SYSTEMS AND METHODS FOR PROVIDING AN ADVANCED ATC DATA LINK

• US 20100079329A1
• Filed: 05/18/2009
• Published: 04/01/2010
• Est. Priority Date: 04/24/2007
• Status: Active Grant

• Current Assignee: Aviation Communication and Surveillance Systems LLC (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: Stayton, Gregory T.
• Granted Patent: US 8,344,936 B2
• Time in Patent Office: Days
• US Class Current: 342/37
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/784 Coders or decoders therefor; Degarbling systems; Defruiting systems
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 27/10 Frequency-modulated carrier systems, i.e. using frequency-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04L 27/32 Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal

Abstract

Embodiments of the present invention disclose systems and methods for providing an avionics overlay data link. Through embodiments of the present invention, existing ATC (or other) modulated signals using existing frequencies (or other frequencies) may be utilized to transmit (e.g., from an aircraft transponder) additional information in a manner that does not render the transmitted signal unrecognizable by legacy ATC equipment. In various embodiments, legacy equipment may demodulate and decode information that was encoded in the transmitted signal in accordance with preexisting standard modulation formats, and updated equipment can also extract the additional information that was overlaid on transmitted signals.

Claims

1. A method for encoding an overlaid message onto a provided modulated avionics signal, the method comprising:

selecting an overlay modulation protocol; and

modulating the provided modulated avionics signal with an overlay message using the selected overlay modulation protocol to produce a modulated avionics signal.

2. The method as disclosed in claim 1, wherein:

a rise time of the modulated avionics signal is greater than 600 nanoseconds; and

a fall time of the modulated avionics signal is greater than 600 nanoseconds.

3. The method as disclosed in claim 1, wherein:

a rise time of the modulated avionics signal is greater than 100 nanoseconds; and

a fall time of the modulated avionics signal is greater than 200 nanoseconds.

4. The method as disclosed in claim 1, wherein preamble data of the modulated avionics signal comprises a set of initial 8PSK data bits that are presented in a predetermined pattern.

5. The method as disclosed in claim 4, wherein the bit dwell time per symbol comprises a desired modulation phase wherein a phase transition rate is unrestricted.

6. The method as disclosed in claim 1, further comprising offsetting the waveform of the modulated avionics signal near frequency tolerance edges.

7. The method as disclosed in claim 1, wherein an amplitude of the waveform of the modulated avionics signal comprises a varied amplitude based on range to intended recipient.

8. The method as disclosed in claim 1, wherein the provided modulated avionics signal is modulated with pulse position modulation protocol.

9. The method as disclosed in claim 1, wherein the overlay modulation protocol is phase shift keying modulation.

10. The method as disclosed in claim 9, wherein a plurality of phase states for sequentially defined phases are Gray-Code encoded.

11. The method as disclosed in claim 1, wherein modulating the provided modulated avionics signal with an overlay message using the selected overlay modulation protocol further comprises applying the overlay modulation to a carrier signal within one or more modulated message bit intervals within a data block in the modulated avionics signal.

12. The method as disclosed in claim 11, wherein:

the overlay modulation comprises a PSK protocol; and

a phase transition is modulated into the carrier signal proximate to a mid-point of the bit interval.

13. The method as disclosed in claim 11, wherein:

the overlay modulation comprises a PSK protocol; and

a phase transition is modulated into the carrier signal proximate an initial point of the bit interval.

14. The method as disclosed in claim 11, wherein:

the overlay modulation comprises a PSK protocol; and

a plurality of phase transitions are modulated into the carrier signal within one bit interval.

15. The method as disclosed in claim 11, further comprising transmitting the overlay-modulated modulated avionics signal from at least one of a TCAS transponder;

an ADS-B transponder;

a ATC radar; and

a ground station.

16. The method as disclosed in claim 1, wherein the overlay modulation protocol is selected from the group consisting of:

binary phase shift keying modulation (BPSK);

quadrature phase shift keying modulation (QPSK);

8-phase shift keying modulation (8-PSK);

differential phase-shift keying (DPSK);

DNPSK modulation, where N is an even integer and a multiple of 2;

frequency shift keying (FSK);

amplitude shift keying (ASK);

quadrature amplitude modulation (QAM);

orthogonal frequency-division multiplexing (OFDM);

minimum-shift keying (MSK);

asymmetric phase-shift keying, (APSK);

pulse position modulation (PPM);

amplitude modulation (AM);

frequency modulation (FM); and

combinations thereof.

17. The method as disclosed in claim 1, wherein the overlay modulation protocol is selected from the group consisting of:

modulation by amplitude characteristics, modulation by phase characteristics, modulation by frequency characteristics, and any combination thereof.

18. The method as disclosed in claim 1, wherein the provided modulated avionics signal comprises a signal selected from the group consisting of:

a transponder reply signal;

a squitter signal;

an ADS-B reply signal;

a 1030 MHz interrogation signal;

a 1030 MHz TCAS signal;

by

a General Aviation UAT transceiver signal on a UHF frequency band;

at least one of a signal within a voice band or a data band operating within an ATC HF, VHF, and UHF band,

a VDL Mode 4 ADS-B modulated signal;

a DME signal;

SATCOM signal;

a signal originating from any avionics equipment that radiates a modulated RF signal;

a baseband signal for transmitting data; and

combinations thereof.

19. The method as disclosed in claim 1, further comprising encrypting the overlay message.

20. The method as disclosed in claim 1, further comprising applying a second overlay modulation protocol to the overlay-modulated signal.

21. The method as disclosed in claim 20, wherein the second overlay modulation protocol is selected from the group consisting of:

binary phase shift keying modulation (BPSK);

quadrature phase shift keying modulation (QPSK);

8-phase shift keying modulation (8-PSK);

differential phase-shift keying (DPSK);

DNPSK modulation, where N is an even integer and a multiple of 2;

frequency shift keying (FSK);

amplitude shift keying (ASK);

quadrature amplitude modulation (QAM);

orthogonal frequency-division multiplexing (OFDM);

minimum-shift keying (MSK);

asymmetric phase-shift keying, (APSK);

pulse position modulation (PPM);

amplitude modulation (AM);

frequency modulation (FM); and

combinations thereof.

22. The method as disclosed in claim 20, wherein the second overlay modulation protocol is selected from the group consisting of:

modulation by amplitude characteristics, modulation by phase characteristics, modulation by frequency characteristics, and any combination thereof.

23. The method as disclosed in claim 1, further comprising encoding, within the overlay message, at least one of:

one or more parity bits;

one or more CRC bits;

Reed-Solomon bit error detection and correction data; and

one or more error correction code bits.

24. The method as disclosed in claim 1, wherein modulating the provided modulated avionics signal with an overlay message using the selected overlay modulation protocol further comprises interleaving the overlay message into message bit intervals.

25. The method as disclosed in claim 1, wherein the modulated avionics signal does not conform to the criteria for waveforms established in RTCA standard DO-181C, Minimum Operational Performance Standards for Air Traffic Control Radar Beacon System/Mode Select (ATCRBS/Mode S) Airborne Equipment.

26. The method as disclosed in claim 1, further comprising processing the data for overlay and data extraction.

27. The method as disclosed in claim 1, further comprising decoding the overlay signal.