US 2017/0285170 A9 · Multi-Constellation GNSS Integrity Check for Detection of Time Signal Manipulation

Abstract

The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.

Claims14

Dependent claims

A time distribution device for receiving and distributing a time signal, comprising:

a Global Navigation Satellite System (GNSS) receiver suitable for receiving a first time signal from a first GNSS constellation;
a local time source suitable for providing a local time signal;
a time quality module configured to:
receive the first time signal and local time signal
determine a first profile using the first time signal and the local time signal, wherein the first profile includes a rate of change of the local time signal within a time period based on the first time signal;
and
in response to detecting a change in the first profile, determine that the first time signal has been manipulated;
and
a time output for distributing a time signal to a receiving device.

6 more elements

Dependencies are inferred from the claim text.

Multi-Constellation GNSS Integrity Check for Detection of Time Signal Manipulation

Life of this patent

Multi-Constellation GNSS Integrity Check for Detection of Time Signal Manipulation

Life of this patent

Abstract

Claims14