CRPA & GPS Security

This presentation gives a plain-language introduction to protecting drones from GNSS interference using Controlled Reception Pattern Antennas (CRPA). It starts with why GNSS signals are so weak and easy to disrupt, covering the noise floor, decibels and processing gain, and compares jamming, spoofing and meaconing. It then explains how a CRPA works: direction finding, beamforming and nulling. It classifies CRPA types by control method (blind vs. aided), build (analog vs. digital), element count and platform. It also covers the technology of the receivers and antennas that form the heart of any CRPA, with a civil vs. defence comparison. The deck also covers the limits of CRPA (degrees-of-freedom exhaustion, wideband jammers, calibration, nulling a satellite by mistake, multi-antenna spoofing) and how signal authentication (OSNMA, CHIMERA, M-code) complements it. It closes with the GPS code family (C/A, P(Y), M, L1C, L2C, L5) and the status of the world's navigation constellations as of September 2026. It is intended as an educational overview for students, engineers and non-specialists, not as a design specification.