Abstract: A Longwall equipment for mechanical extraction in longwall mining, in particular in underground coal mining, having a face conveyor arranged along the coal face, having an extraction machine which can be displaced along the face conveyor and having shield support units attached to the face conveyor at an angle thereto, is characterized in that, in order to determine the absolute height position of determined elements of the longwall equipment, a liquid-filled hydrostatic tube balance (17) is installed along the coalface (10) on the selected elements (12, 15, 31) of the longwall equipment and is connected to a base station (19) arranged in one of the gate roads (13, 14) and determined precisely in its height as a reference point, wherein pressure sensors (22) are incorporated into the tube conduit (18, 23, 24) of the hydrostatic tube balance (17), distributed over the course of the longwall equipment on individual elements (12, 15, 31) of the longwall equipment, and are connected to a central evaluation and co

Abstract: In a brake system, when setting a control origin position for a resolver for detecting a moved position of a booster piston, communication between a master cylinder and wheel cylinders is interrupted by cut valves. Thereafter, the booster piston is moved forward by an electric actuator in a direction in which a hydraulic pressure is generated so that a position detected by the resolver upon detection of generation of the hydraulic pressure by a hydraulic pressure sensor (position at a time of generation of hydraulic pressure) is obtained. A position obtained by moving backward the position at the time of generation of hydraulic pressure by a predetermined amount is set as the control origin position.

Abstract: In a combined GPS/altimeter device, the calibration and hence the accuracy of barometric altimeter measurements are enhanced with the aid of derived altitudes from a GPS. The device determines the need for calibration and perform the subsequent computations necessary to facilitate the calibration. Furthermore, the device determines a correction quantity that should be applied to barometric altitude readings, thereby allowing the device to be calibrated while in motion. Both of these features ultimately result in a more accurate determination of altitude.

Abstract: A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location of the unit as determined by GPS and altitude information as determined by the barometric altimeter and GPS. The device provides an enhancement of the calibration and hence the accuracy of barometric altimeter measurements with the aid of derived altitudes from a GPS. The device is able to determine the need for calibration and perform the subsequent computations necessary to facilitate the calibration. Furthermore, the device is able to determine a correction quantity that should be applied to barometric altitude readings, thereby allowing the device to be calibrated while in motion. Both of these features ultimately result in a more accurate determination of altitude.

Abstract: To provide a movement-detecting altimeter designed so as to be capable of avoiding excessive accumulation of errors. The movement-detecting altimeter has a movement dependent altitude updating unit which updates an indicated altitude when a moving condition is maintained, and which avoids updating of the indicated altitude when the moving condition is not maintained.

Abstract: A gauge for monitoring the relative height of two points comprises a generally tubular conduit extending from a first end thereof via a first limb thereof to a monitoring position spaced from the first end and via a second limb of the conduit from the monitoring position to a second end of the conduit in the region of its first end, two immiscible fluids of different densities, each in one of the first and second limbs with a mutual interface within the region of the monitoring position, means to vary the relative vertical positions of the monitoring position on the one hand and the first and second conduit ends on the other, and a pressure comparator to compare the pressures of the fluids at the conduit ends.