|  | G |
SECTION G — PHYSICS

INSTRUMENTS

|  | G01 |
MEASURING (counting Fulltext... Hierarchy... Expanded...G06M); TESTING

|  | G01S |
RADIO DIRECTION-FINDING, LOCATING, DISTANCE OR VELOCITY MEASURING; RADIO NAVIGATION SYSTEMS; ANALOGOUS SYSTEMS EMPLOYING OTHER WAVES (navigation in general Fulltext... Hierarchy... Expanded...G01C; measuring infrasonic, sonic, or ultrasonic vibrations Fulltext... Hierarchy... Expanded...G01H; measuring infra-red, visible, or ultra-violet radiations Fulltext... Hierarchy... Expanded...G01J; testing or measuring electric values Fulltext... Hierarchy... Expanded...G01R; aerials Fulltext... Hierarchy... Expanded...H01Q; electromechanical transducers Fulltext... Hierarchy... Expanded...H04R)

|  | G01S |
Note(s) Attention is drawn to the notes immediately following the class title (Fulltext... Hierarchy... Expanded...G01).

|  | G01S 1/00 |
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 Fulltext... Hierarchy... Expanded...G01S 5/00) [2]

|  | G01S 1/02 |
· | using radio waves

|  | G01S 1/04 |
· · | Details

|  | G01S 1/06 |
· · · | Means for providing multiple indication, e.g. coarse and fine indications

|  | G01S 1/08 |
· · | Systems for determining direction or position line

|  | G01S 1/10 |
· · · | 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

|  | G01S 1/12 |
· · · · | 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

|  | G01S 1/14 |
· · · | using amplitude comparison of signals transmitted simultaneously from aerials or aerial systems having differently-oriented overlapping directivity-characteristics

|  | G01S 1/16 |
· · · · | Azimuthal guidance systems, e.g. system for defining aircraft approach path, localiser system

|  | G01S 1/18 |
· · · · | Elevational guidance systems, e.g. system for defining aircraft glide path

|  | G01S 1/20 |
· · · | using a comparison of transit time of synchronised signals transmitted from non-directional aerials or aerial systems spaced apart, i.e. path-difference systems

|  | G01S 1/22 |
· · · · | 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

|  | G01S 1/24 |
· · · · | 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

|  | G01S 1/26 |
· · · · · | 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

|  | G01S 1/28 |
· · · · · · | wherein the predetermined time-relationship is maintained automatically

|  | G01S 1/30 |
· · · · | 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

|  | G01S 1/32 |
· · · · · | Systems in which the signals received, with or without amplification, or signals derived therefrom, are compared in phase directly

|  | G01S 1/34 |
· · · · · | 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

|  | G01S 1/36 |
· · · · · | 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

|  | G01S 1/38 |
· · · | 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

|  | G01S 1/40 |
· · · · | the apparent movement of the aerial being produced by cyclic sequential energisation of fixed aerials

|  | G01S 1/42 |
· · | 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

|  | G01S 1/44 |
· · | Rotating or oscillating beam beacons defining directions in the plane of rotation or oscillation

|  | G01S 1/46 |
· · · | 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

|  | G01S 1/48 |
· · · · | wherein the phase angle of the direction-dependent envelope signal is a multiple of the direction angle, e.g. for "fine" bearing indication, for resolving phase ambiguities

|  | G01S 1/50 |
· · · · | wherein the phase angle of the direction-dependent envelope signal is compared with a non-direction-dependent reference signal

|  | G01S 1/52 |
· · · · | 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

|  | G01S 1/54 |
· · · | 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

|  | G01S 1/56 |
· · · · | Timing the pulse-type envelope signals derived by reception of beam

|  | G01S 1/58 |
· · · · | wherein a characteristic of the beam transmitted or of an auxiliary signal is varied in time synchronously with rotation or oscillation of the beam

|  | G01S 1/60 |
· · · · · | Varying frequency of beam signal or of auxiliary signal

|  | G01S 1/62 |
· · · · · | Varying phase-relationship between beam and auxiliary signals

|  | G01S 1/64 |
· · · · · | Varying pulse timing, e.g. varying interval between pulses radiated in pairs

|  | G01S 1/66 |
· · · · · | Superimposing direction-indicating intelligence signals, e.g. speech, Morse

|  | G01S 1/68 |
· · | Marker, boundary, call-sign, and like beacons transmitting signals not carrying directional information

|  | G01S 1/69 |
· | using subatomic particles [2]

|  | G01S 1/70 |
· | using electromagnetic waves other than radio waves

|  | G01S 1/72 |
· | using ultrasonic, sonic, or infrasonic waves (signalling devices Fulltext... Hierarchy... Expanded...G08B)

|  | G01S 3/00 |
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 Fulltext... Hierarchy... Expanded...G01S 5/00; for geophysical measurement Fulltext... Hierarchy... Expanded...G01C; telescope mountings Fulltext... Hierarchy... Expanded...G02B)

|  | G01S 3/02 |
· | using radio waves

|  | G01S 3/04 |
· · | Details

|  | G01S 3/06 |
· · · | Means for increasing effective directivity, e.g. by combining signals having differently-oriented directivity characteristics, by sharpening the envelope waveform of the signal desired from a rotating or oscillating beam aerial (comparing amplitude of signals having differently-oriented directivity characteristics to determine direction Fulltext... Hierarchy... Expanded...G01S 3/16, Fulltext... Hierarchy... Expanded...G01S 3/28; modifications of aerials or aerial systems Fulltext... Hierarchy... Expanded...H01Q)

|  | G01S 3/08 |
· · · | Means for reducing polarisation errors, e.g. by use of Adcock or spaced loop aerial systems

|  | G01S 3/10 |
· · · | Means for reducing or compensating for quadrantal, site, or like errors

|  | G01S 3/12 |
· · · | 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 Fulltext... Hierarchy... Expanded...G01S 3/24, Fulltext... Hierarchy... Expanded...G01S 3/34)

|  | G01S 3/14 |
· · | Systems for determining direction or deviation from predetermined direction

|  | G01S 3/16 |
· · · | 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

|  | G01S 3/18 |
· · · · | derived directly from separate directional aerials

|  | G01S 3/20 |
· · · · | derived by sampling signal received by an aerial system having periodically-varied orientation of directivity characteristic

|  | G01S 3/22 |
· · · · | derived from different combinations of signals from separate aerials, e.g. comparing sum with difference

|  | G01S 3/24 |
· · · · · | 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

|  | G01S 3/26 |
· · · · · | the separate aerials having differently- oriented directivity characteristics

|  | G01S 3/28 |
· · · | using amplitude comparison of signals derived simultaneously from receiving aerials or aerial systems having differently-oriented directivity characteristics

|  | G01S 3/30 |
· · · · | derived directly from separate directional systems

|  | G01S 3/32 |
· · · · | derived from different combinations of signals from separate aerials, e.g. comparing sum with difference

|  | G01S 3/34 |
· · · · · | 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

|  | G01S 3/36 |
· · · · · | the separate aerials having differently- oriented directivity characteristics

|  | G01S 3/38 |
· · · | 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 (Fulltext... Hierarchy... Expanded...G01S 3/16, Fulltext... Hierarchy... Expanded...G01S 3/28 take precedence)

|  | G01S 3/40 |
· · · · | adjusting orientation of a single directivity characteristic to produce maximum or minimum signal, e.g. rotatable loop aerial, equivalent goniometer system

|  | G01S 3/42 |
· · · · | the desired condition being maintained automatically

|  | G01S 3/44 |
· · · · | the adjustment being varied periodically or continuously until it is halted automatically when the desired condition is attained

|  | G01S 3/46 |
· · · | using aerials spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems

|  | G01S 3/48 |
· · · · | the waves arriving at the aerials being continuous or intermittent and the phase difference of signals derived therefrom being measured

|  | G01S 3/50 |
· · · · | the waves arriving at the aerials being pulse modulated and the time difference of their arrival being measured

|  | G01S 3/52 |
· · · | using a receiving aerial moving, or appearing to move, in a cyclic path to produce a Doppler variation of frequency of the received signal

|  | G01S 3/54 |
· · · · | the apparent movement of the aerial being produced by coupling the receiver cyclically and sequentially to each of several fixed spaced aerials

|  | G01S 3/56 |
· · · | Conical-scan beam systems using signals indicative of the deviation of the direction of reception from the scan axis

|  | G01S 3/58 |
· · · | 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 (Fulltext... Hierarchy... Expanded...G01S 3/14 takes precedence)

|  | G01S 3/60 |
· · · · | 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

|  | G01S 3/62 |
· · · · · | wherein the phase angle of the signal is indicated by a cathode-ray tube

|  | G01S 3/64 |
· · · · · | wherein the phase angle of the signal is determined by phase comparison with a reference alternating signal varying in synchronism with the directivity variation

|  | G01S 3/66 |
· · · · | 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

|  | G01S 3/68 |
· · · · · | 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 Fulltext... Hierarchy... Expanded...G01S 7/10)

|  | G01S 3/70 |
· · · · · | 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

|  | G01S 3/72 |
· · | Diversity systems specially adapted for direction-finding

|  | G01S 3/74 |
· · | 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 Fulltext... Hierarchy... Expanded...G01S 3/04, Fulltext... Hierarchy... Expanded...G01S 3/14)

|  | G01S 3/76 |
· | using subatomic particles

|  | G01S 3/78 |
· | using electromagnetic waves other than radio waves

|  | G01S 3/80 |
· | using ultrasonic, sonic, or infrasonic waves

|  | G01S 3/82 |
· · | with means for adjusting phase or compensating for time-lag errors

|  | G01S 3/84 |
· · | with indication presented on cathode-ray tubes

|  | G01S 3/86 |
· · | with means for eliminating undesired waves, e.g. disturbing noises

|  | G01S 5/00 |
Position-fixing by co-ordinating two or more direction or position-line determinations; Position-fixing by co-ordinating two or more distance determinations [2]

|  | G01S 5/02 |
· | using radio waves

|  | G01S 5/04 |
· · | Position of source determined by a plurality of spaced direction-finders

|  | G01S 5/06 |
· · · | co-ordinating a plurality of position lines defined by path-difference direction-finding systems

|  | G01S 5/08 |
· · | Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location

|  | G01S 5/10 |
· · · | by co-ordinating a plurality of position lines defined by path-difference beacon systems

|  | G01S 5/12 |
· · | by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical, radial (radar indicators providing co-ordinated display of direction and distance Fulltext... Hierarchy... Expanded...G01S 7/10)

|  | G01S 5/14 |
· · | Determining absolute distances from plurality of spaced points of known location

|  | G01S 5/15 |
· | using subatomic particles [2]

|  | G01S 5/16 |
· | using electromagnetic waves other than radio waves

|  | G01S 5/18 |
· | using ultrasonic, sonic, or infrasonic waves

|  | G01S 7/00 |
Details of systems according to group Fulltext... Hierarchy... Expanded...G01S 9/00

|  | G01S 7/02 |
· | of radio-wave systems

|  | G01S 7/04 |
· · | Display arrangements

|  | G01S 7/06 |
· · · | Cathode-ray tube displays

|  | G01S 7/08 |
· · · · | with vernier indication of distance, e.g. using two cathode-ray tubes

|  | G01S 7/10 |
· · · · | Providing two-dimensional co-ordinated display of distance and direction

|  | G01S 7/12 |
· · · · · | Plan-position indicators, i.e. P. P. I.

|  | G01S 7/14 |
· · · · · · | Sector, off-centre, or expanded- angle display

|  | G01S 7/16 |
· · · · · | Signals displayed as intensity modulation with rectangular co-ordinates representing distance and bearing, e.g. type B

|  | G01S 7/18 |
· · · · · | Distance-height displays; Distance-elevation displays, e.g. type RHI, type E

|  | G01S 7/20 |
· · · · | Stereoscopic displays; Three-dimensional displays; Pseudo-three-dimensional displays

|  | G01S 7/22 |
· · · · | Producing cursor lines and indicia by electronic means

|  | G01S 7/24 |
· · · · | the display being orientated or displaced in accordance with movement of object carrying the transmitting and receiving apparatus, e.g. true-motion radar

|  | G01S 7/26 |
· · · | Displays using electroluminescent panels

|  | G01S 7/28 |
· · | Details of pulse systems

|  | G01S 7/30 |
· · · | Employing storage or delay devices which preserve the pulse form of the echo signal, e.g. for comparing and combining echoes received during different periods

|  | G01S 7/32 |
· · · | Shaping echo pulse signals; Deriving non-pulse signals from echo pulse signals

|  | G01S 7/34 |
· · · | Gain of receiver varied automatically during pulse-recurrence period, e.g. anti-clutter gain control

|  | G01S 7/36 |
· · | Means for anti-jamming (in general Fulltext... Hierarchy... Expanded...H04K 3/00)

|  | G01S 7/38 |
· · | Jamming means, e.g. producing false echoes (in general Fulltext... Hierarchy... Expanded...H04K 3/00) [2]

|  | G01S 7/40 |
· · | Means for monitoring or calibrating

|  | G01S 7/42 |
· · | Diversity systems specially adapted for radar

|  | G01S 7/44 |
· · | Means for transforming co-ordinates or for evaluating data, e.g. using computers

|  | G01S 7/46 |
· · | Means for tracking by using numerical data

|  | G01S 7/48 |
· | of electromagnetic-wave systems other than radio-wave systems

|  | G01S 7/50 |
· · | of infra-red systems

|  | G01S 7/52 |
· | of ultrasonic, sonic, or infrasonic systems

|  | G01S 7/54 |
· · | with receivers spaced apart

|  | G01S 7/56 |
· · | Display arrangements

|  | G01S 7/58 |
· · · | for providing variable ranges

|  | G01S 7/60 |
· · · | for providing a permanent recording

|  | G01S 7/62 |
· · | Cathode-ray tube displays

|  | G01S 7/64 |
· · · | Luminous indications (Fulltext... Hierarchy... Expanded...G01S 7/62 takes precedence)

|  | G01S 7/66 |
· · | with means for eliminating undesired waves, e.g. disturbing noises

|  | G01S 9/00 |
Radar systems; Analogous systems (locating faults in transmission lines Fulltext... Hierarchy... Expanded...G01R 31/11)

|  | G01S 9/00 |
Note(s) For the purpose of this group, "radar systems" are defined as: Systems using the reflection or re-radiation of radio waves from an object for detecting the presence of the object, for determining the distance or relative velocity of the object, or for providing a coordinated display of the distance and direction of the object. Means for determining the direction of the object are classified in group Fulltext... Hierarchy... Expanded...G01S 1/00. Systems arranged for mounting on a moving craft or vehicle and using the reflection of radio waves from an extended surface external to the craft, e.g. the surface of the earth, to determine the velocity and direction of motion of the craft relative to the surface. Analogous systems are those systems having the characteristics set out in Note (1) above but using, instead of radio waves, other electromagnetic waves or ultrasonic, sonic, or infrasonic waves.

|  | G01S 9/02 |
· | Radar systems

|  | G01S 9/04 |
· · | Distance-determination systems (distance indicated by display arrangements Fulltext... Hierarchy... Expanded...G01S 7/04)

|  | G01S 9/06 |
· · · | using transmission of interrupted pulse-modulated waves

|  | G01S 9/08 |
· · · · | wherein the pulse-recurrence frequency is varied to provide a desired time relationship between the transmission of a pulse and the receipt of the echo of a preceding pulse

|  | G01S 9/10 |
· · · · · | wherein the pulse-recurrence frequency is controlled automatically

|  | G01S 9/12 |
· · · · | wherein a locally-generated strobe pulse or other signal is brought into coincidence or other predetermined time relationship with the echo pulse

|  | G01S 9/14 |
· · · · · | the predetermined time relationship being maintained automatically, i.e. automatic range tracking

|  | G01S 9/16 |
· · · · · · | with continuous variation of timing of locally-generated signal terminated automatically when predetermined time relationship attained, i.e. automatic range search with lock-on

|  | G01S 9/18 |
· · · · · · | with timing of locally-generated signal maintained for limited "memory" period, if echo signal fails, in accordance with timing immediately prior to failure of echo signal

|  | G01S 9/20 |
· · · · | wherein a voltage or current pulse is initiated and terminated in accordance respectively with the pulse transmission and echo-reception, e.g. by initiating and terminating the charging of a capacitor

|  | G01S 9/22 |
· · · · | wherein distance elevation, and azimuth information are all derived from a common transmitted pulse, e.g. monopulse radar

|  | G01S 9/23 |
· · · · | wherein the pulses transmitted use a frequency- or phase-modulated carrier wave (determining distance by comparison of frequencies of transmitted and received frequency-modulated waves Fulltext... Hierarchy... Expanded...G01S 9/24)

|  | G01S 9/233 |
· · · · · | with time compression of the received pulses

|  | G01S 9/24 |
· · · | using transmission of frequency-modulated waves and the received signal, or a signal derived therefrom, being heterodyned with a locally-generated heterodyne signal related to the contemporaneous transmitting signal to give a beat-frequency

|  | G01S 9/26 |
· · · · | wherein the rate of change of transmitted frequency is adjusted to give a beat of predetermined constant frequency, e.g. by adjusting the amplitude or frequency of the frequency-modulating signal

|  | G01S 9/28 |
· · · · | wherein the rate of change of transmitted frequency is varied cyclically such that the time at which the instantaneous frequency of the beat-frequency signal is equal to a predetermined value is a measure of the distance

|  | G01S 9/30 |
· · · · · | with cyclic variation of rate of change of transmitted frequency effected by cyclic variation of amplitude or frequency of the frequency of the frequency modulating signal

|  | G01S 9/32 |
· · · · | wherein the rate of change of frequency of the local heterodyne signal has a difference from that of transmitted frequency such that the time at which the instantaneous frequency of the beat-frequency signal is equal to a predetermined value is a measure of the distance (Fulltext... Hierarchy... Expanded...G01S 9/34, Fulltext... Hierarchy... Expanded...G01S 9/36 take precedence)

|  | G01S 9/34 |
· · · · | wherein the frequency of locally-generated heterodyne signal is displaced from that of the transmitted wave by a constant amount, i.e. same frequency variation

|  | G01S 9/36 |
· · · · | wherein the received sihnal is heterodyned with constant-frequency signal before heterodyning with locally-generated heterodyne signal related to transmitted signal

|  | G01S 9/37 |
· · · | using transmission of continuous unmodulated waves, or amplitude-, frequency- or phase-modulated waves (Fulltext... Hierarchy... Expanded...G01S 9/24 and Fulltext... Hierarchy... Expanded...G01S 9/56 take precedence) [2]

|  | G01S 9/38 |
· · · · | with phase comparison between the received signal and the contemporaneously transmitted signal

|  | G01S 9/39 |
· · · · · | wherein more than one modulation frequency is used

|  | G01S 9/40 |
· · · · · | wherein the frequency of the transmitted signal is adjusted to give a predetermined phase relationship

|  | G01S 9/42 |
· · | Discriminating between fixed and moving objects or between objects moving at different speeds

|  | G01S 9/44 |
· · | Velocity determination systems; Sense-of-movement determination systems

|  | G01S 9/46 |
· · · | wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed of aircraft

|  | G01S 9/48 |
· · · · | Determining both velocity and drift angle of object

|  | G01S 9/50 |
· · · | Determining sense of movement

|  | G01S 9/52 |
· · | Determining drift angle or ground track of moving object by radar mounted on the object (determining both drift angle and velocity Fulltext... Hierarchy... Expanded...G01S 9/48)

|  | G01S 9/56 |
· · | Interrogator-responder systems, e.g. I.F.F.D.M.E.

|  | G01S 9/58 |
· · · | wherein the signal transmitted from the interrogator and the contemporaneously received signal from the responder are of different frequency and are heterodyned to give a beat-frequency signal which is compared in phase with another signal of like frequency

|  | G01S 9/60 |
· · | Obtaining meteorological information

|  | G01S 9/62 |
· | Systems employing electromagnetic waves other than radio waves

|  | G01S 9/64 |
· · | employing infra-red waves

|  | G01S 9/66 |
· | Systems employing ultrasonic, sonic, or infrasonic waves

|  | G01S 9/68 |
· · | Distance determination systems

|  | G01S 9/70 |
· · | specially adapted for locating fish

|  | G01S 11/00 |
Systems for determining distance or velocity not using reflection or reradiation (direction-finders Fulltext... Hierarchy... Expanded...G01S 3/00; position-fixing by co-ordinating two or more distance determinations Fulltext... Hierarchy... Expanded...G01S 5/00) [2]