Patent ID: 9719788
Date: 2017-08-01
CPC Classifications: G01C,G01S

Claim:
1. A machine-implemented method for determining a spatial orientation of a body frame of reference of a body with respect to a navigation frame of reference, the method comprising: receiving, by receiving equipment on the body, at least three sets of electromagnetic signals, each of the sets of electromagnetic signals arriving at the body from a different one of at least three separate directions, and obtaining, by the receiving equipment, signal amplitude measurement information for each one of the sets of electromagnetic signals; determining a location in space of the body; calculating, for each one of the sets of electromagnetic signals, azimuth angle information partially specifying a direction of arrival of the set of electromagnetic signals at the body relative to a body azimuth axis in the body frame of reference; determining, by a computing device, the spatial orientation, including yaw, pitch, and roll angles, of the body frame of reference with respect to the navigation frame of reference; measuring, using the receiving equipment, rate of change of the azimuth angle information for each of the sets of electromagnetic signals; transforming, for each of the sets of electromagnetic signals, the rate of change of the azimuth angle information into a body measurement rate matrix; and iteratively refining an approximation of an angular velocity of the body frame of reference with respect to the navigation frame of reference using the body measurement rate matrices, wherein the determination of the spatial orientation is performed without using detected elevation angle information.