Abstract: A method for recursively determining alignment of a flight vehicle during flight is provided. The method includes generating data in a reference coordinate frame and in a second coordinate frame at a plurality of points in time during the flight, recursively generating first and second matrices from the data in the reference coordinate frame and the second coordinate frame, and at each point in time, determining an alignment output based on the inverted first matrix and the second matrix.

Abstract: A sensor alignment system and method is provided that facilitates the precise alignment determination of satellite sensors. The system and method utilizes an Inertial Measurement Unit (IMU) to facilitate alignment determination of multiples sensors on a satellite. The system and method performs a roll of the satellite around a preliminary sensor active axis, using the IMU to measure the rotation rate in both magnitude and direction. The sensor input is monitored by the IMU during the roll around the preliminary sensor axis. The data from sensor output obtained during the roll can be processed to calculate the difference between the preliminary sensor axis and the actual sensor axis. From this calculation the actual alignment of the sensor axis can be determined. Furthermore, by performing this alignment determination operation for multiple sensors the relative alignment between sensors can be determined.

Abstract: An inertial measurement unit is provided which includes a core inertial measurement unit having accelerometers and gyroscopes aligned along x, y and z axes to provide signals to an onboard computer to determine position of the vehicle upon which they are mounted while in movement. A fourth accelerometer is pivoted perpendicular to the direction of the gravitational field for measuring the gravitational field about the axis upon which it is mounted to provide a reference set of data to an onboard computer prior to movement of the vehicle upon which the system is mounted.

Abstract: In the present invention the inertial measurement unit system comprises a basic strapdown inertial measurement unit and an isolated fourth gyro strapped to a rotatable platform which is commanded to rotate at a rate equal to the spin rate of the vehicle body but in an opposition direction. The rotatable platform is controlled substantially by a control signal to cause the rotatable platform to turn at a rate substantially equal to the roll of the vehicle body but in an opposite direction. A signal processing means operates on (i) the output of an inertial navigational system computer representative of the rate of rotation of the inertial measurement unit along the roll axis, (ii), the output of the isolation gyro, and (iii) an output of a counter which counts the complete revolutions of the rotatable platform. In turn, an error signal is provided which is related to the rotation measurement error of the first rotation signal.