Use of APNT to Protect GNSS-Based RNP Services from Intentional and Unintentional RF Interference

Abstract

We present a method to detect intentional ranging errors on GNSS measurements. Intentional ranging errors can be introduced by targeted radio interference, or spoofing, and are considered a significant threat to aviation safety. The proposed method assumes a functioning APNT capability, able to provide RNP 0.3 or equivalent services independently of GNSS. We present two variants of the method, one based on available legacy technology and one based on future APNT systems. The legacy method protects against horizontal position errors in the order of 550 m, while the future method will likely provide protection at 35 m horizontal error.