US 11,698,461 B1
GPS denial detection and reporting and mitigation
Frank D. Messina, Huntington, NY (US); and Michael Stein, Patchogue, NY (US)
Assigned to Telephonics Corp., Farmingdale, NY (US)
Filed by Telephonics Corporation, Farmingdale, NY (US)
Filed on Dec. 15, 2020, as Appl. No. 17/121,853.
Application 17/121,853 is a continuation in part of application No. 17/088,768, filed on Nov. 4, 2020.
Claims priority of provisional application 62/948,937, filed on Dec. 17, 2019.
Claims priority of provisional application 62/937,815, filed on Nov. 20, 2019.
Int. Cl. G01S 19/01 (2010.01); G08G 5/00 (2006.01); G01S 19/25 (2010.01); H04W 72/23 (2023.01)
CPC G01S 19/015 (2013.01) [G01S 19/258 (2013.01); G08G 5/0013 (2013.01); H04W 72/23 (2023.01)] 14 Claims
OG exemplary drawing
 
1. A method of identifying and responding to a global positioning system (GPS) denial of service, said method comprising the steps of:
equipping an aircraft with a mode S airborne transponder;
configuring the aircraft's mode S transponder for transmitting a GPS-derived time-of-day as a message;
transmitting the aircraft's time-of-day message as a downlink format message using an available binary data storage (BDS) register;
configuring an aircraft surveillance system for receiving a GPS time-of-day message transmitted as a downlink format message;
receiving, by the aircraft surveillance system, the time-of-day message from the aircraft;
configuring the aircraft surveillance system for comparing the received time-of-day message from the aircraft to a comparison time of day;
validating reception of authentic GPS signals by the aircraft when the received time-of-day message is within a threshold amount of the comparison time of day;
indicating when the received time-of-day message is beyond the threshold amount of the comparison time of day; and
mitigating erroneous aircraft navigation when the received time-of-day message is beyond the threshold amount of the comparison time of day.