Apparatus for generating a nutating electromagnetic field

• US 4,017,858 A
• Filed: 02/24/1975
• Issued: 04/12/1977
• Est. Priority Date: 07/30/1973
• Status: Expired due to Term

• Current Assignee: Kaiser Aerospace & Electronics Corporation
• Original Assignee: Polhemus Navigation Sciences Incorporated
• Inventors: Kuipers, Jack
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/552,339
• Time in Patent Office: 778 Days
• Field of Search: 343/112 D, 343/108 SM, 343/100 R, 324/34 PS, 324/41, 340/258 C, 318/653, 317/155.5
• US Class Current: 342/350
• CPC Class Codes: F41G 7/00 Direction control systems for self-propelled missiles flight control B64C, G05D1/00 ; counter-measures against guided missiles F41H11/02; spin-stabilised missiles F42B10/26; self-propelled or guided missiles having direction control systems only installed aboard F42B15/01; rocket torpedoes F42B17/00; marine torpedoes or sea-mines having self-propulsion means F42B19/00; locating by use of radio or other waves G01S; computing aspects G06
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 1/42 Conical-scan beacons transmitting signals which indicate at a mobile receiver any displacement of the receiver from the conical-scan axis, e.g. for "beam-riding" missile control

Abstract

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.

Claims

1. Apparatus for generating a nutating electromagnetic field which comprises:

a. three orthogonal radiators adapted to pass a current; and

b. means for supplying the appropriate mixture of signals from three sources, supplying a DC signal, a first AC signal and a second AC signal in phase quadrature with the first AC signal, respectively, to the three radiators such that the electromagnetic field produced by the currents in the three radiators is caused to nutate in a conical manner about an arbitrarily directed pointing vector of the field, the apex of the cone being at the intersection of the generating radiators.

2. Apparatus for generating a nutating electromagnetic field which comprises:

a. at least two orthogonal radiators adapted to pass a current; and

b. means for supplying the appropriate mixture of signals from sources supplying a DC signal, and a first AC signal to the radiators such that the electromagnetic field generated by the currents in the radiators is caused to nutate about an arbitrarily specified pointing vector of the field.

3. The apparatus of claim 2 in which the excitation signals cause the field to nutate in a nodding motion in a plane defined by the axes of the two radiators excited.

4. The apparatus of claim 2 in which there are three radiators and in which the signal source also supplies a second AC signal in phase quadrature to the first AC signal;

and, means for supplying the appropriate mixture of each of the three source signals to the three radiators whereby the magnetic field is caused to nutate in a conical manner about an arbitrarily but specifically directed pointing vector of the field, the apex of the cone being at the intersection of the generating coils.