Abstract: A platform with a signal generation unit and a transmitting unit. The signal generation unit is adapted to generate a spreading code sequence. The spreading code sequence has a reference chip with a rising edge and a falling edge. The signal generation unit is adapted to adjust the spreading code sequence to ensure that the rising edge or the falling edge of the reference chip arrives at a Virtual Timing Reference Station, VTRS, on a predetermined time (tref,VTRS). The transmitting unit is adapted to engage with the signal generation unit and adapted to transmit the spreading code sequence. Further, a user device for receiving the transmitted spreading code sequence.

Abstract: A method for each of a plurality of satellites of a secondary Global Navigation Satellite System, GNSS, in a Low Earth Orbit, LEO, comprising receiving GNSS signals, in a first frequency band, from Line-Of-Sight, LOS, satellites of at least one primary GNSS in a Medium Earth Orbit. Candidate sets of orbit and clock corrections for the LOS satellites are received. A Position-Velocity-Time, PVT, calculation is performed based on code and/or carrier pseudo-ranges between a respective satellite of the secondary GNSS and the LOS satellites. The code and/or carrier pseudo-ranges are derived from the GNSS signals and are corrected by a single set of the candidate sets. A short-term prediction model is determined for an orbit and clock of the respective satellite based on the PVT and is included in a navigation message, transmitted in a second frequency band, modulated onto a LEO navigation signal intended for terrestrial user equipment.

Abstract: A method of detecting a direction of arrival of at least one interference signal interfering a wanted signal in a plurality of received signals involves receiving, by a number of antennas of an antenna array, a number of signals, identifying an interference signal in the received signals, applying a beam forming signal processing technique to the identified interference signal, and detecting the direction of arrival from the results of the beam forming signal processing.

Abstract: A platform with a signal generation unit and a transmitting unit. The signal generation unit is adapted to generate a spreading code sequence. The spreading code sequence has a reference chip with a rising edge and a falling edge. The signal generation unit is adapted to adjust the spreading code sequence to ensure that the rising edge or the falling edge of the reference chip arrives at a Virtual Timing Reference Station, VTRS, on a predetermined time (tref,VTRS). The transmitting unit is adapted to engage with the signal generation unit and adapted to transmit the spreading code sequence. Further, a user device for receiving the transmitted spreading code sequence.

Abstract: A wireless communication unit for compensating for Ionospheric group delay in a satellite communication system. The wireless communication unit comprises: a receiver configured to receive a multi-carrier signal from a satellite; and a processor coupled to the receiver. The processor is configured to: process the multi-carrier signal to produce a plurality of digital representations of individual carriers of the multi-carrier signal; estimate, from the plurality of digital representations of individual carriers of the multi-carrier signal, a Total Electron Content, TEC, value associated with a communication path between the satellite and the wireless communication unit through Earth's Ionosphere; and apply compensation for Ionospheric group delay subjected to the multi-carrier signal based on the determined TEC value.

Abstract: This relates to a method for disseminating data in a navigation or communication system comprising several transmitters for signals, wherein a common frame structure is provided for the signals and each transmitter disseminates common data and transmitter-dedicated data with its transmitted signal, and wherein the method comprises the following acts to be executed by each one of the transmitters: receiving the common data encoded with a first encoding scheme; encoding transmitter-dedicated data onboard the transmitter with a second encoding scheme; assigning the encoded common data to a number of first frames of the frame structure provided for the signals and assigning the encoded transmitter-dedicated data to a number of second frames of the frame structure provided for the signals, wherein the second frames differ from the first frames; assembling a signal to be transmitted from the number of first and second frames; and transmitting the assembled signal.

Abstract: A receiver for spread spectrum signals comprising a first part for preprocessing and digitizing a received signal, and a second part for tracking the digitized signal comprising a carrier loop and a code loop. The code loop comprises a generator for a reference receiver signal for correlation with the received signal and the code loop is configured to modify the reference signal to shape a correlation function between the received signal and the reference receiver signal. The first part is adapted to multiply the received spread spectrum signal with a first analog spectral offsetting signal provided for down-converting the received signal to an intermediate frequency and a sub-carrier frequency, selected from a set of sub-carrier frequencies, such that the received signal is down-converted and spectrally offset in the analog domain during a time interval covering at least one chip of a spreading code of the received signal.

Abstract: A method for determining an indicator of an amount of noise comprised within a received signal within a satellite communication network or a GNSS involves extracting a received modulating signal from the received signal. An estimate of the transmission delay is determined based on the in-phase component of the modulating signal. A prompt replica of the modulating signal is generated using the estimate of the transmission delay. A prompt quadrature correlation of the quadrature component of the received modulating signal and of the quadrature component of the prompt replica is determined, and the indicator of the amount of noise comprised within the received signal is determined based on the prompt quadrature correlation.

Abstract: A method for each of a plurality of satellites of a secondary Global Navigation Satellite System, GNSS, in a Low Earth Orbit, LEO, comprising receiving GNSS signals, in a first frequency band, from Line-Of-Sight, LOS, satellites of at least one primary GNSS in a Medium Earth Orbit. Candidate sets of orbit and clock corrections for the LOS satellites are received. A Position-Velocity-Time, PVT, calculation is performed based on code and/or carrier pseudo-ranges between a respective satellite of the secondary GNSS and the LOS satellites. The code and/or carrier pseudo-ranges are derived from the GNSS signals and are corrected by a single set of the candidate sets. A short-term prediction model is determined for an orbit and clock of the respective satellite based on the PVT and is included in a navigation message, transmitted in a second frequency band, modulated onto a LEO navigation signal intended for terrestrial user equipment.

Abstract: A receiver for spread spectrum signals comprising a first part for preprocessing and digitizing a received signal, and a second part for tracking the digitized signal comprising a carrier loop and a code loop. The code loop comprises a generator for a reference receiver signal for correlation with the received signal and the code loop is configured to modify the reference signal to shape a correlation function between the received signal and the reference receiver signal. The first part is adapted to multiply the received spread spectrum signal with a first analog spectral offsetting signal provided for down-converting the received signal to an intermediate frequency and a sub-carrier frequency, selected from a set of sub-carrier frequencies, such that the received signal is down-converted and spectrally offset in the analog domain during a time interval covering at least one chip of a spreading code of the received signal.

Abstract: A system for tracking a received signal with a subcarrier, the received signal representing a carrier signal modulated with a code signal and with a subcarrier signal. The system comprises independent and cooperatively operating loops: a phase lock loop tracking the carrier signal, a subcarrier lock loop tracking the subcarrier signal, and a delay lock loop tracking the code signal. The subcarrier lock loop comprises a first controllable oscillator and a first early-minus-late discriminator generating a control signal for the first controllable oscillator. The delay lock loop comprising a second controllable oscillator and a second arctan discriminator generating a control signal for the second controllable oscillator.

Abstract: A method for evaluating the position of an aerial vehicle involves receiving a radio signal from the aerial vehicle with an antenna array, determining the direction of arrival of the received radio signal, forming a reception beam of the antenna array depending on the determined direction of arrival for receiving one or more further radio signals from the aerial vehicle, calculating the ranging between the aerial vehicle and the antenna array based on a radio signal provided for ranging and received from the aerial vehicle, and evaluating the position of the aerial vehicle based on the calculated ranging, the determined direction of arrival, and the known position of the antenna array.

Abstract: Receiver using antenna beam forming for tracking a transmitter signal and method for tracking the transmitter signal. The receiver includes a beam forming network comprising at least one beam forming channel for weighting each of N signals received from an N-element antenna array with an assigned weighting factor for forming a beam for tracking a transmitter signal of a certain transmitter, and a calibrator structured and arranged to calibrate the weighting factor (Wi) assigned to a signal (i) selected from the N signals by determining an average phase difference (??) between consecutive samples of the selected signal and consecutive samples of a reference signal and structured and arranged to adapt the weighting factor (Wi) of the selected signal depending on the determined average phase difference (??), where (i) is a number between 1 and N.

Abstract: A system for tracking a received signal with a subcarrier, the received signal representing a carrier signal modulated with a code signal and with a subcarrier signal. The system comprises independent and cooperatively operating loops: a phase lock loop tracking the carrier signal, a subcarrier lock loop tracking the subcarrier signal, and a delay lock loop tracking the code signal. The subcarrier lock loop comprises a first controllable oscillator and a first early-minus-late discriminator generating a control signal for the first controllable oscillator. The delay lock loop comprising a second controllable oscillator and a second arctan discriminator generating a control signal for the second controllable oscillator.

Abstract: A wireless communication unit for compensating for Ionospheric group delay in a satellite communication system. The wireless communication unit comprises: a receiver configured to receive a multi-carrier signal from a satellite; and a processor coupled to the receiver. The processor is configured to: process the multi-carrier signal to produce a plurality of digital representations of individual carriers of the multi-carrier signal; estimate, from the plurality of digital representations of individual carriers of the multi-carrier signal, a Total Electron Content, TEC, value associated with a communication path between the satellite and the wireless communication unit through Earth's Ionosphere; and apply compensation for Ionospheric group delay subjected to the multi-carrier signal based on the determined TEC value.

Abstract: A method for generating a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal includes obtaining a sequence of data symbols for a data channel, obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel, obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel, and generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips.

Abstract: This relates to a method for disseminating data in a navigation or communication system comprising several transmitters for signals, wherein a common frame structure is provided for the signals and each transmitter disseminates common data and transmitter-dedicated data with its transmitted signal, and wherein the method comprises the following acts to be executed by each one of the transmitters: receiving the common data encoded with a first encoding scheme; encoding transmitter-dedicated data onboard the transmitter with a second encoding scheme; assigning the encoded common data to a number of first frames of the frame structure provided for the signals and assigning the encoded transmitter-dedicated data to a number of second frames of the frame structure provided for the signals, wherein the second frames differ from the first frames; assembling a signal to be transmitted from the number of first and second frames; and transmitting the assembled signal.

Abstract: A receiver acquires and tracks a spread spectrum navigation signal with changing subcarriers. The carrier signal changes between several subcarriers according to a hopping frequency and is modulated with data and a pseudorandom noise code signal. The receiver includes a carrier wipe off unit for down converting a received spread spectrum navigation signal from its carrier frequency to a baseband frequency, a frequency hopping wipe off unit for wiping off the hopping frequency from the received spread spectrum navigation signal, and a replica signal generation unit for generating at least one replica signal of the pseudorandom noise code signal for acquiring and tracking the received spread spectrum navigation signal after carrier wipe off.

Abstract: A method for generating a spread spectrum Gaussian Minimum Shift Keying (GMSK) signal includes obtaining a sequence of data symbols for a data channel, obtaining at least one first spread spectrum code comprising a first sequence of spread spectrum chips for the data channel, obtaining at least one second spread spectrum code comprising a second sequence of spread spectrum chips for a pilot channel, and generating a sequence of pre-modulation chips by combining the sequence of data symbols for the data channel with the spread spectrum chips of the first sequence of the at least one first spread spectrum code and data symbols for the pilot channel with the spread spectrum chips of the second sequence of the at least one second spread spectrum code to a combined sequence of chips.

Abstract: A receiver acquires and tracks a spread spectrum navigation signal with changing subcarriers. The carrier signal changes between several subcarriers according to a hopping frequency and is modulated with data and a pseudorandom noise code signal. The receiver includes a carrier wipe off unit for down converting a received spread spectrum navigation signal from its carrier frequency to a baseband frequency, a frequency hopping wipe off unit for wiping off the hopping frequency from the received spread spectrum navigation signal, and a replica signal generation unit for generating at least one replica signal of the pseudorandom noise code signal for acquiring and tracking the received spread spectrum navigation signal after carrier wipe off.