A method for determining attitude of an object having multiple GNSS antennas, the method including receiving GNSS signals from at least five satellites, wherein at least 2 of the five belong to a different satellite constellation than the other satellites; processing each of the GNSS signals to generate pseudorange code and carrier phase measurements; resolving carrier phase ambiguities for all the received GNSS signals; generating unbiased carrier phase measurements based on the resolving; determining the attitude, including heading, pitch, and roll angles ,,, respectively, by solving a quadratically constrained quadratic minimization problem through finding a minimum of a linear function subject to a linear matrix inequality constraint; and outputting the attitude.

A method for determining attitude of an object having multiple GNSS antennas, the method including receiving GNSS signals from at least five satellites, wherein at least 2 of the five belong to a different satellite constellation than the other satellites; processing each of the GNSS signals to generate pseudorange code and carrier phase measurements; resolving carrier phase ambiguities for all the received GNSS signals; generating unbiased carrier phase measurements based on the resolving; determining the attitude, including heading, pitch, and roll angles ,,, respectively, by solving a quadratically constrained quadratic minimization problem through finding a minimum of a linear function subject to a linear matrix inequality constraint; and outputting the attitude.

Systems and methods of heading determination with global navigation satellite system (GNSS) signal measurements are provided herein. A pair of antennas may be separated by a known baseline length and mounted on a vehicle. A GNSS receiver may obtain pseudorange and carrier phase measurements for GNSS satellites within view. An LRU may estimate carrier phase ambiguities and a two-dimensional vector, using the known baseline length and a linearized measurement model. The LRU may determine integer ambiguities using the estimated carrier phase ambiguities. The LRU may determine assumed wrong fixes of the integer ambiguities and a probability of almost fixed value. The LRU may store the set of integer ambiguities. The LRU may determine, from accumulated data over measurement epochs, updated integer ambiguities. The LRU may correct the carrier phase measurements using the updated integer ambiguities. The LRU may compute the heading using the corrected carrier phase measurements.

Systems and methods of heading determination with global navigation satellite system (GNSS) signal measurements are provided herein. A pair of antennas may be separated by a known baseline length and mounted on a vehicle. A GNSS receiver may obtain pseudorange and carrier phase measurements for GNSS satellites within view. An LRU may estimate carrier phase ambiguities and a two-dimensional vector, using the known baseline length and a linearized measurement model. The LRU may determine integer ambiguities using the estimated carrier phase ambiguities. The LRU may determine assumed wrong fixes of the integer ambiguities and a probability of almost fixed value. The LRU may store the set of integer ambiguities. The LRU may determine, from accumulated data over measurement epochs, updated integer ambiguities. The LRU may correct the carrier phase measurements using the updated integer ambiguities. The LRU may compute the heading using the corrected carrier phase measurements.

The present application provides a navigation augmentation method and system, the method includes: broadcasting, by satellites of a Low Earth Orbit (LEO) constellation, navigation direct signals and navigation augmentation information; performing, by a user receiver, precise positioning, speed measurement and timing according to the navigation direct signals of navigation satellites, the navigation direct signals of the LEO satellites and the navigation augmentation information broadcasted by the LEO satellites.

The present application provides a navigation augmentation method and system, the method includes: broadcasting, by satellites of a Low Earth Orbit (LEO) constellation, navigation direct signals and navigation augmentation information; performing, by a user receiver, precise positioning, speed measurement and timing according to the navigation direct signals of navigation satellites, the navigation direct signals of the LEO satellites and the navigation augmentation information broadcasted by the LEO satellites.

Disclosed is a system and method for detecting false Global Navigation Satellite System (GNSS) satellite signals. False GNSS satellite signals can be used malevolently to take control of a body such as a vehicle or ship that is using GNSS satellite signals for navigation. In some embodiments a GNSS attitude system is used to detect the false GNSS satellite signals. The GNSS attitude system measures the code or carrier phase of the GNSS satellite signals at two or more antennas to detect the false GNSS satellite signals. In some embodiments the attitude system computes first measured and second estimated carrier phase differences in order to detect the false GNSS satellite signals. The attitude system may compute the attitude of a baseline vector between the two antennas. Once false GNSS satellite signals are detected, the method can include preventing the attitude determining system from outputting position or location data.

Disclosed is a system and method for detecting false Global Navigation Satellite System (GNSS) satellite signals. False GNSS satellite signals can be used malevolently to take control of a body such as a vehicle or ship that is using GNSS satellite signals for navigation. In some embodiments a GNSS attitude system is used to detect the false GNSS satellite signals. The GNSS attitude system measures the code or carrier phase of the GNSS satellite signals at two or more antennas to detect the false GNSS satellite signals. In some embodiments the attitude system computes first measured and second estimated carrier phase differences in order to detect the false GNSS satellite signals. The attitude system may compute the attitude of a baseline vector between the two antennas. Once false GNSS satellite signals are detected, the method can include preventing the attitude determining system from outputting position or location data.

A method for determining attitude of an object having multiple GNSS antennas, the method including receiving GNSS signals from at least five satellites, wherein at least 2 of the five belong to a different satellite constellation than the other satellites; processing each of the GNSS signals to generate pseudorange code and carrier phase measurements; resolving carrier phase ambiguities for all the received GNSS signals; generating unbiased carrier phase measurements based on the resolving; determining the attitude, including heading, pitch, and roll angles ,,, respectively, by solving a quadratically constrained quadratic minimization problem through finding a minimum of a linear function subject to a linear matrix inequality constraint; and outputting the attitude.

A high performance attitude determination system, including a global navigation satellite system (GNSS) receiver, the receiver including a first radio-frequency front-end (RF1) connected to a main antenna; a second radio-frequency front-end (RF2) connected to an auxiliary antenna; and a digital section connected to both RF1 and RF2. The digital section (i) generates a first set of GNSS raw measurements based on signals received from RF1; (ii) generates a second set of GNSS raw measurements based on signals received from RF2; (iii) computes a spatial attitude of a baseline between main and auxiliary antennas, using the first and the second sets of GNSS raw measurements, and based on carrier phase integer ambiguity resolution; (iv) continues updating the spatial attitude using the first and the second sets of GNSS raw measurements without carrier phase integer ambiguity resolution, and using fractional carrier phases. Optionally, RF1 and RF2 use a common clock.