Expert Opinions: How simulation can aid in anti-spoofing developments

Q: How can simulation aid in the development of anti-spoofing measures or product features?

Lou, Pelosi, VP, Cast Navigation

A: Anti-spoofing is a receiver function. It is the ability of a GNSS receiver to distinguish between actual navigation signals and false signals. Simulators allow a receiver developer to play “what if” games with their receiver. A simulator user controls every variable that a receiver processes. Time, satellite information and almanac are all specifiable.

Mark Wilson, Vice President of Sales, IFEN

A: With a simulator, a user may include spoofing signals in a variety of test scenarios. The results from the receiver under test may then be compared to the “truth” data available from the simulator, in order to demonstrate any susceptibility to spoofing. As anti-spoofing measures or product features are developed and applied, the same tests may be repeated, in order to evaluate the effectiveness of the countermeasures.

Said Jackson, President, Jackson Labs Technologies

A: Since live-air spoofing is illegal, simulators provide a fully controlled and repeatable environment for evaluating spoofing resilience of algorithms and products. Newly available low-cost simulators may also reduce the overall cost and time, and increase the confidence level as well as reduce the environmental impact compared to having to go to a military test-range for live testing. Simulators also provide the ability to test spoofing scenarios that may not yet be possible with today’s technology, such as multi-GNSS spoofing.

Mark Sampson
LabSat Product Manager, Racelogic

A: Simulation is of great benefit when developing product features due to its repeatability. By replaying a consistent scenario, new products can have GNSS capabilities edge-tested for criteria such as receiver sensitivity, programming robustness and latency. Additionally, by replaying two scenarios created with signal-generator software on a multi-constellation simulator, starting at the same position and time and using the same constellation(s) but with one that diverges in position, spoofing vulnerabilities can be assessed.

Iurie Ilie, CTO & Co-Founder, Skydel

A: One of the most effective methods for mitigating GNSS spoofing is spatial discrimination. This supposes two or more receiving antennas are used. To test such systems and help designers to tune their algorithms in a controlled environment, the spoofing and truth GNSS signals must be simulated by a wavefront approach. This ensures that the signals’ code and carrier-phase offsets at the antennas’ phase center will be a function of the relative receiver/transmitter geometry.

Phil Bonilla, Systems Engineer, Spirent Federal

A: A flexible, high-quality RF constellation simulator provides the capability to model a multitude of scenarios in realistic environments. Users can configure signals and data to perform spoofing attacks, echoing both those observed and those purely theoretical today. Performing these tests via RF simulation provides highly controlled, repeatable system tests while providing flexibility to evaluate performance thresholds. The ability to assess risk and evaluate system robustness using simulation is vital in the evolving GNSS threat environment.

Joel Korsakissok, President, Syntony GNSS

A: A spoofer is a simulator that has been modified to be a slave of a master system, which defines the signal and trajectory to be emitted. To test an anti-spoofing system, it is necessary to have two simulators: the first will emit the real GPS constellation and the second will emit the spoofing signal, which will be probably synchronized in time and position at the beginning, but with divergent evolution in time.

Tim Erbes, Chief Technology Officer, Talen-X

A: Simulation is currently the best method to develop and test anti-spoofing algorithms. To ensure realism, it is often necessary to simulate both the true and spoofed signals from separate simulators. This provides flexibility for the threat to be modeled differently than the real satellites, a critical nuance that is often overlooked. Without the repeatability and control that such simulation provides, it would be impossible to adequately test the anti-spoofing capabilities of a GNSS receiver.