Space Systems/loral, LLC

Globalstar L.p. and Daimler-benz Aerospace Ag

John James Rodden

Homer Darling Stevens

Xenophon H Price

Stephane Carrou

Andrew E Turner

Walter Fichter

Richard A Fuller

Ernst Bruederle

Philip Conway Hirschberg

Nobuo Furumoto

David P Hong

A system for controlling attitude about pitch, yaw, and roll axes and axial thrust of a body. The system comprises a main thrust generator located on an aft portion of the body and at least one reaction control system (RCS) located on a forward portion of the body. A thrust vector controller (TVC) is connectable to the main thrust generator and at least one RCS controller is connectable to the RCS. The RCS controller and the TVC are synchronized to adjust the direction of the principal line of thrust through the body center of gravity.

Method and system for synchronized forward and Aft thrust vector control

An attitude control system comprising a controller and a noise screen device coupled to the controller. The controller is adapted to control an attitude of a vehicle carrying an actuator system that is adapted to pulse in metered bursts in order to generate a control torque to control the attitude of the vehicle in response to a control pulse. The noise screen device is adapted to generate a noise screen signal in response to the control pulse that is generated when an input attitude error signal exceeds a predetermined deadband attitude level. The noise screen signal comprises a decaying offset signal that when combined with the attitude error input signal results in a net attitude error input signal away from the predetermined deadband level to reduce further control pulse generation.

Noise screen for attitude control system

A control system for providing attitude control in spacecraft. The control system comprising a primary attitude reference system, a secondary attitude reference system, and a hyper-complex number differencing system. The hyper-complex number differencing system is connectable to the primary attitude reference system and the secondary attitude reference system.

Method and apparatus for rate integration supplement for attitude referencing with quaternion differencing

Yaw steering momentum system

An attitude control system and method operative with a thruster controls the attitude of a vehicle carrying the thruster, wherein the thruster has a valve enabling the formation of pulses of expelled gas from a source of compressed gas. Data of the attitude of the vehicle is gathered, wherein the vehicle is located within a force field tending to orient the vehicle in a first attitude different from a desired attitude. The attitude data is evaluated to determine a pattern of values of attitude of the vehicle in response to the gas pulses of the thruster and in response to the force field. The system and the method maintain the attitude within a predetermined band of values of attitude which includes the desired attitude. Computation circuitry establishes an optimal duration of each of the gas pulses based on the pattern of values of attitude, the optimal duration providing for a minimal number of opening and closure operations of the valve. The thruster is operated to provide gas pulses having the optimal duration.

Adaptive mass expulsion attitude control system

An improved GPS Attitude Receiver for spacecraft uses concurrent line-bias estimates derived from GPS signals for attitude determination. Attitude determination is obtained from GPS measurements by an interactive solution of the known 'Attitude Master Equation', using RF differential phase measurements and calibrated parameters of baseline vectors and line-biases. A 'weighted fit error' W, is derived from the sum squared of discrepancies between predicted and actual measurements, weighted by measurement variances. By minimizing W, the line-bias estimations obtained give more current data including thermal effects and eliminate separate ground calibration tests.

Global positioning system self calibration attitude determination

A method and apparatus for steering a low-earth-orbit communication satellite requiring sun-orientation for solar-power accumulation is disclosed. Momentum-bias both maintains nadir pointing and adds yaw-steering moments for sun-trackig attitude control, simultaneously. The method has two principal steps: 1) open-loop momentum decoupling, for correcting the calculated steering torque, and closed-loop attitude compensation, to correct for perturbations about the calculated attitude in accordance with one of two control law definitions. This combines the advantage of stable gyroscopic attitude control with those of open-loop yaw steering.

Growing community of inventors

Los Altos, CA, United States of America

John James Rodden