The present invention provides a space vehicle comprising an optical system having a field of view, the optical system comprising at least two optical elements spaced from one another along an optical axis of the optical system, thereby defining an interior cavity of the optical system; at least one control system, the control system comprising at least one physical element configured for performing one or more functions for enabling operation of the vehicle; and at least one holding assembly for holding the at least one control system, the holding assembly comprising a folding mechanism configured and operable to move between a folded position corresponding to an inoperative mode of the optical system, and a deployed position corresponding to an operative mode of the optical system, such that in the folded position of the folding mechanism, the control system that is held by the holding assembly is at least partially located in the interior cavity of the optical system for stowage, and in the deployed position of the folding mechanism, the control system that is held by the holding assembly is located outside the interior cavity and outside the field of view of the optical system, thereby allowing operation of the optical system.

A configuration for a satellite constellation has a plurality of planes, each plane including a plurality of satellites therein, at least some of the planes situated at a different altitude than other of the planes. In some embodiments, all planes contain the same number of satellites; in some other embodiments, at least one plane includes a different number of satellites than the other planes in the constellation. In some embodiments, the satellites in each plane are evenly spaced.

The invention relates to a navigation satellite (10, 10, 10), in particular for a medium earth orbit (MEO), having a housing (12) and a navigation antenna (16) connected to the housing (12) for emission of navigation signals in a preferred direction. Furthermore, the navigation satellite (10, 10, 10) has an optical communication system (22) for unidirectional or bidirectional signalling having at least one other satellite advancing in the direction of movement and/or having at least one other satellite following in the direction of movement. The navigation satellite (10, 10, 10) has a holder (for example as navigation antenna), which is arranged rotatably on the housing (12) about an axis of rotation (17), the optical communication system being (22) arranged on the holder.

A radar satellite of the present invention comprises a radar unit including a plurality of radar panels coupled to each other in a single flat plate shape, each of the plurality of radar panels including a plurality of antennas which transmit and receive radar waves, and a solar cell; and a communication/control unit which performs communications with a spot on an earth or a spacecraft. The radar unit includes: a radar panel array which is a plate-shaped structure including the plurality of radar panels; and a deployable truss structure including a plurality of side frame members supporting the plurality of radar panels, respectively, and coupled to each other in such a manner that the side frame members are foldable and deployable.

Disclosed is a method for achieving space-based autonomous navigation of global navigation satellite system (GNSS) satellites, and relates to the field of satellite navigation technologies. The method includes the following steps: optimizing a DRO, and establishing a dynamic model of an earth-moon space satellite orbit; establishing measurement links, by a low earth orbit (LEO) data relay satellite, with an earth-moon space DRO satellite and a GNSS respectively, and measuring an inter-satellite distance for modeling and linearization; adopting an extended Kalman filter (EKF) method to process inter-satellite measurement data, and autonomously determining a position and velocity of the global navigation satellite system without depending on the ground measurement and control support.

An apparatus receives values of parameters defining an orbit of a satellite of a satellite navigation system for a validity period. The apparatus furthermore determines whether a received value of at least one parameter of a predetermined set of the parameters is saturated. The apparatus then takes into account whether a received value of at least one parameter of the predetermined set of parameters is determined to be saturated in a process of extending the validity period of the received values of parameters.

The invention relates to a navigation satellite (10, 10, 10), in particular for a medium earth orbit (MEO), having a housing (12) and a navigation antenna (16) connected to the housing (12) for emission of navigation signals in a preferred direction. Furthermore, the navigation satellite (10, 10, 10) has an optical communication system (22) for unidirectional or bidirectional signalling having at least one other satellite advancing in the direction of movement and/or having at least one other satellite following in the direction of movement. The navigation satellite (10, 10, 10) has a holder (for example as navigation antenna), which is arranged rotatably on the housing (12) about an axis of rotation (17), the optical communication system being (22) arranged on the holder.

A method, computer program product and system where a processor(s) configures sensor(s) on an unmanned aircraft system, to capture data related to a surface of a defined geographic area. The processor(s) navigate the unmanned aircraft system in a repeatable defined travel path proximate to the defined geographic area, such that the sensor(s) capture surface data related to the defined geographic area during the navigating, wherein a position of the unmanned aircraft system in the travel path is within a satellite view geometry of a satellite. The processor(s) maintain the unmanned aircraft system at a distance from the surface at which atmosphere does not obscure the data and obtain the data collected by the sensor(s). The processor(s) compares the data collected by the sensor(s) to data collected by one or more instruments on the satellite related to the defined geographic area to determine is the instrument(s) of the satellite are calibrated.

A software-defined receiver (SDR) using real long term evolution (LTE) signals may be used for navigation. The LTE SDR leverages the structure of the downlink LTE signal, and provides signal acquisition, navigation-relevant high-level system information extraction, and signal tracking. The LTE SDR also provides the ability to obtain a time-of-arrival (TOA) estimate from received LTE signals, which provides a navigation solution comparable to a GPS-only navigation solution.

A satellite orbiting in one of a plurality of orbital planes of a satellite constellation system at an altitude range corresponding to low earth orbit includes at least one processor configured to generate satellite state data, and to generate a navigation signal based on the satellite state data. The satellite includes at least one transmitter configured to transmit the navigation signal for receipt by at least one client device on earth. Each of the plurality of orbital planes includes a corresponding one of a plurality of satellite subsets of a plurality of satellites of the satellite constellation system. Each of the plurality of orbital planes is within the altitude range, and the plurality of orbital planes includes a set of inclined orbital planes at a non-polar inclination.