Performance Evaluation of BDS/GPS Combined Single Point Positioning with Low-cost Single-Frequency Receiver

Abstract. This paper proposes a new mathematical method of ionospheric delay estimation in single point positioning (SPP) using a single-frequency receiver. The proposed approach focuses on the ΔVTEC component estimation (MSPPwithdVTEC) with the assumption of an initial and constant value equal to 5 in any observed epoch. The principal purpose of the study is to examine the reliability of this approach to become independent from the external data in the ionospheric correction calculation process. To verify the MSPPwithdVTEC, the SPP with the Klobuchar algorithm was employed as a reference model, utilizing the coefficients from the navigation message. Moreover, to specify the level of precision of the MSPPwithdVTEC, the SPP with the IGS TEC map was adopted for comparison as the high-quality product in the ionospheric delay determination. To perform the computational tests, real code data was involved from three different localizations in Scandinavia using two parallel days. The criterion were the ionospheric changes depending on geodetic latitude. Referring to the Klobuchar model, the MSPPwithdVTEC obtained a significant improvement of 15–25 % in the final SPP solutions. For the SPP approach employing the IGS TEC map and for the MSPPwithdVTEC, the difference in error reduction was not significant, and it did not exceed 1.0 % for the IGS TEC map. Therefore, the MSPPwithdVTEC can be assessed as an accurate SPP method based on error reduction value, close to the SPP approach with the IGS TEC map. The main advantage of the proposed approach is that it does not need external data.

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Benefit of Sparse Reference Network in BDS Single Point Positioning with Single-Frequency Measurements

Journal of Navigation ◽

10.1017/s0373463317000765 ◽

2017 ◽

Vol 71 (2) ◽

pp. 403-418 ◽

Cited By ~ 1

Author(s):

Xiaomin Luo ◽

Yidong Lou ◽

Xiaopeng Gong ◽

Shengfeng Gu ◽

Biyan Chen

Keyword(s):

Single Point ◽

Elevation Angle ◽

Systematic Errors ◽

Base Stations ◽

Single Frequency ◽

Reference Network ◽

Average Technique ◽

Single Point Positioning ◽

Point Positioning ◽

Residual Errors

The current positioning accuracy of the BeiDou Navigation Satellite System (BDS) Single Point Positioning (SPP) with code measurement is in the order of several metres due to systematic errors. To further reduce the systematic errors in SPP, this contribution develops a new strategy to BDS SPP with a sparse reference network, named Augmented SPP (A-SPP). In this method, the Combined Residual Errors (CRE) products of BDS B1I measurement are integrated with three optional base stations that are close to the rover station. Based on the Satellite Elevation Angle Weighted (SEAW) average technique, the code residual errors of each BDS satellite observed by the rover station can be acquired epoch-by-epoch. Finally, the corrected code observations for the rover station can be utilised to achieve an A-SPP solution. The validation of this method is confirmed by both static and kinematic tests. Results clearly show that the accuracies of the A-SPP solution for horizontal and vertical directions are better than 0·5 m and 1·0 m. This study suggests that the proposed A-SPP solution is a good option for single-frequency GNSS users to improve their positioning performance.

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Benefit of the NeQuick Galileo Version in GNSS Single-Point Positioning

International Journal of Navigation and Observation ◽

10.1155/2013/302947 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 19

Author(s):

Antonio Angrisano ◽

Salvatore Gaglione ◽

Ciro Gioia ◽

Marco Massaro ◽

Salvatore Troisi

Keyword(s):

Single Point ◽

Three Dimensional ◽

Signal Propagation ◽

Maximum Error ◽

Theoretical Physics ◽

Single Frequency ◽

Ionospheric Model ◽

Single Point Positioning ◽

Complex Architectures ◽

Point Positioning

The GNSS measurements are strongly affected by ionospheric effects, due to the signal propagation through ionosphere; these effects could severely degrade the position; hence, a model to limit or remove the ionospheric error is necessary. The use of several techniques (DGPS, SBAS, and GBAS) reduces the ionospheric effect, but implies the use of expensive devices and/or complex architectures necessary to meet strong requirements in terms of accuracy and reliability for safety critical application. The cheapest and most widespread GNSS devices are single frequency stand-alone receivers able to partially correct this kind of error using suitable models. These algorithms compute the ionospheric delay starting from ionospheric model, which uses parameters broadcast within the navigation messages. NeQuick is a three-dimensional and time-dependent ionospheric model adopted by Galileo, the European GNSS, and developed by International Centre for Theoretical Physics (ICTP) together with Institute for Geophysics, Astrophysics, and Meteorology of the University of Graz. The aim of this paper is the performance assessment in single point positioning of the NeQuick Galileo version provided by ESA and the comparison with respect to the Klobuchar model used for GPS; the analysis is performed in position domain and the errors are examined in terms of RMS and maximum error for the horizontal and vertical components. A deep analysis is also provided for the application of the exanimated model in the first possible Galileo only position fix.

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Evaluation of Quad-Constellation GNSS Precise Point Positioning in Egypt

Artificial Satellites ◽

10.1515/arsa-2017-0002 ◽

2017 ◽

Vol 52 (1) ◽

pp. 9-18

Author(s):

Emad El Manaily ◽

Mahmoud Abd Rabbou ◽

Adel El-Shazly ◽

Moustafa Baraka

Keyword(s):

Urban Areas ◽

Precise Point Positioning ◽

Low Cost ◽

Single Point ◽

Convergence Time ◽

Reference Station ◽

Single Frequency ◽

Major Drawback ◽

Positioning Accuracy ◽

Point Positioning

Abstract Commonly, relative GPS positioning technique is used in Egypt for precise positioning applications. However, the requirement of a reference station is usually problematic for some applications as it limits the operational range of the system and increases the system cost and complexity On the other hand; the single point positioning is traditionally used for low accuracy applications such as land vehicle navigation with positioning accuracy up to 10 meters in some scenarios which caused navigation problems especially in downtown areas. Recently, high positioning accuracy can be obtained through Precise Point Positioning (PPP) technique in which only once GNSS receiver is used. However, the major drawback of PPP is the long convergence time to reach to the surveying grade accuracy compared to the existing relative techniques. Moreover, the PPP accuracy is significantly degraded due to shortage in satellite availability in urban areas. To overcome these limitations, the quad constellation GNSS systems namely; GPS.GLONASS, Galileo and BeiDou can be combined to increase the satellite availability and enhance the satellite geometry which in turn reduces the convergence time. In Egypt, at the moment, the signals of both Galileo and BeiDou could be logged with limited number of satellites up to four and six satellites for both Systems respectively. In this paper, we investigated the performance of the Quad-GNSS positioning in both dual- and single-frequency ionosphere free PPP modes for both high accurate and low cost navigation application, respectively. The performance of the developed PPP models will be investigated through GNSS data sets collected at three Egyptian cities namely, Cairo, Alexandria and Aswan.

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