|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

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

|  | G01 |
Note(s) This class covers, in addition to "true" measuring instruments, other indicating or recording devices of analogous construction, and also signalling or control devices insofar as they are concerned with measurement (as defined in Note 2 below) and are not specially adapted to the particular purpose of signalling or control. In this class, the following term is used with the meaning indicated: "measuring" is used to cover considerably more than its primary or basic meaning. In this primary sense, it means finding a numerical expression of the value of a variable in relation to a unit or datum or to another variable of the same nature, e.g. expressing a length in terms of another length as in measuring a length with a scale; the value may be obtained directly (as just suggested) or by measuring some other variable of which the value can be related to the value of the required variable, as in measuring a change in temperature by measuring a resultant change in the length of a column of mercury. However, since the same device or instrument may, instead of giving an immediate indication, be used to produce a record or to initiate a signal to produce an indication or control effect, or may be used in combination with other devices or instruments to give a conjoint result from measurement of two or more variables of the same or different kinds, it is necessary to interpret "measuring" as including also any operation that would make it possible to obtain such a numerical expression by the additional use of some way of converting a value into figures. Thus the expression in figures may be actually made by a digital presentation or by reading a scale, or an indication of it may be given without the use of figures, e.g. by some perceptible feature (variable) of the entity (e.g. object, substance, beam of light) of which the variable being measured is a property or condition or by an analogue of such a feature (e.g. the corresponding position of a member without any scale, a corresponding voltage generated in some way). In many cases there is no such value indication but only an indication of difference or equality in relation to a standard or datum (of which the value may or may not be known in figures); the standard or datum may be the value of another variable of the same nature but of a different entity (e.g. a standard measure) or of the same entity at a different time. In its simplest form, measurement may give merely an indication of presence or absence of a certain condition or quality, e.g. movement (in any direction or in a particular direction), or whether a variable exceeds a predetermined value. Attention is drawn to the Notes following the title of section G, especially as regards the definition of the term "variable". In many measuring arrangements, a first variable to be measured is transformed into a second, or further, variables. The second, or further, variables may be (a) a condition related to the first variable and produced in a member, or (b) a displacement of a member. Further transformation may be needed. [6] When classifying such an arrangement, (i) the transformation step, or each transformation step, that is of interest is classified, or (ii) if interest lies only in the system as a whole, the first variable is classified in the appropriate place. [6] This is particularly important where two or more conversions take place, for instance where a first variable, for example pressure, is transformed into a second variable, for example an optical property of a sensing body, and that second variable is expressed by means of a third variable, for example an electric effect. In such a case, the following classification places should be considered: the place for the transformation of the first variable, that for sensing the condition caused by that variable, subclass Fulltext... Hierarchy... Expanded...G01D for expression of the measurement, and finally the place for the overall system, if any. [6] The measurement of change in the value of a physical property is classified in the same subclass as the measurement of that physical property, e.g. measurement of expansion of length is classified in subclass Fulltext... Hierarchy... Expanded...G01B.

|  | G01C |
MEASURING DISTANCES, LEVELS, OR BEARINGS, FOR SURVEYING OR NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY (measuring dimensions or angles of objects Fulltext... Hierarchy... Expanded...G01B; measuring liquid level Fulltext... Hierarchy... Expanded...G01F; measuring intensity or direction of magnetic fields, other than the earth's field, in general Fulltext... Hierarchy... Expanded...G01R; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effect, propagation time, of radio waves, analogous arrangements using other waves Fulltext... Hierarchy... Expanded...G01S; optical systems therefor Fulltext... Hierarchy... Expanded...G02B; maps, globes Fulltext... Hierarchy... Expanded...G09B)

|  | G01C |
Note(s) In this subclass, the following term is used with the meaning indicated: "navigation" means determining the position and course of land vehicles, ships, aircraft, and space vehicles. Attention is drawn to the Notes following the title of class Fulltext... Hierarchy... Expanded...G01.

|  | G01C |
Subclass index
MEASURING INSTRUMENTS |
For measuring angles; inclinations | 1/00; 9/00
For measuring distances; heights or levels | 3/00, 22/00; 5/00
Compasses; gyroscopes; other navigation instruments | 17/00; 19/00; 21/00
Other surveying instruments | 15/00
Combined instruments | 23/00
Manufacture, calibrating | 25/00
TRACING PROFILES | 7/00
PHOTOGRAMMETRY | 11/00
SURVEYING OPEN WATER | 13/00

|  | G01C 1/00 |
Measuring angles (in compasses Fulltext... Hierarchy... Expanded...G01C 17/00)

|  | G01C 1/02 |
· | Theodolites

|  | G01C 1/04 |
· · | combined with cameras

|  | G01C 1/06 |
· · | Arrangements for reading scales

|  | G01C 1/08 |
· | Sextants

|  | G01C 1/10 |
· · | including an artificial horizon (Fulltext... Hierarchy... Expanded...G01C 1/14 takes precedence; artificial horizons per se Fulltext... Hierarchy... Expanded...G01C 15/14)

|  | G01C 1/12 |
· · · | with a stabilised mirror (tilt compensation in general Fulltext... Hierarchy... Expanded...G12B)

|  | G01C 1/14 |
· · | Periscopic sextants (periscopes in general Fulltext... Hierarchy... Expanded...G02B 23/08)

|  | G01C 3/00 |
Measuring distances in line of sight; Optical rangefinders (tapes, chains, or wheels for measuring length Fulltext... Hierarchy... Expanded...G01B; coupling rangefinders with operating parts of photographic apparatus Fulltext... Hierarchy... Expanded...G03B)

|  | G01C 3/02 |
· | Details

|  | G01C 3/04 |
· · | Adaptation of rangefinders for combination with telescopes or binoculars (rangefinders coupled with focusing arrangements of cameras Fulltext... Hierarchy... Expanded...G03B 13/20)

|  | G01C 3/06 |
· · | Use of electric means to obtain final indication

|  | G01C 3/08 |
· · · | Use of electric radiation detectors

|  | G01C 3/10 |
· | using a parallactic triangle with variable angles and a base of fixed length in the observation station, e.g. in the instrument

|  | G01C 3/12 |
· · | with monocular observation at a single point, e.g. coincidence type (Fulltext... Hierarchy... Expanded...G01C 3/20 takes precedence)

|  | G01C 3/14 |
· · | with binocular observation at a single point, e.g. stereoscopic type (Fulltext... Hierarchy... Expanded...G01C 3/20 takes precedence)

|  | G01C 3/16 |
· · · | Measuring marks

|  | G01C 3/18 |
· · | with one observation point at each end of the base (Fulltext... Hierarchy... Expanded...G01C 3/20 takes precedence)

|  | G01C 3/20 |
· · | with adaptation to the measurement of the height of an object

|  | G01C 3/22 |
· | using a parallactic triangle with variable angles and a base of fixed length at, near, or formed by, the object

|  | G01C 3/24 |
· | using a parallactic triangle with fixed angles and a base of variable length in the observation station, e.g. in the instrument

|  | G01C 3/26 |
· | using a parallactic triangle with fixed angles and a base of variable length at, near, or formed by, the object

|  | G01C 3/28 |
· · | with provision for reduction of the distance into the horizontal plane

|  | G01C 3/30 |
· · · | with adaptation to the measurement of the height of an object, e.g. tacheometers

|  | G01C 3/32 |
· | by focusing the object, e.g. on a ground glass screen

|  | G01C 5/00 |
Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels (Fulltext... Hierarchy... Expanded...G01C 3/20, Fulltext... Hierarchy... Expanded...G01C 3/30 take precedence; tracing profiles Fulltext... Hierarchy... Expanded...G01C 7/00; levels indicating inclination at a single point Fulltext... Hierarchy... Expanded...G01C 9/00)

|  | G01C 5/02 |
· | involving automatic stabilisation of the line of sight (regulation of direction in general Fulltext... Hierarchy... Expanded...G05D 3/00; tilt compensation in general Fulltext... Hierarchy... Expanded...G12B)

|  | G01C 5/04 |
· | Hydrostatic levelling, i.e. by flexibly interconnected liquid containers at separated points

|  | G01C 5/06 |
· | by using barometric means (barometers per se Fulltext... Hierarchy... Expanded...G01L)

|  | G01C 7/00 |
Tracing profiles (by photogrammetry Fulltext... Hierarchy... Expanded...G01C 11/00)

|  | G01C 7/02 |
· | of land surfaces

|  | G01C 7/04 |
· · | involving a vehicle which moves along the profile to be traced

|  | G01C 7/06 |
· | of cavities, e.g. tunnels (survey of wells Fulltext... Hierarchy... Expanded...E21B 47/00)

|  | G01C 9/00 |
Measuring inclination, e.g. by clinometers, by levels

|  | G01C 9/02 |
· | Details

|  | G01C 9/04 |
· · | Transmission means between sensing element and final indicator for giving an enlarged reading

|  | G01C 9/06 |
· · | Electric or photoelectric indication or reading means

|  | G01C 9/08 |
· · | Means for compensating acceleration forces due to movement of instrument

|  | G01C 9/10 |
· | by using rolling bodies

|  | G01C 9/12 |
· | by using a single pendulum (plumb lines Fulltext... Hierarchy... Expanded...G01C 15/10)

|  | G01C 9/14 |
· · | movable in more than one direction

|  | G01C 9/16 |
· | by using more than one pendulum

|  | G01C 9/18 |
· | by using liquids

|  | G01C 9/20 |
· · | the indication being based on the inclination of the surface of a liquid relative to its container

|  | G01C 9/22 |
· · · | with interconnected containers in fixed relation to each other

|  | G01C 9/24 |
· · | in closed containers partially filled with liquid so as to leave a gas bubble

|  | G01C 9/26 |
· · · | Details

|  | G01C 9/28 |
· · · · | Mountings

|  | G01C 9/30 |
· · · · | Means for adjusting dimensions of bubble

|  | G01C 9/32 |
· · · · | Means for facilitating the observation of the position of the bubble, e.g. illuminating means

|  | G01C 9/34 |
· · · | of the tubular type, i.e. for indicating the level in one direction only

|  | G01C 9/36 |
· · · | of the spherical type, i.e. for indicating the level in all directions

|  | G01C 11/00 |
Photogrammetry; Photographic surveying (cameras combined with surveying instruments, e.g. with theodolite, Fulltext... Hierarchy... Expanded...G01C 1/00, Fulltext... Hierarchy... Expanded...G01C 3/00, Fulltext... Hierarchy... Expanded...G01C 5/00, Fulltext... Hierarchy... Expanded...G01C 9/00; surveying cameras Fulltext... Hierarchy... Expanded...G03B 37/00)

|  | G01C 11/02 |
· | Picture-taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures

|  | G01C 11/04 |
· | Interpretation of pictures

|  | G01C 11/06 |
· · | by comparison of two or more pictures of the same area

|  | G01C 11/08 |
· · · | the pictures not being supported in the same relative position as when they were taken

|  | G01C 11/10 |
· · · · | using computers to control the position of the pictures (computers per se Fulltext... Hierarchy... Expanded...G06)

|  | G01C 11/12 |
· · · | the pictures being supported in the same relative position as when they were taken

|  | G01C 11/14 |
· · · · | with optical projection (Fulltext... Hierarchy... Expanded...G01C 11/26 takes precedence)

|  | G01C 11/16 |
· · · · · | in a common plane

|  | G01C 11/18 |
· · · · · · | involving scanning means

|  | G01C 11/20 |
· · · · · | in separate planes

|  | G01C 11/22 |
· · · · | with mechanical projection (Fulltext... Hierarchy... Expanded...G01C 11/26 takes precedence)

|  | G01C 11/24 |
· · · · | with optical-mechanical projection (Fulltext... Hierarchy... Expanded...G01C 11/26 takes precedence)

|  | G01C 11/26 |
· · · · | using computers to control the position of the pictures (computers per se Fulltext... Hierarchy... Expanded...G06)

|  | G01C 11/28 |
· · · | Special adaptation for recording picture point data, e.g. for profiles

|  | G01C 11/30 |
· · | by triangulation

|  | G01C 11/32 |
· · · | Radial triangulation

|  | G01C 11/34 |
· · · | Aerial triangulation

|  | G01C 13/00 |
Surveying specially adapted to open water, e.g. sea, lake, river, canal (liquid level metering Fulltext... Hierarchy... Expanded...G01F; measuring liquid velocity Fulltext... Hierarchy... Expanded...G01P; determining existence or flow of underground water Fulltext... Hierarchy... Expanded...G01V)

|  | G01C 15/00 |
Surveying instruments or accessories not provided for in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01C 1/00-G01C 13/00

|  | G01C 15/02 |
· | Means for marking measuring points

|  | G01C 15/04 |
· · | Permanent marks; Boundary markers

|  | G01C 15/06 |
· · | Surveyors' staffs; Movable markers

|  | G01C 15/08 |
· · · | Plumbing or registering staffs or markers over ground marks

|  | G01C 15/10 |
· | Plumb lines

|  | G01C 15/12 |
· | Instruments for setting out fixed angles, e.g. right angles

|  | G01C 15/14 |
· | Artificial horizons (tilt compensation in general Fulltext... Hierarchy... Expanded...G12B 5/00)

|  | G01C 17/00 |
Compasses; Devices for ascertaining true or magnetic north for navigation or surveying purposes (using gyroscopic effect Fulltext... Hierarchy... Expanded...G01C 19/00; for geophysical or prospecting purposes Fulltext... Hierarchy... Expanded...G01V 3/00)

|  | G01C 17/02 |
· | Magnetic compasses

|  | G01C 17/04 |
· · | with north-seeking magnetic elements, e.g. needles

|  | G01C 17/06 |
· · · | Suspending magnetic elements

|  | G01C 17/08 |
· · · · | by flotation

|  | G01C 17/10 |
· · · | Comparing observed direction with north indication

|  | G01C 17/12 |
· · · · | by sighting means, e.g. for surveyors' compasses

|  | G01C 17/14 |
· · · · | by reference marks, e.g. for ships' compasses

|  | G01C 17/16 |
· · · · | by clinometers, e.g. for determining dip or strike of geological strata

|  | G01C 17/18 |
· · · | Supporting or suspending compasses, e.g. by gimbal, by flotation

|  | G01C 17/20 |
· · · | Observing the compass card or needle

|  | G01C 17/22 |
· · · · | by projection

|  | G01C 17/24 |
· · · · | Illumination

|  | G01C 17/26 |
· · · · | using electric pick-offs for transmission to final indicator, e.g. photocell

|  | G01C 17/28 |
· · | Electromagnetic compasses (with north-seeking magnetic elements and having electric pick-offs Fulltext... Hierarchy... Expanded...G01C 17/26)

|  | G01C 17/30 |
· · · | Earth-inductor compasses

|  | G01C 17/32 |
· · · | Electron compasses

|  | G01C 17/34 |
· | Sun- or astro-compasses

|  | G01C 17/36 |
· | Repeaters for remote indication of readings of a master compass

|  | G01C 17/38 |
· | Testing, calibrating, or compensating of compasses

|  | G01C 19/00 |
Gyroscopes; Turn-sensitive devices using gyroscopic effect, e.g. using gas, using electron beam

|  | G01C 19/02 |
· | Rotary gyroscopes

|  | G01C 19/04 |
· · | Details

|  | G01C 19/06 |
· · · | Rotors

|  | G01C 19/08 |
· · · · | electrically driven (Fulltext... Hierarchy... Expanded...G01C 19/14 takes precedence; dynamo-electric machines Fulltext... Hierarchy... Expanded...H02K)

|  | G01C 19/10 |
· · · · · | Power supply

|  | G01C 19/12 |
· · · · | fluid driven (Fulltext... Hierarchy... Expanded...G01C 19/14 takes precedence)

|  | G01C 19/14 |
· · · · | Fluid rotors

|  | G01C 19/16 |
· · · | Suspensions; Bearings (bearings in general Fulltext... Hierarchy... Expanded...F16C; balancing rotors Fulltext... Hierarchy... Expanded...G01M)

|  | G01C 19/18 |
· · · · | providing movement of rotor with respect to its rotational axes (Fulltext... Hierarchy... Expanded...G01C 19/20, Fulltext... Hierarchy... Expanded...G01C 19/24 take precedence)

|  | G01C 19/20 |
· · · · | in fluid

|  | G01C 19/22 |
· · · · | torsional

|  | G01C 19/24 |
· · · · | using magnetic or electrostatic fields

|  | G01C 19/26 |
· · · | Caging, i.e. immobilising moving parts, e.g. for transport (applicable to instruments in general Fulltext... Hierarchy... Expanded...G01D 11/20)

|  | G01C 19/28 |
· · · | Pick-offs, i.e. devices for taking off an indication of the displacement of the rotor axis

|  | G01C 19/30 |
· · · | Erection devices, i.e. devices for restoring rotor axis to a desired position (for instrument indicating the vertical Fulltext... Hierarchy... Expanded...G01C 19/46)

|  | G01C 19/32 |
· · · | Indicating or recording means specially adapted for rotary gyroscopes (in general Fulltext... Hierarchy... Expanded...G01D)

|  | G01C 19/34 |
· · | for indicating a direction in the horizontal plane, e.g. directional gyroscopes

|  | G01C 19/36 |
· · · | with north-seeking action by magnetic means, e.g. gyromagnetic compasses

|  | G01C 19/38 |
· · · | with north-seeking action by other than magnetic means, e.g. gyrocompasses using earth's rotation

|  | G01C 19/40 |
· · | for control by signals from a master compass, i.e. repeater compasses

|  | G01C 19/42 |
· · | for indicating rate of turn; for integrating rate of turn

|  | G01C 19/44 |
· · | for indicating the vertical

|  | G01C 19/46 |
· · · | Erection devices for restoring rotor axis to a desired position

|  | G01C 19/48 |
· · · · | operating by electrical means (Fulltext... Hierarchy... Expanded...G01C 19/54 takes precedence)

|  | G01C 19/50 |
· · · · | operating by mechanical means (Fulltext... Hierarchy... Expanded...G01C 19/54 takes precedence)

|  | G01C 19/52 |
· · · · | operating by fluid means (Fulltext... Hierarchy... Expanded...G01C 19/54 takes precedence)

|  | G01C 19/54 |
· · · · | with correction for acceleration forces due to movement of instrument

|  | G01C 19/56 |
· | Turn-sensitive devices with vibrating masses, e.g. tuning fork

|  | G01C 19/58 |
· | Turn sensitive devices without moving masses [3]

|  | G01C 19/60 |
· · | Electronic or nuclear magnetic resonance gyrometers (magnetic resonance arrangements in general Fulltext... Hierarchy... Expanded...G01R 33/20) [3,4]

|  | G01C 19/62 |
· · · | with optical pumping [3]

|  | G01C 19/64 |
· · | Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams [3]

|  | G01C 19/66 |
· · · | Ring laser gyrometers (ring lasers in general Fulltext... Hierarchy... Expanded...H01S 3/083) [5]

|  | G01C 19/68 |
· · · · | Lock-in prevention [5]

|  | G01C 19/70 |
· · · · · | by mechanical means [5]

|  | G01C 19/72 |
· · · | with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers [5]

|  | G01C 21/00 |
Navigation; Navigational instruments not provided for in preceding groups (measuring distance traversed on the ground by a vehicle Fulltext... Hierarchy... Expanded...G01C 22/00; measuring linear or angular speed or acceleration Fulltext... Hierarchy... Expanded...G01P)

|  | G01C 21/02 |
· | by astronomical means (Fulltext... Hierarchy... Expanded...G01C 21/24 takes precedence; measuring time by using position of the sun, moon, or stars Fulltext... Hierarchy... Expanded...G04B 49/00)

|  | G01C 21/04 |
· | by terrestrial means (Fulltext... Hierarchy... Expanded...G01C 21/24 takes precedence; marking of navigation route for ships Fulltext... Hierarchy... Expanded...B63B 51/00)

|  | G01C 21/06 |
· · | involving measuring of drift angle; involving correction for drift

|  | G01C 21/08 |
· · | involving use of the magnetic field of the earth

|  | G01C 21/10 |
· | by using measurement of speed or acceleration (Fulltext... Hierarchy... Expanded...G01C 21/24 takes precedence)

|  | G01C 21/12 |
· · | executed aboard the object being navigated; Dead reckoning

|  | G01C 21/14 |
· · · | by recording the course traversed by the object (Fulltext... Hierarchy... Expanded...G01C 21/16 takes precedence)

|  | G01C 21/16 |
· · · | by integrating acceleration or speed, i.e. inertial navigation

|  | G01C 21/18 |
· · · · | Stabilised platforms, e.g. by gyroscope

|  | G01C 21/20 |
· | Instruments for performing navigational calculations (Fulltext... Hierarchy... Expanded...G01C 21/24 takes precedence; computing in general Fulltext... Hierarchy... Expanded...G06)

|  | G01C 21/22 |
· · | Plotting boards (in general Fulltext... Hierarchy... Expanded...B43L)

|  | G01C 21/24 |
· | specially adapted for cosmonautical navigation

|  | G01C 22/00 |
Measuring distance traversed on the ground by vehicles, persons, animals, or other moving solid bodies, e.g. using odometers, using pedometers (counting mechanisms per se Fulltext... Hierarchy... Expanded...G06M)

|  | G01C 22/02 |
· | by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator

|  | G01C 23/00 |
Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed, acceleration

|  | G01C 25/00 |
Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the preceding groups (testing, calibrating, or compensating compasses Fulltext... Hierarchy... Expanded...G01C 17/38)