# US 11,908,335 B2 · System and method for suggesting switching operational modes of a ground proximity warning system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,908,335 B2 - Document ID: US11908335B2 - Status: Granted - Kind: B2 - Application number: 17/822,216 - Filed: 2022-08-25 - Published: 2024-01-18 - Granted: 2024-02-20 - Earliest claimed: 2022-07-13 - Assignees: Honeywell International Inc. - Applicants: Honeywell International Inc. - Inventors: Yasuo Ishihara; Margaret Wintermute; Supratik Gon - Web page: https://patentgrep.com/patent/US11908335B2 ## CPC - G08G 5/80: Anti-collision systems - B64D 45/04: Landing aids; Safety measures to prevent collision with earth's surface - G08G 5/21: located onboard the aircraft - G08G 5/74: for monitoring terrain - B64C 27/00: Rotorcraft; Rotors peculiar thereto - G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93}) - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - B64C: AEROPLANES; HELICOPTERS ## Abstract An avionic system for a rotorcraft includes a data source and an enhanced ground proximity warning system. The data source has terrain data and obstacle data stored therein. The enhanced ground proximity warning system can be selectively switched, by a pilot, to operate in either a normal mode or a desensitized mode. The enhanced ground proximity warning system receives flight data, retrieves terrain data and obstacle data from the data source, evaluates the retrieved terrain data and the obstacle data to determine variations in elevations of terrain and obstacles in predetermined area that is a predetermined distance ahead of the current position and along the flight path, and based at least in part on the determined variations, selectively generate a prompt that suggests that the pilot switch the ground proximity warning system to the desensitized mode. ## Claims ### Claim 1 An avionic system for a rotorcraft, comprising: a data source having terrain data and obstacle data stored therein; and an enhanced ground proximity warning system that can be selectively switched, by a pilot, to operate in either a normal mode or a desensitized mode, the enhanced ground proximity warning system in operable communication with the data source, the enhanced ground proximity warning system coupled to receive flight data that is representative of at least a current position of the rotorcraft and of a flight path of the rotorcraft and configured, upon receipt thereof, to: retrieve terrain data and obstacle data from the data source along the current flight path of the rotorcraft, evaluate the retrieved terrain data and the obstacle data to determine variations in elevations of terrain and obstacles in predetermined area that is a predetermined distance ahead of the current position and along the flight path, and based at least in part on the determined variations, selectively generate a prompt that suggests that the pilot switch the ground proximity warning system to the desensitized mode. ### Claim 2 (depends on 1) The avionic system of claim 1, wherein the flight path is one of a current flight path or an intended flight path. ### Claim 3 (depends on 1) The avionic system of claim 1, wherein: the flight data includes an aircraft altitude; the terrain data and obstacle data are digital representations of the elevation of terrain and obstacles at a number of discrete points; and the enhanced ground proximity warning system evaluates the retrieved terrain data and obstacle data to determine variations in elevations of terrain and obstacles by counting, at the predetermined distance ahead of the current position and along the flight path, the number of discrete data points that indicate an altitude above the aircraft altitude in the predetermined area along the flight path. ### Claim 4 (depends on 3) The avionic system of claim 3, wherein the enhanced ground proximity warning system generates the prompt when the number of discrete data points exceeds a predetermined number. ### Claim 5 (depends on 1) The avionic system of claim 1, wherein: the flight data includes an aircraft altitude; the terrain data and the obstacle data are digital representations of the elevation of terrain and obstacles at a number of discrete points; and the enhanced ground proximity warning system evaluates the retrieved terrain and obstacle data to determine variations in elevations of terrain and obstacles by determining, for the predetermined area and at the predetermined distance ahead of the flight path, (i) a statistical distribution of the elevations of the terrain and obstacles and (ii) calculating a standard deviation of the statistical distribution. ### Claim 6 (depends on 5) The avionic system of claim 5, wherein the enhanced ground proximity warning system generates the prompt when the standard deviation exceeds a predetermined magnitude. ### Claim 7 (depends on 1) The avionic system of claim 1, wherein the data source comprises: a terrain database having the terrain data stored therein; and an obstacle database having the obstacle data stored therein. ### Claim 8 A method for suggesting that a pilot switch operation of an enhanced ground proximity warning system installed in a rotorcraft from a normal mode to a desensitized mode, the method comprising the steps of: supplying a data source that includes terrain data and obstacle data; and in the ground proximity warning system: receiving flight data that is representative of at least a current position of the rotorcraft and of a flight path of the rotorcraft, retrieving terrain data and obstacle data from the data source along the flight path of the rotorcraft, evaluating the retrieved terrain data and the retrieved obstacle data to determine variations in elevations of terrain and obstacles in a predetermined area at a predetermined area ahead of the current position and along the flight path of the rotorcraft, and based at least in part on the determined variations, selectively generating an prompt that suggests that the pilot switch the ground proximity warning system to the desensitized mode. ### Claim 9 (depends on 8) The method of claim 8, wherein the flight path is one of a current flight path or an intended flight path. ### Claim 10 (depends on 8) The method of claim 8, wherein: the flight data includes an aircraft altitude; the terrain data and the obstacle data are digital representations of the elevations of terrain and obstacles at a number of discrete points; and the step of evaluating the retrieved terrain data and obstacle data to determine variations in elevations of terrain and obstacles is implemented by counting, at the predetermined distance ahead of the current position and along the flight path, the number of discrete data points that indicate an altitude above the aircraft altitude in the predetermined area along the flight path. ### Claim 11 (depends on 10) The method of claim 10, wherein the prompt is generated when the number of discrete data points exceeds a predetermined number. ### Claim 12 (depends on 8) The method of claim 8, wherein: the current flight path includes an aircraft altitude; the terrain data and the obstacle data are digital representations of the elevation of terrain and obstacles at a number of discrete points; the step of evaluating the retrieved terrain and obstacle data to determine variations in elevations of terrain and obstacles is implemented by determining, for the predetermined area and at the predetermined distance ahead of the flight path, (i) a statistical distribution of the elevations of the terrain and obstacles and (ii) calculating a standard deviation of the statistical distribution. ### Claim 13 (depends on 12) The method of claim 12, wherein the prompt is generated when the standard deviation exceeds a predetermined magnitude. ### Claim 14 (depends on 8) The method of claim 8, wherein the data source comprises: a terrain database having the terrain data stored therein; and an obstacle database having the obstacle data stored therein. ### Claim 15 A rotorcraft, comprising: a fuselage; a data source disposed within the fuselage and having terrain data and obstacle data stored therein; and an enhanced ground proximity warning system disposed within the fuselage and that can be selectively switched, by a pilot, to operate in either a normal mode or a desensitized mode, the enhanced ground proximity warning system in operable communication with the data source, the enhanced ground proximity warning system coupled to receive flight data that is representative of at least a current position and of a flight path of the rotorcraft and configured, upon receipt thereof, to: retrieve terrain data and obstacle data from the data source along the current flight path of the rotorcraft, evaluate the retrieved terrain data and the obstacle data to determine variations in elevations of terrain and obstacles in predetermined area that is a predetermined distance ahead of the current position and along the flight path, and based at least in part on the determined variations, selectively generate a prompt that suggests that the pilot switch the ground proximity warning system to the desensitized mode. ### Claim 16 (depends on 15) The rotorcraft of claim 15, wherein: the flight data includes an aircraft altitude; the terrain data and obstacle data are digital representations of the elevation of terrain and obstacles at a number of discrete points; and the enhanced ground proximity warning system evaluates the retrieved terrain data and obstacle data to determine variations in elevations of terrain and obstacles by counting, at the predetermined distance ahead of the current position and along the flight path, the number of discrete data points that indicate an altitude above the aircraft altitude in the predetermined area along the flight path. ### Claim 17 (depends on 16) The rotorcraft of claim 16, wherein the enhanced ground proximity warning system generates the prompt when the number of discrete data points exceeds a predetermined number. ### Claim 18 (depends on 15) The rotorcraft of claim 15, wherein: the flight data includes an aircraft altitude; the terrain data and the obstacle data are digital representations of the elevation of terrain and obstacles at a number of discrete points; the enhanced ground proximity warning system evaluates the retrieved terrain and obstacle data to determine variations in elevations of terrain and obstacles by determining, for the predetermined area and at the predetermined distance ahead of the flight path, (i) a statistical distribution of the elevations of the terrain and obstacles and (ii) calculating a standard deviation of the statistical distribution. ### Claim 19 (depends on 18) The rotorcraft of claim 18, wherein the enhanced ground proximity warning system generates the prompt when the standard deviation exceeds a predetermined magnitude. ### Claim 20 (depends on 15) The rotorcraft of claim 15, wherein the data source comprises: a terrain database having the terrain data stored therein; and an obstacle database having the obstacle data stored therein.