A Holistic Approach to Guarantee the Reliability of Positioning Based on Carrier Phase for Indoor Pseudolite

Abstract

Featured Application: This work is potentially applied to indoor high-precision engineering/ industrial measurement, such as parts installation, tunnel engineering, dynamic rail inspection, path planning, etc. Especially in case of pseudolite faulty, the reliability and availability of positioning can be guaranteed. 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.

An Adaptive Weighted Wi-Fi FTM-Based Positioning Method in an NLOS Environment

“…According to the above analysis, the ranging error caused by clock drift can be assumed to have a nonlinear relationship with the ranging result. However, in the LOS environment, ranging is also affected by other factors, such as multipath and random error [27][28][29]. To analyse these factors, the ranging results are collected in the LOS environment as shown in Fig.…”

Integrity Monitoring for Bluetooth Low Energy Beacons RSSI Based Indoor Positioning

“…Yuqin Wang et al [8] proposed a method of using the shorttime reliability of PDR to aid in visual integrity monitoring and to reduce positioning error. Yinzhi Zhao et al [9] aimed at indoor high-precision engineering application proposed carrier phase-based integrity monitoring (CRAIM) algorithm to identify and exclude potential faults of the pseudolites, the CRAIM ensured the accuracy and reliability of positioning results and achieved accuracies at the centimeter level for dynamic experiments and millimeter levels for static ones. In [39], specific thresholds of integrity monitoring were proposed to the prevention of theft and criminal surveillance, etc., including the alarm time (TTA, Time to Alarm) and the Horizontal Alarm Limit (HAL).…”

“…However, the study did not carry out specific integrity monitoring algorithms. In [5][6][7][8][9], the proposed integrity monitoring algorithms only focus on a single fault (single gross error), and all lack an alert mechanism for cases when positioning accuracy completely dissatisfies user requirements.…”

LSOS: An FG Position Method Based on Group Phase Ranging Ambiguity Estimation of BeiDou Pseudolite

“…Using the existing four GNSS antenna platforms, Dr. Zhao proposed a baseline-constrained ambiguity function method. This method can effectively improve the unreliable or inaccurate estimation solution of RTK localization, and further directly assist the estimation of altitude direction [12][13][14][15]. Professor Takuji Ebinuma of the Japanese Waseda University has been working on indoor pseudolite for many years and has extensive experience in rapid RTK positioning.…”