Abstract: Passively measured NEO bearings are used to augment an existing navigation system on-board the platform to correct the position estimate generated by the navigation system. The technology provides only a position correction based on passive NEO sightings but is applicable to a wide variety of platforms with different maneuvering profiles and update requirements. The technology directly calculates a position error based on the current position estimate and the passively measured and estimated bearings to three or more NEOs and provides the position error to the navigation system as a correction to the position estimate. The estimated bearings are computed from the current position estimate and the known orbits of the NEOs. The position error may be calculated from a single observation of multiple NEOs, allowing for frequent updates as needed and placing no restriction on platform maneuverability.

Abstract: Passively measured NEO bearings are used to augment an existing navigation system on-board the platform to correct the position estimate generated by the navigation system. The technology provides only a position correction based on passive NEO sightings but is applicable to a wide variety of platforms with different maneuvering profiles and update requirements. The technology directly calculates a position error based on the current position estimate and the passively measured and estimated bearings to three or more NEOs and provides the position error to the navigation system as a correction to the position estimate. The estimated bearings are computed from the current position estimate and the known orbits of the NEOs. The position error may be calculated from a single observation of multiple NEOs, allowing for frequent updates as needed and placing no restriction on platform maneuverability.

Abstract: It is presumed and commonly accepted by those skilled in the art of satellite navigation and Kalman filter design that the filter must be provided with the tracker position and velocity a priori in order to determine target position and velocity. Indeed, it is generally asserted that without a priori knowledge (known or measured values) of the tracker position and velocity, line of sight measurements between satellites do not contain adequate information to infer target states. Passive and autonomous navigation of space vehicles without a priori values for the position and velocity of either the target or tracker vehicle is achieved by reconfiguring the extended Kalman filter, or more generally any predictor/correction class filter, to include states for both the target and tracker vehicles. The target and tracker vehicles must both follow trajectories in an inertial frame of reference through the gravitational field of a gravitational body having a known gravitational model.

Abstract: A device for grappling orbital debris includes a chain of interconnected links, each having a corresponding contact sensor (for sensing contact with the orbital debris), and each connected to a subsequent link by an actuator (e.g., a worm drive assembly or the like). The actuators are configured to sequentially cause rotation of each link in the chain until the corresponding contact sensor indicates that the link has made contact with the orbital debris. Subsequently, the next link in the chain is rotated, and so on, until the chain of interconnected links substantially surrounds at least a portion of the orbital debris.

Abstract: An integrated circuit for generating image data comprises a focal-plane array of unit cells, a controller, and a memory structure having a plurality of storage locations. Each unit cell may store charge based on detected photons. The controller may read a value based on the stored charge from at least some of the unit cells, and either add the read value to an existing value in the corresponding storage location when operating in frame-sum mode, or add the read value to an existing value in a shifted storage location when operating in time-delay integration (TDI) mode. This may allow faint objects as well as objects moving in the field-of-view of the focal-plane array to be observed. The integrated circuit may be fabricated from radiation-hardened CMOS technology and may be a layer of a sensor chip assembly.

Abstract: A device for grappling orbital debris includes a chain of interconnected links, each having a corresponding contact sensor (for sensing contact with the orbital debris), and each connected to a subsequent link by an actuator (e.g., a worm drive assembly or the like). The actuators are configured to sequentially cause rotation of each link in the chain until the corresponding contact sensor indicates that the link has made contact with the orbital debris. Subsequently, the next link in the chain is rotated, and so on, until the chain of interconnected links substantially surrounds at least a portion of the orbital debris.

Abstract: Geosynchronous surveillance is conducted by injecting one or more observer satellites into a retro sub or super geosynchronous orbit at approximately zero inclination. The observer satellite spins about an approximately North-South axis in an Earth frame of reference to sweep a sensor's FOV around the geobelt. Sensor time delay integration (TDI) is synchronized to the observer satellite's spin-rate and possibly the sum of the spin-rate and the target inertial LOS rate to realize longer integration times. This approach facilitates faster scans of the entire geobelt, more timely updates of the catalog of tracked objects and resolution of small and closely spaced objects. An inexpensive small-aperture body-fixed visible sensor may be used.

Abstract: An integrated circuit for generating image data comprises a focal-plane array of unit cells, a controller, and a memory structure having a plurality of storage locations. Each unit cell may store charge based on detected photons. The controller may read a value based on the stored charge from at least some of the unit cells, and either add the read value to an existing value in the corresponding storage location when operating in frame-sum mode, or add the read value to an existing value in a shifted storage location when operating in time-delay integration (TDI) mode. This may allow faint objects as well as objects moving in the field-of-view of the focal-plane array to be observed. The integrated circuit may be fabricated from radiation-hardened CMOS technology and may be a layer of a sensor chip assembly.

Abstract: Geosynchronous surveillance is conducted by injecting one or more observer satellites into a retro sub or super geosynchronous orbit at approximately zero inclination. The observer satellite spins about an approximately North-South axis in an Earth frame of reference to sweep a sensor's FOV around the geobelt. Sensor time delay integration (TDI) is synchronized to the observer satellite's spin-rate and possibly the sum of the spin-rate and the target inertial LOS rate to realize longer integration times. This approach facilitates faster scans of the entire geobelt, more timely updates of the catalog of tracked objects and resolution of small and closely spaced objects. An inexpensive small-aperture body-fixed visible sensor may be used.

Abstract: It is presumed and commonly accepted by those skilled in the art of satellite navigation and Kalman filter design that the filter must be provided with the tracker position and velocity a priori in order to determine target position and velocity. Indeed, it is generally asserted that without a priori knowledge (known or measured values) of the tracker position and velocity, line of sight measurements between satellites do not contain adequate information to infer target states. Passive and autonomous navigation of space vehicles without a priori values for the position and velocity of either the target or tracker vehicle is achieved by reconfiguring the extended Kalman filter, or more generally any predictor/correction class filter, to include states for both the target and tracker vehicles. The target and tracker vehicles must both follow trajectories in an inertial frame of reference through the gravitational field of a gravitational body having a known gravitational model.