Patent ID: 9719782
Date: 2017-08-01
CPC Classifications: B64D,G01C,G01S

Claim:
1. An avionics system comprising: one or more attitude sources, each configured to produce a respective calculated attitude solution; at least one magnetometer configured to measure magnetic field in a frame of the avionics system and provide the measurement as a measured magnetic field estimate; and at least one attitude monitor configured to use the respective calculated attitude solution from at least one of the one or more attitude sources to project at least one of the measured magnetic field estimate or an Earth Magnetic Field Model estimate such that the measured magnetic field estimate and the Earth Magnetic Field Model estimate are in a common shared frame; wherein the at least one attitude monitor is further configured to determine a respective difference between the measured magnetic field estimate and the Earth Magnetic Field Model estimate in the common shared frame; wherein the at least one attitude monitor is further configured to output an alert, which indicates that the respective calculated attitude solution used to project at least one of the measured magnetic field estimate or the Earth Magnetic Field Model estimate is in error, when the respective difference between the measured magnetic field estimate and the Earth Magnetic Field Model estimate exceeds a predetermined threshold; and wherein the at least one attitude monitor is configured to provide an indication that the difference between the measurement magnetic field estimate and the Earth Magnetic Field Model estimate is not valid when an attitude sensitivity level of the at least one attitude monitor is less than the predetermined threshold.