System for the measurement of rotation and translation for modal analysis

• US 5,915,278 A
• Filed: 02/27/1995
• Issued: 06/22/1999
• Est. Priority Date: 02/27/1995
• Status: Expired due to Term

• Current Assignee: Brian C. Mallick
• Original Assignee: Brian C. Mallick
• Inventors: Mallick, Brian C.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): Kwok, Helen C.
• Application Number:
  US08/394,475
• Time in Patent Office: 1,576 Days
• Field of Search: 73/579, 73/654, 73/658, 343/700 MS, 343/753, 343/853, 455/67.1
• US Class Current: 73/658
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them

Abstract

A system for making modal analysis is disclosed which uses multiple frequencies for calculating the bearing and distance of a sensor from a remote receiver component. The sensor'"'"'s adaptor to be secured to a structure-under-test. Microwave oscillators are formed on the substrate. Each oscillator has a separate microstrip antenna coupled to its output. At least one of these antennas has a separate dielectric lens to shape its microwave signal to have a different beam shape than the microwave signals transmitted by the other antennas. A remote receiver component is positioned in a line of sight relation with the sensor and includes a base and a separate receiver for each antenna. A stored program processor measures lapsed time between receipt of a query signal and receipt of a signal reception indication and calculates the distance between the sensor and the remote receiver component. A piezoresistive accelerometer generates an acceleration signal that can be used by a stored program processor to calculate displacement of the sensor normal to the plane of the sensor and the antennas. The stored program processor also compares the relative signal strengths to the signals received by the remote receiver component from the various antennas of the sensor and, using this data, calculates the bearing of the remote receiver component from the sensor.

Claims

1. A system comprising:

a signal transmission component adapted to be positioned on a structure-under-test, said transmission component including;

a planar substrate;

a first microwave oscillator, monolithically formed on the substrate, having a first output, and operable to generate at the first output a first signal having a first frequency;

a second microwave oscillator, monolithically formed on the substrate, having a second output, and operable to generate at the second output a second signal having a second frequency;

a third microwave oscillator, monolithically formed on the substrate, having a third output, and operable to generate at the third output a third signal having a third frequency;

a first microstrip antenna, coupled to the output of the first microwave oscillator and responsive to the first microwave oscillator, and operable to transmit the first signal as a symmetrical directional signal having a first cross-section;

a second microstrip antenna, coupled to the output of the second microwave oscillator and responsive to the second microwave oscillator, and operable to transmit the second signal as a symmetrical directional signal having a second cross-section;

a third microstrip antenna, coupled to the output of the third microwave oscillator and responsive to the third microwave oscillator, and operable to transmit the third signal as a symmetrical directional signal having a third cross-section;

wherein the first, second, and third microstrip antennas are positioned on the substrate generally symmetrically about a reference point on the substrate, to transmit the first, second, and third signals in a generally common direction normal to the substrate at the reference point;

wherein the first, second, and third frequencies are different one from the other; and

wherein the first, second, and third cross-sections are different one from the other; and

a receiver component adapted to be positioned remote from the transmission component in a line-of-sight relation with the transmission component, said receiver component including;

a base;

a first receiver mounted on said base, and operable to detect the first signal, to determine a signal strength for the first signal, and to generate a first signal strength indication signal indicative of the signal strength for the first signal;

a second receiver mounted on said base, and operable to detect the second signal, to determine a signal strength for the second signal, and to generate a second signal strength indication signal indicative of the signal strength for the second signal; and

a third receiver mounted on said base, and operable to detect the third signal, to determine a signal strength for the third signal, and to generate a third signal strength indication signal indicative of the signal strength for the third signal.

2. The system of claim 1 wherein the receiver component further comprises:

a query signal transmitter operable to generate a microwave signal to energize the first, second, and third microwave oscillators of the signal transmission component.

3. The system of claim 1 wherein the receiver component further comprises a stored program processor operable to receive the first, second, and third signal strength indication signals, and to calculate a position for each of the first, second, and third microwave oscillators relative to the receiver component.

4. The system of claim 1 wherein the signal transmission component further comprises a piezoresistive accelerometer positioned on the substrate, generally at the reference point.

5. A sensor comprising:

a substrate adapted to be secured to a structure-under-test;

n microwave oscillators monolithically formed on the substrate in a common plane, where n is at least three, each of said microwave oscillators having an output and being capable of generating at said output an unmodulated microwave signal having a particular frequency, wherein the particular frequency is different for each of the n microwave oscillators;

n microstrip antennas, each said microstrip antenna being coupled to the output of one of said n microwave oscillators and operable to transmit the unmodulated microwave signal generated by the microwave oscillator to which the microstrip antenna is coupled;

said n microstrip antennas being positioned on said substrate to transmit in a generally common direction; and

an accelerometer positioned on the substrate to detect vibrations in a direction generally normal to the common plane.

6. The sensor of claim 5 wherein the accelerometer comprises a piezoresistive accelerometer.

7. A system comprising:

a signal transmission component adapted to be positioned on a structure-under-test, said transmission component including;

a planar substrate;

n microwave oscillators monolithically formed on the substrate, where n is at least three, each of said microwave oscillators having an output and being capable of generating a signal having a particular frequency, wherein the particular frequency is different for each of the n microwave oscillators;

a piezoresistive accelerometer positioned on said substrate generally central to said n microwave oscillators;

n microstrip antennas, each said microstrip antenna being mounted on the substrate and coupled to the output of one of said n microwave oscillators and operable to transmit the signal generated by the microwave oscillator to which the microstrip antenna is coupled, said n microstrip antennas being positioned on said substrate to transmit in a generally common direction; and

n dielectric lenses, each said dielectric lens covering one of said n microstrip antennas and operable to shape the signal transmitted by the microstrip antenna covered by said dielectric lens to have a particular beam shape, wherein the particular beam shape is different for at least three of the n microstrip antennas; and

a receiver component adapted to be positioned remote from the transmission component in a line-of-sight relation with the transmission component, said receiver component including;

a base; and

n receivers mounted on said base, each said receiver being capable of detecting the signal transmitted by one of said n microstrip antennas, measuring the strength of the signal, and generating a voltage that is a function of the strength of the signal.

8. A system comprising:

a signal transmission component having;

a planar substrate;

n microwave oscillators monolithically formed on the substrate, where n is at least three, each said microwave oscillators having an output and being capable of generating a signal having a particular frequency, wherein the particular frequency is different for each of the n microwave oscillators;

n microstrip antennas, each said microstrip antennas being mounted on the substrate and coupled to the output of one of said n microwave oscillators and operable to transmit the signal generated by the microwave oscillator to which the microstrip antenna is coupled, said n microstrip antennas being positioned on said substrate to transmit in a generally common direction; and

n dielectric lenses, each said dielectric lens covering one of said n microstrip antennas and operable to shape the signal transmitted by the microstrip antenna covered by said dielectric lens to have a particular beam shape, wherein the particular beam shape is different for at least three of the n microstrip antennas; and

a receiver component having;

a query signal transmitter for generating a query signal and for energizing at least one of said n microwave oscillators with said query signal;

a base;

n receivers, each of said n receivers operable to receive the signal transmitted by one of said n microstrip antennas and to generate a signal strength indication signal; and

a stored program processor for receiving said query signal and the signal strength indication signal of each of said n receivers, and operable to calculate a position for each of said n microwave oscillators relative to the receiver component, using predetermined signal strength ratios.

9. The system of claim 8 wherein each receiver is tuned to a receiver frequency equal to the particular frequency of one of the n microwave oscillators, wherein the receiver frequency is different for each of the n receivers.

10. The system of claim 8 wherein the signal strength indication signal of each receiver comprises a signal strength indication signal value representative of a position unique to one of the n microwave oscillators.

11. The system of claim 8 wherein the predetermined signal strength ratios are stored in the stored program processor'"'"'s memory, and wherein the stored program processor is operable to determine modal properties of a structure under test.