Publications
GPS-squitter experimental results
October 30, 1994
Conference Paper
Published in:
13th AIAA/IEEE Digital Avionics Systems Conf., 30 October - 3 November 1994, pp. 521-527.
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Summary
GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent Surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance and data link that permits equipped aircraft to participate in ADS or beacon ground environments. This offers many possibilities for transition from beacon to ADS-based surveillance. This paper briefly defines the GPS-Squitter concept and its principal applications. The thrust of the paper is the presentation of surface and airborne surveillance measurements made at Hanscom Field in Bedford, Massachusetts and at the Logan International Airport in Boston. In each case the measurements show the excellent surveillance performance provided by this concept.
Summary
GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent Surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance and data link that permits equipped aircraft to participate in ADS or beacon ground environments. This offers many possibilities for transition...
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Documentation of 9-PAC Beacon Target Detector processing function
July 26, 1994
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-220
Summary
This project report documents the algorithms and flow of the Beacon Target Detector (BTD) processing function incorporated as part of the ASR-9 Processor Augmentation Card (9-PAC). The BTD function combines replies that arise from the same aircraft to form beacon targets, and sends these beacon targets to the 9-PAC merge process where they are combined with primary radar reports. The 9-PAC BTD process was designed to solve two problems with the ASR-9 Array Signal Processor (ASP) BTD: identifying and removing false beacon targets due to reflections, and preventing merging or splitting of targets due to reply overlap and garble. The BTD reflection processing algorithm marks each beacon target as either real or false, and provides this information to the 9-PAC merge process. Discrete Mode A reflection false targets are identified when duplicate code reports satisfying stringent conditions are located. In order to find non-discrete Mode A code reflection false targets, the BTD builds an automated, dynamic reflector database based on the geography of pairs of discrete real and false targets.
Summary
This project report documents the algorithms and flow of the Beacon Target Detector (BTD) processing function incorporated as part of the ASR-9 Processor Augmentation Card (9-PAC). The BTD function combines replies that arise from the same aircraft to form beacon targets, and sends these beacon targets to the 9-PAC merge...
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Solid state radar demonstration test results at the FAA technical center
June 17, 1994
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-221
Summary
In 1992 and 1993 ITT Gilfillan teamed with Thomson CSF to develop a solid state transmitter system for airport surveillance radar applications. Because of the low peak power limitations of the solid state transmitter, the radar uses pulse compression techniques to obtain 55 nmi detection performance. In the Fall of 1992 ITT/Thompson executed a Cooperative Research and Development Agreement with the FAA?s Terminal Area Surveillance System (TASS) program office to demonstrate the transmitter at the FAA Technical Center using the FAATC's ASR-9. The Laboratory participated in these tests, which were completed in April 1993. The Laboratory test plan included an assessment of the solid state radar's time sidelobe levels, stability, susceptibility to short pulse interference, and target detection performance. Although the tests were limited in scope and the data required several post-collection processing corrections, the radar exhibited very low time sidelobe levels, had excellent stability, and showed adequate detection performance. The pulse compression receiver was vulnerable to short pulse interference and will require specialized processing techniques to minimize its effects. It was not possible to take weather data, and the FAA Technical Center radar environment has no stressing clutter. Recommendations are made for the follow-on effort at a mountainous site to more completely characterize the solid state ATC radar.
Summary
In 1992 and 1993 ITT Gilfillan teamed with Thomson CSF to develop a solid state transmitter system for airport surveillance radar applications. Because of the low peak power limitations of the solid state transmitter, the radar uses pulse compression techniques to obtain 55 nmi detection performance. In the Fall of...
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Airport surface surveillance using differential GPS and the Mode S data link
June 6, 1994
Conference Paper
Published in:
Proc. 50th Annual Mtg. of the Institute of Navigation, 6-8 June 1994, pp. 335-344.
Summary
A new concept for providing surface surveillance of aircraft and ground vehicles has recently been tested at Hanscom Field in Bedford, Massachusetts. This concept, known as GPS-Squitter, combines the capabilities of differential GPS for navigation with those of the Mode S data link for communications. Together these systems provide accurate surveillance data along with a positive identification of surface traffic, both very important for an effective surface meillance system. The GPS-Squitter concept is based on the use of the Mode S squitter. The current squitter is a 56bit Mode S all-call reply message spontaneously broadcast by all aircraft Mode S transponders at a 1Hz rate. This message provides the unique Mode S address of an aircrsft and is used by TCAS (Traffic Alert and Collision Avoidance System) for acquisition of nearby aircraft. In the Hanscom testing, this squitter was extended to include GPS-based surveillance information. Two target vehicles participated in the experiments - one aircraft and one ground vehicle. They determined their position, heading, and speed using differential GPS and automatically broadcast that surveillance information to ground transmit/receive stations using the modified squitter. Differential GPS pseudorange and pseudorange rate corrections were formed by a reference station located at Hanscom Field and were transmitted by the ground transmit receive stations to the target vehicles. This paper describes the configuration of the target vehicles, the ground transmit/receive stations, and the differential GPS reference station. Results of the surface surveillance testing are provided including: system coverage, surveillance update rate, and differential GPS data quality. Ongoing testing at Logan International Airport is also discussed.
Summary
A new concept for providing surface surveillance of aircraft and ground vehicles has recently been tested at Hanscom Field in Bedford, Massachusetts. This concept, known as GPS-Squitter, combines the capabilities of differential GPS for navigation with those of the Mode S data link for communications. Together these systems provide accurate...
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Demonstration of GPS Automatic Dependent Surveillance of aircraft using spontaneous Mode S broadcast messages
June 1, 1994
Journal Article
Published in:
Navig. J. Inst. Navig., Vol. 41, No. 2, Summer 1994, pp. 187-206.
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Summary
A new Automatic Dependent Surveillance (ADS) system concept combining GPS-based positions with Mode S data communications is described. Several potential applications of this concept are presented with emphasis on surface surveillance at airports. The navigation and data link performance are analyzed. Compact ADS position formats are included. The results of the first tests at Hanscom Field, demonstrating the feasibility of the spontaneous broadcast of ADS positions using Mode S messages are presented. Test aircraft, vehicles, avionics equipment and the ground system configuration are described. Avionics standards and GPS interface requirements are discussed. Multipath and airport surface coverage issues are addressed. Further testing in an operational environment is continuing at Logan Airport.
Summary
A new Automatic Dependent Surveillance (ADS) system concept combining GPS-based positions with Mode S data communications is described. Several potential applications of this concept are presented with emphasis on surface surveillance at airports. The navigation and data link performance are analyzed. Compact ADS position formats are included. The results of...
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GPS-squitter capacity analysis
May 20, 1994
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-214
Summary
GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent SurveiIlance (ADS) and the Mode S beacon radar. The resuit is an integrated concept for seamless surveillance and data link that permits equipped aircraft to participate in ADS and/or beacon ground environments. This concept offers many possibilities for transition from a beacon to an ADS-based environment. This report provides the details of the techniques used to estimate GPS-Squitter surveillance and data link capacity. Surveillance capacity of airborne aircraft is calculated for the omni and six-sector ground stations. Next, the capacity of GPS-Squitter for surface traffic is estimated. The interaction between airborne and surface operations is addressed to show de independence of these systems. Air ground data link capacity for GPS-Squitter is estimated, together with an estimate of the use of the Mode S link to support other ground surveillance and data link activities as well as TCAS operation. The analysis indicates the low transponder occupancy resulting from the total effect of these activities. Low occupancy is a key requirement in avoiding interference with the operation of the current ATCRRS and future Mode S interrogators.
Summary
GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent SurveiIlance (ADS) and the Mode S beacon radar. The resuit is an integrated concept for seamless surveillance and data link that permits equipped aircraft to participate in ADS and/or beacon ground environments. This concept offers many possibilities for...
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The influence of data link-provided graphical weather on pilot decision-making
April 6, 1994
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-215
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Summary
This report documents the findings of a human factor study conducted to estimate the effects of the Graphical-Weather Service (GWS) on general aviation (GA) aircraft utility, pilot situational awareness, and the weather dissemination workload on ground personnel. GWS is a data link application, being developed at MIT Lincoln Lbaoratory through the sponsorship of the Federal Aviation Administration, that will provide near-real time graphical weather information to the General Aviation pilot in the cockpit. Twenty instrument-rated pilots participated in the study. Subjects were presented with recorded actual weather information in the context of a series hypothetical pre-flight briefings and accompanying "flights." GWS images were accessible on a Macintosh TM Computer. The study design enabled the analysis of the effects of GWS and the determination of whether those efforts were influenced by the experience level of the pilot/user. Objective and subjective measures of effectiveness were collected. Results indicate that GWS had a substantial effects on weather-related decision-making. This was true for pilots with varying levels of instrument experience. Subject confidence in the ability to assess the weather situation was markedly increased when GWS was used. Subjects with GWS made fewer calls for weather information to weather dissemination ground personnel, thus indicating a potential decrease in ground personnel workload. Subjects found GWS to be very useful and were enthusiastic about receiving data link services in the GA cockpit in the future.
Summary
This report documents the findings of a human factor study conducted to estimate the effects of the Graphical-Weather Service (GWS) on general aviation (GA) aircraft utility, pilot situational awareness, and the weather dissemination workload on ground personnel. GWS is a data link application, being developed at MIT Lincoln Lbaoratory through...
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Connected components and temporal association in airport surface radar tracking
April 4, 1994
Conference Paper
Published in:
SPIE, Vol. 2220, Sensing, Imaging, and Vision for Control and Guidance of Aerospace Vehicles, 4-5 April 1994, pp. 357-379.
Summary
MIT Lincoln Laboratory, under sponsorship of the FAA, has installed a modified Raytheon pathfinder x-band marine radar at Logan Airport in Boston, Mass. and has developed a real- time surveillance system based on the pathfinder's digitized output. The surveillance system provides input to a safety logic system that will ultimately activate a set of runway status lights. This paper describes the portion of the surveillance system following the initial clutter- rejecting preprocessing, described elsewhere. The overall mechanism can be simply described as a temporal constant false alarm rate front end followed by binary morphological operations including connected components feeding a scan-to-scan tracker. However, a number of refinements have been added leading to a system which is close to being fieldable. Both the special difficulties and the current solutions are examined. The radar hardware as well as the computational environment are discussed. An overview of the clutter rejection preprocessing is given, as well as physical and processing related challenges associated with the data. Algorithmic description of the current system is presented and its real-time implementation outlined. Performance statistics and envisioned algorithmic improvements are presented.
Summary
MIT Lincoln Laboratory, under sponsorship of the FAA, has installed a modified Raytheon pathfinder x-band marine radar at Logan Airport in Boston, Mass. and has developed a real- time surveillance system based on the pathfinder's digitized output. The surveillance system provides input to a safety logic system that will ultimately...
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Radar images of Logan Airport and application in automated aircraft tracking
April 4, 1994
Conference Paper
Published in:
SPIE, Vol. 2220, Sensing, Imaging, and Vision for Control and Guidance of Aerospace Vehicles, 4-5 April 1994, pp. 316-327.
Summary
To enhance safety and expedite aircraft traffic control at airports, the Federal Aviation Administration (FAA) is in the process of developing automation aids for controllers and pilots. These automation improvements depend on reliable surveillance of the airport traffic, in the form of computerized target reports for all aircraft. One means of surveillance of the airport is primary radar. A short range radar of this type is called airport surface detection equipment or (ASDE). Lincoln Laboratory is participating in this development program by testing a system of surveillance and automation aids at Logan International Airport in Boston, Mass. This work is sponsored by the FAA. This paper describes the radar equipment being used for surface surveillance at Logan Airport and the characteristics of the radar images it produces. Techniques for automatic tracking of this radar data are also described along with a summary of the tracking performance that has been achieved. Two companion papers in this session relate to this same radar surveillance and provide more in-depth descriptions of the radar processing.
Summary
To enhance safety and expedite aircraft traffic control at airports, the Federal Aviation Administration (FAA) is in the process of developing automation aids for controllers and pilots. These automation improvements depend on reliable surveillance of the airport traffic, in the form of computerized target reports for all aircraft. One means...
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Target detection using radar images of an airport surface
April 4, 1994
Conference Paper
Published in:
SPIE, Vol. 2220, Sensing, Imaging, and Vision for Control and Guidance of Aerospace Vehicles, 4-5 April 1994, pp. 338-356.
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Summary
Automation aids which increase the efficiency of the controller and enhance safety are being sought by the Federal Aviation Administration (FAA). This paper describes the target detection algorithms developed by the MIT Lincoln Laboratory as part of the airport surface traffic automation (ASTA) and runway surface safety light system (RSLS) programs sponsored by the FAA that were demonstrated at Logan International Airport in Boston, Mass. from September 1992 through December 1993. A companion paper to this conference describes the ASTA and RSLS system demonstration. Another companion paper describes the tracking algorithms. Real-time, parallel processing implementations of these surveillance algorithms are written in C++ on a Silicon Graphics Inc. Unix multiprocessor. The heavy reliance on commercial hardware, standard operating systems, object oriented design, and high-level computer languages allows a rapid transition from a research environment to a production environment.
Summary
Automation aids which increase the efficiency of the controller and enhance safety are being sought by the Federal Aviation Administration (FAA). This paper describes the target detection algorithms developed by the MIT Lincoln Laboratory as part of the airport surface traffic automation (ASTA) and runway surface safety light system (RSLS)...
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