Tight integration of ambiguity-fixed PPP and INS: model description and initial results

Liu, Shuai; Sun, Fuping; Zhang, Lundong; Li, Wanli; Zhu, Xinhui

doi:10.1007/s10291-015-0464-2

Cited by 53 publications

(28 citation statements)

References 20 publications

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“…However, the high-accuracy INS is expensive, and the error will accumulate over time [1]. It often relies on external auxiliary information for correction [2,3]. In the early stages of the GPS (Global Positioning System) system construction, some people put forward the idea of using GPS for attitude determination.…”

Section: Introductionmentioning

confidence: 99%

A Novel GNSS Attitude Determination Method Based on Primary Baseline Switching for A Multi-Antenna Platform

et al. 2020

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The global navigation satellite system (GNSS)-based attitude determination system has attracted more and more attention with the advantages of having simplified algorithms, a low price and errors that do not accumulate over time. However, GNSS signals may have poor quality or lose lock in some epochs with the influence of signal fading and the multipath effect. When the direct attitude determination method is applied, the primary baseline may not be available (ambiguity is not fixed), leading to the inability of attitude determination. With the gradual popularization of low-cost receivers, making full use of spatial redundancy information of multiple antennas brings new ideas to the GNSS-based attitude determination method. In this paper, an attitude angle conversion algorithm, selecting an arbitrary baseline as the primary baseline, is derived. A multi-antenna attitude determination method based on primary baseline switching is proposed, which is performed on a self-designed embedded software and hardware platform. The proposed method can increase the valid epoch proportion and attitude information. In the land vehicle test, reference results output from a high-accuracy integrated navigation system were used to evaluate the accuracy and reliability. The results indicate that the proposed method is correct and feasible. The valid epoch proportion is increased by 16.2%, which can effectively improve the availability of attitude determination. The RMS of the heading, pitch and roll angles are 0.52°, 1.25° and 1.16°.

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Section: Introductionmentioning

confidence: 99%

A Novel GNSS Attitude Determination Method Based on Primary Baseline Switching for A Multi-Antenna Platform

et al. 2020

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“…This method is mostly used in the precise point positioning (PPP)/INS tightly coupled system. The INS information is used to assist in PPP ambiguity resolution, which can effectively improve the speed of re-fixing the ambiguity after losing lock, but the initialization time is still long [27][28][29][30]. To improve the reliability of the RTK algorithm, Dorn et al introduced single-difference ambiguity into the state equation to achieve high-precision positioning results, but it also introduced receiver clock bias and clock drift [31].…”

Section: Introductionmentioning

confidence: 99%

A Novel Ambiguity Parameter Estimation and Elimination Strategy for GNSS/INS Tightly Coupled Integration

et al. 2020

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The estimation of ambiguity in the global navigation satellite system/inertial navigation system (GNSS/INS) tightly coupled system is a key issue for GNSS/INS precise navigation positioning. Only when the ambiguity is solved correctly can the integrated navigation system obtain high-precision positioning results. Aiming at the problem of ambiguity parameter estimation in GNSS/INS tightly coupled system, a new strategy for ambiguity parameter estimation and elimination is proposed in this paper. Here, the ambiguity parameter is first added to the state equations of GNSS/INS in the estimation process. Then, the strategy of eliminating the parameter is used to improve efficiency. A residual test is carried out based on introducing the ambiguity parameter, thereby reducing or avoiding its influence on the filtering estimation process. Two groups of experiments were carried out and compared with GNSS positioning results. The results showed that, in the open sky observation environment, the positioning accuracy of the GNSS/INS tightly coupled method proposed in this paper was within 5 cm, and the ambiguity fixed rate was more than 97%, which is basically consistent. In a GNSS-denied environment, the positioning accuracy of the GNSS/INS tightly coupled method proposed in this paper was obviously better than that of GNSS, and the positioning accuracy in X, Y, and Z directions was improved by 82.46%, 78.87%, and 79.67%, respectively. The fixed rate of ambiguity increased from 73% to 78.57%. Therefore, in a GNSS-challenged environment, the novel strategy of the GNSS/INS tightly coupled system has higher ambiguity fixed rate and significantly improves positioning accuracy and continuity.

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“…Liu realized GPS PPP ambiguity fixed solution and PPP/INS tight coupling model of ambiguity fixed solution by using integer phase clock products and inter satellite single difference model. The results showed that the positioning accuracy could reach centimeter level after ambiguity fixed, the velocity and attitude accuracy were equivalent to DGNSS/INS combination accuracy, and INS could speed up the re-fixed time of PPP under the condition of poor signal [24]. Han improved the PPP/INS tight coupling algorithm by using the prior information constraint of tropospheric delay, and the positioning accuracy was improved to a certain extent [25].…”

Section: Introductionmentioning

confidence: 99%

BDS PPP/INS Tight Coupling Method Based on Non-Holonomic Constraint and Zero Velocity Update

Sun

Yang

2020

IEEE Access

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According to the problem that the positioning error increased with the increase of navigation time in the environment of complete lack of satellite signals such as viaduct and tunnel, the precise point positioning (PPP) / inertial navigation system (INS) tight coupled continuous positioning with nonholonomic constraint (NHC) and zero velocity update (ZUPT) in BeiDou navigation satellite system (BDS) was proposed. Firstly, the ionospheric composite model was analyzed from the aspects of observation equation, parameter estimation, fuzziness, degree of freedom and noise. The BDS PPP dynamic positioning model of ionospheric composite was established, and the errors that affect the positioning accuracy and convergence rate were analyzed. According to the motion characteristics of land vehicles, a scheme of velocity NHC was proposed to limit the accumulation of system positioning error with time, and ZUPT was used to increase the navigation accuracy of the integrated system when the vehicle was in the static state at the traffic light. The experimental results showed that the horizontal positioning accuracy of converged BDS PPP was better than 5 cm, the vertical positioning accuracy was better than 10 cm, and the dynamic positioning results are different from the high-precision real-time kinematic (RTK) / INS integrated navigation results by centimeters. The positioning accuracy of the system could be effectively improved by the BDS PPP/INS tight coupling method of NHC+ZUPT. Compared with the PPP/INS tight coupled positioning results without any constraints, the accuracy of the method in the three directions of East, North, and Up was increased by 0.08 m, 0.02 m and 0.01 m respectively. INDEX TERMS BeiDou precise point positioning, velocity non-holonomic constraint, zero velocity update, tight coupled navigation Wei Sun, male, born in 1984, is currently a professor of the College of Geomatics, a tutor of doctor's degree students. His research direction is inertial and integrated navigation. Yihan Yang, female, born in 1994, is a PHD student of Liaoning Technical University. Her research direction is inertial and magnetic multisource integrated navigation.

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Tight integration of ambiguity-fixed PPP and INS: model description and initial results

Cited by 53 publications

References 20 publications

A Novel GNSS Attitude Determination Method Based on Primary Baseline Switching for A Multi-Antenna Platform

A Novel GNSS Attitude Determination Method Based on Primary Baseline Switching for A Multi-Antenna Platform

A Novel Ambiguity Parameter Estimation and Elimination Strategy for GNSS/INS Tightly Coupled Integration

BDS PPP/INS Tight Coupling Method Based on Non-Holonomic Constraint and Zero Velocity Update

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