Global Navigation Satellite Systems Engineering, Policy, and Design
Working Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Em. Univ.-Prof. Dr.-Ing. habil. Dr. h.c. Günter W. Hein.
By Günter W. Hein
Q: What is navigation message authentication?
A: As of today, all open civil GNSS signals are transmitted in the clear, conforming to interface specifications that are fully available in the public domain. Receivers will accept any input that conforms to the specifications and treat it as if it came from a GNSS satellite. Combined with the extremely low power levels of GNSS signals this makes it almost trivially simple to spoof a GNSS receiver.
By Inside GNSS
In the past two decades, satellite navigation systems have undergone great development. The development of new generations of global navigation satellite systems (GNSS), represented by GPS III, Galileo, and the BeiDou global system (BDS), is rapidly advancing.
By Inside GNSS
Multipath is a major phenomenon that degrades the integrity of GNSS-based navigation services. Under multipath, a receiver Delay-Lock Loop (DLL) does not correctly estimate the actual peak of the correlation curve, resulting in ranging errors. To overcome this effect, mitigation techniques have been developed, a detailed discussion of which
By Inside GNSS
Figures 1 – 10Q: Do modern multi-frequency civil receivers eliminate the ionospheric effect?
By Mark Petovello
Figures 1 – 6, Table 1There are many good reasons for getting excited about highly automated vehicles, or HAVs, which is the acronym used by the National Highway Traffic Safety Administration (NHTSA). HAVs can make driving more fuel- and time-efficient. They can significantly reduce traffic congestion and emissions by driving a precise speed, minimizing lane changes, and maintaining an exact distance to neighboring cars. They can also increase accessibility and mobility for disabled and elderly persons.
By Inside GNSSToday’s headlines frame my thoughts about securing GNSS assets, which one expert has characterized as our “least visible and most vulnerable infrastructure.”
By Inside GNSS
Equations 1 – 4
EquationsGNSS is the technology of choice in most applications due to its dedicated infrastructure, Earth coverage, medium to high accuracy, and large market penetration. Most of the applications, including those we download on our smartphones, are in the category of Location Based Services (LBS). However, there are many other services and businesses that rely heavily on GNSS performance and reliability. For instance, Intelligent Transportation Systems (ITS) make extensive use of GNSS technology and this dependence will only grow in the future.
By Inside GNSS
Figures 1 – 8, Tables 1 & 2, Equation 3The vulnerability of GNSS to various forms of malicious interference have been widely discussed in recent years, and have considered a wide range of both real and potential attacks. Some of these have included extensive studies of commercially available jamming devices, while others have considered the more comprehensive case of spoofing, where the interference takes the form of genuine GNSS signals (For details, see papers listed in Additional Resources, including M. G. Amin et alia).
By Inside GNSS
Two aircraft flying at the same altitude
Figures 3 & 4Motivation and Background
By Inside GNSS
