Ground guidance system for airplanes
First Claim
1. A ground guidance system for airplanes in an airplane taxiway divided in a plurality of control sections, which comprises a plurality of loop coils in which the side parallel to the direction of advance of airplanes has a length larger than the length of an automobile but smaller than the length of an airplane and which are arranged in the direction of advance of airplanes in the control sections at intervals smaller than the length of an airplane, a plurality of airplane-detecting means arranged for the respective loop coils to generate detection outputs indicating the presence or absence of an airplane based on changes of self-inductances of the corresponding loop coils, display means for displaying admission of advance or inhibition of advance in the control sections for an airplane, and control means of controlling said display means based on detection outputs of a plurality of said airplane-detecting means,wherein the airplane-detecting means is constructed so that a high-level output is generated at the time of non-detection of an airplane and a low-level output is generated at the time of detection of an airplane, and at the time of a failure, the output errs to a voltage corresponding to said low-level output at the time of detection of an airplane,said airplane-detecting means comprising a high-frequency signal generator, a bridge circuit including three resistors and a resonance circuit consisting of one said loop coil and a capacitor, which becomes substantially resonant with the output frequency of the high-frequency signal generator, an alternating current amplifier for amplifying the output of the bridge circuit, a wave-detecting circuit for detecting an envelope of the amplified output of the alternating current amplifier, a window comparator having such a window characteristic that the output signal of the wave-detecting circuit is received as the input signal, the output level of the wave-detecting circuit obtained when an airplane is not present in the taxiway is within the window and the output level of the wave-detecting circuit obtained when an airplane is present and the self-inductance of the loop coil is changed is outside the window, and generating an output when an input signal of the level within the window is put in, and a voltage multiplying rectifying circuit for rectifying the output of the window comparator.
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Accused Products
Abstract
A ground guidance system for airplanes in which loop coils of a predetermined shape are continuously buried in a specific section of a taxiway for airplanes, an airplane is continuously detected based on changes of self-inductances of the loop coils with movement of the airplane while discriminating airplanes from other objects and admission or inhibition of advance in the specific section to a subsequent airplane according to the presence or absence of the airplane in the specific section and which has a fail-safe structure not generating an output at the time of a system or circuit failure or accident.
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Citations
36 Claims
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1. A ground guidance system for airplanes in an airplane taxiway divided in a plurality of control sections, which comprises a plurality of loop coils in which the side parallel to the direction of advance of airplanes has a length larger than the length of an automobile but smaller than the length of an airplane and which are arranged in the direction of advance of airplanes in the control sections at intervals smaller than the length of an airplane, a plurality of airplane-detecting means arranged for the respective loop coils to generate detection outputs indicating the presence or absence of an airplane based on changes of self-inductances of the corresponding loop coils, display means for displaying admission of advance or inhibition of advance in the control sections for an airplane, and control means of controlling said display means based on detection outputs of a plurality of said airplane-detecting means,
wherein the airplane-detecting means is constructed so that a high-level output is generated at the time of non-detection of an airplane and a low-level output is generated at the time of detection of an airplane, and at the time of a failure, the output errs to a voltage corresponding to said low-level output at the time of detection of an airplane, said airplane-detecting means comprising a high-frequency signal generator, a bridge circuit including three resistors and a resonance circuit consisting of one said loop coil and a capacitor, which becomes substantially resonant with the output frequency of the high-frequency signal generator, an alternating current amplifier for amplifying the output of the bridge circuit, a wave-detecting circuit for detecting an envelope of the amplified output of the alternating current amplifier, a window comparator having such a window characteristic that the output signal of the wave-detecting circuit is received as the input signal, the output level of the wave-detecting circuit obtained when an airplane is not present in the taxiway is within the window and the output level of the wave-detecting circuit obtained when an airplane is present and the self-inductance of the loop coil is changed is outside the window, and generating an output when an input signal of the level within the window is put in, and a voltage multiplying rectifying circuit for rectifying the output of the window comparator.
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4. A ground guidance system for airplanes in an airplane taxiway divided in a plurality of control sections, which comprises a plurality of loop coils in which the side parallel to the direction of advance of airplanes has a length larger than the length of an automobile but smaller than the length of an airplane and which are arranged in the direction of advance of airplanes in the control sections at intervals smaller than the length of an airplane, a plurality of airplane-detecting means arranged for the respective loop coils to generate detection outputs indicting the presence or absence of an airplane based on changes of self-inductances of the corresponding loop coils, display means for displaying admission of advance or inhibition of advance in the control sections for an airplane, and control means for controlling said display means based on detection outputs of a plurality of said airplane-detecting means,
wherein the control means comprises a direction- and object-discriminating circuit for detecting the advance direction of an airplane and discriminating an airplane from an automobile based on an output from the airplane-detecting means corresponding to the loop coil within the control section in which an airplane advances and a display-instructing circuit for generating a signal for instructing admission of advance of an airplane or a signal for inhibition of advance of an airplane in the control section in the rear of the control section in which an airplane advances, based on the output of the airplane-detecting means corresponding to the loop coil of said rear control section and the output of the direction- and object-discriminating circuit.
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21. In a ground guidance system for airplanes having an airplane taxiway divided into a plurality of control sections, each control section having a plurality of loop coils for detecting vehicles on said taxiway, the improvement comprising:
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said loop coils having a dimension parallel to the direction of advance of airplanes which is smaller than the length of an airplane to be detected and said loop coils being arranged in the direction of advance of airplanes on said taxiway in the control sections at intervals smaller than the length of an airplane, said length of said dimension of said loop coils in said direction of advance of airplanes being larger than the length of an automobile;
each said loop coil being directly connected to airplane-detecting means to generate detection outputs indicating the presence or absence of an airplane in the vicinity of each said loop coil,wherein said airplane-detecting means comprises a high-frequency signal generator, a bridge circuit including three resistors and a resonance circuit consisting of one said loop coil and a capacitor, which becomes substantially resonant with the output frequency of the high-frequency signal generator, an alternating current amplifier for amplifying the output of the bridge circuit, a wave-detecting circuit for detecting an envelope of the amplified output of the alternating current amplifier, a window comparator means responsive to said wave-detecting circuit having a window characteristic such that the output level of the wave-detecting circuit obtained when an airplane is not present in the taxiway is within the window and the output level of the wave-detecting circuit obtained when an airplane is present and the self-inductance of the loop coil is changed is outside the window, for generating an output when an input signal of the level within the window is put in, and a voltage multiplying rectifying circuit for rectifying the output of the window comparator.
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29. A ground guidance system having an airplane taxiway divided into a plurality of control sections, each control section having a plurality of loop coils for detecting vehicles on said taxiway, wherein
said loop coils have a dimension parallel to the direction of advance of airplanes which is smaller than the length of an airplane to be detected and said loop coils are arranged in the direction of advance of airplanes on said taxiway in the control sections at intervals smaller than the length of an airplane, said length of said dimension of said loop coils in said direction of advance of airplanes being larger than the length of an automobile; - each said loop coil being directly connected to vehicle-detecting means to generate detection outputs indicating the presence or absence of an airplane in the vicinity of each said loop coil,
wherein said vehicle-detecting means comprises a high-frequency signal generator, a bridge circuit including three resistors and a resonance circuit consisting of one said loop coil and a capacitor, which becomes substantially resonant with the output frequency of the high-frequency signal generator, an alternating current amplifier for amplifying the output of the bridge circuit, a wave-detecting circuit for detecting an envelope of the amplified output of the alternating current amplifier, a window comparator means responsive to said wave-detecting circuit having a window characteristic such that the output level of the wave-detecting circuit obtained when an airplane is not present in the taxiway is within the window and the output level of the wave-detecting circuit obtained when an airplane is present and the self-inductance of the loop coil is changed is outside the window, for generating an output when an input signal of the level within the window is put in, and a voltage multiplying rectifying circuit for rectifying the output of the window comparator. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
- each said loop coil being directly connected to vehicle-detecting means to generate detection outputs indicating the presence or absence of an airplane in the vicinity of each said loop coil,
Specification