Channel encoding for distance measurement equipment
AssigneeInternational Telephone and Telegraph Corporation
InventorsSven H. Dodington, Jesse S. LeGrand
Life of this patent
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Abstract
An adapter is provided for insertion between a conventional DME airborne interrogator and antenna. The adpater converts conventional interrogations into phase-coded or amplitude coded signals which are received by new Microwave Landing System (MLS) transponders. Each transponder will process interrogations having the correct code and frequency and will respond with precision reply signals. The precision replies are then received by the airborne equipment, converted back to standard reply pulses and processed to provide distance measurement. Also provided is a new transponder for use at MLS sites.
Claims8
An Apparatus for generating interrogation signals for use with airborne equipment of the type which transmits interrogation signals containing at least one pulse of a first type to a ground beacon, said beacon of a type which responds to interrogation signals of a second type with reply signals of said second type, and wherein said airborne equipment processes reply signals of said first type, said airborne equipment including a transmitter, a receiver, an interrogator and an antenna, said apparatus comprising:
- means for detecting said first type of interrogation signal;
- means for converting said at least one pulse to at least one second pulse having a reduced amplitude;
- means for generating a coded signal;
- and
- means for modulating said at least one second pulse with said coded signal to produce an interrogation signal of said second type.
An apparatus for use with airborne equipment of the type which transmits interrogation signals comprising at least one pulse of a first type to a ground beacon, said beacon of a type which responds to interrogation signals of a second type with reply signals of said second type and wherein said equipment processes reply signals of said first type, said airborne equipment including a transmitter, a receiver, an interrogator and an antenna, said apparatus comprising:
- means for detecting said first type interrogation signal;
- means for converting said at least one pulse to at least one second pulse having a reduced amplitude;
- means for generating a coded signal;
- means for modulating said at least one second pulse with said coded signal to produce an interrogation signal of said second type;
- means for receiving said reply signals of said second type;
- and
- means for converting said reply signals of said second type to said first type for processing in said airborne equipment.
In a distance measuring system, a beacon for receiving coded interrogation signals, processing interrogation signals having a correct code and generating a reply signal in response to said interrogation signals comprising:
- means for detecting the presence of an interrogation signal;
- means for decoding said interrogation signal to determine if it is one to which a response should be made;
- means for determining the frequency of said interrogation signal to determine if it is one to which a response should be made;
- and
- means for generating a coded reply signal in response to an interrogation having a correct code and frequency.
Dependencies are inferred from the claim text.