High-Capacity Location and Identification System for Cooperating Mobiles With Frequency Agile and Time Division Transponder Device on Board

• US 20080106457A1
• Filed: 10/11/2005
• Published: 05/08/2008
• Est. Priority Date: 10/14/2004
• Status: Active Grant

• Current Assignee: Universita' Degli Studi Di Roma Tor Vergata (Repubblica Italiana)
• Original Assignee: Universita' Degli Studi Di Roma La Sapienza (Repubblica Italiana)
• Inventors: Bartolini, Simone, Galati, Gaspare
• Granted Patent: US 7,570,195 B2
• Time in Patent Office: Days
• US Class Current: 342/40
• CPC Class Codes: G01S 13/781 Secondary Surveillance Radar [SSR] in general
• CPC Class Codes: G01S 13/784 Coders or decoders therefor; Degarbling systems; Defruiting systems

Abstract

Cooperating mobiles (ground vehicles, aircraft) are located and identified by Multilateration and Automatic Dependent Surveillance-Broadcast (ADS-B) techniques using the frequency band and the format of the Secondary Surveillance Radar (SSR) signals in high traffic situations. Standard messages, transmitted by the mobile on the downlink channel, i.e. to a set of fixed receiving stations, and including the identification code, permit the location of the mobile by multiple time measurements (Multilateration) from a subset of the set of fixed receiving stations; when the message contains the position (GPS and, later, Galileo datum) the mobile may be located with the ADS-B when in view even of a few stations or of a single station. In order to overcome the problem that arises with high traffic, i.e. the superimposition of signals, called garbling.

Claims

1. High-capacity surveillance and data link system able to locate and identify cooperating mobiles (ground vehicles, aircraft) using Multilateration and/or Automatic Dependent Surveillance-Broadcast (ADS-B) techniques by means of transmission of position, identification, status information and ancillary data from the mobiles to fixed receiving stations on the Secondary Surveillance Radar (SSR) Mode S channel, and implemented with a flexible and modular architecture.

2. High-capacity location and identification system, as in claim 1, characterized by the transmission of commands, controls, nearby traffic information and ancillary data from fixed transmitting stations to the cooperating mobiles on the Secondary Surveillance Radar (SSR) Mode S channel.

3. High-capacity location and identification system, as in claim 1, characterized by the use of a variable carrier frequency—

also referred to as frequency agility—

in the Secondary Surveillance Radar (SSR) Mode S channel, thereby implementing a frequency-division multiple access.

4. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized by the use of a time division multiple access for the transmission from and to the mobiles, according to time slots assigned to each mobile and managed by a central processing and managing subsystem (CPMS).

5. Transponder device, part of the location and identification system as defined in claim 1, characterized in that for every signal transmitted by this device—

i.e. a reply to an interrogation by a SSR/Multilateration station or a spontaneous emission (squitter)—

the carrier frequency can be changed within the maximum range as specified by the international according to an input from the central processing and managing subsystem or from the human machine interface of the device itself.

6. Device, as in claim 5, characterized in that the values of the central frequency variation with respect to the standard value are grouped in a number of different channels corresponding one-to-one to receiving channels in the system'"'"'s receiving stations.

7. Device, as in claim 5, characterized in that the central frequency variation—

belonging to a set of predefined values—

is stored in a digital selector that drives a frequency generation system which, in turn, generates the carrier frequency for the signals transmitted by the said device .

8. Device, as in claim 5, characterized in that the frequency generation system synthesizes a suitable intermediate frequency from which the carrier frequency is obtained.

9. Device, as in claim 5, characterized in that the intermediate frequency is obtained by a direct digital synthesis.

10. Device, as in claim 5, characterized in that the carrier frequency is obtained from the intermediate frequency by multiplication and frequency conversion.

11. Device, as in claim 5, characterized in that the carrier frequency represents the central frequency of the spectrum of the signal that, after amplitude modulation, is amplified and emitted from the antenna.

12. Device, as in claim 5, characterized by a Global Navigation Satellite System (GNSS:

GPS/Egnos, Galileo) receiver whose position data are used to locate the mobile in the ADS-B operation and whose time datum is used—

as an input to the timing unit—

to control the emission time in the time division multiple access operation.

13. Device, as in claim 5, characterized in that the emission time is regulated by a timing unit having at its input, from the central processing and managing subsystem (CPMS), a time information and a GNSS integrity monitoring signal, permitting the correct time division multiple access even in the case of unavailability of the Global Navigation Satellite System.

14. Device, as in claim 5, characterized in that it receives from nearby devices—

and/or from the central processing and managing subsystem—

signals containing the position of nearby mobiles, and displays the traffic information to the operator by a suited human—

machine interface.

15. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized by a fixed infrastructure (made up by transmitting stations, receiving stations, squitter generation units and a central processing and management subsystem) implementing a coordinated and simultaneous use of a frequency division multiple access and of a time division multiple access for the transmission from and to the mobiles, having on board a device characterized in that for every signal transmitted by this device—

i.e. a reply to an interrogation by a SSR/Multilateration station or a spontaneous emission (squitter)—

the carrier frequency can be changed within the maximum range as specified by the international according to an input from the central processing and managing subsystem or from the human machine interface of the device itself.

16. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized by fixed transmitting stations being able to interrogate a transponder device eliciting replies either immediately or in the next time slot assigned to the transponder device itself.

17. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized by the analysis of the time of arrival of signals from the mobiles and from reference signal generators (called squitter generator units), the detection of time errors with respect of the scheduled time values and the transmission of the error data to each mobile, permitting the correction of the timing by a filter/estimator.

18. High-capacity location and identification system for cooperating mobiles, as in previous claim 1, characterized in that it can be used in the surface movements guidance and control system of an airport for the control and management of traffic on runways, taxiways and pertaining connections.

19. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized in that it can be used in the control and management of movements and operations on the Apron of an airport.

20. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized in that it can be used for the control and management of aircraft nearby the airport, in the Terminal Manoeuvring Area and in the surrounding airways complex.

21. High-capacity location and identification system for cooperating mobiles, as in claim 1, characterized in that it can be used for the management of marine traffic in the vessel traffic system context.