(0)G01S:1/4:

(0)G01S:1/4:

IPC6

SECTION G - PHYSICS

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

G01S

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G01S003/00 - G01S003/86

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Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received (position-fixing by co-ordinating a plurality of determinations of direction or position lines G 01 S 5/00; for geophysical measurement G 01 C; telescope mountings G 02 B)

using radio waves

Means for increasing effective directivity, e.g. by combining signals having differently- oriented directivity characteristics, by sharpening the envelope waveform of the signal derived from a rotating or oscillating beam aerial (comparing amplitude of signals having differently-oriented directivity characteristics to determine direction G 01 S 3/16, G 01 S 3/28; modifications of aerials or aerial systems H 01 Q)

Means for reducing polarisation errors, e.g. by use of Adcock or spaced loop aerial systems

Means for reducing or compensating for quadrantal, site, or like errors

Means for determining sense of direction, e.g. by combining signals from directional aerial or goniometer search coil with those from non-directional aerial (determining direction by amplitude comparison of signals derived by combining directional and non-directional signals G 01 S 3/24 , G 01 S 3/34)

Systems for determining direction or deviation from predetermined direction

using amplitude comparison of signals derived sequentially from receiving aerials or aerial systems having differently-oriented directivity characteristics or from an aerial system having periodically-varied orientation of directivity characteristic

derived directly from separate directional aerials

derived by sampling signal received by an aerial system having periodically-varied orientation of directivity characteristic

derived from different combinations of signals from separate aerials, e.g. comparing sum with difference

the separate aerials comprising one directional aerial and one non-directional aerial, e.g. combination of loop and open aerials producing a reversed cardioid directivity characteristic

the separate aerials having differently- oriented directivity characteristics

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

derived directly from separate directional systems

derived from different combinations of signals from separate aerials, e.g. comparing sum with difference

the separate aerials comprising one directional aerial and one non-directional aerial, e.g. combination of loop and open aerials producing a reversed cardioid directivity characteristic

the separate aerials having differently- oriented directivity characteristics

using adjustment of real or effective orientation of directivity characteristic of an aerial or an aerial system to give a desired condition of signal derived from that aerial or aerial system, e.g. to give a maximum or minimum signal (G 01 S 3/16, G 01 S 3/28 take precedence)

adjusting orientation of a single directivity characteristic to produce maximum or minimum signal, e.g. rotatable loop aerial, equivalent goniometer system

the desired condition being maintained automatically

the adjustment being varied periodically or continuously until it is halted automatically when the desired condition is attained

using aerials spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems

the waves arriving at the aerials being continuous or intermittent and the phase difference of signals derived therefrom being measured

the waves arriving at the aerials being pulse modulated and the time difference of their arrival being measured

using a receiving aerial moving, or appearing to move, in a cyclic path to produce a Doppler variation of frequency of the received signal

the apparent movement of the aerial being produced by coupling the receiver cyclically and sequentially to each of several fixed spaced aerials

Conical-scan beam systems using signals indicative of the deviation of the direction of reception from the scan axis

Rotating or oscillating beam systems using continuous analysis of received signal for determining direction in the plane of rotation or oscillation or for determining deviation from a predetermined direction in such a plane (G 01 S 3/14 takes precedence)

Broad-beam systems producing in the receiver a substantially-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 transmitter from the receiver and a reference direction from the receiver, e.g. cardioid system

wherein the phase angle of the signal is indicated by a cathode-ray tube

wherein the phase angle of the signal is determined by phase comparison with a reference alternating signal varying in synchronism with the directivity variation

Narrow-beam systems producing in the 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 transmitter from the receiver and a reference direction from the receiver; Overlapping broad-beam systems defining in the receiver a narrow zone and producing 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 transmitter from the receiver and a reference direction from the receiver

wherein the timing of the pulse-type envelope signal is indicated by cathode-ray tube (radar cathode-ray tube indicators providing co-ordinated display of distance and direction G 01 S 7/10)

wherein the timing of the pulse-type envelope signal is determined by bringing a locally-generated pulse-type signal into coincidence or other predetermined time-relationship with the envelope signal

Diversity systems specially adapted for direction-finding

Multi-channel systems specially adapted for direction-finding, i.e. having a single aerial system capable of giving simultaneous indications of the directions of different signals (systems in which the directions of different signals are determined sequentially and displayed simultaneously G 01 S 3/04, G 01 S 3/14)

(covered by G 01 T 1/29)

using electromagnetic waves other than radio waves

Systems for determining direction or deviation from predetermined direction [5]

using amplitude comparison of signals derived from static detectors or detector systems [5]

using a mosaic of detectors [5]

using adjustment of orientation of directivity characteristics of a detector or detector system to give a desired condition of signal derived from that detector or detector system [5]

the desired condition being maintained automatically [5]

using rotating reticles producing a direction-dependent modulation characteristic [5]

producing a frequency modulation characteristic [5]

using rotating or oscillating beam systems, e.g. using mirrors, prisms [5]

using ultrasonic, sonic, or infrasonic waves

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

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

using adjustment of real or effective orientation of directivity characteristics of a transducer or transducer system to give a desired condition of signal derived from that transducer or transducer system, e.g. to give a maximum or minimum signal [5]

the desired condition being maintained automatically [5]

using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems [5]

Rotating or oscillating beam systems using continuous analysis of received signal for determining direction in the plane of rotation or oscillation or for determining deviation from a predetermined direction in such a plane [5]

with means for adjusting phase or compensating for time-lag errors

with indication presented on cathode-ray tubes

with means for eliminating undesired waves, e.g. disturbing noises

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