# US 12,190,745 B2 · Controlling aircraft to avoid terrain obstacles using reduced order closed loop models > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,190,745 B2 - Document ID: US12190745B2 - Status: Granted - Kind: B2 - Application number: 17/690,864 - Filed: 2022-03-09 - Published: 2023-09-14 - Granted: 2025-01-07 - Earliest claimed: 2022-03-09 - Assignees: Lockheed Martin Corporation - Applicants: Lockheed Martin Corporation - Inventors: Navid Dadkhah Tehrani; Kwok K. Cheng - Web page: https://patentgrep.com/patent/US12190745B2 ## CPC - G08G 5/21: located onboard the aircraft - G08G 5/80: Anti-collision systems - G01C 21/20: Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) - G05D 1/622: Obstacle avoidance (predicting or avoiding probable or impending collision of road vehicles B60W30/08) - G08G 5/22: located on the ground - G08G 5/30: Flight plan management - G08G 5/53: for cruising - G08G 5/55: for a single aircraft - G08G 5/57: for unmanned aircraft - G08G 5/59: in accordance with predefined flight zones, e.g. to avoid prohibited zones - G08G 5/74: for monitoring terrain - G05D 2105/22: of humans - G05D 2109/20: Aircraft, e.g. drones - 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}) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract This disclosure relates to apparatuses, systems, and methods for controlling an aircraft. A computing system may identify a first command signal received via a flight control at a time point to control navigation of the aircraft through an environment. The computing system may attenuate the first command signal using a fade function over a time window relative to the time point to generate a second command signal. The computing system may input the second command signal to a model to generate predicted paths for the aircraft through the environment over the time window. The computing system may determine that at least one predicted path intersects with an obstacle in the environment during the time window. The computing system may generate a location to which to navigate the aircraft to avoid the obstacle. The computing system may perform an action to direct the aircraft to the location. ## Claims ### Claim 1 A method of controlling an aircraft, comprising: identifying, by a computing system on an aircraft, a first plurality of command signals derived from an input received from one or more inceptors at a time point to control navigation of the aircraft through an environment; attenuating, by the computing system, the first plurality of command signals using a fade function over a time window relative to the time point the input is received from the one or more inceptors to generate a second plurality of command signals; inputting, by the computing system, the second plurality of command signals generated by the fade function to a reduced order model related to a full order architecture to generate one or more predicted paths for the aircraft through the environment over the time window; determining, by the computing system, that at least one predicted path of the one or more predicted paths intersects with an obstacle in the environment during the time window; generating, by the computing system, a location to which to navigate the aircraft to avoid the obstacle responsive to determining that the at least one predicted path intersects with the obstacle; and performing, by the computing system, an action to direct the aircraft to the location. ### Claim 2 (depends on 1) The method of claim 1, wherein the reduced order model is configured to approximate at least one of an inverse plant model, a corrective feedback model, a control mixing model, or a servos control unit in a flight control system for the aircraft. ### Claim 3 (depends on 1) The method of claim 1, wherein inputting the second plurality of command signals further comprises inputting the second plurality of command signals to the reduced order model, at an interval of time, to generate the one or more predicted paths for the aircraft through the environment. ### Claim 4 (depends on 1) The method of claim 1, wherein determining that the at least one predicted path intersects the obstacle further comprises comparing the at least one predicted path for the aircraft with a world model for the environment. ### Claim 5 (depends on 1) The method of claim 1, further comprising identifying, by the computing system, whether the aircraft is operating in at least one of a first mode or a second mode based on a speed of the aircraft, responsive to determining that the at least one predicted path intersects with the obstacle. ### Claim 6 (depends on 1) The method of claim 1, further comprising generating, by the computing system, a potential field map using a world model for the environment, the potential field map identifying whether the environment is occupied or free at an altitude of the aircraft. ### Claim 7 (depends on 1) The method of claim 1, wherein generating the location further comprises generating the location to hover the aircraft relative to the obstacle in the environment, responsive to a speed of the aircraft being below a threshold. ### Claim 8 (depends on 1) The method of claim 1, wherein generating the location further comprises generating a plurality of waypoints through which to navigate the aircraft to evade the obstacle by at least a clearance distance, responsive to a speed of the aircraft being above a threshold. ### Claim 9 (depends on 1) The method of claim 1, wherein performing the action further comprises providing an output to an operator of the aircraft to navigate the aircraft to the location to avoid the obstacle, the output including at least one of a visual cue, an audio cue, or a tactile cue. ### Claim 10 (depends on 1) The method of claim 1, wherein performing the action further comprises switching, without corrective input to avoid the obstacle from an operator of the aircraft, the aircraft from a manual flight mode to an autonomy flight mode to navigate the aircraft to the location to avoid the obstacle. ### Claim 11 A system for controlling an aircraft, comprising: a computing system having one or more processors coupled with memory on an aircraft, the computing system configured to: identify a first plurality of command signals derived from an input received from one or more inceptors at a time point to control navigation of the aircraft through an environment; attenuate the first plurality of command signals using a fade function over a time window relative to the time point the input is received from the one or more inceptors to generate a second plurality of command signals; input the second plurality of command signals generated by the fade function to a reduced order model related to a full order architecture to generate one or more predicted paths for the aircraft through the environment over the time window; determine that at least one predicted path of the one or more predicted paths intersects with an obstacle in the environment during the time window; generate a location to which to navigate the aircraft to avoid the obstacle responsive to determining that the at least one predicted path intersects with the obstacle; and perform an action to direct the aircraft to the location. ### Claim 12 (depends on 11) The system of claim 11, wherein the reduced order model is configured to approximate at least one of an inverse plant model, a corrective feedback model, a control mixing model, or a servos control unit in a flight control system for the aircraft. ### Claim 13 (depends on 11) The system of claim 11, wherein the computing system is further configured to input the second plurality of command signals to the reduced order model, at an interval of time, to generate the one or more predicted paths for the aircraft through the environment. ### Claim 14 (depends on 11) The system of claim 11, wherein the computing system is further configured to compare the at least one predicted path for the aircraft with a world model for the environment to determine that the at least one predicted path intersects the obstacle. ### Claim 15 (depends on 11) The system of claim 11, wherein the computing system is further configured to identify whether the aircraft is operating in at least one of a first mode or a second mode based on a speed of the aircraft, responsive to determining that the at least one predicted path intersects with the obstacle. ### Claim 16 (depends on 11) The system of claim 11, wherein the computing system is further configured to generate a potential field map using a world model for the environment, the potential field map identifying whether the environment is occupied or free at an altitude of the aircraft. ### Claim 17 (depends on 11) The system of claim 11, wherein the computing system is further configured to generate the location to hover the aircraft relative to the obstacle in the environment, responsive to a speed of the aircraft being below a threshold. ### Claim 18 (depends on 11) The system of claim 11, wherein the computing system is further configured to generate a plurality of waypoints through which to navigate the aircraft to evade the obstacle by at least a clearance distance, responsive to a speed of the aircraft being above a threshold. ### Claim 19 (depends on 11) The system of claim 11, wherein the computing system is further configured to provide an output to an operator of the aircraft to navigate the aircraft to the location to avoid the obstacle, the output including at least one of a visual cue, an audio cue, or a tactile cue. ### Claim 20 (depends on 11) The system of claim 11, wherein the computing system is further configured to switch, without corrective input to avoid the obstacle from an operator of the aircraft, the aircraft from a manual flight mode to an autonomy flight mode to navigate the aircraft to the location to avoid the obstacle.