| 摘要 |
Guiding of an observer for example in an aircraft, moving along an approach path (2) is effected by means of two beams (3', 3) rotating in opposite directions situated one on each side of the approach path (2), in such a manner that the displacements of these beams relative to that of the observer (6) are perceived as a sequence of two luminous flashes, giving the effect of a tracer bullet moving towards the path. Sweeping is discontinuous at least over a part of the capture zone (5) of the system, being produced essentially by a succession of angular jumps in the rotation of the beams, separated by fixed intervals. This enables the definition of an angular zone within which the beams overlap and are visible in perfect simultaneity (for example) to delimit an acceptable range of error, whilst outside this zone, the respective beams succeed each other at an interval which is sufficient to produce the tracer bullet effect which is used for guiding, without the existence of any intermediate zones ambiguous to the observer.
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