A method comprises computing position information from a global navigation satellite system (GNSS); computing an altitude measurement based on retrieved information from a vertical position sensor; determining a vertical protection level (VPL) associated with the position information; splitting the VPL into an upward VPL component and a downward VPL component; determining a vertical alert limit (VAL) associated with the altitude measurement; and splitting the VAL into an upward VAL component and a downward VAL component. The method optimizes an integrity budget allocation between the upward and downward VPL components. The method then recomputes the upward and downward VPL components given the optimized integrity budget allocation.

A method comprises computing position information from a global navigation satellite system (GNSS); computing an altitude measurement based on retrieved information from a vertical position sensor; determining a vertical protection level (VPL) associated with the position information; splitting the VPL into an upward VPL component and a downward VPL component; determining a vertical alert limit (VAL) associated with the altitude measurement; and splitting the VAL into an upward VAL component and a downward VAL component. The method optimizes an integrity budget allocation between the upward and downward VPL components. The method then recomputes the upward and downward VPL components given the optimized integrity budget allocation.

The present disclosure provides a compliance test method and system for Receiver Autonomous Integrity Monitoring (RAIM) performance of a BeiDou navigation satellite system (BDS) airborne equipment. The method includes: acquiring BDS almanac parameters and test parameters (101); determining whether the satellites are visible according to the almanac parameters and the test parameters (102); acquiring space-time points when the satellites are visible (103); computing the Horizontal Protection Limit (HPL) of each of the space-time points (104); selecting marginal geometries space-time points according to the HPL (105); test the space-time points and the marginal geometries space-time points to obtain a first test result (106); acquiring the configuration parameters and the BDS almanac of the satellite navigation vector signal generator for the marginal geometries space-time points (107); decoding the configuration parameters and the BDS almanac to obtain the number of visible satellites (108); determining whether the number of visible satellites is greater than a threshold (109); testing the marginal geometries space-time points to obtain the second test result if yes (110); and determining whether the first test result is matched with the second test result (111). The method can check whether the BDS airborne equipment meets airworthiness requirements.

A device that includes a receiver that receives multiple positioning signals from a satellite, including a positioning signal and remaining positioning signals, and a processor communicatively coupled to the receiver. The processor determines a speed value of the device based on a Doppler shift of the positioning signal. The speed value is a magnitude of a velocity of the device in a direction. The processor also determines that the speed value is not consistent with at least one other measurement and determines the position of the device using the remaining positioning signals.

Some embodiments of the invention relate to generating correction information based on global or regional navigation satellite system (NSS) multiple-frequency signals observed at a network of reference stations, broadcasting the correction information, receiving the correction information at one or more monitoring stations, estimating ambiguities in the carrier phase of the NSS signals observed at the monitoring station(s) using the correction information received thereat, generating residuals, generating post-broadcast integrity information based thereon, and broadcasting the post-broadcast integrity information. Other embodiments relate to receiving and processing correction information and post-broadcast integrity information at NSS receivers or at devices which may have no NSS receiver, as well as to systems, NSS receivers, devices which may have no NSS receiver, processing centers, and computer programs. Some embodiments may for example be used for safety-critical applications such as highly-automated driving and autonomous driving.

Some embodiments of the invention relate to generating correction information based on global or regional navigation satellite system (NSS) multiple-frequency signals observed at a network of reference stations, broadcasting the correction information, receiving the correction information at one or more monitoring stations, estimating ambiguities in the carrier phase of the NSS signals observed at the monitoring station(s) using the correction information received thereat, generating residuals, generating post-broadcast integrity information based thereon, and broadcasting the post-broadcast integrity information. Other embodiments relate to receiving and processing correction information and post-broadcast integrity information at NSS receivers or at devices which may have no NSS receiver, as well as to systems, NSS receivers, devices which may have no NSS receiver, processing centers, and computer programs. Some embodiments may for example be used for safety-critical applications such as highly-automated driving and autonomous driving.

The disclosure relates to a method for checking the integrity of GNSS correction data, comprising at least the following steps: a) receiving GNSS correction data, which are provided without associated integrity information, b) receiving reference data which allow for a conclusion to be drawn in respect of the integrity of the GNSS correction data received in step a), and c) checking the integrity of the GNSS correction data received in step a) by means of the reference data received in step b).

A method or system can include or be configured to receive a set of satellite observations, receiving sensor data, determining a position estimate and associated positioning error for a rover based on the set of satellite observations and the sensor data, determine a protection level associated with the position estimate based on a set of potential faults, and optionally provide an alert when the positioning error exceeds the protection level.

A method for compensating for the absence of GPS data during a period of GPS signal loss in determining travel mileage of a vehicle includes: detecting vehicle motion using an accelerometer during a period of time in which a GPS tracking device is unable to determine a location of the vehicle due to loss of GPS signal; determining a first location of the vehicle corresponding to the last known GPS location data point stored in memory; determining a second location of the vehicle corresponding to a point at which the GPS signal is reacquired; and calculating the distance between the first and second locations based on a straight-line distance calculation between the first and second locations, or based on the use of geospatial mapping data to plot a roadway route between the first and second locations.

A method for compensating for the absence of GPS data during a period of GPS signal loss in determining travel mileage of a vehicle includes: detecting vehicle motion using an accelerometer during a period of time in which a GPS tracking device is unable to determine a location of the vehicle due to loss of GPS signal; determining a first location of the vehicle corresponding to the last known GPS location data point stored in memory; determining a second location of the vehicle corresponding to a point at which the GPS signal is reacquired; and calculating the distance between the first and second locations based on a straight-line distance calculation between the first and second locations, or based on the use of geospatial mapping data to plot a roadway route between the first and second locations.