Real-time carrier phase multipath detection based on dual-frequency C/N0 data

Zhang, Zhetao; Li, Bofeng; Gao, Yang; Shen, Yunzhong

doi:10.1007/s10291-018-0799-6

Cited by 76 publications

(26 citation statements)

References 39 publications

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“…Compared with BDS, the SNR values at two different GPS frequencies are quite different, but the SNR values at two BDS frequencies are almost the same from Fig. 8 and Table Ⅵ. (c) It can also be observed from the Table V and Table VI, that different receiver types correspond to different SNRs of the two systems, reflecting the correlation between the SNR and the receiver type [28]. The main reason for this phenomenon is that the SNR itself has a certain relationship with the hardware equipment.…”

Section: (3) Satellite Elevation Angle and Snrmentioning

confidence: 84%

Positioning Performance Comparison Between GPS and BDS With Data Recorded at Four MGEX Stations

et al. 2020

IEEE Access

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In December 2018, the BeiDou III (BDS-3) basic system was completed and began to provide global services. along with the BeiDou second-generation satellite navigation system (BDS-2) and Beidou first-generation satellite navigation system (BDS-1), the whole BDS has advantages in the number of satellites, coverage, and positioning performance. This paper focuses on the comprehensive evaluation of BDS by comparing the data quality and positioning performance of BDS and those of Global Positioning System (GPS). The performance evaluation and comparison is based on 7-day observation data collected in April 2020 at three different geographical locations in China. The experimental results show that GPS and BDS have a number of significant differences. The number of visible satellites in BDS is twice that of GPS in China. The SNRs of GPS signals of different frequencies are quite different from each other, while BDS signals of different frequencies have very similar SNR observations. BDS-3 and GPS achieve similar positioning performance in terms of internal positional error, external positional accuracy, coordinate time series and Dilution of Precision (DOP). The mean and STD of the internal positional error of GPS and BDS are less than 3 m, while the external positional accuracy of both systems is better than 5 m. It is also observed that the overall variation in coordinate time series of the three coordinates of BDS is slightly smaller than that of GPS. In addition, the BDS DOP is basically equivalent to the GPS DOP, although occasionally the former is greater than the latter. The results are largely contrary to most of the results associated with performance comparison between BDS and GPS reported in the literature. The main reason would be that the number of visible satellites, observations and DOP of BDS are superior to GPS and single BDS-1, BDS-2 or BDS-3 in China. We believe that the development of BDS is still in progress and BDS is making continuous performance enhancement.

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Section: (3) Satellite Elevation Angle and Snrmentioning

confidence: 84%

Positioning Performance Comparison Between GPS and BDS With Data Recorded at Four MGEX Stations

et al. 2020

IEEE Access

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“…where ‫ܣ‬ ௗ and ‫ܣ‬ indicate the amplitudes of direct (LOS) and reflected (NLOS) signals respectively, ∅ denotes the phase and ∆∅ denotes the phase shift in the NLOS signal [10,11]. The amplitude composite signal ( ܵ ெ ) and phase shift can be estimated as:…”

Section: Methodsmentioning

confidence: 99%

Complexity and Limitations of GNSS Signal Reception in Highly Obstructed Enviroments

Hussain

Akhtar

Khand

et al. 2021

Eng. Technol. Appl. Sci. Res.

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Multipath (MP) and/or Non Line-Of-Sight (NLOS) reception remains a potential vulnerability to satellite-based positioning and navigation systems in high multipath environments, such as an urban canyon. In such an environment, satellite signals are reflected, scattered or faded, and sometimes completely blocked by roofs and walls of high-rise buildings, fly-over bridges, complex road structures, etc. making positioning and navigation information inaccurate, unreliable, and largely unavailable. The magnitude of the positioning error depends on the satellite visibility, geometric distribution of satellites in the sky, and received signal quality and characteristics. The quality of the received signal (i.e. its statistical characteristics) can significantly vary in different environments and these variations can reflect in signal strength or power, range measurements (i.e. path delay and phase difference), and frequency, all of which distort the correlation curve between the received signal and receiver-generated replicas, resulting in range errors of tens of meters. Therefore, in order to meet stringent requirements defined for the Standard Positioning Service (SPS), the characterization of distortions that could significantly affect a Global Navigation Satellite System (GNSS) signal is essentially important. The scope of this paper is to detect possible imperfections/deviations in the GNSS signal characteristics that can occur due to MP or NLOS reception and analyze its effects. For this purpose, analysis of fading patterns in received signal strength (i.e. Carrier-to-Noise Ratio and strength fluctuations) is carried out in both clear LOS and high MP environment and then its impact on satellite lock state (i.e. tracking) is assessed. Furthermore, phase fluctuations and range residuals are computed to analyze the effects of path delays. The results show that significant variations can occur in GNSS signal characteristics in the MP environment that may result in loss of lock event and inaccurate/faulty range measurements.

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“…Therefore, the systematic error and time-variant characteristics of code multipath can be analyzed by using the MP value. Since MP combinations describe the peak-to-peak behavior of the code multipath, their variations can catch the magnitude of multipath to some extent [17]. Note that the MP amplitude is proportional to that of the code multipath error, and the C/N 0 difference amplitude is proportional to that of the carrier phase multipath error, so their amplitudes of oscillation do not correspond [16].…”

Section: Multipath Detection Based On C/n 0 Differencementioning

confidence: 99%

“…This method is suitable for geodetic applications and shows good performance in the detection of short-delay multipath and diffraction based on three-frequency C/N 0 measurements. Subsequently, Zhang et al [17] extended the idea to GPS dual-frequency receivers. Nevertheless, the classic method actually falls into a statistical trap.…”

Section: Introductionmentioning

confidence: 99%

Robust Statistical Detection of GNSS Multipath Using Inter-Frequency C/N0 Differences

et al. 2020

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Multipath detection and mitigation are crucial issues for global navigation satellite system (GNSS) high-precision positioning. The multi-frequency carrier power-to-noise density ratio (C/N0)-based multipath detection technique has achieved good results in real-time static and low-dynamic applications, and shown better practicability because of the low computational load and the requirement for little additional hardware. However, the classic multipath detection method based on inter-frequency C/N0 differences directly employs the 3σ rule to determine the threshold without considering the distribution of detection statistics and their variation characteristics with elevation angle, and ignores the interference of outliers to the reference functions. A robust multipath detection method is proposed in this paper. The reference functions of C/N0 differences are fitted using least absolute deviation (LAD) to obtain more accurate nominal values. According to the skew characteristics of the detection statistics, a medcouple (MC)-based adjusted boxplot is employed to determine the threshold. The performance of the new detection method is verified in the multipath environments. The experimental results show that compared with the classic method, the new multipath detector has strong robustness and can respond more accurately to large changes in multipath (MP) combination values at most elevation angles. It is sensitive to short-delay multipath and diffraction, and is an important supplement to multipath detection techniques.

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Real-time carrier phase multipath detection based on dual-frequency C/N0 data

Cited by 76 publications

References 39 publications

Positioning Performance Comparison Between GPS and BDS With Data Recorded at Four MGEX Stations

Positioning Performance Comparison Between GPS and BDS With Data Recorded at Four MGEX Stations

Complexity and Limitations of GNSS Signal Reception in Highly Obstructed Enviroments

Robust Statistical Detection of GNSS Multipath Using Inter-Frequency C/N0 Differences

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