초록 ▼

An attitude sensing apparatus for determining the attitude of a mobile unit is provided 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 th

An attitude sensing apparatus for determining the attitude of a mobile unit is provided 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.

대표청구항 ▼

What is claimed is: 1. An attitude sensing apparatus having a GPS attitude sensing system which determines the attitude of a mobile unit in an antenna coordinate system and an IMU attitude sensing system which determines the attitude of the mobile unit in an IMU coordinate system, and further deter

What is claimed is: 1. An attitude sensing apparatus having a GPS attitude sensing system which determines the attitude of a mobile unit in an antenna coordinate system and an IMU attitude sensing system which determines the attitude of the mobile unit in an IMU coordinate system, and further determining the attitude of the mobile unit by integrating the attitudes of the mobile unit determined in the antenna coordinate system and the IMU system, 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 GPS 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 sequentially updating the estimated alignment angle 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. 2. The attitude sensing apparatus according to claim 1, wherein individual components θx,θy, θ z of the alignment angle satisfy the following conditions: -85째≦θx≦85째, -85째≦θy≦85째, -85째≦θz≦90째 and the estimated alignment angle is successively fed back together with the updated alignment angle for use in the alignment angle estimation process. 3. The attitude sensing apparatus according to claim 1 or 2, wherein said alignment angle estimator successively estimates a sensor error caused by an inertia sensor of said IMU attitude sensing system from the estimated alignment angle, said attitude sensing apparatus further comprising: a sensor error adder for generating an updated sensor error by cumulatively adding the successively estimated sensor error and thereby updating the estimated sensor error in sequence and for outputting the updated sensor error to said alignment angle estimator; wherein the updated sensor error is successively fed back for use in the alignment angle estimation process. 4. The attitude sensing apparatus according to claim 1 further comprising: a setter for setting a provisional alignment angle upon installation of a GPS antenna of said GPS attitude sensing system and an inertia sensor of said IMU attitude sensing system; wherein initial conditions for said alignment angle estimator are set by using the provisional alignment angle. 5. The attitude sensing apparatus according to claim 1, wherein the alignment angle estimation process is performed until the alignment angle is finally determined. 6. 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 a GPS coordinate system; an IMU attitude sensing system which determines the attitude of the mobile unit in an IMU 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 sequentially updating the estimated alignment angle 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. 7. The attitude sensing apparatus according to claim 6, wherein individual components θx, θy, θz of the alignment angle satisfy the following conditions: -85째≦θx≦85째, -85째≦θy≦85째, -85째≦θz≦90째, and the estimated alignment angle is successively fed back together with the updated alignment angle for use in the alignment angle estimation process. 8. The attitude sensing apparatus according to claim 6 or 7, wherein said alignment angle estimator successively estimates a sensor error caused by an inertia sensor of said IMU attitude sensing system from the estimated alignment angle, said attitude sensing apparatus further comprising: a sensor error adder for generating an updated sensor error by cumulatively adding the successively estimated sensor error and thereby updating the estimated sensor error in sequence and for outputting the updated sensor error to said alignment angle estimator; wherein the updated sensor error is successively fed back for use in the alignment angle estimation process. 9. The attitude sensing apparatus according to claim 6 further comprising: a setter for setting a provisional alignment angle upon installation of a GPS antenna of said GPS attitude sensing system and an inertia sensor of said IMU attitude sensing system; wherein initial conditions for said alignment angle estimator are set by using the provisional alignment angle. 10. The attitude sensing apparatus according to claim 6, wherein the alignment angle estimation process is performed until the alignment angle is finally determined. 11. A method for attitude sensing including a GPS attitude sensing system which determines the attitude of a mobile unit in an antenna coordinate system and an IMU attitude sensing system which determines the attitude of the mobile unit in an IMU coordinate system and determining the attitude of the mobile unit by integrating the attitudes of the mobile unit determined in the antenna coordinate system and the IMU coordinate system, said method comprising: 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 based on the estimated alignment angle, which is fed back for use in the alignment angle estimation process. 12. The attitude sensing method according to claim 11, wherein individual components θx, θy, θz of the alignment angle satisfy the following conditions: -85째≦θx≦85째, -85째≦θy≦85째, -85째≦θz≦90째 and the estimated alignment angle is successively fed back together with the updated alignment angle for use in the alignment angle estimation process. 13. The attitude sensing method according to claim 11 or 12, wherein there are successive estimates of a sensor error caused by an inertia sensor of said IMU attitude sensing system from the estimated alignment angle, said method further comprising: generating an updated sensor error by cumulatively adding the successively estimated sensor error and thereby updating the estimated sensor error in sequence and outputting the updated sensor error; wherein the updated sensor error is successively fed back for use in the alignment angle estimation process. 14. The attitude sensing method according to claim 11 further comprising: setting a provisional alignment angle upon installation of a GPS antenna of said GPS attitude sensing system and an inertia sensor of said IMU attitude sensing system; wherein initial conditions for said alignment angle estimator are set by using the provisional alignment angle. 15. The attitude sensing method according to claim 11, wherein the alignment angle estimation process is performed until the alignment angle is finally determined. 16. An attitude sensing method for determining the attitude of a mobile unit, comprising: determining the attitude of the mobile unit in an antenna coordinate system with a GPS attitude sensing system; determining the attitude of the mobile unit in an IMU 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 sequentially updating the estimated alignment angle 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. 17. The attitude sensing method according to claim 16, wherein individual components θx, θy, θz of the alignment angle satisfy the following conditions: -85째≦θx≦85째, -85째≦θy≦85째, -85째≦θz≦90째 and the estimated alignment angle is successively fed back together with the updated alignment angle for use in the alignment angle estimation process. 18. The attitude sensing method according to claim 16 or 17, wherein there are successive estimates of a sensor error caused by an inertia sensor of said IMU attitude sensing system from the estimated alignment angle, said attitude sensing method further comprising: generating an updated sensor error by cumulatively adding the successively estimated sensor error and thereby sequentially updating the estimated sensor error and for outputting the updated sensor error; wherein the updated sensor error is successively fed back for use in the alignment angle estimation process. 19. The attitude sensing method according to claim 16 further comprising: setting a provisional alignment angle upon installation of a GPS antenna of said GPS attitude sensing system and an inertia sensor of said IMU attitude sensing system; wherein initial conditions for said alignment angle estimator are set by using the provisional alignment angle. 20. The attitude sensing method according to claim 16, wherein the alignment angle estimation process is performed until the alignment angle is finally determined. 21. The attitude sensing method according to claim 11, further comprising: generating an updated alignment angle by cumulatively adding the successively estimated alignment angle and thereby sequentially updating the estimated alignment angle 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.