Patent GB-195088-A (GB)
Title: Improvements in and relating to systems of and apparatus for permitting the exact determination of the direction of magnetic or electromagnetic fields of low, medium or high frequency relatively to a given direction in space
IPC: G01S1/02
Filed: 1923-03-17
Abstract: 195,088. Soc. Industrielle des Procedes W. A. Loth. March 18, 1922, [Convention date]. Aerials and like radiating and receiving conductors; directive signalling; bearings, determining; leader gear for assisting navigation. - Relates to means for determining the direction of magnetic or electromagnetic fields of any frequency, applicable to the reception or emission of fields or signals in guiding moving objects along a route by means of current-carrying cables, in avoiding collisions between moving objects, in wireless telegraphy and telephony and radiogoniometry, and in affording security on railways. An armature with one or more windings arranged about a common axis, connected in series and forming closed circuits, is exposed to the field and brushes 5, 6, Fig. 2, contact with the windings or with commutator segments connected to the windings and arranged near the armature or at a distance, the currents collect-ed by the brushes being the sum or integral of the currents induced in the windings by the field and being dependent on the angle between the brushes and the field. This angle is determined by observing maxima or minima or other values of the current, collected, the brushes 5, 6 being arranged in circuits resonant to the frequency of the field and being connected directly or through amplifiers and/or transformers to a telephone receiver 21 or other current detector. The windings may he mounted on the side or curved face of a cylinder, cone, or frustum of same, or other solid of revolution or polyhedron, solid or hollow and of wood, metal or other material, the individual coils being separate or overlapping, or the windings may follow the outlines of diametral sections of such solids as shown in Fig. 2. In one. form, the armature comprises a solid so wound with its axis horizontal or vertical or suitably positioned relatively to the field. In modifications, a number of such solids are combined to form an armature, for example, two cylinders with diametral windings may be combined with axes at right-angles. In other forms, the windings are arranged on the surface of a sphere as shown in Fig. 8, or a number of coil frames 14, Fig. 5, are connected together with the coils in closed circuit. Armatures, may be combined with other coil frames or other armatures. Single or multiple layers of windings may be used; and to vary the sensitiveness, shunts may be employed or the number of windings connected to the detector may be varied. Compensation for parasitic fields may be obtained by means of small armatures or coils controlled by the movement of the brushes 5, 6 or connected to commutators the brushes of which are so controlled. The brushes 5, 6 may be reciprocated or rotated continuously, being connected to the current detector through slip rings if necessary, and may be moved manually or driven mechanically by clockwork or an electric motor at a speed controlled by a governor. Several detecting circuits may be connected successively or simultaneously to one armature. If the armature is placed on land, the windings may comprise cables and the whole receiver may be mounted within the armature. In guiding a boat, submarine, hydro-aircraft, or aircraft along a predetermined route by means of a cable or guide-wire immersed in the sea, following the coast, on land, buried in the ground, or mounted on posts, and carrying a current of musical frequency producing a field of circular or double-lemniscate form. the moving object may carry an armature with axis horizontal or vertical. or two armatures may be used both with axes vertical or horizontal or one with axis horizontal and one with axis vertical, the armatures being located fore and aft or on either side. of the object. Combination of such arrangements with each other and with other coils may also be used. The horizontal axes may be parallel or perpendicular to the major axis of the moving object, or one armature may have two horizontal axes at rightangles. one parallel to the axis of the object. The armatures and coils may be connected separately or in combinations to a common detector circuit, the position, direction and degree of inclination of the moving object relative to the cable being thus determined. In connection with the landing of aircraft, a wire surrounding the aerodrome is used. The armatures may be used for signalling between the moving objects, or between a moving object and a lightship or land station, which may be the station at the end of the guide cable, collisicns being thus avoided. In directive reception or transmission in wireless signalling,. breaks may be arranged in the windings, or commutator to 'form a number of separate closed directive windings which may be used selectively.