Vehicle navigation system with adaptive gyroscope bias compensation

Patent metadata

Field	Value
Publication number	US-2016290810-A1
Application number	US-201514676595-A
Country	US
Kind code	A1
Filing date	Apr 1, 2015
Priority date	Apr 1, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

Adaptive gyroscope bias compensation allows a vehicle navigation module to estimate position and velocity reliably during temperature changes.

First claim

What is claimed is:

1 . A method for improving the accuracy of a vehicle navigation module, the method comprising:
the vehicle navigation module including a MEMS gyroscope and a navigation filter, the navigation filter: (a) storing average gyroscope bias versus temperature data; (b) computing rate of change of gyroscope bias versus temperature from the average gyroscope bias versus temperature data; (c) estimating gyroscope bias by comparing rotation rate as measured by the gyroscope to a reference rotation rate, when a reference rotation rate is available; and, (d) estimating gyroscope bias, when no reference rotation rate is available, via linear extrapolation from a known bias value, the linear extrapolation taking into account a temperature change from the known bias value and rate of change of gyroscope bias versus temperature obtained in step (b).

2 . The method of claim 1 further comprising storing rate of change of gyroscope bias versus temperature obtained in step (b).

3 . The method of claim 1 further comprising:
updating the average gyroscope bias versus temperature data from results of step (c).

4 . The method of claim 1 further comprising:
in step (b), excluding average gyroscope bias versus temperature data points for which a number of gyroscope bias estimates used to compute the average is less than a specified minimum number of gyroscope bias estimates.

5 . The method of claim 1 further comprising:
in step (b), excluding average gyroscope bias versus temperature data points for which a variance of gyroscope bias estimates used to compute the average is greater than a specified maximum variance.

6 . The method of claim 1 , the reference rotation rate being estimated from attitude rates or changes determined from GNSS velocity data.

7 . The method of claim 1 , the reference rotation rate being estimated from attitude rates or changes determined by map-matching techniques.

8 . The method of claim 1 , the reference rotation rate being estimated from attitude rates or changes determined from video data.

9 . The method of claim 1 , step (c) being performed when the gyroscope is stationary and the reference rotation rate being zero.

10 . The method of claim 1 , the navigation module being installed in a vehicle, and the navigation filter performing steps (a)-(d) regardless of whether the vehicle is turned on or off.

11 . The method of claim 1 , the navigation module being installed in a vehicle, and the navigation module being programmed to turn on periodically whenever electrical power is available even if the vehicle in which the module is installed is not turned on.

12 . A vehicle navigation module comprising:
a MEMS gyroscope; and, a navigation filter that: (a) stores average gyroscope bias versus temperature data; (b) computes rate of change of gyroscope bias versus temperature from the average gyroscope bias versus temperature data; (c) estimates gyroscope bias by comparing rotation rate as measured by the gyroscope to a reference rotation rate, when a reference rotation rate is available; and, (d) estimates gyroscope bias, when no reference rotation rate is available, via linear extrapolation from a known bias value, the linear extrapolation taking into account a temperature change from the known bias value and rate of change of gyroscope bias versus temperature obtained in step (b).

13 . The module of claim 12 , the navigation filter further storing rate of change of gyroscope bias versus temperature data obtained in step (b).

14 . The module of claim 12 , the navigation filter further updating the average gyroscope bias versus temperature data from results of step (c).

15 . The module of claim 12 , the navigation filter further, in step (b), excluding average gyroscope bias versus temperature data points for which a number of gyroscope bias estimates used to compute the average is less than a specified minimum number of gyroscope bias estimates.

16 . The module of claim 12 , the navigation filter further, in step (b), excluding average gyroscope bias versus temperature data points for which a variance of gyroscope bias estimates used to compute the average is greater than a specified maximum variance.

17 . The module of claim 12 , the reference rotation rate being estimated from attitude rates or changes determined from GNSS velocity data.

18 . The module of claim 12 , the reference rotation rate being estimated from attitude rates or changes determined by map-matching techniques.

19 . The module of claim 12 , the reference rotation rate being estimated from attitude rates or changes determined from video data.

20 . The module of claim 12 , the navigation filter performing step (c) when the gyroscope is stationary, and the reference rotation rate being zero.

Assignees

• Zhi Xiaorong
• Hoshizaki Takayuki
• Loomis Peter Van Wyck
• Stockwell Walter Kenneth
• Trimble Navigation Ltd

Inventors

• Zhi Xiaorong
• Hoshizaki Takayuki
• Loomis Peter Van Wyck
• Stockwell Walter Kenneth

Classifications

• G01C25/005

  initial alignment, calibration or starting-up of inertial devices · CPC title

• G01C21/20

  Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) · CPC title

• G01C21/18 Primary

  Stabilised platforms, e.g. by gyroscope · CPC title

• G01C19/56

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title

• G01S19/52

  Determining velocity · CPC title