(0)G01S:0/4:

IPC6

SECTION G - PHYSICS

RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING...

G01S

1/5

G01S001/00 - G01S001/82

G 01 S

RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES (detecting masses or objects by methods not involving reflection or reradiation of radio, acoustic or other waves G 01 V)

Notes

(1)

In this subclass, the following term is used with the meaning indicated: [6]

-	"transponder" means an arrangement which reacts to an incoming interrogating or detecting wave by emitting a specific answering or identifying wave. [6]

(2)	Attention is drawn to the Notes following the title of class G 01 and to Note (1) following the title of subclass G 09 B.

Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith (position-fixing by co-ordinating a plurality of determinations of direction or position lines G 01 S 5/00) [2]

Means for providing multiple indication, e.g. coarse and fine indications

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Systems for determining direction or position line

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using amplitude comparison of signals transmitted sequentially from aerials or aerial systems having differently-oriented overlapping directivity-characteristics, e.g. equi-signal A-N type

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the signals being transmitted sequentially from an aerial or aerial system having the orientation of its directivity characteristic periodically varied, e.g. by means of sequentially effective reflectors

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using amplitude comparison of signals transmitted simultaneously from aerials or aerial systems having differently-oriented overlapping directivity-characteristics

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Azimuthal guidance systems, e.g. system for defining aircraft approach path, localiser system

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Elevational guidance systems, e.g. system for defining aircraft glide path

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using a comparison of transit time of synchronised signals transmitted from non-directional aerials or aerial systems spaced apart, i.e. path-difference systems

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the synchronised signals being frequency modulations on carrier waves and the transit times being compared by measuring difference of instantaneous frequencies of received carrier waves

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the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations

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Systems in which pulses or time-base signals are generated locally at the receiver and brought into predetermined time-relationship with received signals, e.g. pulse duration coincides with time interval between arrival of significant part of modulation of signals received from first and second aerials or aerial systems

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wherein the predetermined time-relationship is maintained automatically

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the synchronised signals being continuous waves or intermittent trains of continuous waves, the intermittency not being for the purpose of determining direction or position line and the transit times being compared by measuring the phase difference

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Systems in which the signals received, with or without amplification, or signals derived therefrom, are compared in phase directly

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Systems in which first and second synchronised signals are transmitted from both aerials or aerial systems and a beat frequency, obtained by heterodyning the first signals with each other is compared in phase with a beat frequency obtained by heterodyning the second signals with each other

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Systems in which a beat frequency, obtained by heterodyning the synchronised signals, is compared in phase with a reference signal having a phase substantially independent of direction

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using comparison of (1) the phase of the envelope of the change of frequency, due to Doppler effect, of the signal transmitted by an aerial moving, or appearing to move, in a cyclic path with (2) the phase of a reference signal, the frequency of this reference signal being synchronised with that of the cyclic movement, or apparent cyclic movement, of the aerial

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the apparent movement of the aerial being produced by cyclic sequential energisation of fixed aerials

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Conical-scan beam 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 [5]

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Rotating or oscillating beam beacons defining directions in the plane of rotation or oscillation [5]

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Broad-beam systems producing at a receiver a substantially continuous sinusoidal envelope signal of the carrier wave of the beam, the phase angle of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon, e.g. cardioid system [5]

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wherein the phase angle of the direction-dependent envelope signal is a multiple of the direction angle, e.g. for "fine" bearing indication [5]

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wherein the phase angle of the direction-dependent envelope signal is compared with a non-direction- dependent reference signal [5]

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wherein the phase angles of a plurality of direction-dependent envelope signals produced by a plurality of beams rotating at different speeds or in different directions are compared [5]

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Narrow-beam systems producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon; Overlapping broad beam systems defining a narrow zone and producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon [5]

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Timing the pulse-type envelope signals derived by reception of beam [5]

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wherein a characteristic of the beam transmitted or of an auxiliary signal is varied in time synchronously with rotation or oscillation of the beam [5]

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Varying frequency of beam signal or of auxiliary signal [5]

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Varying phase-relationship between beam and auxiliary signal [5]

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Varying pulse timing, e.g. varying interval between pulses radiated in pairs [5]

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Superimposing direction-indicating intelligence signals, e.g. speech, Morse [5]

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Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information

(covered by G 01 T 1/29)

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using electromagnetic waves other than radio waves

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using ultrasonic, sonic, or infrasonic waves (signalling devices G 08 B)

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Details [5]

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Systems for determining direction or position line (sound focusing or directing using electrical steering of transducer arrays, e.g. beam steering, in general, G 10 K 11/34) [5]

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using amplitude comparison of signals transmitted from transducers or transducer systems having differently-oriented characteristics [5]

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using a comparison of transit time of synchronised signals transmitted from non-directional transducers or transducer systems spaced apart, i.e. path-difference systems [5]

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Rotating or oscillating beam beacons defining directions in the plane of rotation or oscillation [5]