Abstract
The integrity monitoring algorithm based on pseudorange observations has been widely used outdoors and plays an important role in ensuring the reliability of positioning. However, pseudorange observations are greatly affected by the error sources such as multipath, clock drift, and noise in indoor pseudolite system, thus the pseudorange observations cannot be applied to high-precision indoor positioning. In general, double differenced (DD) carrier phase observations are used to obtain a high-precision indoor positioning result. What’s more, the carrier phase-based integrity monitoring (CRAIM) algorithm is applied to identify and exclude potential faults of the pseudolites. In this article, a holistic method is proposed to ensure the accuracy and reliability of positioning results. Firstly, if the reference pseudolite operates normally, extended Kalman filter is used for parameter estimation on the premise that the number of common pseudolites meets positioning requirements. Secondly, the innovation sequence in the Kalman filter is applied to construct test statistics and the corresponding threshold is determined from the Chi distribution with a given probability of false alert. The pseudolitehorizontal protection level (HPL) is calculated by the threshold and a prior probability of missed detection. Finally, compared the test statistics with the threshold to exclude the faultypseudolite for the reliability of positioning. The experiment results show that the proposed method improves the accuracy and stability of the results through faults detection and exclusion. This method ensures accuracies at the centimeter level for dynamic experiments and millimeter levels for static ones.
Highlights
The global navigation satellite system (GNSS) has been widely applied in outdoor positioning.it is difficult to obtain reliable GNSS signals in sheltered environments or indoors [1], where a pseudolite system can make up for the shortage of GNSS [2,3].Relative to the GNSS, indoor pseudolite observations have no tropospheric and ionospheric errors.The PL/receiver clock and antenna phase error can be eliminated by DD observations which greatly reduce the difficulty in processing error sources in indoor PL positioning [4]
There is a large deviation in positioning results, and they fixed in some epochs, it is fixed incorrectly
The reason for which confirms the regular pattern of two motion periods and observations are stable
Summary
The global navigation satellite system (GNSS) has been widely applied in outdoor positioning.it is difficult to obtain reliable GNSS signals in sheltered environments or indoors [1], where a pseudolite system can make up for the shortage of GNSS [2,3].Relative to the GNSS, indoor pseudolite observations have no tropospheric and ionospheric errors.The PL/receiver clock and antenna phase error can be eliminated by DD observations which greatly reduce the difficulty in processing error sources in indoor PL positioning [4]. It is difficult to obtain reliable GNSS signals in sheltered environments or indoors [1], where a pseudolite system can make up for the shortage of GNSS [2,3]. Relative to the GNSS, indoor pseudolite observations have no tropospheric and ionospheric errors. The multipath effect, noise, and fixed satellite constellations are still the problems indoors. The indoor pseudolite system has a great nonlinear effect due to the close distance between the receivers and pseudolites. If initial position estimation has poor accuracy, the nonlinear error caused by linearization will be severe. Large code measurement errors caused bythe above factors may result in low accuracy and reliability of positioning results
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
