Method for determining protection levels of navigation solutions, associated computer program product and receiver
AssigneeThales
InventorsPatrick Bartolone, Denis Bouvet
Life of this patent
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Abstract
A method for determining protection levels that comprises a preliminary phase carried out at least one time and a main phase carried out upon determining each new navigation solution. The preliminary phase comprises the steps of acquiring a first error value, providing a set of numbers of monitored faults, determining a plurality of computation coefficients, and storing the set of determined computation coefficients. The main phase includes the steps of determining a current number of monitored faults, and determining a protection level of the corresponding navigation solution by using an integrity relationship and the computation coefficients determined during the preliminary phase.
Claims12
A method for determining protection levels for navigation solutions, each navigation solution being determined from electromagnetic signals emitted by satellites of one or several satellite global positioning systems, called constellation, the method comprising a preliminary phase and a main phase, the preliminary phase being carried out at least one time before the main phase, the main phase being carried out upon determining each new navigation solution;
- wherein the preliminary phase comprises the following steps:
- for each predetermined dimension, acquiring a first error value corresponding to the likelihood of providing a navigation solution whose error rate does not exceed a predetermined integrity threshold according to this dimension and a second error value corresponding to the likelihood of determining a false alarm according to this dimension;
- providing a set of numbers of monitored faults;
- for each number of monitored faults and for each predetermined dimension, determining a plurality of computation coefficients, each computation coefficient being determined using the reverse function of a function defined using the distribution function of the Gaussian law, the reverse function being computed from a determined point based on the second error value corresponding to this dimension and the corresponding number of monitored faults and/or the first error value corresponding to this dimension;
- storing the set of determined computation coefficients;
- and
- wherein the main phase comprises the following steps:
- determining a current number of monitored faults based on the number of constellations used and the number of satellites visible in each of these constellations;
- and
- determining a protection level of the corresponding navigation solution according to a given dimension using an integrity relationship and the computation coefficients determined during the preliminary phase for the current number of monitored faults and for this dimension, the integrity relationship analytically connecting this protection level and the first and second error values.
Dependencies are inferred from the claim text.