Antennas used aboard vehicles to communicate with satellites or ground stations may have complex antenna patterns, which may vary as the vehicle moves throughout a given coverage area. Techniques are disclosed for dynamically adjusting the instantaneous power fed to an antenna system to ensure that the antenna transmits at the regulatory or coordinated effective isotropic radiated power (EIRP) spectral limit. The antenna may transmit, in accordance with vehicle location and attitude, steerable beam patterns at different scan and skew angle combinations, causing variations in antenna gain and fluctuations in the transmitted EIRP. Using on-board navigational data, an antenna gain and ESD limit may be calculated for a particular scan and skew angle, which may be used to adjust power fed to the antenna such that the antenna transmits substantially at maximum allowable EIRP as the steerable beam pattern is adjusted.

Antennas used aboard vehicles to communicate with satellites or ground stations may have complex antenna patterns, which may vary as the vehicle moves throughout a given coverage area. Techniques are disclosed for dynamically adjusting the instantaneous power fed to an antenna system to ensure that the antenna transmits at the regulatory or coordinated effective isotropic radiated power (EIRP) spectral limit. The antenna may transmit, in accordance with vehicle location and attitude, steerable beam patterns at different scan and skew angle combinations, causing variations in antenna gain and fluctuations in the transmitted EIRP. Using on-board navigational data, an antenna gain and ESD limit may be calculated for a particular scan and skew angle, which may be used to adjust power fed to the antenna such that the antenna transmits substantially at maximum allowable EIRP as the steerable beam pattern is adjusted.

Disclosed is incorporating an IQ stream into a test signal for a receiver in motion, configuring a path for the motion of the receiver during simulation, a period of the simulation, a transmitter constellation to emulate, and a path of at least one IQ stream transmitter. Also generating signals emulating the transmitter constellation and conditioning the stream to be merged with the signals, using distance and relative motion between receiver and transmitter to determine delay and Doppler shift between transmitter and receiver in motion, scheduling sampling of the signal, including interpolation among samples of the stream, based on delay and Doppler shift, and synthesizing a conditioned stream from the interpolation between the samples, taking into account signal level of the stream, in addition to delay and shift, and merging the conditioned signal with the signals emulating the transmitter constellation and supplying the merged signals to the receiver during the test.

Disclosed is incorporating an IQ stream into a test signal for a receiver in motion, configuring a path for the motion of the receiver during simulation, a period of the simulation, a transmitter constellation to emulate, and a path of at least one IQ stream transmitter. Also generating signals emulating the transmitter constellation and conditioning the stream to be merged with the signals, using distance and relative motion between receiver and transmitter to determine delay and Doppler shift between transmitter and receiver in motion, scheduling sampling of the signal, including interpolation among samples of the stream, based on delay and Doppler shift, and synthesizing a conditioned stream from the interpolation between the samples, taking into account signal level of the stream, in addition to delay and shift, and merging the conditioned signal with the signals emulating the transmitter constellation and supplying the merged signals to the receiver during the test.

Described herein is a method for improving the reception of a satellite navigation message divided in several pages and transmitted by one or several satellites. A satellite navigation message M of k pages is encoded inn pages, and any k retrieved pages from any satellite enables decoding of the original satellite navigation message M. An implementation of the method uses parallel block encoding for a binary erasure channel with high parity and zero overhead, where symbols at a fixed position of all pages are encoded in parallel into shorter codes. This method achieves full page interchangeability in the message transmission, optimizes message reception and reduces decoding cost.

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.

A satellite communications system can comprise at least one that satellite, an antenna structure deployed on the at least one satellite, and radio hardware coupled to the antenna structure that can provide for transmitting a first channel simultaneously with a second channel, wherein the first channel is transmitted using directive beams and the second channel is transmitted using a wide beam and wherein the directive beams are for data communication signals and the wide beam is for navigation signals.

Embodiments of the present invention provide a method, system and computer program product for bit transition enhanced direct position estimation (DPE) from global navigation satellite system (GNSS) signals and includes the reception in a GNSS receiver of signals from multiple, different satellites in multiple satellite constellations adapted for use with the GNSS. The method estimates the GNSS receiver parameters position, velocity, clock bias, clock drift, and optionally and if unknown, the receiver time. The method generates a model of the received GNSS signals that depends on the receiver parameters. Uniquely, the method includes the synchronization of both a primary code and also a secondary code in the received GNSS signal model, in addition to time delays, Doppler shifts, and other relevant parameters for positioning. Finally, if the secondary code of a particular signal is unknown, the method determines the combination of bit transitions that maximizes the optimization problem.

Disclosed are a method for modulation of a variable binary offset carrier (VBOC) having a discrete time-variant frequency and a satellite navigation signal generator using the same. The method for modulation of a VBOC having a discrete time-variant frequency may comprise: generating navigation message data; generating a carrier; generating a VBOC subcarrier; generating a pseudo-random code; synthesizing the pseudo code and the VBOC subcarrier; and synthesizing a synthesized signal of the pseudo code and the VBOC subcarrier, the carrier, and the navigation message data.

Methods and apparatuses for controlling a satellite antenna based on its motion are disclosed. In some embodiments, the method comprises determining a motion state of an antenna for communication with a satellite, determining a motion profile for the antenna based on the motion state, and controlling the antenna based on the motion profile.