Tightly-coupled GNSS/IMU integration filter having calibration features
First Claim
Patent Images
1. An apparatus comprising:
- an integration filter for a sensor-assisted global navigation satellite system (GNSS) receivera GNSS measurement engine for providing GNSS measurement data to said integration filter;
an inertial measurement unit (IMU); and
an inertial navigation system (INS) block for calculating INS navigation information using a plurality of inertial sensor outputs,wherein said integration filter performs a blending operation for combining said GNSS measurement data and said INS navigation information, and for estimating and compensating a speed bias and a heading bias in said INS measurement, wherein at least one of said speed bias and said heading bias is included in state variables of said integration filter and is compensated in calculating said blended GNSS measurement data and INS navigation information, and wherein said integration filter processes a plurality of INS user velocity data from said INS block in a measurement equation of said integration filter using a method comprising;
including a plurality of INS measurements in a local navigation coordinate in said measurement equation in a way that said INS measurements are a function of velocity variables and speed and/or heading bias variables of an integration filter state with a plurality of measurement noises.
1 Assignment
0 Petitions
Accused Products
Abstract
Embodiments of the invention provide a blending filter based on extended Kalman filter (EKF), which optimally integrates the IMU navigation data with all other satellite measurements (tightly-coupled integration filter). Two more states in the EKF for estimating/compensating the speed bias and the heading bias in the INS measurement are added. The integration filter has no feedback loop for INS calibration, and can estimate/compensate the navigation error in the INS measurement within the integration filter.
-
Citations
9 Claims
-
1. An apparatus comprising:
-
an integration filter for a sensor-assisted global navigation satellite system (GNSS) receiver a GNSS measurement engine for providing GNSS measurement data to said integration filter; an inertial measurement unit (IMU); and an inertial navigation system (INS) block for calculating INS navigation information using a plurality of inertial sensor outputs, wherein said integration filter performs a blending operation for combining said GNSS measurement data and said INS navigation information, and for estimating and compensating a speed bias and a heading bias in said INS measurement, wherein at least one of said speed bias and said heading bias is included in state variables of said integration filter and is compensated in calculating said blended GNSS measurement data and INS navigation information, and wherein said integration filter processes a plurality of INS user velocity data from said INS block in a measurement equation of said integration filter using a method comprising; including a plurality of INS measurements in a local navigation coordinate in said measurement equation in a way that said INS measurements are a function of velocity variables and speed and/or heading bias variables of an integration filter state with a plurality of measurement noises. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification