TRUE NORTH SEEKING AND ATTITUDE SYSTEM

摘要

A strap-down system is hereby submitted made by a static part and a continuous rotating part, able to independently calculate (without the assistance of a GPS or magnetic field) triming and direction in respect to true North using a configuration of five degrees of freedom (three accelerometers and two gyroscopes) with sensors arranged and set between the fixed part and the continuous rotating part of the system as follows: two mutually orthogonal accelerometers (104 and 105) with sensitive axis on the horizontal plane and a gyroscope (110) with sensitive axis in the vertical direction in the fixed part of the system, plus the third accelerometer (111) with a sensitive axis on the horizontal plane and the second gyroscope (108) with direction of the sensitive axis on the horizontal plane in the continuous rotating part of the system. A calculating block (112) calculates triming and direction in respect to true north based on the measures given by sensors and by an estimated value of latitude. Such configuration with five degrees of freedom can be increased to have a higher precision or reduced to have a decline of performance of triming direction in respect to true North.