Abstract: Systems and methods are provided for dynamically allocating and routing resource in a wireless communication system. The system includes at least one scheduled resource, a first terminal having a resource requirement and configured to acquire an alternate resource in response to an out-of-band signal, and a controller. The controller is configured to determine the alternate resource from the scheduled resource, schedule the alternate resource for the first terminal based on the resource requirement, and direct the first terminal to a set of frequencies of the alternate resource via the out-of-band signal The method includes determining an alternate resource in the wireless communication system from scheduled resource uses, scheduling the alternate resource for a terminal based on a scheduled resource use of the terminal, and directing the terminal to acquire the alternate resource at a set of frequencies of the alternate resource.

Abstract: The attitude of a physical platform (62) is altered by a summation of forces from an attitude actuator (74), disturbance forces (80) and random noise (82). Attitude sensors (64) sense the attitude of the physical platform (62) and output measured attitude parameters to a disturbance force effects (DFE) filter (66) and an attitude filter (68). The DFE filter (66) outputs an attitude perturbation command to the attitude filter (68) and a command translator (72). Effects of the attitude perturbation are used by the DFE filter (66) to estimate the effects of disturbances on the physical platform (62). A trigger signal (76) from the attitude actuator (74) is used by DFE filter (66) to select an appropriate gain matrix used in the estimation process.

Abstract: A spacecraft (10) body (20) located in an external magnetic field (12) has a substantially unbalanced electrical power bus (18) that generates a composite local magnetic field The electrical power bus (18) substantially surrounds an external surface (22) of the spacecraft (10). Current in the electrical power bus (18) is solar panel (14and 16) and/or battery (34) generated and can flow in different directions through different current paths. Electrical loads (58) are coupled to power converters (56) and current path switches (54) to couple the power converters (56) to the various current paths. A controller (28) takes sensor data (82), determines a required attitude adjustment torque (84), translates that adjustment torque into a composite magnetic field (86), determines an unbalanced bus current profile (88) to generate that composite magnetic field, selects a current source (90) and regulates current path switches (92) to achieve a desired attitude adjustment torque for the spacecraft (10).

Abstract: One or more deployable thermal panels (24, 28, 70) are actively controlled throughout the orbit of a satellite (20) to provide thermal dissipation. Adjusting the incident angle between the panel (24, 28, 70) and the sun and controlling the flow of fluid through optional flexible heat pipes loads and unloads heat to provide thermal stability for components (62) which have special thermal requirements. An optional antenna panel (70) on a nadir side (64) of the satellite (20) offers an antenna side (74) on one surface and a thermal radiating side (72) on an opposing surface. In addition, thermal panel movements are controlled (96) to provide counter-disturbance torques (140).

Abstract: A spacecraft (10) has combined propulsion and active thermal control systems. A propellant storage tank (20) couples to a pressurant storage tank (18). A working fluid (52) resides in the pressurant storage tank (18) and propels propellant when needed while concurrently acting as a thermal working fluid. The working fluid (52) is expanded then routed to selected cooled components (64). After passing by the cooled components (64), the working fluid (52) is compressed and passed by selected heated components (82). A controller (36) monitors temperature sensors (88) and controls valve assemblies (60, 78) to determine the components (64, 82) to which the working fluid (52) is routed.

Abstract: In a satellite (20), two-axis solar panel drives (56, 58) allow two degrees of rotational freedom of movement for solar panels (22, 24). Regulation of electrical current loops (46, 48) within the solar panels (22, 24) generates a magnetic field. When the solar panels (22, 24) are tilted about an overturning axis (28), the magnetic field provides a component of a control torque about a pitch axis (30). An on-board processor (52) commands the panel drives (56, 58) and a magnetic torque actuator (60) to instantaneously and simultaneously damp disturbance torques about a windmill axis (26), an overturning axis (28), and a pitch axis (30). The processor (52) allows disturbance torque to be corrected continuously rather than periodically over the course of an orbit. Counter-disturbance torques (90) are applied (88) in synchronism with a satellite nutation frequency (76) but out of phase with the nutation so that nutation is damped.

Abstract: A satellite attitude/orbit control system (300) for managing a satellite cluster (200) in a satellite constellation (207). A satellite cluster (200) comprises a master satellite (203) and secondary satellites (201, 202, 204, 204). The master satellite (203) receives sensor data from secondary satellites (201, 202, 204, 204) and combines such secondary sensor data with master sensor data from a master satellite (203) to calculate attitude/orbit estimates for all satellites within the satellite cluster (200). Attitude estimates are forwarded to each satellite for initiation of attitude/orbit control. Each satellite cluster (200) subordinates to a constellation master satellite (301) for receiving additional attitude/orbit estimates for use in determining and controlling satellite attitude/orbits.

Abstract: A satellite assembly (60, 68, 70) is formed from any number of bus modules (22) which have a substantially common shape and interior space volume. Each bus module (22) includes a structural frame (20) which is part of a structural subsystem and at least one and possibly all of a propulsion subsystem (28), a power subsystem (30), a thermal subsystem (32), an attitude, orientation and control subsystem (34), a telemetry, tracking and control subsystem (42) and a payload subsystem (44). Within each bus module (22), the subsystems are substantially non-redundant. Bus modules (22) attach together permanently or temporarily through attachment mechanisms (36). Permanent attachment is used to form large and/or redundancy within the satellites. Temporary attachment is used to increase the structural rigidity of individual bus modules (22) for launch purposes, then the assembly (60) is decomposed into individual satellites.

Abstract: An enhanced services communication system (10) has a standard services region and an enhanced services region (58) in which communication may be carried out. Subscriber units (49, 109) located within the enhanced services region (58) request enhanced services that include dynamic allocation of bandwidth. A variable bandwidth repeater switch (42) evaluates the availability of requested bandwidth and allocates the bandwidth to the subscriber units (49, 109) when available. Transmission of data using enhanced services occurs using wideband wired interfaces (115), wideband wireless interfaces (70), or PSTN interfaces (103). Selection of dynamic allocation of bandwidth may rely upon economic, propagation duration, or link quality factors, among other considerations.

Abstract: A method and system (12) for controlling the attitude of a spacecraft during its transfer orbit using an on-board, stand-alone, three-axes attitude determination and control system. The system utilizes a set of on-board sensors to define two independent angular measurements, which will initially identify the z-axis orientation of the spacecraft from an arbitrary attitude after launch vehicle separation. A set of three-axis gyros are then bias calibrated in order to measure the transverse rates of the spacecraft. The three-axis attitude of the spacecraft is continously determined by integrating the gyro outputs even if the Earth or Sun is not visible by an on-board sensor. A state estimator model is provided to determine the three-axis attitude of the spacecraft in the presence of large wobble and nutation. The system also utilizes a linear combination of the estimated attitude, rate and acceleration states to generate commanded rate increments with a pulse-width frequency modulator.

Abstract: The estimation and compensation of fixed, but unknown uncertainties of a thruster (22) for improving satellite attitude estimation and control as well as eliminating the need for nutation damping devices is disclosed. A thruster (22) is fired and an attitude state is estimated using an estimator (116). A commanded rate change (122) is calculated, which is modified using a compensating feedforward command (126) as updated by a fixed uncertainty estimator (124) unless an estimated rate is less than an absolute value of a threshold rate. The modified commanded rate change (130) is used to incrementally adjust thruster fire on-time (104) until a predetermined satellite trajectory is reached.