Abstract: A method of operating a synthetic aperture radar “SAR” to acquire SAR echo data for the formation of an image, comprises calculating a nadir ambiguity index for the nadir of the platform; determining a frequency sweep direction sequence for successive pulses of a waveform to be transmitted by the SAR based on the nadir ambiguity index; obtaining a relative phase sequence for the successive pulses of the waveform; and encoding the waveform with the determined frequency sweep direction sequence and the relative phase sequence.

Abstract: A computer-implemented method for identifying one or more changes across a plurality of images, the method comprising: receiving, at a convolutional neural network, CNN, encoder, CNN input data comprising data associated with each pixel of each of the plurality of images; propagating the CNN input data through the CNN encoder to generate a plurality of feature maps, wherein each feature map comprises a feature classification of each pixel of a respective image of the plurality of images according to a feature classification scheme, wherein the feature classification scheme comprises a plurality of classifications and is generated by the CNN encoder based on training data; receiving, at a ConvLSTM network, ConvLSTM input data comprising the plurality of feature maps generated by the CNN encoder; and propagating the ConvLSTM input data through the ConvLSTM network to generate a change map, wherein the change map comprises change data indicative of one or more changes across the plurality of images.

Abstract: The present disclosure relates to a method of generating auxiliary data for controlling a satellite travelling in orbit around Earth, the method comprising: receiving tracking data for the satellite; applying an orbit determination algorithm including: estimating an orbit for the satellite based on the tracking data; and predicting, based on the estimated orbit, future ephemerides data of the satellite; generating auxiliary data comprising predicted future ephemerides data; and transmitting the auxiliary data to the satellite for use in the satellite's attitude and orbit control.

Abstract: An assembly jig comprises: a support member providing a support surface; a tool configured to receive one component of a faster pair such that the component is not rotatable relative to the tool; one or more alignment members to locate the tool relative to the support member; wherein the one or more alignment members and the tool are configured such that, when the tool is located by the one or more alignment members on the support member, the tool is still rotatable with respect to the support member about an axis perpendicular to the support surface.

Abstract: A method of method of detecting ambiguities in synthetic aperture radar (SAR) image data is performed on SAR data comprising, for each pixel in an image, an amplitude and a phase value. The method comprises: calculating at least one phase derivative value for respective pixels represented by the SAR data with respect to a spatial direction, determining a threshold for the phase derivative value, and determining pixels with phase derivative values above the threshold to be ambiguous. A method of suppressing azimuth ambiguities in synthetic aperture radar “SAR” single look complex image data, is performed on a Doppler spectrum obtained from received SAR signals.

Abstract: A method of operating a Synthetic Aperture Radar ‘SAR’ to acquire image data of a swath comprising one or more subswath(s) is provided, wherein the SAR is carried on a platform moving along a flight direction and a radiated beam is directed towards the swath, the method comprising: electronically steering the beam in azimuth direction along one subswath for each burst; and mechanically steering the beam in a direction opposite to the flight direction during each burst. The method allows to obtain an improved swath to resolution ratio.

Abstract: A method of providing Earth observation data comprises: acquiring Earth observation echo data on a first satellite in a low Earth orbit, determining a time required to downlink predetermined data to a ground station on Earth from the first satellite at the current position of the first satellite. If the time required exceeds a predetermined threshold, the predetermined data may be transmitted to another satellite in orbit above Earth using space-to-space radio communication. Alternatively, the first satellite may receive data relating to the current position of another satellite in orbit above Earth, determine a time required to the predetermined data to a ground station via the other satellite at the current position of the at least one other satellite, and if the determined time for the other satellite is less than the time determined for the first satellite, transmit the predetermined data to the other satellite in orbit above Earth using space-to-space radio communication.

Abstract: A computer-implemented method of classifying objects in an image, the method comprising: receiving image data associated with the image; receiving incidence angle data, wherein the incidence angle data is indicative of an incidence angle from which the image data is collected by a detector; and using a machine learning model to classify one or more objects within the image as belonging to one of one or more categories, wherein classifying the one or more objects within the image is based on: the incidence angle data, and respective values of one or more parameters of the image data.

Abstract: An RF switching circuit for switching RF signals, the RF switching circuit comprises one or more RF switch drivers and one or more RF switches, the RF switch drivers configured to drive the one or more RF switches by supplying power to the one or more RF switches, the RF switch driver comprising an isolated gate driver comprising one or more inputs, one or more outputs, and electrical separation between the input circuitry and the output circuitry of the isolated gate driver, the RF switch driver configured to receive an input signal indicating when the one or more RF switches should be turned on and/or off, and to send in response an appropriate signal at the appropriate voltage to the one or more RF switches to turn them on or off according to the input signal.

Abstract: A computer-implemented method for encrypting image, wherein the image data is generated by collection of a signal, the signal having a bandwidth, and the image data comprises data corresponding to a plurality of pixels of an image, wherein each pixel has an associated phase value; and the method comprises the step of modifying each of the phase values respectively associated with each of the plurality of pixels based on a first encryption key, wherein a rate of change of phase between adjacent pixels, after the step of modifying each of the phase values, does not exceed the bandwidth.

Abstract: There are provided methods of processing satellite state data, comprising receiving satellite state data in the form of multiple separate files via one or more ground stations and compiling the received satellite state data into a single dataset accessible via an application programming interface and searchable by time range. There are further provided methods of processing satellite state data comprising receiving raw satellite state data; receiving manoeuvre data relating to one or more scheduled manoeuvres of the satellite; and filtering the received raw satellite state data in an orbit determination process to provide filtered satellite state data, wherein the manoeuvre data is used in the filtering of the received raw satellite state data.

Abstract: A system and a method for transmitting information from a synthetic aperture radar satellite to a client receiver. In one aspect, the synthetic aperture radar satellite includes a processing unit configured to form information from a previously measured synthetic aperture radar raw data stored in a data storage; a modulator configured to modulate the information to a synthetic aperture radar transmission signal; a transmitter for transmitting the modulated synthetic aperture radar transmission signal. The processing unit is configured to suppress the modulation from a received echo signal of the modulated synthetic aperture radar transmission signal to form and store a synthetic aperture radar raw data in the data storage. The client receiver includes an antenna for receiving the transmitted modulated synthetic aperture radar transmission signal; and a demodulator configured to demodulate the received transmitted modulated synthetic aperture radar transmission signal to obtain the information.

Abstract: A satellite comprising a body and a generally planar structure extending from the body. One or more radio frequency “RF” antennas, an amplification system for rf signals, and a power distribution system for the amplification system are mounted on the generally planar structure. Two or all of the power distribution system, the one or more RF antennas and the amplification system are arranged on respective parallel boards forming part of the generally planar structure. One or more of the parallel boards and the components mounted thereon may be connected to another similar board to form, respectively a larger power distribution system, antenna array or amplification system, for example arranged in a plurality of modules, each comprising at least one antenna, at least one power distribution system and at least one amplifier supported on at least two respective boards.

Abstract: A computer-implemented method for encrypting image, wherein the image data is generated by collection of a signal, the signal having a bandwidth, and the image data comprises data corresponding to a plurality of pixels of an image, wherein each pixel has an associated phase value; and the method comprises the step of modifying each of the phase values respectively associated with each of the plurality of pixels based on a first encryption key, wherein a rate of change of phase between adjacent pixels, after the step of modifying each of the phase values, does not exceed the bandwidth.

Abstract: An Earth monitoring system comprises a satellite constellation (310) and a schedule calculation module (302) located on Earth. The schedule calculation module (302) may be configured to implement a satellite management method receiving a request post-launch for a location to be imaged; recalculating an existing schedule of the satellites to provide an updated schedule that includes imaging the location; and providing the updated schedule for transmission to one or more of the satellites.

Abstract: A satellite comprises a body and a generally planar structure extending from the body. One or more radio frequency “RF” antennas, an amplification system for RF signals, and a power distribution system for the amplification system are mounted on the generally planar structure. Two or all of the power distribution system, the one or more RF antennas and the amplification system are arranged on respective parallel boards (310, 312, 314) forming part of the generally planar structure (300). One or more of the parallel boards (310, 312, 314) and the components mounted thereon may be connected to another similar board to form, respectively, a larger power distribution system, antenna array or amplification system, for example arranged in a plurality of modules, each comprising at least one antenna, at least one power distribution system and at least one amplifier supported on at least two respective boards.

Abstract: A satellite (140) for operation in orbit around the earth comprises an ADCS (131, FIG. 1) configured for mechanically steering the satellite in the azimuth direction to prolong a dwell time (1105), during which a selected target is visible from the satellite, as the satellite orbits over the target. A processor at the ground station may be configured to process raw SAR data from any of the satellites described here. The raw SAR data may be processed in a number of ways to provide image information including but not limited to forming multilook images, compiling video sequences and colour coding images.

Abstract: A method of operating a power amplifier supplying power to an antenna, supplying switched power to the power amplifier comprises in a first mode of operation via a driver circuit and one or more switches to switch the supply of power to the power amplifier on and off periodically; and calibrating the power amplifier in a second mode of operation. The calibrating comprises supplying voltage to the power amplifier via the same driver circuit and one or more switches for a calibration pulse duration longer than the on/off period. A power supply and an RF front end comprising the power supply are also disclosed.

Abstract: A system and a method for transmitting information from a synthetic aperture radar satellite to a client receiver. In one aspect, the synthetic aperture radar satellite includes a processing unit configured to form information from a previously measured synthetic aperture radar raw data stored in a data storage; a modulator configured to modulate the information to a synthetic aperture radar transmission signal; a transmitter for transmitting the modulated synthetic aperture radar transmission signal. The processing unit is configured to suppress the modulation from a received echo signal of the modulated synthetic aperture radar transmission signal to form and store a synthetic aperture radar raw data in the data storage. The client receiver includes an antenna for receiving the transmitted modulated synthetic aperture radar transmission signal; and a demodulator configured to demodulate the received transmitted modulated synthetic aperture radar transmission signal to obtain the information.

Abstract: A system and a method for transmitting information from a synthetic aperture radar satellite to a client receiver. In one aspect, the synthetic aperture radar satellite includes a processing unit configured to form information from a previously measured synthetic aperture radar raw data stored in a data storage; a modulator configured to modulate the information to a synthetic aperture radar transmission signal; a transmitter for transmitting the modulated synthetic aperture radar transmission signal. The processing unit is configured to demodulate a received echo signal of the modulated synthetic aperture radar transmission signal to form and store a synthetic aperture radar raw data in the data storage. The client receiver includes an antenna for receiving the transmitted modulated synthetic aperture radar transmission signal; and a demodulator configured to demodulate the received transmitted modulated synthetic aperture radar transmission signal to obtain the information.