Page 4 - 卫星导航2021年第1-2合期

Research Summary
Volume 2, Issue 1-2, July 2021
Reviews
Indoor navigation
The Positioning, Localization, and Navigation (PLAN) technology has been widely studied and
successfully commercialized in many applications such as mobile phones and unmanned systems. In
particular, indoor PLAN technology is becoming increasingly important with the emergence of new
chip-level Micro-Electromechanical System (MEMS) sensors, positioning big data, and Artificial
Intelligence (AI) technology, as well as the increase of public interest and social potential.
This paper reviews the state of the art and future trends of indoor PLAN. It covers the requirements,
the main players, sensors, and techniques for indoor PLAN. Other than the navigation sensors such as
Inertial Navigation System (INS) and Global Navigation Satellite System (GNSS), the environmental-
perception sensors such as High-Definition map (HD map), Light Detection and Ranging (LiDAR),
camera, the fifth generation of mobile network communication technology (5G), and Internet-
of-Things (IoT) signals are becoming important aiding sensors for PLAN. The PLAN systems are
expected to be more intelligent and robust under the emergence of more advanced sensors, multi-
platform/multi-device/multi-sensor information fusion, self-learning systems, and the integration
with artificial intelligence, 5G, IoT, and edge/fog computing.
Related article: Indoor navigation: state of the art and future trends (doi: 10.1186/ s43020-021-
00041-3)
GNSS: PPP vulnerability and integrity
Autonomous driving, as a representative technology of Intelligent Transport System (ITS), will make
great changes in transportation. It requires decimetre to sub-metre accuracy positioning as well as high
integrity. This paper gives an overview of vulnerabilities in GNSS PPP in order to identify the faults
that need to be monitored when developing PPP integrity monitoring methods in ITS applications.
They are classified into different groups according to their sources to assist integrity fault analysis,
e.g., failure modes and effects analysis and fault tree analysis. The causes and characteristics, impacts,
fault models and some probabilities of these threats are summarised, with detailed discussion on
some major threats. The development of PPP integrity research, with a focus on ITS context is also
reviewed. Requirements, challenges, and existing integrity monitoring methods, including system-
level (network-end) and user-level (user-end) approaches, for PPP in urban environments are
discussed. Overall, the ITS integrity requirements, probabilities of many of the threats (i.e., a threat
model), and PPP integrity methods are still under investigation and require comprehensive studies.
Some open research issues regarding PPP vulnerabilities and integrity for ITS applications are pointed
out in this paper.
Related article: Vulnerabilities and integrity of precise point positioning for intelligent
transport systems: overview and analysis (doi: 10.1186/ s43020-020-00034-8)
Communications
SBAS authentication：An effective anti-spoofing method
Satellite-based Augmentation System (SBAS) provides the corrections and integrity information to
users, but as its signal format is opened to the public and Global Navigation Satellite System (GNSS)
spoofing technology becomes more realistic, more feasible and cheaper. It’ s foreseeable that there
will be risks of spoofing threats against SBAS in the future. SBAS signal authentication technology
provides a system-level solution to spoofing threats by adding special markers to SBAS signals so that
receivers can verify whether the SBAS signals are from the on-orbit Geostationary Earth Orbit（GEO）
satellites or whether the signal information has been forged and tampered with. Firstly, this article
discusses the development of SBAS authentication, analyzes the Elliptic Curve Digital Signature
Algorithm (ECDSA) and Timed Efficient Stream Loss-Tolerant Authentication (TESLA) protocols.
Then it discusses four possible solutions in a combination with the existing SBAS Interface Control
Document (ICD). Two main Key Performance Indicators (KPIs), Time Between Authentication
(TBA) and Authentication Latency (AL), obtained in the four main scenarios are compared. By
analyzing the EGNOS Authentication Security Testbed (EAST) test simulation results of European
Geostationary Navigation Overlay Service (EGNOS) in Europe, the impact of SBAS after joining the
authentication service is obtained.
Related article: Advances of SBAS authentication technologies (doi: 10.1186/ s43020-021-
00043-1)