Abstract
GNSS observation outage occurs inevitably in various situations, e.g., automobile driving in urban environments. Although the ambiguity resolution (AR) significantly shortens the initialization time of precise point positioning (PPP), frequent re-initialization of PPP AR may be needed due to outages. The inertial navigation system (INS) can be used for acquiring highly accurate position information during GNSS outages. In the previous studies, the GPS PPP/INS with the ambiguity resolution model is proposed, and the experimental results confirm that the INS could facilitate the re-fixing of the interrupted GNSS ambiguity. Multiple GNSS can also be used to shorten the PPP convergence time. We compare the contribution of multi-GNSS and the INS to the ambiguity re-fixing during GNSS outage. Results show that the multi-GNSS, e.g., Galileo, GLONASS and BDS, without ambiguity resolution has little contribution to the re-fixing of GPS ambiguity in PPP/INS, while INS can provide highly accurate positioning results during the GNSS outages. The higher the accuracy of the predicted INS positioning, the lower the contribution of multi-GNSS to the re-fixing of the ambiguity in the PPP/INS. The finding is verified by a theoretical analysis, carborne experiment and shipborne experiment. Experiment results show that the re-fixing time is 43 s for GPS PPP and MEMS-grade INS coupled system in GNSS outage of 1 s. The re-fixing time of GPS is slightly changed when adding the multi-GNSS, e.g., Galileo, GLONASS and BDS, without the ambiguity resolution. However, by performing ambiguity resolution to the added GNSS system, the re-fixing time of PPP/INS is significantly reduced from 43 to 4 s. The reason is that, although the multi-GNSS provides little improvement on the accuracy of the ambiguity, it enlarges the number of the ambiguity parameter. The possibility of ambiguity resolution is increased due to the large candidate set of the ambiguity, which reduces re-fixing time.
Similar content being viewed by others
Data Availability
The data that support the findings of this study are available from the corresponding author upon reasonable request.
References
Abd Rabbou M, El-Rabbany A (2015) Tightly coupled integration of GPS precise point positioning and MEMS-based inertial systems. GPS Solut 19(4):601–609
Du S, Gao Y (2010) Integration of PPP GPS and low cost IMU. In: The 2010 Canadian geomatics conference and symposium of commission I, ISPRS, Calgary, Alberta, Canada, 15–18 June
Du Z, Chai H, Xiao G, Xiang M, Yin X, Shi M (2020a) The realization and evaluation of PPP ambiguity resolution with INS aiding in marine survey. Mar Geodesy. https://doi.org/10.1080/01490419.2020.1852986
Du Z, Chai H, Xiao G, Wang M, Yin X, Chong Y (2020b) A method for undifferenced and uncombined PPP ambiguity resolution based on IF FCB. Adv Space Res 66(12):2888–2899
Gao Z, Zhang H, Ge M, Niu X, Shen W, Wickert J, Schuh H (2017) Tightly coupled integration of multi-GNSS PPP and MEMS inertial measurement unit data. GPS Solut 21(2):377–391
Ge M, Gendt G, Rothacher M, Shi C, Liu J (2008) Resolution of GPS carrier-phase ambiguities in precise point positioning (PPP) with daily observations. J Geod 82(7):389–399
Geng J, Guo J, Chang H, Li X (2019) Toward global instantaneous decimeter-level positioning using tightly coupled multi-constellation and multi-frequency GNSS. J Geod 93(7):977–991
Groves PD (2008) Principles of GNSS, inertial, and multisensory integrated navigation systems. Artech House, London
Gu S, Lou Y, Shi C et al (2015) BeiDou phase bias estimation and its application in precise point positioning with triple-frequency observable. J Geod 89(10):979–992
Hatch Ron (1982) The Synergism of GPS Code and Carrier Measurements. Proceedings of the Third International Symposium on Satellite Doppler Positioning at Physical Sciences Laboratory of New Mexico State University, Feb. 8–12, vol 2, pp 1213–1231
Kleusberg A, Teunissen PJG (1996) GPS for Geodesy. Lecture Notes in earth science. Springer, Berlin
Laurichesse D, Mercier F, Berthias JP, Bijac J (2008) Real time zero-difference ambiguities fixing and absolute RTK. In: Proceedings of ION national technical meeting, San Diego
Li B, Shen Y (2010) Global navigation satellite system ambiguity resolution with constraints from normal equations. J Surv Eng 136(2):63–71
Li P, Zhang X (2015) Precise point positioning with partial ambiguity fixing. Sensors 15(6):13627–13643
Li P, Zhang X, Ren X, Zuo X, Pan Y (2016) Generating GPS satellite fractional cycle bias for ambiguity-fixed precise point positioning. GPS Solut 20(4):771–782
Li P, Zhang X, Ge M, Harald S (2018) Three-frequency BDS precise point positioning ambiguity resolution based on raw observables. J Geod 5:1–13
Liu S, Sun F, Zhang L, Li W, Zhu X (2016) Tight integration of ambiguity-fixed PPP and INS: model description and initial results. GPS Solut 20(1):39–49
Li X, Ge M, Dai X, Ren X, Fritsche M, Wickert J, Schuh H (2015) Accuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo. J Geod 89(6):607–635
Li X, Ge M, Zhang H, Zhang H, Wickert J (2013) A method for improving uncalibrated phase delay estimation and ambiguity-fixing in real-time precise point positioning. J Geod 87(5):405–416
Li X, Zhang X (2012) Improving the estimation of uncalibrated fractional phase offsets for PPP ambiguity resolution. J Navig 65(3):513–529
Petovello MG, Cannon ME, Lachapelle G (2004) Benefits of using a tactical-grade IMU for high-accuracy positioning. Navigation 51(1):1–12
Shi J, Gao Y (2014) A comparison of three PPP integer ambiguity resolution methods. GPS Solut 18(4):519–528
Teunissen PJG (1995) The least-squares ambiguity decorrelation adjustment a method for fast GPS integer ambiguity estimation. J Geod 70(1–2):65–82
Teunissen PJG, Odijk D, Zhang B (2010) PPP-RTK: Results of CORS network-based PPP with integer ambiguity resolution. J Aeron Astron Aviat 42(4):223–230
Wang J, Huang G, Yang Y, Zhang Q, Gao Y, Xiao G (2019) FCB estimation with three different PPP models: Equivalence analysis and experiment tests. GPS Solut 23(4):93
Xiao G, Li P, Sui L, Heck B, Schuh H (2018a) Estimating and assessing Galileo satellite fractional cycle bias for PPP ambiguity resolution. GPS Solut 23(1):3–10
Xiao G, Sui L, Heck B, Zeng T, Tian Y (2018b) Estimating satellite phase fractional cycle biases based on Kalman filter. GPS Solut 22(3):1–12
Zhang X, Li P (2013) Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale. J Geod 87(6):579–589
Zhang X, Zhu F, Tao X, Duan R (2017) New optimal smoothing scheme for improving relative and absolute accuracy of tightly coupled GNSS/SINS integration. GPS Solut 21(3):861–872
Zhang X, Zhu F, Zhang Y, Freeshah M, Zhou W (2019) The improvement in integer ambiguity resolution with INS aiding for kinematic precise point positioning. J Geod 93(7):993–1010
Zhang Y, Gao Y (2008) Integration of INS and un-differenced GPS measurements for precise position and attitude determination. J Navig 61(1):87–97
Acknowledgements
We are grateful to the IGS-MGEX and GFZ for providing the GNSS data and products. This work was partly supported by the National Natural Science Foundation of China (Grants Nos. 42074014, 41604013 and 41904039).
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Du, Z., Chai, H., Xiao, G. et al. Analyzing the contributions of multi-GNSS and INS to the PPP-AR outage re-fixing. GPS Solut 25, 81 (2021). https://doi.org/10.1007/s10291-021-01121-2
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10291-021-01121-2