PASSIVE MONITORING OF SENSOR CALIBRATION STATUS

• US 20180038718A1
• Filed: 08/08/2016
• Published: 02/08/2018
• Est. Priority Date: 08/08/2016
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Carney, Kenneth
• Granted Patent: US 10,436,616 B2
• Time in Patent Office: Days
• CPC Class Codes: G01D 18/006 Intermittent recalibration

Abstract

A system has at least one sensor and a control for analyzing a signal from the sensor. The sensor is operable to send a signal indicative of a presence of a particular occurrence to the control. The sensor also sends a background signal even without the presence of the particular occurrence. The control evaluates the background signal to identify a need for calibration. A method is also disclosed.

Claims

1. A system comprising:

at least one sensor and a control for analyzing a signal from said sensor, said sensor being operable to send a signal indicative of a presence of a particular occurrence to said control, and said sensor also sending a background signal to said control even without the presence of the particular occurrence; and

said control evaluating said background signal to identify a need for calibration.

2. The system as set forth in claim 1, wherein there are a plurality of said sensors communicating with said control.

3. The system as set forth in claim 2, wherein a change in said background signal is monitored to identify the need for calibration.

4. The system as set forth in claim 3, wherein said background signal has an offset and the change in the offset is monitored over time to determine the need for calibration.

5. The system as set forth in claim 4, wherein said offset changes over time and said control evaluates the rate of change and identifies the need for calibration when the rate of change increases.

6. The system as set forth in claim 4, wherein said control compares the offset to a limit and identifies the need for calibration should said offset be above said limit.

7. The system as set forth in claim 3, wherein said control monitors noise in said background signal and a change in said noise to identify said need for calibration.

8. The system as set forth in claim 3, wherein said control looks to a number of noise spikes in said background signal to identify the need for calibration.

9. The system as set forth in claim 1, wherein a background signal at a first point in time is compared to the background signal at a second later point in time to identify the need for calibration.

10. The system as set forth in claim 1, wherein a feature of the background noise is compared to a limit to identify the need for calibration.

11. The system as set forth in claim 1, wherein an ambient condition is sensed, and a change in the background signal caused by a change in the ambient condition is monitored, and a variation in the amount of change to the background signal for a given change in the ambient condition is monitored to identify the need for calibration.

12. The system as set forth in claim 1, wherein said background signal has a frequency range that is monitored over time, and a change in the frequency range is monitored to identify the need for calibration.

13. A method of monitoring a system comprising the steps of:

monitoring signals from a sensor operable to send a signal indicative of a presence of a particular occurrence at a control, and also sending a background signal from the sensor even without the presence of the particular occurrence, and evaluating said background signal to identify a need for calibration.

14. The method of monitoring a system as set forth in claim 13, further including the steps of monitoring a change in said background signal to identify the need for calibration.

15. The method of monitoring a system as set forth in claim 14, wherein said background signal has an offset and monitoring a change in the offset over time to determine the need for calibration.

16. The method of monitoring a system as set forth in claim 15, wherein said offset changes over time and said control evaluating the amount of change and identifying the need to calibrate when the amount of change increases.

17. The method of monitoring a system as set forth in claim 16, further including the steps of comparing the offset to a limit and identifying said need for calibration should said offset be above said limit.

18. The method of monitoring a system as set forth in claim 14, further including the steps of monitoring noise in said background signal and using a change in said noise to identify said need for calibration.

19. The method of monitoring a system as set forth in claim 13, further including the steps of comparing a background signal at a first point in time to a background signal at a second later point in time to identify the need for calibration.

20. The method of monitoring a system as set forth in claim 13, further including the steps of comparing a feature of the background noise to a limit to identify the need for calibration.