Aircraft parking system

Claim 2

Apparatus for providing guidance indications to the operator of a vehicle with respect to a predetermined path comprising: alternating potential supply means supplying a potential of a predetermined frequency, optically fluorescent surface means adapted to be mounted on said vehicle, ultraviolet light source means activated by said potential of said predetermined frequency illuminating said optically fluorescent surface means at twice said predetermined frequency for exciting said optically fluorescent surface means to produce at twice said predetermIned frequency impulses of fluorescent optical radiation, said ultraviolet light source means being located adjacent an end of said predetermined path, photosensitive detector means adjacent said end of said predetermined path having first and second electrode means responsive to said fluorescent optical radiation for providing respective first and second output signals of twice said predetermined frequency. sum circuit means for generating a summation of said first and second output signals, threshold detector means responsive to said sum circuit means for forming an output only when said summation exceeds a predetermined magnitude, and display means adjacent said end of said predetermined path responsive to said threshold detector means for indicating to said operator when said optically fluorescent surface means is substantially located over said predetermined path.

Claim 3

Apparatus as described in claim 1 further including filter means for passing signals substantially only of twice said predetermined frequency from said respective first and second electrode means to said sum circuit means.

Claim 4

Apparatus for providing guidance indications to the operator of a vehicle with respect to a predetermined path comprising: alternating potential supply means supplying a potential of a predetermined frequency, optically fluorescent surface means adapted to be mounted on said vehicle, ultraviolet light source means activated by said potential of said predetermined frequency illuminating said optically fluorescent surface means at twice said predetermined frequency for exciting said optically fluorescent surface means to produce at twice said predetermined frequency impulses of fluorescent optical radiation, said ultraviolet light source means being located adjacent an end of said predetermined path, photosensitive detector means adjacent said end of said predetermined path having first and second electrode means responsive to said fluorescent optical radiation for providing respective first and second output signals of twice said predetermined frequency, subtractive circuit means for generating a signal representing the difference between said first and second signals, frequency doubler means responsive to said alternating potential supply means, phase sensitive demodulator means responsive to said subtractive circuit means and to said frequency doubler means, and display means adjacent said end of said predetermined path responsive to said phase sensitive demodulator means for providing guidance correction indications to said operator.

Claim 5

Apparatus for providing guidance indications to the operator of a vehicle with respect to a predetermined path comprising: alternating potential supply means supplying a potential of a predetermined frequency, optically fluorescent surface means adapted to be mounted on said vehicle, ultraviolet light source means activated by said potential of said predetermined frequency illuminating said optically fluorescent surface means at twice said predetermined frequency for exciting said optically fluorescent surface means to produce at twice said predetermined frequency impulses of fluorescent optical radiation, said ultraviolet light source means being located adjacent an end of said predetermined path, photosensitive detector means adjacent said end of said predetermined path having first and second electrode means responsive to said fluorescent optical radiation for providing respective first and second output signals of twice said predetermined frequency, subtractive circuit means for generating a signal representing the difference between said first and second signals, frequency doubler means responsive to said alternating potential supply means, phase sensitive demodulator means responsive to said subtractive circuit means and to said frequency doubler means, and display means adjacent said end of said predetermined path responsive to said phase sensitive demodulator means for providing guidance correction indications to said operator.

Claim 6

Apparatus as described in claim 3 wherein said display means comprises: first indicator means for providing guidance correction indications of a first sense of direction to said operator, and second indicator means for providing guidance correction indications of a second sense of direction to said operator.

Claim 7

Apparatus as described in claim 3 further including: sum circuit means for generating a summation of said first and second output signals, threshold detector means responsive to said sum circuit means for forming an output only when said summation exceeds a predetermined magnitude, and additional display means responsive to said threshold detector means for indicating to said operator when said optically fluorescent surface means is substantially located over said predetermined path.

Claim 8

Apparatus as described in claim 5 further including means for inhibiting operation of said display means responsive to said phase sensitive demodulator means when said summation of said first and second signal exceeds said predetermined magnitude.

Claim 9

Apparatus as described in claim 5 further including control means for inhibiting operation of said additional display means when one of said first and second signals exceeds a predetermined value.

Claim 10

Apparatus for providing guidance indications to the operator of a veHicle with respect to a predetermined path comprising: alternating potential supply means supplying a potential of a predetermined frequency, optically fluorescent surface means adapted to be mounted on said vehicle, ultraviolet light source means activated by said potential of said predetermined frequency illuminating said optically fluorescent surface means at twice said predetermined frequency for exciting said optically fluorescent surface means to produce at twice said predetermined frequency impulses of fluorescent optical radiation, said ultraviolet light source means being located adjacent an end of said predetermined path, photosensitive detector means adjacent said end of said predetermined path having first and second electrode means responsive to said fluorescent optical radiation for providing respective first and second output signals of twice said predetermined frequency, said photosensitive detector means being mounted on shaft means for angular movement thereabout, subtractive circuit means for generating a signal representing the difference between said first and second signals, frequency doubler means responsive to said alternating potential supply means, phase sensitive demodulator means responsive to said subtractive circuit means and to said frequency doubler means, motive means coupled to said shaft means and responsive to said phase sensitive demodulator means for causing said photosensitive detector means to track said vehicle as it moves along said predetermined path, and display means adjacent said end of said predetermined path responsive to said phase sensitive demodulator means for providing guidance correction indications to said operator.

Claim 11

Apparatus for providing guidance indications to the operator of a veHicle with respect to a predetermined path comprising: alternating potential supply means supplying a potential of a predetermined frequency, optically fluorescent surface means adapted to be mounted on said vehicle, ultraviolet light source means activated by said potential of said predetermined frequency illuminating said optically fluorescent surface means at twice said predetermined frequency for exciting said optically fluorescent surface means to produce at twice said predetermined frequency impulses of fluorescent optical radiation, said ultraviolet light source means being located adjacent an end of said predetermined path, photosensitive detector means adjacent said end of said predetermined path having first and second electrode means responsive to said fluorescent optical radiation for providing respective first and second output signals of twice said predetermined frequency, said photosensitive detector means being mounted on shaft means for angular movement thereabout, subtractive circuit means for generating a signal representing the difference between said first and second signals, frequency doubler means responsive to said alternating potential supply means, phase sensitive demodulator means responsive to said subtractive circuit means and to said frequency doubler means, motive means coupled to said shaft means and responsive to said phase sensitive demodulator means for causing said photosensitive detector means to track said vehicle as it moves along said predetermined path, and display means adjacent said end of said predetermined path responsive to said phase sensitive demodulator means for providing guidance correction indications to said operator.

Claim 12

Apparatus as described in claim 8 further including means for providing a separate indication visible to said operator when said vehicle has reached a predetermined point along said predetermined path.