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The Principle of North Finder

May 24, 2018


By measuring the angular velocity of the earth's rotation,it determines autonomously the true north direction value of the attached carrier.North Finder is free from the influence of external magnetic fields or other environments. In addition, North Finder can also be combined with acceleration for horizontal angle measurement and correction.


Earth rotates around the earth at a constant auto-reflective angular velocity ωe. For a point on the Earth with a dimension of φ, the angular rate of the earth at this point can be decomposed into two components: the horizontal component ωe1 = ωecosφ, pointing along the earth's meridian to true north; the vertical component ωe2 = ωesinφ, vertically upward along the earth's vertical line. The northward information of the measured points on the earth can be obtained by using the inertial technology to measure the horizontal component of the angular speed of the earth's rotation.

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