Attitude determination by pulse beacon and low cost inertial measuring unit
AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorsMichael J. Choiniere, Jason H. Batchelder, Matthew F. Chrobak
Life of this patent
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Abstract
The system and method of attitude determination by pulse beacon and extremely low cost inertial measuring unit. A pulse beacon is used to generate a plurality of pulses detected by a detector or receiver located on the rear of a projectile such that direction of arrival can be determined. A synchronized clock proved for velocity and range information. Altitude can also be determined and may use an altimeter or the like. The use of a low cost IMU is possible with internal calibration by the system. Real-time attitude information provides for correction for crosswind and other drift enabling the system to have less down range dispersion.
Claims20
A system for attitude determination of an airborne object, comprising:
- a pulse beacon located on a fire control system, the beacon being configured to deliver a sequence of timed pulses;
- a rearward facing sensor configured to detect the sequence of timed pulses;
- a clock located and synchronized with the pulse beacon, the clock being configured to initiate a time stamp upon detection of the timed pulses by the rearward facing sensor;
- an inertial measurement unit (IMU), the IMU configured to determine attitude of the airborne object;
- a barometer or altitude sensor configured to detect changes in altitude of the airborne object;
- and
- a processor configured to integrate data from at least the sensor, the clock, and the IMU and compare it to a pre-flight script of range, position, and altitude for the airborne object to determine a direction of arrival for the sequence of timed pulses, a range and a velocity for the airborne object based on an increasing time differential between pulses, and attitude of the airborne object.
A method of attitude determination, comprising:
- detecting a sequence of timed pulses from a pulse beacon via a rearward facing sensor located on an airborne object;
- synchronizing a precision clock located on the airborne object with the pulse beacon;
- initiating a time stamp upon detection of a timed pulse by the rearward facing sensor;
- determining an attitude of the airborne object via an inertial measurement unit (IMU) located on the airborne object;
- detecting changes in altitude of the airborne object via a barometer located on the airborne object;
- integrating data from at least the sensor, the clock, and the IMU via a processor located on the airborne object;
- comparing the data from at least the sensor, the clock, and the IMU to a pre-flight script of range, position, and altitude for the airborne object;
- and
- determining a direction of arrival for the sequence of timed pulses, a range and a velocity for the airborne object based on an increasing time differential between pulses, and the attitude of the airborne object.
A method of attitude determination of a projectile, comprising:
- pulsing infrared (IR) or radio frequency (RF) energy based on a predetermine pulse timing sequence;
- receiving the pulsed energy at a rearward facing sensor located on the projectile;
- determining a direction of arrival (DOA) for the pulsed energy;
- initiating a time stamp using a precision clock when the pulsed energy is received by the sensor;
- determining range and velocity of the projectile from an increasing differential due to an increased range along a flight path;
- calculating changes in altitude of the airborne object with respect to a fire control system;
- decomposing measured sensor angles into pitch and yaw in earth's reference;
- calculating pitch and yaw in earth's reference and calibrating an inertial measurement unit (IMU);
- and
- computing adjustments to account for crosswind and variations in the velocity of the projectile.
Dependencies are inferred from the claim text.