Navigation, communication, and surveillance system based on DME

• US 4,918,610 A
• Filed: 03/16/1989
• Issued: 04/17/1990
• Est. Priority Date: 09/07/1984
• Status: Expired due to Fees

• Current Assignee: Deutsche Telekom AG
• Original Assignee: Deutsche Rentenversicherung Berlin-Brandenburg
• Inventors: Becker, Alfred R. G.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Black, Thomas G.
• Application Number:
  US07/324,319
• Time in Patent Office: 397 Days
• Field of Search: 364/443, 364/449, 364/451, 364/460, 364/461, 342/29, 342/30, 342/32, 342/36, 342/38, 342/50
• US Class Current: 701/218
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/785 Distance Measuring Equipment [DME] systems
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

The distance measuring Equipment (DME) is a well-approved means for short nge navigation in international civil aviation. It utilizes the inherent capacity of the system in most applications to a relatively small degree. Therefore, additional functions can be integrated into the system such as data links, ground derived slant range measurement equipment and direction finders (growth potential). Thus, the DME can be extended to an Integrated Navigation, Communication, and Surveillance System. This system may be superior by technical, as well as by economical and operational reasons, to conventional solutions, which use separate systems for the different functions. The integrated system can be composed in different ways using different sets of the DME growth elements. A promising set is described and applied to a scenario of helicopter operations with oil rigs.

Claims

1. A surveillance system using a 3-way DME and including an aircraft, a central ground station, and at least one ground substation located at a substantial distance from said central ground station and connected with the latter via a respective broad-band link;

said surveillance system comprising;

a DME interrogator on said aircraft for transmitting an interrogating first pulse train, and a DME transponder at said central ground station for receiving said first pulse train from said aircraft and for transmitting to said aircraft with a predetermined delay a marked second pulse train in response to said first pulse train;

means associated with said DME interrogator for transmitting from said aircraft to said central ground station on the DME frequency of said first pulse train a third pulse train in response to receipt of said second pulse train from said central ground station, said third pulse train containing within a marking dead time for said DME transponder respective data identifying the aircraft and its altitude, and means associated with said ground substation for receiving said third pulse train from said DME interrogator and for transmitting said third pulse train from said ground substation via the respective broad-band link to said central ground station;

means on board the aircraft and at said central ground station for calculating a primary slant range between the aircraft and said central ground station based on the direct inter-aircraft/central ground station transit times measured for said first and second pulse trains and for said second and third pulse trains, respectively;

computing means at said central ground station for subtracting from (a) the travel times of said third pulse train received by said central ground station from said aircraft via said ground substation and the associated broad-band link (b) the travel times of said third pulse train received by said central ground station from said ground substation via said broad-band link, for calculating a secondary slant range between said aircraft and said ground substation, and for thereafter determining the aircraft position from (i) said primary slant range and said secondary slant range, (ii) the fixed distance between said central ground station and said ground substation to which the associated secondary slant range has been calculated, and (iii) the altitude of the aircraft transmitted in said third pulse train, said two slant ranges and the associated fixed distance forming the three sides of a triangle, and said computing means serving further for calculating the azimuth angle of the aircraft from the aircraft position; and

means for transmitting the azimuth angle of the aircraft from said central ground station to the aircraft for navigational purposes in said second pulse train within a coding window delayed in said second pulse train for a period of time longer than said marking dead time.

2. A surveillance system using a 3-way DME and including an aircraft and at least two ground stations located at a substantial distance from each other;

said surveillance system comprising;

a DME interrogator on said aircraft for transmitting an interrogating first pulse train, and a respective DME transponder at each of said ground stations for receiving said first pulse train from said aircraft and for transmitting to said aircraft with a predetermined delay a marked second pulse train in response to said first pulse train;

means associated with said DME interrogator for transmitting from said aircraft to said ground stations on the DME frequency of said first pulse train a third pulse train in response to receipt of each of said second pulse trains from the respective ground station, said third pulse train containing within a marking dead time for said DME transponders respective data identifying the aircraft and its altitude, and means associated with each of said ground stations for receiving said third pulse train from said DME interrogator;

first computing means at each of said ground stations for calculating the slant range between the aircraft and the respective ground station based on the direct inter-aircraft/ground station transit time measured for said first and second pulse trains and for said second and third pulse trains, respectively;

second computing means, and respective data links serving to transmit the slant range for each ground station calculated by said first computing means to said second computing means;

said second computing means serving for determining the aircraft position from (i) said two slant ranges between the aircraft and said two ground stations, (ii) the fixed distance between said two ground stations to which the associated slant range has been calculated, and (iii) the altitude of the aircraft transmitted in said third pulse train, said two slant ranges and said fixed distance forming the three sides of a triangle, and said second computing means serving further for calculating the azimuth angle of the aircraft from the aircraft position; and

means for transmitting the azimuth angle of the aircraft from at least one of said ground stations to the aircraft for navigational purposes in the respective said second pulse train within a coding window delayed in that second pulse train for a period of time longer than said marking dead time.

3. A surveillance system according to claim 2, and further comprising a third ground station at a substantial distance from each of said at least two ground stations, said third ground station acting as a central ground station including said second computing means and a DME transponder for receiving said first and third pulse trains from said aircraft and for transmitting to said aircraft with a predetermined delay a marked second pulse train in response to said first pulse train and including said coding window for transmitting the azimuth angle.

4. A surveillance system according to claim 3, wherein said third ground station which acts as a central ground station is connected via a wire data link with both of said at least two ground stations and cooperates therewith for determining the aircraft position.

5. A surveillance system according to claim 4, wherein the azimuth angle transmitted to the aircraft is the azimuth angle relative to said third ground station.