Sensor processing method

1. A method of sensing pressure with a pressure sensor, the method comprising:

subjecting the pressure sensor having on output P which varies based on the sensor's frequency F and the temperature T to several different temperatures and applied pressures;

determining the pressure sensor's frequency F at the different temperatures and applied pressures and collecting data points representing the same;

from the data points and at each different temperature, generating several polynomials P=ƒ(F) and T=ƒ/(F);

using the pressure sensor to sense an unknown pressure Pμ at a temperature Tμ at which the pressure sensor has a frequency Fμ;

selecting, from the generated polynomials, polynomials that surround Tμ and Fμ;

evaluating the selected polynomials for Fμ to calculate values for P=ƒ(Fμ) and T=ƒ(Fμ);

from the calculated values, generating a polynomial P=ƒ(T); and

solving Pμ=ƒ(T) for Tμ and outputting Pμ.

2. The method of claim 1 in which generating the polynomials includes employing Newton's method.

3. The method of claim 1 in which the generated polynomials are stored.

4. The method of claim 1 in which the data points are stored and the polynomials are not generated until the surrounding data points are selected.

5. The method of claim 1 in which solving Pμ=ƒ(T) includes using Lagrange's method.

6. A pressure sensor comprising:

a resonant pressure transducer whose frequency F changes depending on the applied pressure P and the temperature T;

a temperature sensor for measuring the temperature T;

a memory including stored therein data points corresponding to the sensor's frequency F at different applied pressures and temperatures; and a processor configured to:

generate several polynomials P=ƒ/(F) and T=ƒ(F) from the data points,

calculate Pμ at Tμ when the transducer frequency is Fμ by:

selecting, from the generated polynomials, polynomials that surround Fμ and Tμ,

evaluating the selected polynomials for Fμ to calculate values for P=ƒ(Fμ) and T=ƒ(Fμ),

generating a polynomial P=ƒ(T) for the calculated values, and

solving Pμ=ƒ(T) for Tμ, and output Pμ.

7. A method of determining an unknown parameter Z based on two parameters X and Y measured at least a first sensor, the method comprising:

determining Z with a second sensor at different values of X and Y and collecting data points representing the same;

from the data points, generating several polynomials Z=ƒ(X) and X=ƒ(Y);

determining an unknown parameter Zμ at Xμ and Yμ;

selecting, from the generated polynomials, polynomials that surround Xμ and Yμ;

evaluating the selected polynomials for Yμ to calculate values for Z=ƒ(Yμ) and X=ƒ(Yμ);

from the calculated values, generating a polynomial Z=ƒ(X); and

solving Zμ=ƒ(X) for Xμ and outputting Zμ.

8. The method of claim 7 in which generating the polynomials includes employing Newton's method.

9. The method of claim 7 in which the generated polynomials are stored.

10. The method of claim 7 in which the data points are stored and the polynomials are not generated until surrounding data points are selected.

11. The method of claim 7 in which solving Zμ=ƒ(X) includes using Lagrange's method.

12. A sensor system comprising:

a sensor with a parameter Y that changes depending on parameter Z and parameter X;

a device which measures parameter X;

a memory including stored therein data points corresponding to values of parameter Y at different values of Z and X; and

a processor configured to:

generate several polynomials Z=ƒ(X) and X=ƒ(Y) from the data points,

calculate Zμ at Xμ when the sensor measures Yμ by:

selecting, from the generated polynomials, polynomials that surround Yμ and Xμ,

evaluating the selected polynomials for Yμ to calculate values for Z=ƒ(Yμ) and X=ƒ(Yμ),

generating a polynomial Z=ƒ(X) for the calculated values, and solving Zμ=ƒ(X) for Xμ, and output Zμ.