Abstract: An apparatus is disclosed for processing a sequence of samples of a received signal R reflected by a target surface and having a delay and a frequency shift relative to a reference signal D to obtain a delay Doppler map for the reflected signal. A first correlation module can obtain partial correlations z(n?, k) between samples corresponding to the reflected signal R and a samples corresponding to the reference signal D, across a set of delays. An inverse discrete fourier transform (DFT) of a sequence of samples can be derived from at least DFTs of a first reflected signal sequence and second reference signal sequence.

Abstract: A method and apparatus for mitigating a phase anomaly in an analogue-to-digital converter (ADC) output signal is disclosed. A plurality of codewords output by the ADC are received and information about an estimated level of interference between an output of the ADC and an input of the ADC due to the codeword is obtained for each codeword based on the logic values of bits in the codeword. In-phase (I) and quadrature (Q) corrections are obtained based on the information about the estimated level of interference, and applied to I and Q values obtained from the ADC output signal.

Abstract: A satellite communication system includes at least one base station, at least one satellite that can be brought into communication connection with the base station for data transmission, and a plurality of receivers adapted to receive signals transmitted from the satellite. The communication system is designed to transmit data in at least one uplink data stream from the base station to the satellite with a first data transmission rate and to transmit data in at least one downlink data stream from the satellite to the receivers with a second data transmission rate. The first data transmission rate is lower than the second data transmission rate and the satellite is provided with a data storage adapted to store the data transmitted from the base station to the satellite and to supply the data provided for the transmission to the receivers.

Abstract: A received Direct Sequence Spread Spectrum DSSS signal is processed by performing DSSS acquisition to obtain estimates of a frequency offset and a spreading code phase, sequentially obtaining, for each one of a plurality of segments of a received DSSS signal, a correlation function between the DSSS signal segment and a replica of a spreading code by using a Time and Frequency Transform based correlation method, the estimated frequency and the spreading code phase, and performing DSSS carrier tracking by tracking the phase of a correlation peak in the obtained correlation functions, and applying phase corrections to the obtained correlation functions to provide fine Doppler compensation. The time and frequency transform based correlation method involves, for each segment of the received DSSS signal, obtaining a plurality of samples and transforming the samples from the time domain to the frequency domain.

Abstract: A system for controlling a distribution of propellant in a propellant tank assembly for a spacecraft comprises a body for containing the propellant, a plurality of thermal tomography elements, including a plurality of temperature-control elements and a plurality of temperature sensors, disposed around the body for detecting the distribution of the propellant inside the body; and a tomography element control module arranged to control the plurality of temperature-control elements to redistribute the propellant inside the propellant tank body by heating and/or cooling the propellant. In an embodiment, the propellant tank body includes a propellant management device inside the body and the tomography elements are disposed in proximity to the propellant management device. Tomography data can be obtained from the plurality of tomography elements, and a distribution of propellant within the propellant tank body can be determined based on the obtained tomography data.

Abstract: An apparatus for aligning non-synchronous input data streams received in the apparatus, the apparatus comprising an analog to digital converter arrangement for digitizing the data streams into a plurality of sequences of samples; and a synchronization processing arrangement for generating alignment pulses for each sequence of the plurality of sequences of samples, for arranging each sequence of samples with respect to the alignment pulses for the sequence and for synchronization the delivery of said plurality of sequences of samples to a common processor with respect to the respective alignment pulses. The synchronization processing arrangement may comprise a processing chain for each antenna feed of said plurality of antenna feeds and each processing chain may comprise an alignment pulse generator for generating an alignment pulse for the sequence of samples corresponding to the processing chain. The input data streams may be received by a plurality of antenna feeds.

Abstract: A method and apparatus for providing information about an encrypted signal transmitted by a satellite in a satellite navigation system are disclosed. A data sequence of the encrypted signal as transmitted is obtained, a signal sample is extracted from the data sequence, the signal sample including a part of the data sequence having a length less than a total length of the data sequence, and the signal sample and information about when the data included in the signal sample was transmitted by the satellite are transmitted, as the encrypted signal information, to a receiver for use in the satellite navigation system. A method and apparatus for authenticating an unencrypted signal based on the encrypted signal information are also disclosed.

Abstract: There is provided an apparatus for capturing a space object, the apparatus comprising a harpoon element for penetrating the object, the harpoon element being configured to form part of a harpoon for launching towards the object; and penetration control means for controlling the penetration of the harpoon element into the object. The penetration control means can comprise a compressible component, forming part of the harpoon, for absorbing some of the kinetic energy of the harpoon. Alternatively or additionally, it may comprise means for varying the launch speed of the harpoon.

Abstract: A structural panel for a satellite comprising an elongate pipe mounted thereto. The heat pipe is bonded to the panel intermediate its remote ends with a thermally conductive adhesive. The adhesive is omitted proximate at least one distal end of the heat pipe. The at least one distal end of the heat pipe without adhesive is mechanically secured to the panel by at least one bolt received in a cooperating threaded receiving element. A method of manufacturing such a panel is also provided.

Abstract: A method and apparatus for mitigating a phase anomaly in an analogue-to-digital converter (ADC) output signal is disclosed. A plurality of codewords output by the ADC are received and information about an estimated level of interference between an output of the ADC and an input of the ADC due to the codeword is obtained for each codeword based on the logic values of bits in the codeword. In-phase (I) and quadrature (Q) corrections are obtained based on the information about the estimated level of interference, and applied to I and Q values obtained from the ADC output signal.