全球定位系统

2020 Vol. 45, No. 2

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Development analysis of PNT-on-a-chip and Comprehensive PNT network management

JING Guifei

2020, 45(2): 1-6. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.001

[Abstract](448) [PDF 905KB](145)

Abstract:
For the construction of the Comprehensive PNT of ubiquitous navigation and location service, countries are exploring various kinds of navigation and positioning methods to supplement and enrich GNSS. PNT-on-a-Chip is an important direction. By analyzing the development trend of technology and application in the era of Internet-of-Things, this paper puts forward the concept of PNT-on-a-Chip, and analyzes that as an important means to realize ubiquitous space-time service, it will improve rapidly in function and integration with the continuous development of large-scale integrated circuit, and has the largest number and market demand due to its natural good integration ability with IOT chips. The development of Comprehensive PNT network management system assists the integration of PNT-on-a-chip to achieve high performance. In future, R＆D should be intensified in Integration of MEMS and high precision INS, support from Comprehensive PNT network management, and integration of multiple signals on-a-Chip, so as to realize market supply soon.

High-precise data processing and analysis of GPS ultra-short baseline and basenet

WU Shuguang, NIE Guigen, PENG Fengyou, HE Yuefan, WU Changsheng

2020, 45(2): 7-12. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.002

[Abstract](720) [PDF 649KB](192)

Abstract:
With the improvement of the application of surveying and mapping products such as GNSS receivers and electronic total stations, modern geographic information industry is continually growing and developing. As one of the important standards for surveying and mapping instrument calibration, the baseline and basenet has provided important basic support for the development of various aspects of society for a long time. This paper uses GAMIT／GLOBK software to process the newly established ultrashort baseline basenet in high-precision, including baseline processing and network adjustment. The surrounding IGS stations and the Crustal Movement Network of China (CMONOC) reference stations are comprehensively used, and three methods are used to process the data separately. Then different aspects including the normalized root mean square (NRMS) value, baseline repeatability and coordinate robustness after GPS network adjustment, we compared and analyzed the difference of these three methods. Results show that this ultra-short baseline basenet meets the specifications and design requirements. For similar GPS data processing from smallscale station networks, the hierarchical twostep method can be used to obtain a higher solution accuracy. This paper provides some useful experience for the calculation and analysis of high-precision GPS data from ultra-short baseline and basenet or similar regional station networks.

Design and performance evaluation of new signal waveform in eLoran system

LI Wanqing, LIU Zhongwei, LI Shifeng, YE Qinglin

2020, 45(2): 13-20. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.003

[Abstract](772) [PDF 2245KB](142)

Abstract:
As a backup system of satellite navigation system, the enhanced Loran navigation system is a vital development strategy for national PNT (Positioning, Navigation, Timing). At present, the signal of eLoran are vulnerable to cross interference and sky-wave interference, and the rate of transmitting data is low. Therefore we proposed two waveform improvement methods (attenuation-function-method and symmetric-waveform-method) and evaluated the performance of them based on standard Loran signal system. Experimental results show that the two methods can effectively shorten the duration of the waveform, accelerate the decline of the waveform, and reduce the signal transmitting power. The symmetrical-waveform-method can greatly reduce the duration of waveform, but this method will significantly change the spectrum characteristics of the original signal waveform. By contrast, the attenuation-function-method can ensure the spectrum performance of the signal to the greatest extent. Through comprehensive analysis, we think that the new waveform can effectively utilize time domain resources, which can spare time for extra signal transmitting and consequently raise the efficiency of data modulation.

Two-station cooperative precision positioning algorithm with additional baseline constraints

CHEN Wantong, SHANG Zhenghui, WANG Zhuqing

2020, 45(2): 21-29. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.004

[Abstract](278) [PDF 2675KB](56)

Abstract:
Traditional Precise Point Positioning (PPP) has many advantages such as high accuracy and easy operation. PPP usually uses the Kalman filtering (KF) to solve unknown parameters. However, the positioning performance depends on the accurate kinematic model and filtering initial value. The inaccurate kinematic model or initial filtering value will lead to filter performance degradation or even divergence. In order to solve this problem, this paper proposes a twostation cooperative PPP positioning method with additional baseline constraint information. The algorithm uses the direction information and length information of the baseline to modify the estimated position of the two stations. By reduces the error covariance matrix of the floating-point solution, the algorithm improves the accuracy of the floating-point solution. Further validation test based on real GPS data shows that results from baseline vector constraint PPP effectively be improved compared with the traditional PPP parameter estimation method.

Quality analysis of BDS／GPS engineering control network

ZHOU Jianying, CHEN Guoheng, CHEN Meisen

2020, 45(2): 30-36. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.005

[Abstract](490) [PDF 2418KB](73)

Abstract:
Aiming at the application problem of establishing engineering control network of BeiDou Navigation Satellite System (BDS).Taking a control network in Guangdong Province as an example, the indicators are compared with GPS from the quality of observation data, baseline calculation and adjustment accuracy, and differences in coordinate results, which verified the feasibility of the BDS system to establish an engineering control network. The results show that the number of BDS visible satellites is almost as same as GPS, and the accuracy of the BDS baseline solution and adjustment of is slightly lower than GPS as a whole, and it is relatively more obvious in the U direction. When the quality of the station data is good, the average BDS／GPS coordinate results have only millimeter differences, which can completely replace GPS as the final result; When the station data quality is poor, the coordinate results have average millimeter to centimeter differences, which can meet the requirements of general engineering control networks.

Application and accuracy analysis of P4-RTK in irregular deposit volume calculation

LIAN Zengzeng, ZHAO Xiaoming, LI Fei, Yang Fan

2020, 45(2): 37-43. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.006

[Abstract](405) [PDF 2655KB](56)

Abstract:
Aiming at the volumetric calculation of irregular deposit in the production enterprises, this paper uses the Dajiang P4-RTK drone to carry out a large irregular construction waste deposit in a production enterprise based on the high-precision image data acquisition. Meanwhile, GNSS-RTK had been used to measure the discrete point coordinates of the deposits surface. Using the acquired high-precision image data, the point cloud, DEM, DOM and the 3D model of the surface of the deposit are calculated. Finally, the deposit volumetric had been calculated. Compared with the results of the volume calculation of the discrete three-dimensional coordinate points measured by GNSS-RTK using the DTM method, the P4-RTK unmanned aerial vehicle-free image control technology can be used to calculate the irregular stack. And the volume can meet the requirements of actual production.

Single epoch three carrier ambiguity resolution for ground base positioning system

KUANG Yulong, WANG Ling, YUE Le

2020, 45(2): 44-48. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.007

[Abstract](429) [PDF 1311KB](67)

Abstract:
Ground Base Positioning System has poor geometric diversity due to fixed base station position, and that will cause problems in using LAMBDA to solve integer ambiguity. To solve this problem, self-differential two-way ranging technique has been proposed by using the two-way measurement to build a formula to eliminate clock errors. As it got rid of the time errors, we use the self-differential two-way ranging measurement as an alternative to double difference measurement, combining with three-carrier ambiguity resolution algorithm to solve the ambiguity. Experimental result on a pseudolite platform shows that this method can achieve fast single-epoch integer ambiguity resolution.

Application research of GM(1,1) model of power function transform in BDS satellite clock bias prediction

JIANG Yuxiang

2020, 45(2): 49-54. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.008

[Abstract](428) [PDF 1465KB](58)

Abstract:
Due to the high frequency, strong sensitivity of satellite clocks, and the extreme susceptibility to external influences, the observation data fluctuates greatly and the results have low accuracy.The power function transformation method is used to transform and preprocess the initial observation data to improve the smoothness of the observation data.Therefore, a GM (1,1) model based on power function transformation was proposed. The BDS satellite clock difference was used for interpolation and prediction, and the accuracy was verified. The experimental results show that the Lagrange interpolation method can meet the clock interpolation needs of high-precision BDS;The GM (1,1) model using power function transformation has effectively improved the accuracy compared to traditional models.And when the predicted values of the improved model and the traditional model are closer to the actual values,Then the improved GM (1,1) model of the power function has higher accuracy and stronger applicability. It has practical reference value for BDS satellite clock error prediction.

Research on GNSS-R sea surface wind field Information Inversion technology

LIU Yuanhua, HE Mengran, NIU Xinliang

2020, 45(2): 55-59. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.009

[Abstract](558) [PDF 1381KB](91)

Abstract:
Due to the influence of geometric factors, when using the spaceborne GNSS-R to retrieve the sea surface wind speed, the cross-section of the double-base radar obtained cannot be used directly to retrieve the wind speed. The influence of geometric factors on wind speed inversion is studied on the basis of analyzing the characteristics of GNSS sea surface reflection signals. After correcting the cross-sectional area and effective scattering area of the double-base radar, the reflected signal power of the corresponding reflection point is obtained. Finally, these obtained reflection signal parameters are verified by simulation.. The experimental results show that the root mean square error of sea surface wind speed inversion is 2.61 m／s, and the correlation between the inversion wind speed and the real wind speed is 0.75. The normalized double-base radar scattering power after correction can effectively retrieve the sea surface wind speed.

Effect of image control point layout on the accuracy of real-world modeling of small-scale irregular areas of UAVs

ZHANG Guangzu, WANG Chun, XU Yan, TAO Yu, WU Liang, SHENG Shuai

2020, 45(2): 60-67. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.010

[Abstract](248) [PDF 2013KB](78)

Abstract:
The layout and number of image control points have an important impact on the accuracy of real-world modeling. In this paper, a 0.25 km² irregular area in Linquan County, Fuyang City is selected as the experimental area, and two irregular verification areas (0.27 and 0.28 km²) are selected. The real-world model is constructed according to three different image control point layout methods: edge layout, edge plus a small center layout, and center layout. The characteristics of the influence of the number of image control points and the layout position on the accuracy of the model are compared and analyzed. The results show that: 1) The accuracy of the model can only be effectively guaranteed when the convex polygon surrounded by the image control point line contains the entire irregular measurement area. 2) Under the requirements of 1∶500 scale mapping accuracy, five image points are arranged at the edges as the best point layout method, which meets the modeling requirements of high efficiency, high precision and low cost. 3) In the case of ideal placement of image control points, increasing the number of layouts can not significantly improve the accuracy of the real-world model. Image control points should be arranged as needed.

Analysis of noise model of GPS reference stations in Yunnan area

GUAN Yahui, WANG Tan, HU Shunqiang, YANG Zhenyu

2020, 45(2): 68-73. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.011

[Abstract](357) [PDF 1851KB](65)

Abstract:
Taking the observation data of 27 GPS reference stations in Yunnan State Land Network at different time spans from 2011 to 2017 as examples, the Achievement and Bayesian Information Estimation Criterion (AIC／BIC) criterion is used to analyze the solution results. And so as to determine its optimal colored noise model. The results show that the optimal noise model for each coordinate component of the reference station at different time spans is mainly combination of white+flicker noise (WN+FN) and Power-law (PL) noise models. The optimal noise models of some reference stations in the north and vertical directions will change with the accumulation of observation time, and the proportion of PL models will decrease. While the proportion of WN+FN model will increase. When the time span is greater than 5a, the stability of the reference station noise model is significantly improved. As the accumulation time of the coordinate time series increases, the probability of the occurrence of unknown noise components increases accordingly.

Test and analysis of GDCORS multi satellite system positioning platform

DENG Sisheng, LIU Wenjian, HU Sibin

2020, 45(2): 74-79. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.012

[Abstract](395) [PDF 1640KB](76)

Abstract:
Ground based augmentation platform on compass was built from Guangdong Continuous Operational Reference System (GDCORS), and the positioning performance between the new and old platform had been tested. The results of RTK positioning are compared and analyzed from the aspects of internal accuracy， repeatability accuracy, external accuracy evaluation and initialization time. The Result indicate that the new platform can provide Network RTK service with high reliability and high accuracy,which can provide practical reference for GDCORS users to use the new／original platform.

GPS/MET localized water vapor conversion parameters study and analysis of space-time characteristics

MAO Yaping, LIU Haiyan, GAO Lei, WU Fengying, SHENG Tianchen

2020, 45(2): 80-84. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.013

[Abstract](323) [PDF 1394KB](58)

Abstract:
With the rapid development of the global positioning system, its application in the field of surveying and mapping has continued to increase. In the direction of GPS meteorology, we can calculate the water vapor conversion parameters through ground-based GPS technology to obtain the atmospheric precipitation. Using local corresponding water vapor conversion parameters can effectively improve the accuracy of GPS water vapor inversion. This paper uses the data from 12 sounding stations in Southwest China in 2015-2018 to calculate the annual, quarterly, monthly and daily water vapor conversion parameters in Southwest China, and realizes the localization of water vapor conversion parameters. The analysis shows that, within a certain range, the water vapor conversion parameter П gradually increases with the increase of the station height, and the temporal and spatial distribution of the water vapor conversion parameter Π in southwest China has obvious characteristics of climate distribution and latitude zonality.

Design and implementation of the BDS high-precise kinematic detection system

WANG Chenchen, XU Xueyong, WANG Qingtai, ZHOU Ye, SHI Jinjin

2020, 45(2): 85-90. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.014

[Abstract](401) [PDF 2010KB](84)

Abstract:
In order to detect the kinematic performances of BDS user equipment, a detection system are designed which can efficiently and automatically test the kinematic performances of BDS user equipment in real environments. It is named BDS High-Precision Kinematic detection system (BDHDS). This system uses Iveco as a carrier and a high-precision inertial integrated navigation system as a test datum. It consists of professional test equipment such as satellite signal acquisition and playback, satellite signal repeaters, shielding boxes, and monitoring equipment. It also develops automated testing software based on JavaScript. The BDHDS has such functions as satellite signal acquisition, playback, real-time display of test results, automatic generation of test reports, and recording of test processes. In order to test the effectiveness of BDHDS, two types of BDS user equipments are selected for static, low-speed kinematic and high-speed kinematic tests. The test results show that the BDHDS can intuitively and efficiently evaluate the kinematic performance of BDS user equipment.

Construction of new generation BDS high precision datum service platform in Qinghai

LI Yanlong, ZHANG Shengpeng, ZHANG Yongying

2020, 45(2): 91-97. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.015

[Abstract](308) [PDF 2257KB](60)

Abstract:
A new generation of BDS high-precision datum service platform of Qinghai Province is introduced in this paper. The platform has functions such as user management, data processing, spatial environment monitoring, and high-precision positioning. This platform can satisfy the diverse needs of various users, and follows the construction principles of standardized management, strong scalability, good reality, good practicability, strong security, and forward-looking.

BDS multipath errors reducing method based on EMD-LSTM coupled prediction model

XU Xiaowen, TAO Yuan

2020, 45(2): 98-104. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.016

[Abstract](411) [PDF 2057KB](74)

Abstract:
The multipath errors in short baseline measurement of BeiDou Navigation Satellite System (BDS) were the main errors affecting positioning accuracy. Aiming at the nonlinearity of multipath errors and the non-stationarity of coordinate series, a coupled prediction model of EMD-LSTM was proposed by combining empirical mode decomposition (EMD) with long short-term memory (LSTM) to predict multipath errors and weaken the influence of multipath errors. The experimental results show that the EMD-LSTM coupled prediction model can effectively reduce the multipath errors, and the E, N,and U directions were respectively improved by 22％, 36％, and 40％.

Research on the location algorithm of android mobile phone based on extended Kalman filter

YUAN Yang, ZHOU Ruyan, ZHANG Yun

2020, 45(2): 105-111. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.017

[Abstract](313) [PDF 2187KB](107)

Abstract:
At present, there are more and more applications for mobile phone positioning, and many APPs (Applications) in the market will use the positioning function. However, most APPs use traditional positioning algorithms and can not meet the needs of people to obtain high-precision geographic location information in real time. At present, there is less research on the positioning method of the mobile phone's GPS chip raw data. Therefore, this paper mainly studies the feasibility and positioning algorithm of using the mobile phone's GPS raw data. Using the application program interface provided by the Android 7.0 system to obtain the raw data parameters of the GPS chip, according to the speed characteristics of the practical scene of the mobile phone, the static Kalman filtering for static scenes and the dynamic Kalman filtering positioning algorithm for low-speed scenes were designed and implemented respectively. Through static experiments as well as electric vehicle experiments and walking experiments, the experimental results show that compared with traditional positioning algorithms, the static Kalman filtering and dynamic Kalman filtering positioning algorithms designed in this paper have better positioning results and are closer to the actual walking route. It proves the feasibility of using mobile phone GPS raw data to locate, and also proves that the designed Kalman filter algorithm can improve the positioning accuracy. The research results of this paper provide theoretical basis for realizing static and dynamic highprecision mobile phone positioning algorithms.

Study on energy saving of hybrid power ships based on BDS

WANG Yongding, CHENG Xiangyu

2020, 45(2): 112-118. doi: DOI:10.13442/j.gnss.1008-9268.2020.02.018

[Abstract](315) [PDF 2463KB](51)

Abstract:
This paper proposes a hybrid electric propulsion system based on BDS. The two main power sources of the diesel engine and the electric motor adopt PTH driving mode. The fuel and electric energy are used to provide propulsion power. Different navigation areas and speed can be selected according to BDS Power source output. After fuel economy and benefit analysis, compared with the traditional propulsion system, the application of BDS-based hybrid propulsion system reduces the operating cost of official ships by 26％, and the increased initial construction investment cost of tana business ship can be recovered within 3 years; Comprehensive fuel saving of 15％ to 20％, the initial construction investment cost can be recovered within 4 years through the fuel saving method. The hybrid system based on BDS can increase propulsion redundancy, improve ship safety, and has good effects of energy saving and emission reduction and saving operating costs.