Methods and systems utilizing intermediate frequencies to control multiple coriolis gyroscopes
View Patent ↗Apparatus, systems, and methods to control a plurality of gyroscopes utilizing intermediate frequencies are disclosed. The gyroscopes are configured to operate at the same pre-determined intermediate frequency. To accomplish this, the natural frequency of each gyroscope is determined, and a reference signal is added to the output signal of its respective gyroscope such that the sum of the natural frequency and the reference signal frequency equals the pre-determined intermediate frequency. The output signal from each gyroscope is transmitted to a common inertial data processor, and the inertial data processor outputs a directional signal. The directional signal includes a representation of angles from an X-axis, a Y-axis, and a Z-axis. Since each signal output by the gyroscopes has the same frequency, the loss of data is decreased and the accuracy of the data increased.
1. A directional system, comprising:
a plurality of gyroscopes, each gyroscope having a natural frequency of operation (ω R ) and generating an output signal;
circuitry for receiving the output signal from each gyroscope at its natural frequency of operation (ω R ) and generating a signal for each gyroscope at an intermediate frequency (ω IF ) which is the same frequency for each gyroscope; and
a processor receiving the plurality of intermediate frequency signals and processing the signals to generate a directional signal.
2. The system of claim 1 , wherein ω IF is in the range of about 100 hertz (Hz) to about 100 kilohertz (kHz).
3. The system of claim 1 , wherein ω IF is about 8.0 kHz.
4. The system of claim 1 , wherein each gyroscope is a hemispherical resonator gyroscope.
5. The system of claim 4 , further comprising:
a plurality of phase locked loops being in communication with a respective mixer and transmitting the reference signal to the respective mixer.
6. The system of claim 4 , wherein each IF signal comprises at least a (ω LO +ω R ) component and a (ω LO −ω R ) component.
7. The system of claim 6 , further comprising a plurality of bandpass filters, wherein each bandpass filter is in communication with a respective mixer and receives the IF signal and filter at least one of the (ω LO +ω R ) component and the (ω L0 −ω R ) component from the IF signal.
8. The system of claim 6 , wherein each mixer is an analog mixer.
9. The system of claim 6 , wherein each mixer is a digital mixer.
10. The system of claim 6 , wherein each mixer is formed by adding an alternating current voltage (V AB ) and an excitation voltage (V b ) of the first signal on a metallization layer of a resonator in each gyroscope.
11. The system of claim 6 , wherein ω R of at least two IF signals are different frequencies.
12. The system of claim 11 , wherein ω LO of each of the at least two signals are different frequencies.
13. The system of claim 12 , wherein (ω LO −ω R ) of each IF signal has substantially the same frequency.
14. The system of claim 13 , wherein ω R of each IF signal has a frequency of about 4.1 kHz.
15. The system of claim 1 , further comprising:
a plurality of mixers being in communication with a respective gyroscope, receiving a signal having a natural resonate frequency (ω R ) from its respective gyroscope and a reference signal having a reference frequency (ω LO ), and combining the signal received from its respective gyroscope with the reference signal to form the IF signal.
16. A system to control a plurality of gyroscopes, comprising:
a first gyroscope having a natural frequency of operation (ω R ) and generating a first output signal;
first circuitry associated with the first gyroscope for receiving the first output signal and generating an x-coordinate signal at an intermediate frequency (ω IF );
a second gyroscope having a natural frequency of operation (ω R ) and generating a second output signal;
second circuitry associated with the second gyroscope for receiving the second output signal and generating a y-coordinate signal at the intermediate frequency (ω IF );
a third gyroscope having a natural frequency of operation (ω R ) and generating a third output signal:
third circuitry associated with the third gyroscope for receiving the third output signal and generating a z-coordinate signal at the intermediate frequency (ω IF ); and
a processor receiving the x, y, and z coordinate signals, each at the intermediate frequency (ω IF ), and generating a directional signal.
17. The system of claim 16 , wherein the first IF signal has a (ω LOX −ωO RX ) component, the second IF signal has a (ω LOY −ω RY ) component, and the third IF signal has a (ω LOZ −ω RZ ) component, wherein at least two of ω RX , ω LOY , and ω LOZ have different frequencies.
18. The system of claim 17 , wherein at least two of ω LOX , ω LOY , and ω LOZ have different frequencies.
19. The system of claim 18 , wherein the frequency of (ω LOX −ω RX ), (ω LOY −ω RY ), and (ω LOX −ω RZ ) are each in the range of about 100 Hz to about 100 kHz.
20. The system of claim 18 , wherein the frequency of (ω LOX −ω RX ), (ω LOY −ω RY ), and (ω LOZ −ω RZ ) are each about 8.0 kHz.
21. The system of claim 17 , ω RX , ω RY , and ω RZ each having a frequency of approximately 4.1 kHz.
22. A method for controlling a plurality of gyroscopes, the steps of the method comprising:
determining the natural frequency of operation (ω R ) for each one of the plurality of gyroscopes;
adding a reference signal at a predetermined operating frequency to each of the output signals from each one of the plurality of gyroscopes to generate a signal for each of the gyroscopes at the same intermediate frequency (ω IF ); and
processing the signals from each one of the gyroscopes at the intermediate frequency (ω IF ) to generate a directional signal.
23. The method of claim 22 , wherein the operating frequency is in the range of about 100 Hz to about 100 kHz.
24. The method of claim 22 , wherein the operating frequency is about 8.0 kHz.
25. The method of claim 22 , further comprising:
calculating the frequency for each reference signal by adding the operating frequency to the frequency of each respective output signal.
26. The method of claim 22 , further comprising:
outputting the directional signal from the inertial data processor, the directional signal having the operating frequency.