TY - GEN
T1 - Cycle slip detection for triple-frequency GPS observations under ionospheric scintillation
AU - Zhao, Dongsheng
AU - Roberts, Gethin Wyn
AU - Hancock, Craig M.
AU - Lau, Lawrence
AU - Bai, Ruibin
N1 - Funding Information:
Monitoring stations from the network were deployed in the context of the Projects CIGALA and CALIBRA, both funded by the European Commission (EC) in the framework of the FP7-GALILEO-2009-GSA and FP7–GALILEO–2011–GSA–1a, respectively, and FAPESP Project Number 06/04008-2. This work was carried out at the International Doctoral Innovation Center (IDIC). The authors acknowledge the financial support from Ningbo Education Bureau, Ningbo Science and Technology Bureau, China’s MOST and The University of Nottingham. The work is also partially supported by the Ningbo Science and Technology Bureau as part of the International Academy for the Marine Economy and Technology (IAMET) Project “Structural Health Monitoring of Infrastructure in the Logistics Cycle” (2014A35008), and Zhejiang Provincial Natural Science Foundation of China under Grant No. LY16D040001.
Publisher Copyright:
Copyright © (2017) by Institute of Navigation All rights reserved.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - Correctly detecting cycle slips is essential for the application of the GPS carrier phase observations in precise positioning. However it is still a challenge to detect small cycle slips caused by ionospheric scintillation. Severe ionospheric scintillation can directly affect the noise level in code and phase measurements, reducing the accuracy in detecting cycle slips. Thus, this research propose a novel detection method on the basis of triple-frequency observations and a Hatch-Melbourne-Wübena (HMW) combination to detect the cycle slips as a result of ionospheric scintillation. By setting the coefficients of the code measurements in HMW combination to float numbers and introducing the extra-wide-lane signal (0, 1, -1), the proposed method can minimize the effect of the measurement noise, especially the noise of the code measurement, and eliminate the ionospheric delay. The time-differenced ambiguity is used as the detection value. In order to determine a suitable threshold for both normal cases and ionospheric scintillation cases, two methods are reviewed. These are the sample variation method and the Generalized AutoRegressive Conditional Heteroscedasticity (GARCH) method. During ionospheric scintillation, the former method may have a great number of false alarms, while the latter method may ignore small cycle slips. This paper proposes a GARCH with partly fixed threshold method. In this method, the threshold is estimated by the GARCH method, while the threshold will be fixed to 1 cycle when the value provided by GARCH is larger than 1 cycle. Thus this threshold can take into account all sizes of cycle slips in both observation conditions. The proposed method is tested with triple-frequency data observed from a satellite whose data is affected by scintillation during a period with high elevation angle. Compared to the sample variation method and the GARCH method, the threshold estimated by the GARCH with partly fixed threshold method can detect all the possible cycle slips, including both artificially added and real original ones. All the slips are removed in the results of GARCH with partly fixed method, while some small slips are still left when using the other two methods.
AB - Correctly detecting cycle slips is essential for the application of the GPS carrier phase observations in precise positioning. However it is still a challenge to detect small cycle slips caused by ionospheric scintillation. Severe ionospheric scintillation can directly affect the noise level in code and phase measurements, reducing the accuracy in detecting cycle slips. Thus, this research propose a novel detection method on the basis of triple-frequency observations and a Hatch-Melbourne-Wübena (HMW) combination to detect the cycle slips as a result of ionospheric scintillation. By setting the coefficients of the code measurements in HMW combination to float numbers and introducing the extra-wide-lane signal (0, 1, -1), the proposed method can minimize the effect of the measurement noise, especially the noise of the code measurement, and eliminate the ionospheric delay. The time-differenced ambiguity is used as the detection value. In order to determine a suitable threshold for both normal cases and ionospheric scintillation cases, two methods are reviewed. These are the sample variation method and the Generalized AutoRegressive Conditional Heteroscedasticity (GARCH) method. During ionospheric scintillation, the former method may have a great number of false alarms, while the latter method may ignore small cycle slips. This paper proposes a GARCH with partly fixed threshold method. In this method, the threshold is estimated by the GARCH method, while the threshold will be fixed to 1 cycle when the value provided by GARCH is larger than 1 cycle. Thus this threshold can take into account all sizes of cycle slips in both observation conditions. The proposed method is tested with triple-frequency data observed from a satellite whose data is affected by scintillation during a period with high elevation angle. Compared to the sample variation method and the GARCH method, the threshold estimated by the GARCH with partly fixed threshold method can detect all the possible cycle slips, including both artificially added and real original ones. All the slips are removed in the results of GARCH with partly fixed method, while some small slips are still left when using the other two methods.
UR - http://www.scopus.com/inward/record.url?scp=85047979956&partnerID=8YFLogxK
U2 - 10.33012/2017.15326
DO - 10.33012/2017.15326
M3 - Conference article published in proceeding or book
AN - SCOPUS:85047979956
T3 - 30th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2017
SP - 4046
EP - 4054
BT - 30th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2017
PB - Institute of Navigation
T2 - 30th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2017
Y2 - 25 September 2017 through 29 September 2017
ER -