PROJECTILE 3D ATTITUDE FROM 3-AXIS MAGNETOMETER AND SINGLE-AXIS ACCELEROMETER
First Claim
1. A method to determine roll angle, pitch angle, and heading angle of a spinning projectile during a flight of the spinning projectile, the method comprising:
- providing a magnetic unit vector in an inertial frame of the projectile at a projectile launch location prior to launch of the projectile;
determining a magnetic unit vector in a body frame and in an inertial frame of the spinning projectile during the flight of the spinning projectile;
determining a velocity unit vector in the body frame and in the inertial frame of the spinning projectile during the flight of the spinning projectile; and
calculating the roll angle, the pitch angle, and the heading angle of the spinning projectile during the flight of the spinning projectile, regardless of the spin rate of the projectile, wherein the roll angle and the pitch angle of the spinning projectile comprise an attitude of the spinning projectile.
1 Assignment
0 Petitions
Accused Products
Abstract
A method to determine roll angle, pitch angle, and heading angle of a spinning projectile during a flight of the spinning projectile is provided. The method includes providing a magnetic unit vector in an inertial frame of the projectile at a projectile launch location prior to launch of the projectile; determining a magnetic unit vector in a body frame and in an inertial frame of the spinning projectile during the flight of the spinning projectile; determining a velocity unit vector in the body frame and in the inertial frame of the spinning projectile during the flight of the spinning projectile; and calculating the roll angle, the pitch angle, and the heading angle of the spinning projectile during the flight of the spinning projectile, regardless of the spin rate of the projectile. The roll angle and the pitch angle of the spinning projectile form an attitude of the spinning projectile.
-
Citations
20 Claims
-
1. A method to determine roll angle, pitch angle, and heading angle of a spinning projectile during a flight of the spinning projectile, the method comprising:
-
providing a magnetic unit vector in an inertial frame of the projectile at a projectile launch location prior to launch of the projectile; determining a magnetic unit vector in a body frame and in an inertial frame of the spinning projectile during the flight of the spinning projectile; determining a velocity unit vector in the body frame and in the inertial frame of the spinning projectile during the flight of the spinning projectile; and calculating the roll angle, the pitch angle, and the heading angle of the spinning projectile during the flight of the spinning projectile, regardless of the spin rate of the projectile, wherein the roll angle and the pitch angle of the spinning projectile comprise an attitude of the spinning projectile. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. An apparatus to measure a three-dimensional attitude of a spinning projectile during a flight of the spinning projectile, the apparatus including:
-
a three-axis magnetometer to measure the magnetic field of earth; a single-axis accelerometer having a sense axis parallel to a spin axis of the spinning projectile during the flight of the spinning projectile; and an attitude estimator module; at least one processor to receive outputs from the three-axis magnetometer and the single-axis accelerometer and to execute at least one algorithm in the attitude estimator module to determine an attitude and heading angle of the spinning projectile during the flight of the spinning projectile, regardless of a spin rate of the projectile, based on outputs from the three-axis magnetometer and the single-axis accelerometer, wherein the attitude and the heading angle comprise the three-dimensional attitude. - View Dependent Claims (13, 14, 15)
-
-
16. A non-transitory computer readable medium embodying a program of instructions executable by a processor to perform a method comprising:
-
determining a magnetic unit vector in a body frame and in an inertial frame of the spinning projectile during a flight of the spinning projectile; determining a velocity unit vector in the body frame and in the inertial frame of the spinning projectile during the flight of the spinning projectile; and calculating a roll angle, a pitch angle, and a heading angle of the spinning projectile during the flight of the spinning projectile, regardless of a spin rate of the projectile, wherein the roll angle, the pitch angle, and the heading angle of the spinning projectile comprise a three-dimensional attitude of the spinning projectile. - View Dependent Claims (17, 18, 19, 20)
-
Specification