Adaptive multi-axis sensor array

Abstract

A sensor array made up of 2 n piezoelectric oscillators (preferably paired quartz oscillators) is provided in which n equals the number of axes of interest and each one of the pairs of oscillators has a principle axis directed oppositely from the other of its pair. A controller which preferably includes a microprocessor, makes use of the dynamic relationships of the sensors in the array to adaptively assess the magnitude of weighting factors needed to correct the output signal from each oscillator for environmental and systematic effects to provide optimum frequency and phase output for computing position, velocity, and acceleration. Preferably, a seventh reference oscillator is provided in the center of the array which is canted relative to each of the three orthogonal axes by 45°. This adaptive sensor array is capable of determining position within one meter along any of the x, y, and z axes without the need for any external (e.g., GPS) signal. In addition, unlike other sensor systems, it is capable of providing local vertical on a continuous basis. The array can also determine if an object is moving in any translational or rotational direction, within the measurement capabilities of the system.

Description

BACKGROUND AND SUMMARY OF THE INVENTION[0001]The present invention is directed to position determining hardware. More particularly the present invention is directed to an adaptive multi-axis sensor array known as Ensemble of Quartz Clocks Adapting To the Environment (EQUATE).[0002]Systems capable of providing position, acceleration and velocity data are well known in the prior art. The more common ones utilize signals provided by a Global Position System (GPS) which are fed to an interface with a navigation computer to provide position, velocity and time reference signals. Other systems employ microwave signals to provide a localized solution as for an airport. Radio transmitters are used in certain applications to triangulate to provide independent navigation data.[0003]Existing position detecting systems such as satellite based systems including GPS, VOR, cell tower signals, other microwave signals, have significant limitations. Although these systems provide useful information fo...

AI Technical Summary

Benefits of technology

[0006]It is among the objects of the present invention to overcome the limitations and deficiencies of the prior art systems. Particularly, the signal provided by the EQUATE oscillator ensemble provides a signal of the necessary precision enabling the tight synchronization needed for the two data streams. In addition, the EQUATE oscillator array uses an Allan filter which is capable of providing accurate signal correction even when non-linear corrections are necessary and even though non-continuous external data is available, and even though the noise my be non-stationary in nature. What is more, the EQUATE array can provide precision position signals when no external data stream is available.

[0022]At least one, and possibly more, additional oscillator(s) (i.e., reference oscillator) can be placed to have equal sensitivity to +x / +y / +z and −x / −y / −z as a measure of consistency. The algorithms provide a constant health status of the EQUATE sensor array, making the system extremely robust and reliable.

Problems solved by technology

Existing position detecting systems such as satellite based systems including GPS, VOR, cell tower signals, other microwave signals, have significant limitations.

Although these systems provide useful information for vehicular navigation (both earthbound and space / airborne), communications links, geodesy and mapping, to name a few, each has its problems.

Further, such signals are subject to jamming, spoofing, or otherwise degraded, such that significant distortion in accurate positioning determination is created.

However, these attempts to provide a suitable “fail-safe” system are doomed to failure if updated signal information is unavailable for whatever reason.

Further, current applications including deep sea exploration, navigation in polar icecap regions with only minimal satellite GPS data available, determining position in caves or buildings which are not microwave penetrable, deep oil exploration, precisely locating orbiting spacecraft, celestial objects, or objects on the dark side of the moon, find no solution in existing systems.

Most of these systems do not work well in “urban canyons” due to signal blockage and multi-path problems.

If the errors require the system to accommodate a non-linear estimation, involve a discontinuous data stream, or noise that involves non-stationary modeling, the effectiveness of the Kalman filter based system is significantly hampered / limited.

The signals from the available systems are of insufficient precision.

The EQUATE sensor array is unlike other systems whose accuracy degrades with time.

Accordingly, EQUATE's position error performance for a small, low-powered device is unsurpassed when operating independently of external signals, both in the short-term and long-term operations.

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