Abstract: There is provided an information processing apparatus that includes an information acquisition unit and a control prediction unit. The information acquisition unit acquires information regarding a location and a posture of a first mobile object that includes a sensing device. The control prediction unit predicts control performed with respect to the sensing device, on the basis of the information regarding the location and the posture and map information, the information regarding the location and the posture being acquired by the information acquisition unit.

Abstract: The presently disclosed subject matter includes a method and system directed for calculating azimuth of an airborne platform during flight based on IMU measurements, without using GNSS data, gyrocompassing or magnetometers operating on the ground for determining the azimuth.

Abstract: A service satellite for providing station keeping services to a host satellite is disclosed. The service satellite may have a body, and a gripping mechanism attached to the body. The gripping mechanism may be adapted to attach to an interface ring extending from an external surface of the host satellite to form an interconnection between the host satellite and the service satellite through the externally extending interface ring. Attaching the gripping mechanism to the interface ring may form an interconnected unit having a combined center of mass. The service satellite may have at least two thrusters and at least one controller. The at least one controller may maintain the interconnected unit in a substantially stationary orbit by selectively orienting the two thrusters such that the thrust vectors from the two thrusters avoid passing through the combined center of mass, and are each offset from the combined center of mass.

Abstract: An inertial measurement system for a spinning projectile includes: a first, roll gyro to be oriented substantially parallel to the spin axis of the projectile; a second gyro and a third gyro with axes arranged with respect to the roll gyro; a controller, arranged to: compute a current projectile attitude from the outputs of the first, second and third gyros, the computed attitude comprising a roll angle, a pitch angle and a yaw angle; calculate a roll angle error; provide the roll angle error as an input to a Kalman filter that outputs a roll angle correction and a roll rate scale factor correction; and apply the calculated roll angle correction and roll rate scale factor correction to the output of the roll gyro.

Abstract: A method of controlling a satellite and a computer-readable recording medium are provided. The method is for controlling a satellite moving along an orbit having an inclination angle from the equatorial plane to capture due-north images. The method includes: determining a position of the satellite; calculating a roll angle and a pitch angle of the satellite for pointing a line-of-sight vector of the satellite to a first ground surface being a photographing point; determining a compensation angle by considering effects of the inclination angle and rotation of the Earth so as to capture images in the due north direction of the photographing point; calculating a yaw angle based on the compensation angle; and rotating the satellite according to the calculated roll angle, pitch angle, and yaw angle.

Abstract: A system and a method for determining a satellite image loss and a computer-readable recording medium therefor are provided. The satellite image loss determination system includes a data receiving unit configured to receive packet data including satellite image data, time information, and a flag value, and angle data of a scan mirror that generates the satellite image data; a data comparing unit configured to compare the angle data received by the data receiving unit with angle data of the scan mirror previously determined in correspondence with the packet data; and an image loss determining unit configured to determine whether a loss has occurred in a satellite image generated from the satellite image data in consideration of a result of comparison of the data comparing unit.

Abstract: A real-time compensation system of a projectile includes at least one flight controller, at least one imager device, at least one gyroscope, and at least one processor. The at least one flight controller is configured to rotate the projectile about an axis between a first orientation and a second orientation. The at least one imager device is configured to capture a first image at the first orientation and a second image at the second orientation. The at least one gyroscope is configured to sense a first angular rate of the projectile as the projectile rotates from the first orientation to the second orientation. The at least one processor is configured to determine a first rotation angle based upon the first and second images and a second rotation angle based upon the angular rate sensed by the at least one gyroscope, and determine a gyroscope compensation parameter.

Abstract: A satellite system operates at altitudes between 180 km and 350 km relying on vehicles including an engine to counteract atmospheric drag to maintain near-constant orbit dynamics. The system operates at altitudes that are substantially lower than traditional satellites, reducing size, weight and cost of the vehicles and their constituent subsystems such as optical imagers, radars, and radio links. The system can include a large number of lower cost, mass, and altitude vehicles, enabling revisit times substantially shorter than previous satellite systems. The vehicles spend their orbit at low altitude, high atmospheric density conditions that have heretofore been virtually impossible to consider for stable orbits. Short revisit times at low altitudes enable near-real time imaging at high resolution and low cost. At such altitudes, the system has no impact on space junk issues of traditional LEO orbits, and is self-cleaning in that space junk or disabled craft will de-orbit.

Abstract: An attitude angle may be calculated with high precision. In a traveling state calculating device, receiving parts may output data for calculation using positioning signals received by antennas, respectively. A phase difference calculating part may calculate a single phase difference for every base line based on the data for calculation outputted by the receivers. An attitude angle calculating part may calculate an attitude angle using the data for calculation and the single phase difference. A calculating condition determining part may determine a contribution of the data for calculation to the calculation of the attitude angle, corresponding to the component of the attitude angle, based on a spatial relationship between the base line and the positioning satellite.

Abstract: A diode pumped, solid state laser is provided that can produce over 16 billion, 15 mJ, 10 ns Q-Switched laser pulses with a low measured decay rate. The laser can be integrated into a global biomass measuring instrument, and mounted on the International Space Station (ISS).

Abstract: An observation satellite is used for obtaining information about electromagnetic energy emitted from the earth. The observation satellite orbits the earth in an orbit having an inclination larger than 90° and smaller than 270°. Further, the observation satellite comprises at least one receiving antenna, the at least one receiving antenna having a receiving pattern directed towards the earth, and suitable for receiving electromagnetic energy in the radio frequency range as the observation satellite is orbiting relative to the surface of the earth. The observation satellite also comprises a transmitter configured for at least one of: (i) retransmitting the received electromagnetic energy, (ii) transmitting information representing the received electromagnetic energy, and (iii) transmitting information derived from the received electromagnetic energy. The invention also relates to systems and methods therefor.

Abstract: A modular satellite for converting solar energy to microwave energy and transmitting the microwave energy to the earth to be converted into electricity includes solar panels configured to convert solar energy into direct current; a magnetron operatively connected to the solar panels to receive the direct current and configured to convert the direct current into microwave energy; a planar wave guide antenna operatively connected to the magnetron to receive the microwave energy and direct the microwave energy to a station on earth; and a coupling system for coupling with another satellite to form an array in response to at least one of locking, unlocking, and navigational commands. The satellite has a mass equal to or less than four kilograms, and a volume equal to or less than three liters.

Abstract: Apparatus, systems and methods provide for compensating for pointing errors that may occur when using a coarse positioning mechanism for pointing a payload toward a target. According to aspects of the disclosure, a coarse positioning mechanism is configured to compensate for pointing errors that may occur when pointing a payload toward a target over a large angular FOV. The coarse positioning mechanism may be configured for a variety of applications, such as precision tracking applications and precision pointing applications over a large angular FOV. The coarse positioning mechanism may include adjustment mechanisms for one or more axes that are used to adjust the pointing direction of the target.

Abstract: A sensor synchronization system for a sensor apparatus. The system synchronizes a local clock signal with an external timing signal. For example, the external timing signal may correspond to a pulse per second (PPS) signal received from a global positioning system (GPS) receiver. The system further generates a plurality of sensor pulses that are each offset in phase relative to the local clock signal by a respective amount. The system then activates a plurality of sensors of the sensor apparatus based at least in part on the plurality of sensor pulses.

Abstract: A method for determining an attitude of a star sensor based on a rolling shutter imaging is provided. The method comprises: optimizing a relation among an exposure time, a line readout time, an interline integral interval time and a frame processing time of an image for the rolling shutter imaging by using a rolling shutter model of an image sensor in the star sensor based on a line; predicting and extracting locations of M navigation stars comprised in a star map in the star sensor according to the optimized relation among the exposure time, the line readout time, the interline integral interval time and the frame processing time; and transferring an updated the attitude matrix and an updated angular velocity of the star sensor sequentially until a final attitude matrix and a final angular velocity of the star sensor are obtained.

Abstract: Provided are a poor visibility estimation system and a poor visibility estimation method that can estimate poor visibility using a simpler configuration. A center has a change amount calculation unit for calculating the change amounts of operation elements of vehicles. A visibility estimation unit estimates poor visibility on the basis of the change amounts calculated by the change amount calculation unit. The center also has a distribution unit for distributing the estimation results of the visibility estimation unit.

Abstract: The axes of an accelerometer, installed in a vehicle at an arbitrary orientation, may be realigned to the coordinate frame of the vehicle. In one implementation, a method may include determining, based on acceleration measurements from the accelerometer that likely corresponds to stopping, a dominant orientation of the accelerometer in relation to gravity, including calculating a first transformation angle and a second transformation angle as parameters to perform coordinate realignment of a coordinate frame of the accelerometer to a coordinate frame of the vehicle. The method may further include identifying, based on the acceleration measurements, an occurrence of acceleration events of the vehicle; determining, based on an analysis of the acceleration events, a third transformation angle; and storing the first, second, and third transformation angles.

Abstract: A system and methods for calculating an attitude and a position of an object in space are disclosed. Measurements in relation to an object, stars, and a signal timing are received at a combined orbit and attitude determination system to provide received measurements. An estimated separation angle error, an estimated position error, and an estimated attitude error are estimated based upon the received measurements to provide estimated errors.

Abstract: An attitude estimator that uses star tracker measurements and enhanced Kalman filtering, with or without attitude data, to provide three-axis rate estimates. The enhanced Kalman filtering comprises taking an average of forward and rearward propagations of the Kalman filter states and the error covariances. The star tracker-based rate estimates can be used to control the attitude of a satellite or to calibrate a sensor, such as a gyroscope.

Abstract: A method and system are presented for use in determination of the orientation of an aerospace platform with respect to a first rotation axis. A direction of a rotation rate vector of said aerospace platform within a lateral plane intersecting with said first rotation axis is measured and the measured data is analyzed to determine an orientation angle of said aerospace platform about said first rotation axis. While the aerospace platform is in a predetermined-dynamic state movement, a certain direction is determined by measuring a direction of the rotation rate of the aerospace platform within said lateral plane by a sensor assembly mounted on said platform and including at least one rotation rate sensor. An orientation of the platform with respect to said first axis is determined by determining a relation between said certain direction and said known direction within said external reference frame.

Abstract: An attitude estimator that uses sun sensor outputs as the only attitude determination measurements to provide three-axis attitude information. This is accomplished by incorporating the Euler equation into the estimator. An unscented Kalman filter is employed to accommodate various nonlinear characteristics and uncertainties of the spacecraft dynamics and thus improve the robustness and accuracy of the attitude estimate.

Abstract: The method for unloading the inertia wheels of a spacecraft comprising three references axes X, Y, Z, the axis Z corresponding to a pointing direction, consists in inverting the direction of accumulation of the angular momentum in the wheels by automatic rotational flipping of the spacecraft about the axis Z, the pointing direction remaining fixed. The method has application to the field of satellites or of interplanetary probes.

Abstract: A propulsion system and method are described configured to exert a force upon a vehicle. The system includes a concentrated mass which may be discharged from the vehicle by a propellant typically via an ejection tube. The system is optimized so that the discharged concentrated-mass imparts a large impulse upon the vehicle. The system and method may be used to alter the momentum of vehicles for propulsion, attitude correction, vehicle separation and the like.

Abstract: Technology for predicting and correcting a trajectory is described. The technology can create a model to predict a position of the reusable launch vehicle at a time in the future; observe a wind condition during ascent of the reusable launch vehicle; store the observed wind condition in a wind map; predict during ascent a position and a terminal lateral velocity of the reusable launch vehicle at a terminal altitude; and correct a flight trajectory of the reusable launch vehicle based on the wind map.

Abstract: A method of controlling inertial attitude of an artificial satellite in order to perform a navigation function and to maximize terrestrial coverage of the Earth by the satellite. The method includes deploying the artificial satellite in an orbit about the poles of the Earth; applying gyroscopic precession to the artificial satellite spin axis to precess and maintain the satellite near the ecliptic pole; deploying the artificial satellite so that the spin axis is initially perpendicular to or substantially perpendicular to sun lines; and applying gyroscopic precession to the artificial satellite spin axis to precess the spin axis away from an initial deployed attitude at a selectively-variable precession rate and to maintain the spin axis perpendicular to or substantially perpendicular to the sun lines.

Abstract: A solar powered spacecraft power system including a solar photovoltaic array, an electric propulsion system connected directly to the solar photovoltaic array in parallel with the spacecraft power system; the electric propulsion system including a Hall effect thruster, a thruster power supply for driving the thruster; a sensor for sensing the power output of the solar array and a controller responsive to the power output of the solar array and configured to periodically adjust an operating parameter of the thruster to operate the thruster at the maximum available output power of the solar array including comparing a previous solar array output power level with a later solar array output power level, and incrementing the operating parameter with a positive value if the later is greater and with a negative value if the later is lesser; a solar powered spacecraft power system including a solar photovoltaic array, an electric propulsion system connected directly to the solar photovoltaic array, and a power manage

Abstract: Systems and methods of controlling solid propellant gas pressure and vehicle thrust are provided. Propellant gas pressure and a vehicle inertial characteristic are sensed. Propellant gas pressure commands and vehicle thrust commands are generated. A propellant gas pressure error is determined based on the propellant gas pressure commands and the sensed propellant gas pressure, and vehicle thrust error is determined based on the vehicle thrust commands and the sensed vehicle inertial characteristic. Reaction control valves are moved between closed and full-open positions based on the determined propellant gas pressure error and on the determined vehicle thrust error. The system and method allow the reaction control valves to operate at variable frequencies or at fixed frequencies. The system and method also allows propellant pressure to be commanded to follow a predetermined pressure profile or commanded to vary “on-the-fly.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: A method for controlling the attitude of a satellite in orbit around a celestial object, the satellite including an observation instrument, a solar panel, a radiator and a star sensor which are arranged on the satellite such that, in a reference frame associated with the satellite and defined by three orthogonal axes X, Y, and Z, the observation instrument has its observation axis parallel to the Z-axis, the solar panel is parallel to the Y-axis, the radiator is arranged on one of the sides ?X, +Y, or ?Y of the satellite, and the star sensor points to the negative X values side. The roll and pitch attitudes of the satellite are controlled during an activity period to direct the observation instrument towards areas of the celestial object to be observed, and the yaw attitude of the satellite is controlled to keep the sun on the positive X values side and ensure that a solar panel minimum insolation constraint is satisfied during observation phases of the activity period.

Abstract: Methods and systems are provided for using a measurement of only one axis of a three-axis magnetometer to perform at least one corrective action on an unmanned aerial vehicle (“UAV”). An exemplary embodiment comprises (i) receiving from a three-axis magnetometer a measurement representative of an attitude of a UAV, wherein the measurement is of only one axis of the magnetometer, (ii) comparing the measurement to an allowable range of attitudes, (iii) determining that the measurement is not within the allowable range of attitudes, and (iv) performing at least one corrective action on the UAV.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: A method for pointing control of a laser communication terminal on a spacecraft may include measuring a line-of-sight (LOS) error of the laser communication terminal. The method may also include estimating a LOS error of the laser communication terminal based on measurements from a spacecraft gyro and a gimbal gyro onboard the spacecraft. The method may further include switching from a LOS error measurement feedback to a LOS error estimate feedback to control pointing of the laser communication terminal during a power fade condition.

Abstract: Provided are an attitude control system and method of a spacecraft of an artificial satellite that may enhance a maneuverability and a controllability by simultaneously applying a reaction wheel and a thruster among drive units used to maneuver an attitude of the spacecraft of the artificial satellite. The attitude control system may include: a thruster-based attitude controller which control firing time of thrusters mounted on the spacecraft; and a reaction wheel-based attitude controller controlling driving of a reaction wheel mounted on the spacecraft. The spacecraft may include a plurality of reaction wheels. When a defect occurs in the spacecraft due to a partial malfunction of the reaction wheels, an attitude maneuverability of the spacecraft may be corrected by simultaneously applying the thruster-based attitude controller and the reaction wheel-based attitude controller.

Abstract: A system for controlling an aerospace vehicle using on-line inertia estimation may include an attitude sensor to measure an attitude of the aerospace vehicle. The system may also include a processor on board the aerospace vehicle. An inertia estimator operable on the processor may generate an on-line inertia estimate of the aerospace vehicle. A rate and attitude estimator operable on the processor may determine an angular position and angular velocity of the aerospace vehicle using the attitude measurement of the aerospace vehicle and the on-line inertia estimate for controlling movement and orientation of the aerospace vehicle without any rates of rotation of the aerospace vehicle being required.

Abstract: [OBJECT] It is an object to solve a problem that a light-emitting element and a large-capacity battery required for allowing light generated from a satellite to be visually observed from the earth lead to enormously high costs. [SOLUTION] The present invention provides a satellite which comprises a reflecting mirror for reflecting sunlight toward the earth, and a transceiver, wherein the transceiver is operable to receive information including at least a position of the sun, a position of the satellite, and an irradiation point on the earth surface to be irradiated with the reflected light, so as to set a direction of a reflecting surface of the reflecting mirror based on the received information, and wherein the satellite is adapted to orient the reflecting surface of the reflecting mirror in the direction set based on the received information.

Abstract: The electro-optical system for determining the attitude of a mobile part comprises a fixed part and a mobile part, the fixed part being linked rigidly with at least one virtual image plane. The mobile part is linked rigidly with at least one first linear electro-optical device defining a first direction vector, the calculation of the position of the vanishing point of the projection of the straight line comprising the first direction vector in the image plane determining a first direction, representing the direction of the mapping of the first direction vector in the image plane, and a first choice of a first point of the projection in the image plane of the straight line comprising the first direction vector determining a first sense, representing the sense of the mapping of the first direction vector in the image plane.

Abstract: A system for estimating at least one of position, attitude, and heading of a vehicle is disclosed. The system includes at least three gyroscopes configured to output a signal indicative of inertial angular rates around three mutually orthogonal axes of the vehicle and at least three accelerometers configured to output a signal indicative of accelerations along three mutually orthogonal axes of the vehicle. The system further includes a triaxial magnetometer configured to output a signal indicative of a projection of ambient magnetic field on three mutually orthogonal axes of the vehicle. The system also includes a sensor configured to output a signal indicative of vehicle altitude and a differential pressure sensor configured to output a signal indicative of airspeed of the vehicle. The system further includes a device configured to receive the signals and estimate at least of one of position, attitude, and heading of the vehicle.

Abstract: Methods and systems are provided for orienting an agile vehicle using a control moment gyroscope array. A method comprises obtaining initial vehicle parameters for the vehicle and obtaining target vehicle parameters for the vehicle. The method further comprises determining command parameters based on a difference between the target vehicle parameters and the initial vehicle parameters, and simulating operation of the control moment gyroscope array using the command parameters and a torque value being at least equal to a maximum achievable torque for the control moment gyroscope array. When the simulated vehicle parameters are substantially equal to the target vehicle parameters, the method further comprises determining a torque profile for the control moment gyroscope array based on the simulated operation and operating the control moment gyroscope array using the torque profile.

Abstract: The method for generating an integrated guidance law for aerodynamic missiles uses a strength Pareto evolutionary algorithm (SPEA)-based approach for generating an integrated fuzzy guidance law, which includes three separate fuzzy controllers. Each of these fuzzy controllers is activated in a unique region of missile interception. The distribution of membership functions and the associated rules are obtained by solving a nonlinear constrained multi-objective optimization problem in which final time, energy consumption, and miss distance are treated as competing objectives. A Tabu search is utilized to build a library of initial feasible solutions for the multi-objective optimization algorithm. Additionally, a hierarchical clustering technique is utilized to provide the decision maker with a representative and manageable Pareto-optimal set without destroying the characteristics of the trade-off front. A fuzzy-based system is employed to extract the best compromise solution over the trade-off curve.

Abstract: In order to control an attitude of a movable object having a flexible member (50) through an attitude maneuver, first, based on vibration of the flexible member at the time of the attitude maneuver, for example, a sampling function including no frequency components equal to or higher than a particular frequency is obtained. With the use of the sampling function, a control target value is created as a previously-frequency-shaping-type feedforward control law. Based on the control target value, attitude control data is created. The attitude control data can be used for the attitude maneuver with respect to the movable object.

Abstract: The control optimization method for helicopters carrying suspended loads during hover flight utilizes a controller based on time-delayed feedback of the load swing angles. The controller outputs include additional displacements, which are added to the helicopter trajectory in the longitudinal and lateral directions. This simple implementation requires only a small modification to the software of the helicopter position controller. Moreover, the implementation of this controller does not need rates of the swing angles. The parameters of the controllers are optimized using the method of particle swarms by minimizing an index that is a function of the history of the load swing. Simulation results show the effectiveness of the controller in suppressing the swing of the slung load while stabilizing the helicopter.

Abstract: The fuzzy logic-based control method for helicopters carrying suspended loads utilizes a controller based on fuzzy logic membership distributions of sets of load swing angles. The anti-swing controller is fuzzy-based and has controller outputs that include additional displacements added to the helicopter trajectory in the longitudinal and lateral directions. This simple implementation requires only a small modification to the software of the helicopter position controller. The membership functions govern control parameters that are optimized using a particle swarm algorithm. The rules of the anti-swing controller are derived to mimic the performance of a time-delayed feedback controller. A tracking controller stabilizes the helicopter and tracks the trajectory generated by the anti-swing controller.

Abstract: A method of and apparatus for determining and controlling the inertial attitude of a spinning artificial satellite without using a suite of inertial gyroscopes. The method and apparatus operate by tracking three astronomical objects near the Earth's ecliptic pole and the satellite's and/or star tracker's spin axis and processing the track information.

Abstract: The invention refers to a docking device for the docking of a maintenance device to a nozzle of a satellite, including a distance sensor for determining the distance between the maintenance device and the nozzle of the satellite. Further, a locking device is provided for connecting the docking device with the nozzle of the satellite.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes determining a nominal orbital path of a navigation satellite. The method also includes transmitting ephemeris data corresponding to the nominal orbital path from the navigation satellite to a plurality of navigation devices. The method further includes determining an actual orbital path of the navigation satellite locally at the navigation satellite. In addition, the method includes determining a deviation between the actual orbital path and the nominal orbital path locally at the navigation satellite. The method also includes autonomously adjusting the actual orbital path locally at the navigation satellite to reduce the deviation between the actual orbital path and the nominal orbital path.

Abstract: A method of controlling attitude of a spacecraft during a transfer orbit operation is provided. The method includes providing a slow spin rate, determining the attitude of the spacecraft using a unified sensor set, and controlling the attitude of the spacecraft using a unified control law. The use of a unified set of sensors and a unified control law reduces spacecraft complexity, cost, and weight.

Abstract: A method for controlling the attitude of a satellite in orbit around a celestial object, the satellite including an observation instrument, a solar panel, a radiator and a star sensor which are arranged on the satellite such that, in a reference frame associated with the satellite and defined by three orthogonal axes X, Y, and Z, the observation instrument has its observation axis parallel to the Z-axis, the solar panel is parallel to the Y-axis, the radiator is arranged on one of the sides ?X, +Y, or ?Y of the satellite, and the star sensor points to the negative X values side. The roll and pitch attitudes of the satellite are controlled during an activity period to direct the observation instrument towards areas of the celestial object to be observed, and the yaw attitude of the satellite is controlled to keep the sun on the positive X values side and ensure that a solar panel minimum insolation constraint is satisfied during observation phases of the activity period.

Abstract: A system and method for gyroless transfer orbit sun acquisition using only wing current measurement feedback is disclosed. With this system and method, a spacecraft is able to maneuver itself to orient its solar panel to its maximum solar exposure spinning attitude. The disclosed system and method involve controlling a spacecraft maneuver using only the solar wing current feedback as the sole closed-loop feedback sensor for attitude control. A spin controller is used for controlling the spacecraft spin axis orientation and spin rate. The spin controller commands the spacecraft spin axis orientation to align with an inertial fixed-direction and to rotate at a specified spin rate by using a momentum vector. In addition, a method for estimating spacecraft body angular rate and spacecraft attitude is disclosed. This method uses a combination of solar array current and spacecraft momentum as the cost function with solar wing current feedback as the only closed-loop feedback sensor.

Abstract: Methods and apparatus for a spacecraft (1) orbiting about a celestial body such as the Earth to reacquire operational three-axis orientation with respect to that body.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.