Inertial Measurement and Navigation System And Method Having Low Drift MEMS Gyroscopes And Accelerometers Operable In GPS Denied Environments

摘要

An inertial measurement unit includes physically distinct sectors positioned in groups of orthogonally oriented angle rate sensors on a different sector of a base having orthogonally oriented accelerometers positioned thereon. A processor receiving signals from the sensors and accelerometers calculates a change in attitude, position, angular rate, velocity, acceleration of the unit over a plurality of finite time increments, or a combination thereof. The gyros and accelerometers have low-drift measurement accuracy for operation in a GPS-denied environment by preselecting pairs of gyros for physical assignment to achieve low-drift accuracy, determining weights for the gyros to be combined in tiered pairs, preselecting the accelerometers for physical assignment in low-drift pairs, determining weights for accelerometer optimal low-drift pair combining in tiers, or a combination thereof.

主权项

1. A method for fabricating an inertial measurement unit (IMU) to achieve low-drift measurement accuracy for operation in a GPS-denied environment, the method comprising:
(a) preselecting pairs of gyros for physical assignment within the IMU to achieve low-drift measurement accuracy; (b) calibrating each gyro within each gyro pair and orthogonalizing the gyro pairs to form a gyro frame; (c) preselecting individual accelerometers and assigning pairs of accelerometers for the IMU; (d) calibrating each accelerometer within each accelerometer pair and orthogonalizing the accelerometer pairs to form an accelerometer frame; (e) aligning the gyro and accelerometer frames with a body frame of the IMU; (f) applying a gyro weighting function to each gyro and combining the gyros in pairs exhibiting low drift; and (g) applying an accelerometer weighting function to each accelerometer and combining the accelerometers in pairs exhibiting low drift.