The purpose of the present description is to give a general view on the Gi-B3 gyrotheodolite and to help the potential end user, who is otherwise familiar with this type of instrument, to make a decision.
Gi-B3 gyrotheodolites can be used for different applications (mapping, tunnelling) in the surveying practise. This is a well proven, traditional, reliable and rugged, nevertheless high accuracy instrument.
Gi-B3 gyrotheodolites were manufactured in big series. Now these systems are available from stock for a reasonable price.
Gi-B3 gyrotheodolite is a semi-automatic, high precision instrument that is used for determining direction. It can be used in the field of mapping, canalization and tunnelling etc. This unit can also be used in mines which do not require explosion-proof devices.
The Gi-B3 system operates day and night in the presence of external magnetic and electric interferences, in a wide temperature range between the ± 75° geographic latitudes, and at a wind speed of max 5m/s.
It is interesting to note that miners were among the first users of these types of instruments. They applied gyrotheodolites for controlling long traverses and for bringing their maps to coincide with surface maps.
The accuracy of the Gi-B3 can also be well utilised in establishing reference directions for initial settings or even calibrating other equipment.
The gyro unit and the theodolite unit are used together, but are separate instruments and units that are interchangeable. Both units have an independent instrument constant.
The sighting telescope is equipped with an auto-collimation type eye-piece with a built-in illuminating unit (to determine the instrument constant).
Measurement with this instrument runs with the traditional method. The system needs a rough pre-orientation (magnetic compass supplied). The built-in automatic follower system keeps track of the high speed gyro engine's oscillation. The turning points of swingings should be read visually through an auto-collimation system, the angle value belonging to the turning point should then be read through a reading microscope on the horizontal circle of the theodolite. The weighted arithmetic mean of the turning points gives the north direction.
The obtained data should be entered into a measurement sheet, and afterwards the azimuth should be calculated manually as the measurement sheet guides the operator.
- magnification: 30 x
- diameter of object glass: 45 mm
- angle of view: 1°20´
- accuracy of circle reading system: 1"
- mean square error of angle measurement: <1,5"
- mean square error of azimuth determination: 5"-8"
- supply voltage: DC 12 V
- average power consumption: 3,0 V
The Gi-B3 consists of three main units; the gyro unit, the theodolite unit (supplied together for use and for transportation) and the separate electronic unit. Furthermore, the system is also supplied with accessories, a tripod and cables.
The quality of the instrument is not reflected in the price. If the user needs a high accuracy gyrotheodolite and finds a semi-automatic instrument acceptable, then he will be able to purchase this reliable gyrotheodolite for a very reasonable low price.