US 11,487,871 B2Granted

Methods and systems for detecting and defending against invalid time signals

AssigneeSan Diego Gas & Electric Company

InventorsBen A. Abbott, Brian Proctor, Gerardo Trevino, Paul Wood, David Vickers

Life of this patent

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Abstract

Some embodiments of the time resilient system and methods disclosed herein can be configured to detect and defend against invalid time signals. According to various embodiments of the disclosed technology, the time resilient system include a receiver for collecting time signals sourced from an external clock. By way of example only, the external clock may be a high precision clock housed within a Global Positioning System. Other embodiments may include an internal clock calibrated to a time reflected on the external clock so that the internal clock and the external clock are synchronized. Additionally, a controller may monitor changes in time signals of the external over a period of time against the internal clock, where the system is alerted of a timing attack when the time signals collected from the receiver deviate a pre-determined time range with the time of the internal clock.

Claims15

Dependent claims

A time resilient system comprising:

a receiver that collects time signals sourced from an external clock;
an internal clock calibrated to a time reflected on the external clock so that the internal clock and the external clock are synchronized;
and
a controller that monitors a change in time signals of the external clock over a period of time against the internal clock;
wherein the controller provides an alert indicating the presence of a timing attack on the time signals when the time signals collected from the receiver deviate from a pre-determined time range with the time of the internal clock,
wherein the pre-determined time range is based on a trusted time that is calibrated to perform as a high precision clock, and further calibrated to an offset time to produce an adjusted trusted time and a constant time deviation between the initial trusted time and a received time of a time signal;
further comprising time consuming devices synchronized to the internal clock, wherein the controller outputs a timecode comprising time data of the internal clock calibrated to the external clock, such that the time consuming devices are synchronized to the timecode independent from the time signals collected from the receiver, wherein the timecode comprises a trusted IRIG signal which initially mimics the received time signal when first initializing or calibrating the time resilient system.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/348,901Filed 10 Nov 2016 · continuation in part
Priority: 31 Jan 2015
Published: US 2017/0060101 A12 Mar 2017
Granted: 1 Nov 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

G06F 21/554
Detecting local intrusion or implementing counter-measures: involving event detection and direct action
G01S 19/215
Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service: issues related to spoofing
G04R 20/06
The radio signal being sent by a satellite, e.g. GPS: decoding time data; Circuits therefor
G06F 1/14
Generating or distributing clock signals or signals derived directly therefrom: time supervision arrangements, e.g. real time clock

Family

Application14/611,184Parent of this continuation-in-part · filed 31 Jan 2015
US 2017/0060101 A1Pre-grant publication · published 2 Mar 2017
US 10,310,091 B2Parent of this continuation-in-part
US 2016/0223677 A1Published application
US 11,487,871 B2This patent

From the US filing history. Foreign family members aren’t listed.