Attitude determination by pulse beacon and low cost inertial measuring unit

A method of attitude determination, comprising:

• detecting a sequence of timed pluses 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 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 pluses, 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 IR or 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.