| 摘要 |
A lens (1) inclined by approximately 45 DEG images the object area between horizon and zenith in the image plane (3). The beam deflection unit (2) inserted into the beam path makes it possible to displace the image vertically. The respective position of the beam deflection unit preferably built up of rotating prismatic wedges is converted into an analogue electrical measurement value. This measurement value stands for the respective vertical angle of an object point imaged in the centre of the image plane (3), referred to a device-internal so-called reference plane (4). The respective deviations of this - virtual - reference plane (4) from the ideal horizontal measurement position are also detected as analogue electrical values and correct the actual measurement. For this purpose, light reflected from pendulum mirrors (34) or a mercury bubble level (46) is detected by opto-electronic receivers (37) and a comparison circuit (33a/b) and correspondingly converted. In the automatic measurement of the elevations of sun and moon, the lateral deviation of the optical axis (8) from the object to be measured must also be detected as an analogue electrical value for the measurement value correction because of the omission of an accurate visual sighting. For this purpose, two separate images (28) of the sun or of the moon are generated by beam division (19) in a further imaging beam path. Field stops (24) arranged in opposite directions and having wege-shaped apertures (23), provide opto-electronic receivers (22) arranged behind them with different light flux components, depending on degree and direction of the lateral deviation, the total sum always remaining the same. The final measurement value corrected in this manner stands for the vertical angle of the measured object above the true horizon. It is captured at the instant of the precise direction finding by a measurement value storage pulse, also generated, and is stored. In the central logic (41), a complete nautical position information is generated, including the measurement time - obtained from the timebase (42) also integrated - , with the cooperation of an integrated microprocessor and electrically stored nautical data. The measurement value storage pulse is manually triggered in the case of visual direction-finding operations with inserted target marker. In the automatic measurement of sun or moon elevations, the beam deflection unit (2) is brought into an end position. After manual triggering, it automatically runs into the other end position. The measurement value storage pulse is generated in the storage signal converter (25) at the instant at which sun or moon image are located in the reference plane (4) with their vertical centre. For this purpose, the image is again split off by beam division (19) and the measurement value storage pulse is obtained by an opto-electronic comparison circuit in the storage signal converter.
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