Patent ID: 9046894
Filing Date: 2015-06-02
Classification: G01C,G05D,G08G

Abstract:
1. A navigation aid method for determining, by an instruction giver, the path of an aircraft initially following a predetermined path in an approach phase and upon which are defined a safety altitude and an alarm limit, said aircraft comprising a navigation system of an Inertial Navigation System/Global Navigation Satellite System (INS/GNSS) type comprising a satellite navigation receiver and at least one inertial unit, said method comprising: determining a current position of the aircraft; determining a future path of the aircraft from the current position; estimating a predicted protection radii on the future path, starting at a calculation time in a case of a critical situation, in terms of a loss of GNSS position information, which starts at the calculation time; calculating a limit time after which the predicted protection radius is greater than or equal to the alarm limit; calculating a limit extraction time that corresponds to a maximum time after which the aircraft must leave the predetermined path in order to be able to reach the safety altitude by the time limit; and transmitting the value of the limit extraction time to the instruction giver.