Polhemus Navigation Sciences, Inc.

Mcdonnell Douglas Corporation

The Austin Company

Jack Kuipers

A method and apparatus is provided for determining remote object orientation and position with an electromagnetic coupling. A plurality of radiating antennas are provided for radiating electromagnetic energy. Each of the radiating antennas have independent components for defining a source reference coordinate frame. A transmitter is provided for applying electrical signals to the radiating antennas for generating a plurality of electromagnetic fields. The signals are multiplexed so that the fields are distinguishable from one another. A plurality of receiving antennas are disposed on a remote object for receiving the transmitted electromagnetic fields. The receiving antennas have a plurality of independent components for detecting the transmitted electromagnetic fields and defining a sensor reference coordinate frame. An analyzer is provided for receiving the output of the receiving antennas and converting the components of the transmitted electromagnetic fields into remote object position and orientation relative to the source reference coordinate frame. The analyzing means includes means for processing the components of the electromagnetic fields in an uncoupled manner into remote object position and remote object orientation. The processing technique provides an uncoupled, noniterative, closed form solution for both position and orientation which is fast and includes no discontinuities. The processing speed is enhanced with a parallel processing technique which provides for simultaneous determination of the position and orientation parameters. The speed of the processing technique is further enhanced by provision of quaternion solutions for position and orientation. A new virtual real-time binocular computer graphics application is provided which is particularly adapted for generating the cockpit view of an aircraft pilot in a flight simulator.

Method and apparatus for determining remote object orientation and

Two spaced bodies, each including at least two independently oriented radiating antennas, are in communication with each other by such means as an electromagnetic field. The first body receives radiation transmitted from the second body and establishes the pointing angles to the second body with respect to the first body coordinate reference frame. The field received by the first body can include information defining the second body's pointing angles to the first body with respect to the second body's coordinate reference frame and the relative roll about their mutually aligned pointing axis. These pointing angles and relative roll are sufficient for determining the orientation of the first body relative to the second body. The second body receives radiation transmitted from the first body and establishes the pointing angles to the first body with respect to the second body. Analogously, radiation received by the second body can include information defining the first body's pointing angles with respect to the first body coordinate reference frame to the second body and the relative roll between their mutually aligned pointing axes. As before, this information is sufficient for the second body to determine its orientation relative to the first body. Distance between the two bodies can be determined by phase-locking techniques, thus providing the capability of a full six-degree-of-freedom measurement system. A third body, known and defined in the coordinate frame of the first body, can be defined at the second body with respect to the frame of the second body. That is, information is transmitted from the first body and received at the second body which establishes a vector from the second body to the third body thus defining the location of the third body at the second body.

Method and apparatus for tracking objects

A field (e.g., a magnetic field) which nutates about a pointing vector is used to both track or locate an object in addition to determining the relative orientation of this object. Apparatus for generating such a field includes mutually orthogonal coils and circuitry for supplying an unmodulated carrier, hereafter called DC signal, to one coil and an AC modulated carrier signal, hereafter called AC signal, to at least one (usually two) other coil, such that the maximum intensity vector of a magnetic field produced by the currents in the coils nutates about a mean axis called the pointing vector direction of the field.

Apparatus for generating a nutating electromagnetic field

An electromagnetic field which nutates about a pointing vector is used to both track or locate a remote object in addition to determining the relative orientation of the object. Apparatus for generating such a field includes mutually orthogonal dipole radiators, defining a reference coordinate frame, and circuitry for supplying excitations, such that the maximum intensity vector of a vector field produced by these excitations in the radiators nutates about a mean axis or axis of nutation which is called the pointing vector direction of the field. A pointing coordinate frame has the x-axis coincident with the pointing vector and the y-axis in the x-y plane of the reference frame. Mutually orthogonal sensors at the object sense the field and establish a sense coordinate frame, which can be coincident with the coordinate frame of the remote body. Coordinate transformer means, system and process are used in connection with determining the pointing and angular position of the sense frame with respect to the reference frame. A first error signal relating the sense frame to the pointing frame is transformed into a second error signal relating the sense frame to the reference frame. This second error signal is used to generate the three Euler angles defining the orientation of the sense frame relative to the reference frame and to generate the pointing angles defining the translation of the sense frame from the reference frame. Means, system and process are described, thus, capable of continuously measuring five independent angles through the use of one field generating means, one field sensing means at the remote object, and signal processing means. Two of the angles specify the direction to, or location of, the remote object and the remaining three angles define the angular orientation of the remote object, the angles defining the sense frame with respect to the fixed reference coordinate frame of the field generating means.

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Grand Rapids, MI, United States of America

Jack Kuipers