Communications: directive radio wave systems and devices (e.g. – Air traffic control
Reexamination Certificate
1999-11-03
2001-04-03
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Air traffic control
C342S463000, C342S029000, C342S031000
Reexamination Certificate
active
06211811
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
BACKGROUND OF THE INVENTION
This invention relates to surveillance systems. More specifically, the invention depicts a method and apparatus to supplement vehicle surveillance systems by providing vehicle identification and position aiding.
The Federal Aviation Administration (FAA) has installed Airport Surface Detection Equipment (ASDE) primary radar systems at the nations busiest airports. These radars provide a display in the Air Traffic Control (ATC) tower cab of runway/taxiway traffic movement. The display provides the tower controllers with enhanced situational awareness when visibility conditions make maintaining direct visual contact with traffic on the airport surface difficult. There are three key deficiencies associated with the ASDE primary radar: (1) surveillance coverage gaps result when radar installations do not have line-of-sight between the radar and the monitored traffic as is the case for complex airport layouts; (2) false targets are generated on the tower displays when multipath interference occurs and (3) primary radar cannot provide identification of aircraft with flight identification (ID).
In an effort to augment ASDE surveillance and resolve deficiencies, the FAA conducted trials of Aircraft Target Identification System (ATIDS) as described in an article titled “
Positive Identification of Aircraft on Airport Movement Area—Results of FAA Trials
” published in IEEE Aerospace and Electronic Systems Magazine, June 1996. ATIDS uses 1090 MHz multilateration to determine the location of Mode S and Mode A/C transponder equipped aircraft. Similar research using 1090 MHz multilateration is documented in “
Station Arrangement Effects on Ground
-
Referenced Aircraft Height Computation Based on Time Difference of Arrival”
, published in Navigation: Journal of The Institute of Navigation, Vol. 42, No. 2, Summer 1995 and in “
The Czech Passive Surveillance System for Air Traffic Control
” published in the Journal of ATC, January-March 1997. The system also decodes aircraft transponder transmissions to determine each aircraft's 4096 code. ATIDS system elements in the ATC tower use the 4096 code to look up the flight ID available through an interface with Automated Radar Tracking System (ARTS). The FAA has demonstrated that the ATIDS position/Flight ID information can be fused with ASDE surveillance. However, one of the major limitations of ATIDS is that Mode S and Mode A/C transmissions are highly susceptible to multipath interference resulting from reflections off airport structures. Multipath interference results in corrupted 1090 MHz receptions at the ATIDS receive stations. Techniques have been developed to aid in the recovery of corrupted transmissions, for example, U.S. Pat. No. 5,528,244 describes a technique for recovering Mode S and Mode A/C transmissions that was tested in the ATIDS test trials. Even with the application of multipath mitigation techniques, reception performance can be significantly low in high multipath environments as was experienced in the ATIDS test trials. Multilateration using the Time Difference of Arrival (TDOA) technique requires reception from a minimum of 3 receivers to determine a 2D position as described in U.S. Pat. No. 5,191,342. To ensure a minimum of three receptions for each transponder transmission, diversity using more than three receivers is required to guarantee the surveillance update success rates required for the surface surveillance application. The cost of additional receivers beyond the minimum of 3 results in increased ATIDS system costs.
Accordingly, what is needed is a new method for performing multilateration that uses two receivers to provide identification of vehicles and provide a 2D position when reception is only available from two multilateration system receivers.
BRIEF SUMMARY OF THE INVENTION
This invention is an apparatus and method for supplementing vehicle surveillance systems by providing vehicle identification and position aiding. In an embodiment featuring a plurality of mobile radio transmitters and a plurality of ground stations, identification and position updates are provided when two of the ground station receive mobile transmissions. The ground stations time stamp each mobile transmission and decode the transmission identification code. Time stamp information is used to determine a TDOA measurement and a Line Of Position (LOP). The identification function is provided by correlating TDOA measurements expected TDOA from the surveillance sensor requiring target identification. The position aiding function is provided by using LOP, pavement area map, and track information to determine track updates for the surveillance system receiving the aiding.
REFERENCES:
patent: 4196474 (1980-04-01), Buchanan et al.
patent: 4229737 (1980-10-01), Heldwein et al.
patent: 4454510 (1984-06-01), Crow
patent: 4524931 (1985-06-01), Nilsson
patent: 4688046 (1987-08-01), Schwab
patent: 5191342 (1993-03-01), Alsup et al.
patent: 5262784 (1993-11-01), Drobinicki et al.
patent: 5365516 (1994-11-01), Jandrell
patent: 5374932 (1994-12-01), Wyschogrod et al.
patent: 5528244 (1996-06-01), Schwab
patent: 5570095 (1996-10-01), Drouilhet, Jr. et al.
patent: 5596326 (1997-01-01), Fitts
patent: 5627546 (1997-05-01), Crow
patent: 5774829 (1998-06-01), Cisneros et al.
patent: 5867804 (1999-02-01), Pilley et al.
patent: 5999116 (1999-12-01), Evers
patent: 40-6342061 (1994-12-01), None
patent: 40-8146130 (1996-06-01), None
patent: 40-9119983 (1997-05-01), None
patent: 09288175 (1997-11-01), None
Baldwin, Jonathan, “Traffic Alert System Technical Design Summary”.
Rannoch Brochure, “AirScene: The Complete Air Traffic Picture in Real Time”, www.AirScene.com, www.rannoch.com.
Rudel, Marc-Philippe, Baldwin, Jonathan, “GPS Relative Accuracy for Collision Avoidance”, Navigation Technical Meeting in Santa Monica, California, Jan. 1997.
Bell Robert Platt
Rannoch Corporation
Sotomayor John B.
LandOfFree
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