Patent ID: 11874116
Assignee: TRIMBLE INC.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 8:
9. A navigation system comprising:
an inertial measurement unit (IMU) attached to a dynamic platform and configured to measure a specific force vector and an angular rate vector of the dynamic platform;
an inertial navigation system (INS) unit coupled to the IMU and configured to estimate a current navigation solution of a position and an orientation of the dynamic platform based on at least: (i) a previous navigation solution, and (ii) the specific force vector and the angular rate vector measured by the IMU;
a range image sensor (RI sensor) attached to the dynamic platform and configured to acquire range image data (RI data);
an RI data preprocessor coupled to the RI sensor and the INS unit, the RI data preprocessor configured to perform an a priori transformation of the RI data using the current navigation solution to obtain transformed RI data; and
an RI map database storing a plurality of keyframe maps and configured to retrieve a valid keyframe map among the plurality of keyframe maps based on the transformed RI data, the valid keyframe map having a known position and a known orientation in a navigation coordinate frame;
wherein the navigation system is configured to construct a map registration cost gradient (MRCG) measurement based on at least (i) the transformed RI data, and (ii) the known position and the known orientation of the valid keyframe map; and
wherein the INS unit is further configured to determine an absolute navigation solution of a current position and a current orientation of the dynamic platform based on at least (i) the current navigation solution, and (ii) the MRCG measurement.