A Low-Cost Approach of Magnetic Field-Based Location Validation for Global Navigation Satellite Systems

Modern infrastructure heavily relies on various location-based services using global navigation satellite systems (GNSSs) such as the U.S. global positioning system for access to positioning, navigation, and timing information. Location information enables guidance in many applications, including finding the location of vehicles for public safety emergency E-911 services. Nevertheless, GNSS signals can be jammed or manipulated by radio frequency spoofers, so receivers may produce unreliable location data. With increasing reliance on infrastructure and public services on location awareness, location data should be properly validated. This paper presents an approach of validating GNSS data using magnetic field fingerprint maps, which are not sensitive to potential spoofers. It first captures unique or rare geomagnetic profiles (referred to as fingerprints), including all location-dependent fluctuations and anomalies from both natural and man-made sources (referred to as landmarks), on a traveling vehicle. It then tracks their alignment with the GNSS data. A two-tier fingerprint matching localization framework has also been proposed to identify target landmarks by captured fingerprints.

I. Introduction

Today, satellite-based positioning technologies [the U.S. global positioning system (GPS) and other similar global navigation satellite systems (GNSSs)] provide location information for many commonly used applications that are used autonomously or integrated into various location-based services (LBS). Standalone GPS/GNSS receivers perform well outdoors with a clear view of the sky, whereas technologies such as assisted GPS/GNSS (A-GPS/GNSS) and other hybrid solutions help receiver operations in signal-challenged areas, such as urban-like and indoor environments. However, positioning technologies are vulnerable to potential security risks, such as spoofing and jamming threats, which are reported by the U.S. Department of Transportation [1]. These risks exhibit themselves as ambiguous location information from the receivers caused by interfering signals. Although previous studies were applied to address the detection and mitigation of such interference, many challenges still exist [2]–[10]. Therefore, the reliability of location information becomes a major issue and should be addressed, particularly in life-critical applications.