for the Geostaionary Satellite

2011, 40(Sup.):  19-25. 

Asbtract ( )   HTML   PDF (2460KB) ( )  

Related Articles | Metrics

Real time, continuous and high precision orbit is needed for the geostationary satellite (GEO) orbit maneuver. How to recover orbit rapidly for GEO based on short-arc tracking is the key factor. This paper introduced a new kinematic orbit determination approach in order to solve this problem, which was based on 9-parameter ephemeris parameter fitting. The mathematical model and partial derivative model were deduced in detail. And the coordinate rotation method was introduced to solve the singular problem in the ephemeris parameter fitting for the GEO satellite. In order to check the precision and availability of this method, the short-arc orbit determination tests were carried out using real COMPASS GEO C-band transfer ranging data. The results indicated that: 1) with a 10 minutes tracking arc the position accuracy was better than 19 m, the velocity accuracy was 4mm/s, which was better than the MEO satellite; 2) the 5-minute orbit prediction accuracy was 17.76m, and the 10-minute orbit prediction accuracy was 18.168 m; 3) several problems in the dynamics orbit determination and single point position determination were solved, the rapid orbit recovery for GEO was achieved, which satisfied the requirement of RDSS.

Multi-GNSS Precision Orbit Determination

²

2011, 40(Sup.):  26-30. 

Asbtract ( )   HTML   PDF (1517KB) ( )  

Related Articles | Metrics

With progress of multi-GNSS (GPS/GLONASS/Galileo/Compass) and multi-mode receiver chip development, precise orbit and clock offset determination of navigation satellite as well as multi-GNSS data fusion under unified space-temporal reference frame have become key problems in the multi-GNSS integrated application. Based on the self-developed software PANDA, this paper carries out investigations on integrated precise orbit and clock offset determination of multi-GNSS (GPS/GLONASS/Galileo/Compass). Then precise orbit and clock offset determination of GPS, GLONASS and GIOVE have been implemented through actual global multi-mode receiver data, including GPS/GLONASS, GPS/Galileo experimental satellites (GIOVE). By comparison with IGS provided precise orbits for GPS and GLONASS, together with differences of orbit overlap arc, and SLR observable validation, accuracy of the integrated precise orbit have been evaluated. Results show that the 3-D orbit precision of GPS and GLONASS obtained from PANDA and the data fusion method introduced in this paper reach 2.5cm and 6.0cm respectively, while the 3-D orbit precision of GIOVE satellite is superior to 30cm, and the radial precision reaches 10 cm.

Precise orbit determination experiment of COMPASS-GEO based on transponder ranging

2011, 40(Sup.):  31-33. 

Asbtract ( )   HTML   PDF (1201KB) ( )  

Related Articles | Metrics

GEO satellites play a significant role in COMPASS satellite navigation system. So it has important significance using other orbit measurement system for its precision orbit determination, besides using itself pseudo-range and phase measurement. Observing data has been obtained through transponder ranging system build by National Time Service Center, Chinese academy of Science. This paper do the orbit determination for COMPASS-GEO satellite using transponder ranging data, analyze the accuracy of orbit determination through measurement accuracy, orbit residuals and orbit overlap respectively.

Research on Impact of Phase Pattern on LEO POD

2011, 40(Sup.):  34-38. 

Asbtract ( )   HTML   PDF (1685KB) ( )  

Related Articles | Metrics

Up to now, all the LEO mission officials have published precision orbit determination results without phase pattern correction information. In fact, phase pattern error is one of the main sources of error for POD. In this paper, the phase pattern error model is established and based on GRACE real data, the PCV is gained directly from estimated parameters. Finally, some evaluations are conducted with KBR and SLR,the experiment results show that the POD improved greatly when estimated PCV.

A Kind of Long Duration Orbit Prediction Method for Navigation Satellite

2011, 40(Sup.):  39-45. 

Asbtract ( )   HTML   PDF (2595KB) ( )  

Related Articles | Metrics

In this paper, a hybrid predicion modelling method based on neural network is introduced for navigation satellite. The new model is based on dynamical model and the neural network model is adopted to modify it. During the training phase, neural network model tries to approach the difference of dynamical model prediction product, then compensate it in the prediction phase. In this paper, the characteristics of DMM prediction error for GPS are explored, and then predition strategy for long term (longer than 15days) is designed, at the last, a group of tests on GPS satellites are processed to prove and evaluate the performance of the new method, the test results show that the improvement for 15-40days prediction is obvious.

Ephemeris Fitting and Experiments Analysis of GEO Satellite

2011, 40(Sup.):  52-58. 

Asbtract ( )   HTML   PDF (3525KB) ( )  

Related Articles | Metrics

The satellite orbit is described by 15 parameters considering the one scale perturbation in COMPASS, and the bit distribution of navigation message is also consistent with GPS. But because the constellation of GPS is consisted of MEO whose period is approximately 12 hours, the parameterized program and bit distribution program may not applicable to GEO and IGSO which have higher orbit. In the system design of COMPASS, the ephemeris parameters accuracy losing have been taken into consideration, which is caused by the little inclination and small eccentricity of GEO. In the operation of system, thought the accuracy losing is eliminated, in special intervals, some parameters exceed the distributed bit limitation when the ephemeris parameters are coded into navigation message. The phenomenon and regulation of parameter’s exceeding limitation in the operation of system are introduced, and then the reasons are illustrated according to the ill-conditioned equation and the orbital characteristics, Some fitting algorithms are designed on the condition of avoiding accuracy losing, and the experiments are carried out with the actual observation data. The results proves, it is efficient to eliminate the parameter exceeding for the method of fixing one parameter while computing the others or the method of parameter ridge estimate.

Densification of Precise Satellite Clock Errors based on Gaussian Processes

2011, 40(Sup.):  59-62. 

Asbtract ( )   HTML   PDF (1490KB) ( )  

Related Articles | Metrics

In the GPS data processing, it always needs the high-sampling data of the precise clock errors. The general method is to fit or interpolate the 15min or 5min interval precise clock errors, which are provided by IGS, to the user needed interval. In this paper, the Gaussian processes (GP) method is used to densify the 5min interval clock errors to 30s interval with a suitable kernel function. The densification results are compared with the IGS data and the densified clock errors using the four order polynomial interpolation method. The results indicate that the GP method can provide high densification precision and is applicable to densify the clock errors of all GPS on-board atom clocks. The accuracy is up to the centimeter level.

PPP RAIM Method

2011, 40(Sup.):  63-67. 

Asbtract ( )   HTML   PDF (1160KB) ( )  

Related Articles | Metrics

As an important integrant of satellites navigation augment system, receiver autonomous integrity monitoring refers to monitor the integrity of user positioning result based on redundant observations. Precise Point Positioning（PPP）is one of the key technologies in GNSS high precise positioning. In this paper, extended kalman filtering estimate is adopted in PPP, the estimated parameters including station coordinates, receiver clock offset, tropospheric delay and virtual parameters. Based on parity method, correlation distances of design matrix vectors are mainly studied and taken as research objects of detection and recognition of gross error. The set of single and multiple gross errors can be distinguished by using the correlation distances time series of vectors and matrix. The RAIM method of PPP proposed in this paper, solves the issue of quality control and have the characters of simple and easy understanding. It makes the recognition of gross error more clear and can detect multiple gross errors.

The Performance Analysis of Constellation and XPL for COMPASS

2011, 40(Sup.):  68-72. 

Asbtract ( )   HTML   PDF (1909KB) ( )  

Related Articles | Metrics

In this paper, we analyze the COMPASS's structure firstly. Then we simulate and analyze the system's visibility, DOP value and position accuracy in China Mainland. Based on it, according to the features of the system's constellation and referring the principle of Space-Based Augmentation System's integrity algorithm, we analyze the XPL value which the system can provide in China Mainland. We obtain the conclusion that the COMPASS can provide the integrity of APV-Ⅰin China Mainland under a single frequency lastly.

Design and Simulation for Satellite Autonomous Integrity Monitoring Based On Inter-Satellite-Links

2011, 40(Sup.):  73-79. 

Asbtract ( )   HTML   PDF (1529KB) ( )  

Related Articles | Metrics

Since it is very difficult for ground mission and control segment to monitor the satellite’s state all time and in the invisible region, a substitute integrity monitoring method depending on inter-satellite-links is proposed. It mainly focuses on designing and simulation for satellite autonomous integrity monitoring based on inter-satellite-links. By separating clock error and ephemeris error based on ISL observation, the algorithm how to detect the anomaly of satellite clock and ephemeris is studied. The method based on balanced time sequence is studied for detecting the clock anomaly, and the method based on non-centric and square distribution is studied to detect the orbit anomaly. Through the simulation and analysis it is shown that the algorithm based on ISL can detect the anomaly of clock and orbit, and the integrity risk of the satellites navigation system is reduced, and the time of alert is shorten, so the integrity performance of GNSS is enhanced.

Research to power-enhanced technology and coverage areas of global navigation satellites

2011, 40(Sup.):  80-84. 

Asbtract ( )   HTML   PDF (2175KB) ( )  

Related Articles | Metrics

Based on in-depth research of power-enhancement of domestic and international navigation satellites, this paper analyzed the coverage areas of GEO satellites’ antenna beam under different angles of elevation. On the basis of analysis and demonstration of power-enhanced technology and program, this paper mainly discussed the power-enhanced signal’s coverage areas of our global navigation satellite. It gave out simulations of ground receiving power and antenna beam coverage, under different power-enhancement requirements of 10dB, 15dB, 20dB, 25dB. It gave out constraints of power-enhanced requirements to navigation satellites. It proposed suggestions to power-enhanced implementations of Chinese global navigation satellites, finally. Combined with the status of our navigation satellite system, it compared Chinese global navigation satellites to GPSIII at ground receiving signal, coverage areas of power-enhanced, achievement difficulty of power-enhancement, Doppler collision problem. It summarized the paper and gave out the conclusions, finally.

Study on the Minimum of GDOP in Satellite Navigation and Its Applications

2011, 40(Sup.):  85-88. 

Asbtract ( )   HTML   PDF (1149KB) ( )  

Related Articles | Metrics

The DOP is one of the ways to assessment the performance of satellite navigation and positioning. Based on the mathematical and surveying meanings of GDOP, two methods to get the minimum of GDOP were given, and the study on the minimum was made theoretically. The conclusion was drawn that, the traditional idea that DOP is just a factor to decrease the navigation & positioning precision was limited, since all DOPs including GDOP would certainly be less than one and improve the precision as a result with the change of geometrical relationship between satellites and users. On the basis of the above conclusions, CGF (Constellation Geometry Factor), which could be used to assessment the spatial geometrical layout characteristics of constellation, was given. The Test with GPS and Galileo constellations had shown that CGF could give an effective evaluation the spatial geometrical layout characteristics of constellation. The Test on the navigation precision performance in near-earth space with GPS constellation proved that DOP has the attribute to improve precision.

Effects of Dynamic on Multipath to Code Tracking Loop

2011, 40(Sup.):  89-94. 

Asbtract ( )   HTML   PDF (2496KB) ( )  

Related Articles | Metrics

Calculating The Carrier Velocity Based on Robust Least Square Estimation

2011, 40(Sup.):  95-99. 

Asbtract ( )   HTML   PDF (2054KB) ( )  

Related Articles | Metrics

The phase time-differential method, which is based on the phase rate observation to calculate the carrier velocity, is easily influenced by the cycle slips errors in carry phase observations. The widely used cycle slips processing method can correct the slips errors which are greater than 1 cycle, however there is not any easy and convenient method that can correctly solve the problems when slips are smaller than 1cycle. Through analyzing, this kind of error can lead to the accuracy magnitude of calculated velocity down to dm/s, the influence should be corrected in high accuracy velocity calculating application. Aiming at the characteristic of the phase rate observation, this paper calculated the carrier velocity by using the robust least square estimation, choosing the equivalent weight by IGGⅢ principle to lower the contribution of the observation that contain the gross error which is smaller than 1 cycle. By Calculating and analyzing the data acquired from a experiment of aviation flying, the result shows that the accuracy magnitude of velocity can keep on after RLS estimation.

Analysis of ADC's Effects on Navigation Signals and Optimal Parameter Selecting Method

2011, 40(Sup.):  100-104. 

Asbtract ( )   HTML   PDF (1977KB) ( )  

Related Articles | Metrics

The 21st century has witnessed the rapid development of digital signal processing technology. A significantly increasing amount of electronic equipments, including GNSS receiver, select to process the data in digital domain, as it’s more convenient for both software-based simulations and hardware integrations than in the analog domain. The fundamental processing of ADC would more or less bring inevitable signal loss. And we have different requirements for the accuracy corresponding to different standards. In the paper, a precise deducing about the changes of effective information of the navigation signal and signal-to-noise ratio is given, theoretically confirming that an ADC in 2 or 3bits would meet most of the requirements in general receivers. Furthermore, the different influences, determined by the chosen AD threshold, are elaborated too. One result shows that in some very kind of interference, the signal-to-noise ratio increased after the ADC, which is profitable for the ensuing processes thought not agreeing with the common sense. Finally a solution of how to choose the AD threshold in the GNSS receiver so as to get a most gain (a least loss) is demonstrated, which has been proved by the simulation in Matlab project.

The Establishment of Ionospheric Second-order Model and the Analysis of Ionospheric Variation

2011, 40(Sup.):  105-110. 

Asbtract ( )   HTML   PDF (3034KB) ( )  

Related Articles | Metrics

In the area of high precision geodesy research and application, the ionosphere second-order delay cannot be ignored in GPS data-process. This paper adopts surface model which with trigonometric series to establish the ionospheric second-order delay model, then analyses the ionosphere variation in half a year or a year of Xian city in recent five years, finally gets some significant conclusions for research of ionospheric second-order.

A method of DOA estimation based on wavelet transform

2011, 40(Sup.):  111-114. 

Asbtract ( )   HTML   PDF (1112KB) ( )  

Related Articles | Metrics

The accurate estimation of direction of arrival from measurements contaminated by noise is important for improving performance of some application system. Although estimation of signal parameters via rotational invariant techniques has good performance in scenarios of high signal to noise ratio, when signal to noise ratio is low, its performance degrades dramatically. In this paper, the measurements of the array are preprocessed with maximal overlap discrete wavelet transform. The noise power is reduced, so the performance of conventional algorithm of estimation of direction of arrival is improved for real application scenarios. The digital simulation results verified the validity of the new algorithm.

The Application of the Weighted Total Least-Squares on Three Dimensional-Datum Transformation

2011, 40(Sup.):  115-119. 

Asbtract ( )   HTML   PDF (906KB) ( )  

Related Articles | Metrics

The coordinate system transformation between the WGS-84 coordinate system and geodetic coordinate system in GPS is the three dimensional small angular region rectangular coordinates transformation. We researched on the serviceability of weighted total least-squares method, the LS-TLS method and the least-squares method in the three dimensional small angular region rectangular coordinates transformation. We found that when the coordinate observed value was influenced by the error in both of the coordinate systems, using WTLS method could revise the observation vector y and the coefficient matrix A, introduce the coordinate prior precision to the adjustment computation, and fix the constant element and adjust the data element through with the weighted matrix PA.This would make the model to be more precise and more reasonable and obtain the high accuracy parameter solution.

Design of particle filtering algorithm based on mean shift and application in navigation data processing

2011, 40(Sup.):  120-125. 

Asbtract ( )   HTML   PDF (1813KB) ( )  

Related Articles | Metrics

Considering the degeneracy of particle weight and the large amount of calculation existing in the standard particle filtering algorithm, the mean shift algorithm and particle filtering algorithm are fused, then a new particle filtering algorithm is designed based on the mean shift searching algorithm. This approach still obeys the computational outline of the standard particle filtering algorithm. The basic principle of this algorithm is to embed the mean shift searching process into the important sampling process of the particle filtering method via the clustering characteristics of the mean shift algorithm, to have a determinant searching to the particle set, and make each particle converge to local optimal value, approximates the true state distribution by means of the particle clustering of the mean-shift algorithm, and thus achieves good estimation results and improves the status of real time by requiring only a small number of particles compared with the standard PF algorithm on overcoming the defects, such as the degeneracy of the phenomenon of particle weight and the large amount of calculation. The results of a large amount of computational experiments and the GPS / DR integrated navigation experiment show the effectiveness of the new approach.

Arithmetic of frequency drift and time delay between pulse profiles in XNAV

2011, 40(Sup.):  126-132. 

Asbtract ( )   HTML   PDF (1103KB) ( )  

Related Articles | Metrics

Abstract: The frequency drift and time delay are two measurement variables of XNAV. The computation of them should offer high precision. Here we systematically discuss the computation method and propose some modifications. First, we further divide the bin into smaller time-interval, and presume photons received in each interval comply with binomial distribution. The folding of observed profile on such interval results in more accurate frequency drift. The second, the observe profile can be divided into ideal profile and the bias, and the time-of-arrive (TOA) is time lag between ideal profile and standard profile. We point out that Sala’s TOA formula, derived with maximum of correlation function, only hold for ideal profile. The third, we prove that TOA’s error caused by the bias of profile is a constant, in case the observe profile doesn’t change during measurement．As above, the computation method of TOA is proposed and the precision of TOA can be smaller than the discern time of the detector.

Comparison and Simulation of Two Resolve Plane Algorithms in the Strapdown Gyro-north Seeking System

2011, 40(Sup.):  133-136. 

Asbtract ( )   HTML   PDF (1328KB) ( )  

Related Articles | Metrics

Aimed at strapdown gyro-north seeking system, the algorithms of coordinate transform and vector were conducted, the mistakes of vector resolve plane algorithm formula were corrected, which was put forward in the reference; Although the two algorithm formulae are different in forms, their north seeking accuracies were compared. The simulation results show that the two resolve plane algorithms are both right.

Federated Nonlinear Filtering for Attitude Determination System with Star Sensor and GNSS Sensor

2011, 40(Sup.):  137-144. 

Asbtract ( )   HTML   PDF (2882KB) ( )  

Related Articles | Metrics

Gyroless attitude determination system is an important research direction in the aerospace area. In this paper, a federated nonlinear predictive filtering algorithm is presented for the gyroless attitude determination system with multiple sensors. The approach combines the good qualities of both the nonlinear predictive filter (NPF) and federated filter. Moreover, this algorithm can solve the information fusion problem effectively for the system of which the attitude dynamics model error is Non-Gaussian distribution. Firstly, the equivalence relation between NPF and Kalman filter is demonstrated from algorithm structure and estimation criterion. The flow of federated nonlinear predictive filtering algorithm is analyzed and the calculation of the model error covariance is discussed. Secondly, the principles of the star sensor and Global Navigation Satellite System (GNSS) are introduced and the federated nonlinear predictive filtering model of star sensor/GNSS integrated attitude determination system is deduced. At last, simulation results using this algorithm indicate the filter accurately estimates the attitude of the spacecraft with the utilization of the star sensor and GNSS sensor.

Broadcast Ephemeris Parameters Fitting for GEO Satellites Based on Coordinate Transformation

2011, 40(Sup.):  145-150. 

Asbtract ( )   HTML   PDF (2266KB) ( )  

Related Articles | Metrics

An introduction on broadcast ephemeris parameters fitting for GEO satellites based on coordinate transformation is presented. The formulas of the relationship between the new instantaneous orbital elements as well as their perturbation and that before coordinate transformation are derived, and influence of difference inertial coordinate (different X-Axes orientation or different rotation angle) is analyzed. Experiments for broadcast ephemeris parameters fitting from simulated GEO orbit data are conducted to analyze the impact of different rotation angular adopted on the fitted ephemeris parameters. Our analysis and experiments show that: first, the inclination angle of the orbit obtained by simplified coordinate transformation is not constant but subject to periodic variation. Second, the perturbation of inclination angle in original frame may be magnified and then absorbed by the perturbation of inclination angle and perigee in the new coordinate system, while the magnification varies from tens to thousands and sometime singularity happens. Third, the range of some fitted GEO broadcast ephemeris parameters such as “Mean Motion Difference From Computed Value” and “Rate of Right Ascension” gradually decrease as the rotation angle increases