Abstract: Methods, systems, and devices for scanning operations for co-located satellite antennas are described. For instance, a set of co-located satellite antennas may transmit a set of component transmit signals to form a beam, where a first line segment at a boundary of the beam is tangential to a first sphere having a surface that encompasses Earth, where a location on the first line segment tangential to the surface of the first sphere is above a surface of the Earth by a threshold altitude. The set of co-located satellite antennas may receive a set of component receive signals including reflected energy of the beam. A central processor may apply a set of beamforming coefficients to the set of component receive signals to obtain a receive beam signal and may process the receive beam signal to obtain a signature associated with an object within a limb of the Earth.

Abstract: A system for communications may include an antenna array, where an inter-element spacing of antennas of the antenna array may be different across the antenna array; antenna managers that are coupled with respective antennas and configured to transmit and receive ranging signals used to measure parameters representative of distances between a respective antenna and the other antennas; a calibration unit that determines positions of the antennas based on the measured parameters and positions of reference antennas; and a communications manager that communicates with a terminal according to beam coefficients determined for the antenna array based on the determined positions of the antennas.

Abstract: A multi-static synthetic aperture radar using beamforming processing is described. A reception processing system may process feed element signals (e.g., from feed elements on a satellite or from access node terminals in an end-to-end relay system) according to multiple beam weight sets, each corresponding to a beam coverage pattern including one or more radar image pixel beams to generate a set of beam signals. The feed element signals may represent signal energy from a reflected illumination signal (e.g., beacon signal, communication signal), or passively received signal energy (e.g., without a corresponding illumination signal). The multiple sets of beam signals obtained from processing the feed element signals may then be processed to obtain image pixel values, and the image pixel values combined to obtain an image. Multiple sets of feed element signals (e.g., each corresponding to a time period) may be processed and combined to form the image.

Abstract: A multi-static synthetic aperture radar using beamformed illumination beams and multiple collection satellites is described. An illumination satellite may be in first orbit and multiple collection satellites may be in a second orbit. The illumination satellite may transmit beam signals (e.g., communication signals carrying modulated data to user terminals) from an antenna array to different beam coverage areas according to a beamforming matrix. Each of the collection satellites may receive reflections of the beam signals. The reflected signals received at the collection satellites may be processed according to the beam signals and beamforming matrix used to transmit the beam signals to obtain an image of a geographical area. In some cases, the collection satellites may relay the received signals for processing via the illumination satellite.

Abstract: Methods, systems, and devices for co-located satellites with ground based processing are described. A set of co-located satellites may be configured to collect a set of return link signal components, where each co-located satellite includes a first payload configured to receive a respective return link signal component including one or more return link signal transmitted from one or more terminals and a second payload configured to transmit a representation of the respective return link signal component. One or more ground stations may be configured to receive the representations of the respective return link signal components. A central processor may be configured to apply a set of beamforming coefficients to the representations of the respective return link signal components received by the one or more ground stations to obtain one or more return link beam signals corresponding to one or more return link beams from the set of co-located satellites.

Abstract: Methods, systems, and devices for communication operations are described. A first satellite may be in a first orbit, and a set of second satellites may be in second orbits that are lower than the first orbit. The second satellites may detect signal components of a signal originating from a geographic area and relay the respective signal components to the first satellite. A beamformer coupled with the first satellite may form a beam associated with the geographic area. The beamformer may also obtain a beam signal based on he respective signal components and a return channel, where the return channel includes at least a channel component between the geographic area and the set of second satellites.

Abstract: A communication system for communicating low latency data in a fading channel environment using a data structure having data frames modulated on a subcarrier signal and on a commercial radio channel bandwidth. Low latency data is updated relatively rapidly at the low latency data generator. Because of this constant changing of low latency data at the point of generation in the transmitter end, the present invention communicates low latency data from the transmitter end to the receiver end of the communication system with relatively low delay. This communication system encodes and decodes low latency data using a single block encoding/decoding scheme. Such an encoding/decoding scheme introduces relatively less delay during the encoding/decoding processes while ensuring satisfactory data integrity for data communication in a fading channel environment.