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Uplink coverage measurements in the Los Angeles Area for passive BCAS

November 7, 1977
  |
Project Report
Author:
Ferenc Nagy Jr
Published in:
MIT Lincoln Laboratory Report ATC-81
Topic:
surveillance
R&D area:
R&D group:

Summary

Uplink (1030 MHz) measurement results are presented, based on data recorded by the Airborne Measurement Facility of the M.I.T. Lincoln Laboratory during normal landings and take-offs at the LAX, Van Nuys, and San Diego airports. The data presented are relevant to current investigations of passive beacon-based collision avoidance systems and include: (1) the interrogator environment as received; (2) its division between FAA and other interrogators; (3) its dependence on aircraft height during landings and take-offs; and (4) the availability of P2 pulses of sufficient strength for PRF (pulse repetition frequency) tracking. The number of interrogators was found to increase with the aircraft height at the rate of 2.5 to 3 interrogators per 1000 ft. P2 pulse tracking appears to be feasible down to 2000 ft. at LAX, and lower at San Diego.
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Summary

Uplink (1030 MHz) measurement results are presented, based on data recorded by the Airborne Measurement Facility of the M.I.T. Lincoln Laboratory during normal landings and take-offs at the LAX, Van Nuys, and San Diego airports. The data presented are relevant to current investigations of passive beacon-based collision avoidance systems and...

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Uplink coverage measurements in the Los Angeles Area for passive BCAS

Proposed technical characteristics for the Discrete Address Beacon System (DABS)

September 30, 1977
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Project Report
Author:
Jerry D. Welch
…
Published in:
MIT Lincoln Laboratory Report ATC-71
Topic:
surveillance
R&D area:
R&D group:

Summary

This report parallels the Proposed U. S. National Aviation Standard for the Discrete Address Beacon System. However, in addition to the material contained in the Proposed Standard this document provides a more detailed performance specification for the DABS transponder including specifications on transponder receiver sensitivity and performance in interference. It includes specifications for a proposed digital datalink interface and defines message and control fields associated with experimental transponder data applications. It also includes guidance material on the performance of an optional transponder antenna diversity scheme.
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Summary

This report parallels the Proposed U. S. National Aviation Standard for the Discrete Address Beacon System. However, in addition to the material contained in the Proposed Standard this document provides a more detailed performance specification for the DABS transponder including specifications on transponder receiver sensitivity and performance in interference. It...

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Proposed technical characteristics for the Discrete Address Beacon System (DABS)

A hardware implementation of the ATCRBS reply processor used in DABS

September 19, 1977
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Project Report
Author:
Richard G. Nelson
…
Published in:
MIT Lincoln Laboratory Report ATC-78
Topic:
surveillance
R&D area:
R&D group:

Summary

A special-purpose digital hardware processor, which implements the ATCRBS Reply Processing algorithms designed for use in the Discrete Address Beacon System (DABS) has been developed and used in two DABS-related programs. This report gives a detailed functional description of this processor as implemented by Lincoln Laboratory. With minor modifications it could serve as the ATCRBS Reply Processor for a Beacon Collision Avoidance System.
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Summary

A special-purpose digital hardware processor, which implements the ATCRBS Reply Processing algorithms designed for use in the Discrete Address Beacon System (DABS) has been developed and used in two DABS-related programs. This report gives a detailed functional description of this processor as implemented by Lincoln Laboratory. With minor modifications it...

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A hardware implementation of the ATCRBS reply processor used in DABS

L-Band air-to-air multipath measurements

September 6, 1977
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Project Report
Author:
Albert R. Paradis
Published in:
MIT Lincoln Laboratory Report ATC-77
Topic:
L-band
R&D area:
R&D group:

Summary

A series of air-to-air earth-scattered L-Band multipath measurements are described and experimental results presented. During these measurements RF pulses were transmitted between two instrumented general aviation aircraft flying coaltitude, diverging paths over a variety of terrain and water surfaces. Multipath data was collected over grazing angles ranging from ~5?? to ~75??. The objectives of these measurements were the: 1. Characterization of the multipath environment in which beacon based airborne collision avoidance (BCAS) equipment would operate. 2. Investigation of the merits and limitations of various degrees of antenna diversity in the rejection of multipath.
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Summary

A series of air-to-air earth-scattered L-Band multipath measurements are described and experimental results presented. During these measurements RF pulses were transmitted between two instrumented general aviation aircraft flying coaltitude, diverging paths over a variety of terrain and water surfaces. Multipath data was collected over grazing angles ranging from ~5?? to...

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L-Band air-to-air multipath measurements

DABS coverage

August 16, 1977
  |
Project Report
Author:
Steven I. Krich
Published in:
MIT Lincoln Laboratory Report ATC-75
Topic:
surveillance
R&D area:
R&D group:

Summary

DABS sensors are to be installed at FAA ASR and ARSR sites throughout continental U.S. as a part of the evolutionary upgrading of the third generation ATC Radar Beacon System (ATCRBS). It is therefore important to establish: (1) the degree of 3D coverage which would be provided by such deployment; and (2) a reasonable balance between number of installations, sensor maximum range, and coverage. This paper reports on a coverage study in which DABS coverage within CONUS was projected on a statistical or "percent coverage" basis by purely geometrical considerations. Results are given for CONUS, the eastern half of the U.S., and for the Golden Triangle. Profile coverage ("line-of-sight coverage down to...") is given for the Boston-NYC-Washington corridor.
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Summary

DABS sensors are to be installed at FAA ASR and ARSR sites throughout continental U.S. as a part of the evolutionary upgrading of the third generation ATC Radar Beacon System (ATCRBS). It is therefore important to establish: (1) the degree of 3D coverage which would be provided by such deployment...

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DABS coverage

Effects of RF power deviations on BCAS link reliability

June 7, 1977
  |
Project Report
Author:
William H. Harman III
Published in:
MIT Lincoln Laboratory Report ATC-76
Topic:
surveillance
R&D area:
R&D group:

Summary

In the design of BCAS there is some freedom in the choice of specifications for BCAS transmitter power and receiver MTL (Minimum Triggering Level). Transmitter power should be high enough to provide adequate link reliability while being low enough to prevent interference problems. The question of providing adequate link reliability for the DABS mode of BCAS is addressed in this study. The study makes use of aircraft antenna gain data resulting from a model measurement program, and is otherwise analytical. It is concluded that appropriate nominal design values are transmitter power = 500 watts and receiver MTL = -77 dBm (referred to the BCAS unit). It is shown that these values provide sufficient power margin, at the air-to-air ranges appropriate for BCAS, so as to allow for adverse power deviations that might result from aircraft antenna gains, antenna cabling, and the expected transmitter and receiver deviations due to manufacturing nonuniformities and aging.
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Summary

In the design of BCAS there is some freedom in the choice of specifications for BCAS transmitter power and receiver MTL (Minimum Triggering Level). Transmitter power should be high enough to provide adequate link reliability while being low enough to prevent interference problems. The question of providing adequate link reliability...

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Effects of RF power deviations on BCAS link reliability

Air-to-air visual acquisition performance with Pilot Warning Instruments (PWI)

April 25, 1977
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Project Report
Author:
John W. Andrews
Published in:
MIT Lincoln Laboratory Report ATC-73
Topic:
surveillance
R&D area:
R&D group:

Summary

Subject pilot flight tests conducted at the M.I.T. Lincoln Laboratory have produced new data characterizing the ability of general aviation pilots to visually acquire portential collision hazards when aided by Pilot Warning Instruments (PWI). In this paper major issues in the design of Pilot Warning Instruments are reviewed. Visual acquisition performance is described in terms of a non-homogeneous Poisson process and results of previous experiments are reinterpreted in this light. It is shown that the major test results can be explained in terms of an acquisition rate which is proportional to the solid angle subtended by the target. Model parameters appropriate for Lincoln Laboratory flight test data are derived by maximum likelihood techniques. A statistical analysis of significance is performed for other factors which are not explicitly included in this model. Performance predictions for a wide variety of aircraft sizes, approach speeds, and visibility conditions are presented.
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Summary

Subject pilot flight tests conducted at the M.I.T. Lincoln Laboratory have produced new data characterizing the ability of general aviation pilots to visually acquire portential collision hazards when aided by Pilot Warning Instruments (PWI). In this paper major issues in the design of Pilot Warning Instruments are reviewed. Visual acquisition...

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Air-to-air visual acquisition performance with Pilot Warning Instruments (PWI)

ATCRBS mode of DABS

January 31, 1977
  |
Project Report
Author:
Jeffrey L. Gertz
Published in:
MIT Lincoln Laboratory Report ATC-65
Topic:
surveillance
R&D area:
R&D group:

Summary

The Discrete Address Beacon System (DABS) has been designed to be an evolutionary replacement oth the third generation Air Traffic Control Radar Beacon System (ATCRBS). Although the ATCRBS returns processed by DABS will be identical to those currently being employed, the DABS processing system will not merely mimic the present system. Instead, it has been designed to surpass current performance levels even while reducing the number of interrogations transmitted per scan. This will be made possible by utilizing the availability of several new features introduced by the DABS sensor. In particular, the employment of monopulse antenna will permit both more accurate azimuth estimation with fewer replies per scan and improved decoding performance when garble is present. The ATCRBS portion of the DABS sensor has been designed to be a complete, self-contained package that performs all ATCRBS functions required for aircraft surveillance. The major tasks it implements are: 1. Determining the range, azimuth, and code of each received ATCRBS reply 2. Grouping replies from the same aircraft into target reports and discarding fruit replies 3. Identifying all false alarm target reports due to reflections, coincident fruit, splitting, or ringaround 4. Initiating and maintaining a track on all aircraft in the covered airspace The first function has been implemented in hardware while the remaining ones are performed in software. This report will discuss in detail only the software subsystems. The ATCRBS system described in this report has been implemented in the ATCRBS Monopulse Processing System (AMPS) built at Lincoln Laboratory. Although the AMPS design is based upon the specifications contained in the DABS Engineering Requirements (ER), there are two major differences between AMPS and the ER system. First, the design described here is for a standalone ATCRBS system; no capabilities are built in to send, receive, or employ information from other sensors, and no formal interfaces to other ATC functions are defined. Second, this system was not intended to be a production prototype, so no reliability features have been included.
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Summary

The Discrete Address Beacon System (DABS) has been designed to be an evolutionary replacement oth the third generation Air Traffic Control Radar Beacon System (ATCRBS). Although the ATCRBS returns processed by DABS will be identical to those currently being employed, the DABS processing system will not merely mimic the present...

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ATCRBS mode of DABS

Empirical characterization of IPC tracker performance using DABS data

June 9, 1976
  |
Project Report
Author:
John L. Leeper
…
Published in:
MIT Lincoln Laboratory Report ATC-61
Topic:
surveillance
R&D area:
R&D group:

Summary

The performance of a set of tracker algorithms proposed for use in the DABS-based Intermittent Positive Control (IPC) collision avoidance system is assessed. The position projecting tracker algorithms are subjected to actual surveillance data obtained at the Lincoln Laboratory DABS Experimental Facility. Effects of turn-rate, speed, wind and surveillance accuracy upon heading error, speed error and position error are presented.
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Summary

The performance of a set of tracker algorithms proposed for use in the DABS-based Intermittent Positive Control (IPC) collision avoidance system is assessed. The position projecting tracker algorithms are subjected to actual surveillance data obtained at the Lincoln Laboratory DABS Experimental Facility. Effects of turn-rate, speed, wind and surveillance accuracy...

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Empirical characterization of IPC tracker performance using DABS data

PALM - a system for precise aircraft location

May 16, 1976
  |
Journal Article
Author:
Irvin G. Stiglitz
…
Published in:
J. of the Institute of Navigation, Vol. 23, No. 3, Fall 1976, pp. 257-261.
Topic:
air traffic control
R&D area:
R&D group:

Summary

The Precision Altitude and Landing Monitor (PALM) is intended to provide accurate stand-alone three-dimensional position data for aircraft equipped with standard beacon transponders using ground equipment designed for low life cycle cost. The PALM program, to the present time, has focused on an experimental evaluation of the accuracy of elevation measurements. The results of these measurements have successfully validated the theoretical prediction of a 1-mrad (0.06 degree) elevation accuracy at low elevation angles. The key features in the PALM design include (1) No new avionics required, i.e., it uses standard aircraft transponder. IFPALM is used as the data base for certain ground-to-air messages, a standard VHF or DABS data link could be employed. (2) High accuracy position data, i.e., a 1-mrad rms error in elevation and in azimuth at low elevation angles. (3) Broad airspace coverage, e.g., 40 degrees in elevation, 120 degrees in azimuth (expandable to 360 degrees), and several tens of miles in range. (4) Low life cycle equipment cost, i.e., it incorporates a fixed passive receiving antenna array and a minicomputer to perform the signal processing necessary for interference rejection.
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Summary

The Precision Altitude and Landing Monitor (PALM) is intended to provide accurate stand-alone three-dimensional position data for aircraft equipped with standard beacon transponders using ground equipment designed for low life cycle cost. The PALM program, to the present time, has focused on an experimental evaluation of the accuracy of elevation...

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PALM - a system for precise aircraft location
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