# Novel Relative Rotation & Displacement Measurement Technique

Shervin Taghavi Larigani

January 16, 2014

In a number of engineering and scientific disciplines, the ability to directly correlate the magnitude and direction of a force emanating from an external source has a high intrinsic value. By more precisely identifying the nature of the source that generated or generates these forces, the more we improve our ability to predict how the world around us will behave.

Current ranging systems use radar or laser interferometers, which in principle are based on the Doppler Effect. They measure only a change in range, which infers an estimate of the magnitude of that external force. As far as we know, these systems don't allow for the direct measurement of the transverse component of the force, which is expected to have the higher intrinsic value. Besides, the current ranging systems mostly depend on pulse/phase measurement; this novel technique does not.

We are proposing a technique for measuring the relative displacement between several objects (either moving, like satellites, airplanes, balloons, or cars, or static, like stations on the ground, or composed of both moving and static objects) in the plane perpendicular to their range-axis, as well as their relative yaw and pitch rotations. This is done by monitoring the relative displacement of the geometrical center of the energy pattern created by an emitting energy source (located on the emitting object) measured at the receiving object through algorithms using a zero-sum equation, for example.

Any deviation of the geometrical center of the energy pattern relative to the detector can be detected. Such deviation could be used to interpolate or derive a measurement of magnitude of the relative external force experienced by the objects, which is not a phase measurement.

Each object could be either an emitter or a receiver relative to any other objects. By increasing the number of independent measurements, we can measure the relative rotations of the objects in addition to their relative displacements. Instead of just two objects, one could extend this idea to a network of different objects.

In some specific cases where there are no practical limitations, one could envisage to measure all three-dimensional spatial components of the displacement by adding a measurement with a different angle of incidence. This angle would be between the direction of propagation of the incoming energy beam and the perpendicular to the surface containing the detector cells.

Unlike our technique, current-ranging techniques don't measure the relative displacement of objects in the plane perpendicular to their range-axis. Such measurements can provide critical information currently not being assessed. Our technique can be used in diverse applications like remote sensing, as it applies to earth/planetary and geo sciences, oil/gas exploration, and mining, civil, structural, medical engineering, and homeland security & defense, among others. Patent applications have been filed for this technique.

— Shervin Taghavi Larigani attended Caltech where he earned a master's degree and a PhD. He went on to conduct advanced research at NASA Jet Propulsion Laboratory. His research culminated as developing/demonstrating a new 201 Hg+ atomic ion clock with the nuclear spectroscopy of this "new" isotope attaining a precision 100 million times better than any previous application. He is currently the lead scientist of this measurement technique. He can be reached at [email protected].

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