US 2004/0176882 A1 · Attitude sensing apparatus for determining the attitude of a mobile unit

Abstract

The invention provides an attitude sensing apparatus for determining the attitude of a mobile unit that can reliably estimate an alignment angle between a GPS antenna coordinate system and an IMU coordinate system with good accuracy regardless of the magnitude of the alignment angle. Based on observation of the difference between a GPS angular velocity and an IMU angular velocity, an alignment angle estimating section estimates an alignment angle and sensor errors. An alignment angle adder and a sensor error adder cumulatively add and update the estimated alignment angle and sensor errors, respectively. The estimated alignment angle is fed back to an inertia data converter while the estimated sensor errors are fed back to an inertia data correcting section. The apparatus repeatedly performs estimation until the estimated alignment angle gradually approaches a true alignment angle by successively feeding back estimated values to a flow of alignment angle estimation process.

Claims20

Dependent claims

An attitude sensing apparatus having a GPS attitude sensing system which determines the attitude of a mobile unit in a reference coordinate system and an IMU attitude sensing system which determines the attitude of the mobile unit in the reference coordinate system and determining the attitude of the mobile unit by integrating the attitudes of the mobile unit determined in the individual coordinate systems, said attitude sensing apparatus comprising:

an alignment angle estimator for successively estimating an alignment angle to be used in a succeeding calculation process based on the difference between inertia data calculated from observations by said GPS attitude sensing system and inertia data observed by said IMU attitude sensing system;
and
an alignment angle adder for generating an updated alignment angle by cumulatively adding the successively estimated alignment angle and thereby updating the estimated alignment angle in sequence and for outputting the updated alignment angle to said alignment angle estimator;
wherein the estimated alignment angle is successively fed back for use in the alignment angle estimation process.

1 more element

An attitude sensing apparatus for determining the attitude of a mobile unit, comprising:

a GPS attitude sensing system which determines the attitude of the mobile unit in the reference coordinate system;
an IMU attitude sensing system which determines the attitude of the mobile unit in the reference coordinate system;
an alignment angle estimator for successively estimating an alignment angle to be used in a succeeding calculation process based on the difference between inertia data calculated from observations by said GPS attitude sensing system and inertia data observed by said IMU attitude sensing system;
and
an alignment angle adder for generating an updated alignment angle by cumulatively adding the successively estimated alignment angle and thereby updating the estimated alignment angle in sequence and for outputting the updated alignment angle to said alignment angle estimator;
wherein the estimated alignment angle is successively fed back for use in the alignment angle estimation process.

3 more elements

A method for attitude sensing including a GPS attitude sensing system which determines the attitude of a mobile unit in the reference coordinate system and an IMU attitude sensing system which determines the attitude of the mobile unit in the reference coordinate system and determining the attitude of the mobile unit by integrating the attitudes of the mobile unit determined in the individual coordinate systems, said method comprising the steps of:

estimating successively an alignment angle to be used in a succeeding calculation process based on the difference between inertia data calculated from observations by said GPS attitude sensing system and inertia data observed by said IMU attitude sensing system;
and
generating an updated alignment angle by cumulatively adding the successively estimated alignment angle and thereby updating the estimated alignment angle in sequence and for outputting the updated alignment angle to said alignment angle estimator;
wherein the estimated alignment angle is successively fed back for use in the alignment angle estimation process.

1 more element

An attitude sensing method for determining the attitude of a mobile unit, comprising the steps of:

determining the attitude of the mobile unit in the reference coordinate system with a GPS attitude sensing system;
determining the attitude of the mobile unit in the reference coordinate system with an IMU attitude sensing system;
estimating successively an alignment angle to be used in a succeeding calculation process based on the difference between inertia data calculated from observations by said GPS attitude sensing system and inertia data observed by said IMU attitude sensing system;
and
generating an updated alignment angle by cumulatively adding the successively estimated alignment angle and thereby updating the estimated alignment angle in sequence and for outputting the updated alignment angle to said alignment angle estimator;
wherein the estimated alignment angle is successively fed back for use in the alignment angle estimation process.

3 more elements

Dependencies are inferred from the claim text.

Attitude sensing apparatus for determining the attitude of a mobile unit

Life of this patent

Attitude sensing apparatus for determining the attitude of a mobile unit

Life of this patent

Abstract

Claims20