Environmental characteristic determination

• US 7,650,238 B2
• Filed: 05/09/2005
• Issued: 01/19/2010
• Est. Priority Date: 05/09/2005
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Humphrey, Ian, Heckathorn, Donald, Reynolds, Christopher I., Perlmutter, Michael
• Primary Examiner(s): Nguyen; Cuong H
• Application Number:
  US11/125,041
• Publication Number:
  US 20060253253A1
• Time in Patent Office: 1,716 Days
• Field of Search: 701/220, 701/36, 701/20, 701/7, 340/601, 340/939, 340/933, 340/540, 340/500, 340/618, 73/3, 73/17.3, 732/90.R
• US Class Current: 701/220
• CPC Class Codes: G01C 21/166 Mechanical, construction or arrangement details of inertial navigation systems
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

A processor of an apparatus in one example makes a determination of an environmental characteristic based on an average of a plurality of concomitant values that correspond to the environmental characteristic.

Claims

1. An apparatus for sensing an environmental characteristic, comprising:

a processor having a plurality of inputs for receiving a plurality of concomitant values indicative of the environmental characteristic and having an output that provides a determination of the environmental characteristic; and

a plurality of sensors that obtain the plurality of concomitant values;

wherein each of the plurality of sensors comprises an output operatively coupled to a respective input of the processor;

wherein the processor is configured to determine the environmental characteristic based on an average of the plurality of concomitant values;

wherein the processor multiplies each of the plurality of concomitant values by at least one weighting value to determine a weighted average of the plurality of concomitant values;

wherein the at least one weighting value is based on accuracy levels of the plurality of sensors.

2. The apparatus of claim 1, wherein the processor multiplies a more accurate sensor of the plurality of sensors by a higher weighting value than other sensors of the plurality of sensors.

3. The apparatus of claim 1, wherein the plurality of sensors comprise independent sensors of the environmental characteristic.

4. The apparatus of claim 1, wherein the processor determines the average of the plurality of concomitant values in order to reduce error terms in the plurality of concomitant values.

5. The apparatus of claim 1, wherein the plurality of sensors comprise at least one gyroscope and at least one accelerometer.

6. The apparatus of claim 5, wherein the gyroscope is a Micro-Electro-Mechanical Systems gyroscope.

7. The apparatus of claim 5, wherein the accelerometer is a Micro-Electro-Mechanical Systems accelerometer.

8. The apparatus of claim 1, wherein the processor employs the at least one weighting value to give higher priority to more accurate sensors.

9. The apparatus of claim 1, wherein the determination of the environmental characteristic comprises a determination of the environmental characteristic for a pre-determined time period;

wherein the plurality of concomitant values comprise a plurality of concomitant values from the pre-determined time period.

10. The apparatus of claim 1, wherein the combination is an average of the plurality of concomitant values and wherein the average comprises a summation value divided by a scaling value;

and

wherein the summation value comprises a summation of the plurality of concomitant values, wherein the scaling value comprises a number of the plurality of concomitant values multiplied by a scaling factor.

11. The apparatus of claim 1, wherein the environmental characteristic comprises at least one of angular rate, angular anceleration, temperature, pressure, strain, electrical field strength, and magnetic field strength.

12. The apparatus of claim 1, wherein the environmental characteristic is pitch and wherein the output of the processor is a pitch angular rate measurement determined from an average of the plurality of concomitant values.

13. The apparatus of claim 12, wherein the environmental characteristic is pitch and wherein the output of the processor is a pitch angular rate measurement determined from a weighted average of the plurality of concomitant values.

14. The apparatus of claim 1, wherein the environmental characteristic is roll and wherein the output of the process is a roll angular rate measurement determined from an average of the plurality of concomitant values.

15. The apparatus of claim 1, wherein the environmental characteristic is yaw and wherein the output of the process is a yaw anguiar rate measurement determined from an average of the plurality of concomitant values.

16. The apparatus of claim 1, wherein the environmental characteristic is pitch and wherein the output of the process is an average of the plurality of concomitant values.

17. The apparatus of claim 1, wherein the environmental characteristic comprises a pitch angular rate, a roll angular rate, and a yaw angular rate;

wherein the apparatus further comprises;

a pitch circuit for the pitch angular rate that comprises a first instance of the processor as a pitch processor and a first instance of the plurality of sensors as a plurality of independent pitch sensors;

a roll circuit for the roll angular rate that comprises a second instance of the processor as a roll processor and a second instance of the plurality of sensors as a plurality of independent roll sensors; and

a yaw circuit for the yaw angular rate that comprises a third instance of the processor as a yaw processor and a third instance of the plurality of sensors as a plurality of independent yaw sensors,

wherein the pitch circuit, the roll circuit, and the yaw circuit are configured as an inertial measurement unit which provides a measurement of pitch angular rate,

the roll angular rate, and the yaw angular rate.

18. The apparatus of claim 17, wherein at least one of the plurality of independent pitch sensors, the plurality of independent roll sensors, and the plurality of independent yaw sensors comprise at least one Micro-Electro- Mechanical Systems accelerometer.

19. The apparatus of claim 17, wherein the inertial measurement unit provides the pitch angular rate measurement, the roll angular rate measurement, and the yaw angular rate measurement for at least one of a navigation, control, and inertial guidance system.

20. The apparatus of claim 17, wherein at least one of the plurality of independent pitch sensors, the, plurality of independent roll sensors, and the plurality of independent yaw season comprise at least one Micro-Electro- Mechanical Systems gyroscope.