Abstract: An electronic measuring apparatus having a plurality of measuring modes. Each one of the plurality of measuring modes is selectively set to perform a corresponding operation. The electronic measuring apparatus includes a plurality of operational buttons. Information which associates one of the plurality of operational buttons with one of the plurality of measuring modes is stored in a memory. It is then distinguished which one of the plurality of operational buttons has been operated. Information stored in the memory, which associates the distinguished one of the plurality of operational buttons with the one of the plurality of measuring modes is searched and an operation unique to the one of the plurality of measuring modes which is associated with the distinguished one of the plurality of operational buttons is performed.

Abstract: An electronic survey instrument is controlled in accordance with a computer program to store a display image and a count value immediately before a power source is cut off. The display image and count values may then be restored without substantial initialization of the electronic survey instrument. The instrument includes a main system for operating in accordance with a survey program, and plural subsystems for operation based on a control signal from the main system. The main system saves information into a memory immediately before a power-off time and restores the information saved in the memory at the next power-on time. End information corresponding to the saved information is also saved into the memory to normally cut-off the power source. An information restoring process is canceled by the main system at the next power-on time when the end information has not been stored in the memory.

Abstract: The device includes an incremental optical encoder (3) comprising two parts, 4,5) which are displaceable in rotation within one another. One part (5) is associated with a movable component (1) and the other part (4) with a fixed component (2) and its output is connected to a device for determining the angular position of the movable component (1) relative to the fixed component (2) on the basis of the relative angular positions of the two encoder parts. The encoder (3) is carried by one of the components (1), and one if its parts (5) is connected to this component (1) while the other part (4) is connected to an optical device for slaving the encoder part in at least one specified orientation in relation to the other component (2).

Abstract: A system is disclosed for materializing in space a point whose coordinates in a system of reference axes are known, comprising:an optical aiming apparatus, occupying a pre-determined position with respect to said system of axes and making it possible to determine, in said system of axes, the coordinates of any point aimed at, anda tooling assembly comprising a stand, one part at least of which is movable with respect to said system of axes and a hemispherical ball joint mounted in a spherical concave seat fixed to said movable part of the stand, the center of said ball joint being marked so as to be visible by said aiming apparatus.

Abstract: A method for surveying in which the surveying instrument may be positioned in substantially more locations than with prior art surveying methods. The surveying method employs a separate point at which a compass is positioned. The bearing of the object to be located relative to the compass is measured. The distance between a surveying instrument and this object is determined by setting the bearing of the surveying instrument equal to the bearing of the compass, measuring the distance between the compass and the surveying instrument, measuring the angle formed between the compass and surveying instrument and object and instrument, and then determining the distance between the surveying instrument and object using trigonometric principles.

Abstract: A surveying instrument for measuring a rotation angle in which a rotation angle is measured from a reference direction and is displayed. The reference angle is set by zeroing the displayed angle. The display is zeroed only if a reset button is operated twice within a fixed period.

Abstract: The encoder comprises a pendulum (P) mounted to rotate about a horizontal is (O-O) which is substantially coaxial with a reference axis (R-R) of an index disk and which carries vertical optical detector equipment (T.sub.M.pi.E, T.sub.M.pi.R, T.sub.MOE, T.sub.MOR), optical guidance means (M.sub.1, M.sub.2, M.sub.3, M.sub.4, T.sub.5) fixed to the pendulum and suitable for guiding radiation generated by an optical transmitter (T.sub.M.pi.E) towards an associated optical receiver (T.sub.M.pi.R) along a predetermined optical path intersecting the disk (D), and a liquid level forming device (L) fixed to the pendulum (P) and inserted on the optical path upstream from the said point of interception between the optical path and the disk, the said optical guidance means (M.sub.1, M.sub.2, M.sub.3, M.sub.4, M.sub.

Abstract: A transit includes a first rotational member provided with a collimator and supported on the transit for rotation about a predetermined axis, a second rotational member supported on the transit for rotation about the predetermined axis, a detector for generating a pulse in accordance with a predetermined angle of displacement between the first rotational member and the second rotational member, a first counter for counting the number of pulses from the detector, the maximum countable pulse number of the first counter corresponding to the angle of 360.degree., the first counter generating a pulse in accordance with its counting of the maximum pulse number, and a second counter for counting the pulses from the first counter means up to a predetermined number.

Abstract: An angle measuring device includes a mechanism rotatable to define an angle to be measured and a rotating scanner for producing a first number of pulses corresponding to the angle to be measured. The first number of pulses is frequency multiplied to a second, higher number of pulses to decrease the magnitude of measured angle per pulse and thereby increase the accuracy of the resulting measurement. The second number of pulses are counted, converted to an angle value and held in a display for convenient reading. Preferably, the rotatable mechanism is a gun-like member with sights for aiming it at a target the angle to which is to be measured and a trigger for actuating the measuring, and at least the gun-like member is gimbal mounted to adapt the device for use as a pelorus on a ship.

Abstract: The value of three components of an analog signal are compared with zero and in two's compared with one another. Each possible combination of the comparison result, within the range of possible phase argument values of the analog signal, has correlated therewith a respective zone, whereby there is formed a coarse interpolation of a period of the analog signal into phase zones. The components are digitized and there are selected the components having the smallest (X), the intermediate (Y) and the largest (Z) absolute value. There are formed the digital functions H=Y-X and K=Z-Y+X. Each possible combination (H, K) is correlated to a respective predetermined number of steps of the phase argument within the zone, thereby producing a fine interpolation of the zone into steps. Preferably, at the beginning there is substracted from each analog component one-third of the sum of the three components.

Abstract: The corrected values to compensate for errors in instrumental levelling of a theodolite and similar instruments are found by determining angles of elevation and/or horizontal directions, measuring the instrumental levelling errors, and calculating the error free values of the instrument.

Abstract: An angle measuring device comprises a base, a telescope seated thereupon for rotation about an axis, a graduated circle having a line division, a micrometer for subdividing said line division, and photoelectric scanners for detecting angular values from said line division and from said micrometer. A graduated plate provided with a reticle is located in said telescope. Said reticle has a zone limited by two line marks which are arranged in parallel and symmetrically to and on either side of one of the reticle lines. Said two lines are spaced from said reticle line by a width which is at least double the size of one division interval of the graduated circle line division.