Characterizing BDS signal‐in‐space performance from integrity perspective

Abstract

The full deployment of China's BeiDou navigation satellite system (BDS) was finalized in June 2020. To support safety‐critical applications, the system must provide assured signal‐in‐space (SIS) performance. As one of the key steps forward for BDS, this paper characterizes the SIS range errors (SISREs) for both the regional (BDS‐2) and the global (BDS‐3) systems from the integrity perspective. Following the safety standards in aviation, a data‐driven SISRE evaluation scheme is presented in this work. This scheme evaluates the overbounding user range accuracy (URA) and the prior fault probability to respectively capture the nominal and anomalous SIS behaviors. By processing the 4.5‐year ephemerides starting from 2016 for BDS‐2 and the recent 1.5‐year data from 2019 for BDS‐3, we preliminarily provide an overall picture of the BDS SIS characteristics and reveal the significant performance variation among different satellites.

Preliminary Analysis of BDS-3 Performance for ARAIM

“…A BDS-GPS time offset of 14 s should be removed (Montenbruck et al, 2015). Although broadcast orbit uses the China Geodetic Coordinate System 2000 (CGCS2000) and precise orbit is referred to the International Terrestrial Reference Frame 2008 (ITRF2008), the realization of these two frames are commonly considered to agree at the few-centimeters' level (Wang et al, 2021). Since this difference is well below the uncertainty of broadcast ephemerides, it can be disregarded in the following assessment.…”

“…The robust and iterative weighted-average method (Wu et al, 2017) is adopted here to estimate µ with a tolerance of potential clock outliers. Therefore, clock error as the difference between the broadcast and precise clock offsets is calculated by (Wang et al, 2021):…”

“…Similar works were conducted for GLONASS (Walter et al, 2018) and Galileo (Perea et al, 2017). Nominal SISRE behaviors were captured, and fault probabilities were preliminarily suggested for all BDS-2 and a few BDS-3 satellites (Wang et al, 2021). However, it was assumed that the reference time of ephemeris would always match the transmission time of message in the SISRE evaluation scheme, which may underestimate fault probabilities.…”

Measurement Error Detection for Stereo Visual Odometry Integrity

“…The error profiles are presented in terms of folded CDF plots. This is a very mature method in GPS error overbounding, and readers are referred to previous works along this line (Decleene, 2000;Larson, 2018;Rife et al, 2004Wang et al, 2021) for a more detailed explanation of this principle. In each figure, the blue dotted curve corresponds to the folded CDF of the true data.…”

An Error Overbounding Method Based on a Gaussian Mixture Model with Uncertainty Estimation for a Dual-Frequency Ground-Based Augmentation System

“…Based on a differential GNSS structure, a ground-based augmentation system (GBAS) can broadcast differential corrections to improve positioning accuracy and provide integrity, continuity, and availability for civil aircraft during their approaching and landing phases [4]. Among these four criteria, integrity is the key performance criterion for measuring the trust placed in the correctness of the provided navigation information [5]. Integrity refers to the ability to effectively provide warnings to users when system faults cause risks and jeopardize user safety.…”