Method of determining a heading in the geographical north direction by means of an inertial unit
AssigneeSagem Defense Securite
InventorYves Becheret
Life of this patent
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Abstract
A method of determining a heading in the geographical North direction by means of an inertial sensor module having three rate gyro measurement axes and three accelerometer measurement axes, the method comprising the steps of: using data from the inertial sensor module in a North-seeking mode to obtain a first heading value; using data from the inertial sensor module in a gyro-compass mode to obtain a second heading value; and determining the heading in the North direction by using the first heading value and the second heading value.
Claims11
A method of determining a heading in the geographical North direction of a platform by means of an inertial sensor module mounted on the platform having three rate gyro measurement axes and three accelerometer measurement axes with outputs which are received by a computer performing the method, the method comprising the steps of:
- using data from the inertial sensor module in a North-seeking mode to obtain a first heading value of the platform;
- using data from the inertial sensor module in a gyro-compass mode to obtain a second heading value;
- and
- determining the heading in the North direction by using the first heading value and the second heading value of the platform;
- wherein, in the North-seeking mode, the first heading value is calculated from gyro data, data from the accelerometers not being used when calculating the first heading value, but being used to determine a mean horizontal plane relative to the sensor module;
- and in the gyro-compass mode, the second heading value is calculated from accelerometer data, with gyro data being used only for stabilizing the platform.
A method of determining a heading in the geographical North direction of a platform by means of an inertial sensor module mounted on the platform having three rate gyro measurement axes and three accelerometer measurement axes with outputs which are received by a computer performing the method, the method comprising the steps of:
- using data from the inertial sensor module in a North-seeking mode to obtain a first heading value of the platform;
- using data from the inertial sensor module in a gyro-compass mode to obtain a second heading value;
- and
- determining the heading in the North direction by using the first heading value and the second heading value of the platform;
- wherein the heading calculation includes the steps of:
- calculating a difference between the first heading value and the second heading value;
- and
- using as the heading in the North direction either the first heading value or the second heading value, taking account of the calculated difference.
Dependencies are inferred from the claim text.