Oblique and horizontal visibility measurement - is by processing two reflected light pulse sequences of different duration and energy

摘要

The oblique or horizontal visability in the atmosphere can be measured by simple instrumentation, using conventional optical means and producing good results for a wide optical range. Two radiation sources emit light flashes of different duration and energy. The source for the far range uses sequences of pulses with a max. duration of 0.25 mu sec. and the near range uses much shorter pulses of 0.5 mu sec max. duration. The electro-optical receivers are designed for a gain which rises more quickly than with the square of the pulse transit time. The output signal produced by the receivers is integrated continuously or in steps and processed electronically to give a digital or analogue visibility display. The near range extends to 100 m. and the far range to 1500 mm.