Patent ID: 11879969
Assignee: HONEYWELL INTERNATIONAL INC.
Field: Measurement (Instruments)
Classification: CPC G  B | IPC G

Claim 15:
16. A method for providing landing guidance, the method comprising:
providing at least one processer onboard a vehicle, the at least one processer including a radar altimeter inertial vertical loop (RIVL) filter;
inputting horizontal position statistics and vertical position statistics from an onboard navigation filter into an onboard map database, wherein the navigation filter receives aiding data from one or more aiding sensors onboard the vehicle and inertial data from an inertial measurement unit (IMU) onboard the vehicle;
computing an estimated ground/object height, an estimated ground/object velocity, an estimated ground/object acceleration, and error statistics thereof, based on terrain and object map data from the map database;
inputting the estimated ground/object height, the estimated ground/object velocity, the estimated ground/object acceleration, and the error statistics thereof into the RIVL filter;
inputting radar altimeter measurements from an onboard radar altimeter into the RIVL filter;
determining, in the RIVL filter, a relative vertical acceleration based on a difference between a vehicle vertical acceleration and a ground/object vertical acceleration;
determining, in the RIVL filter, a relative vertical velocity based on a difference between a vehicle vertical velocity and a ground/object vertical velocity;
performing, in the RIVL filter, a consistency check on the relative vertical acceleration based on non-zero relative vertical acceleration conditions, and on conditions comparing an integrated relative vertical acceleration to the relative vertical velocity;
performing, in the RIVL filter, a consistency check on the relative vertical velocity based on zero relative vertical acceleration conditions and non-zero relative vertical velocity conditions;
outputting, from the RIVL filter, estimated vertical position and vertical velocity statistics of the vehicle for compensation of estimated vertical position and vertical velocity statistics from the navigation filter; and
outputting, from compensated navigation filter outputs, the compensated estimated vertical position and vertical velocity statistics to provide for landing guidance of the vehicle.