Publications
Automatic Reporting of Height (AROH) design and trade-off studies
November 1, 1976
Technical Report
Published in:
MIT Lincoln Laboratory Report TN-1976-42
Topic:
R&D area:
R&D group:
Summary
Application of MTD signal processing and state-of-the-art data processing can result in a completely automatic nodding beam height finder. The resulting savings in manpower are significant. Calculations show that such a system should have good sensitivity and adequate rejection of ground and weather clutter. Modification of an FPS-6 radar for this purpose is discussed.
Summary
Application of MTD signal processing and state-of-the-art data processing can result in a completely automatic nodding beam height finder. The resulting savings in manpower are significant. Calculations show that such a system should have good sensitivity and adequate rejection of ground and weather clutter. Modification of an FPS-6 radar for...
READ MORE
The PMP, a programmable radar signal processor
October 7, 1976
Conference Paper
Published in:
Monthly Mtg. of Boston IEEE, Mitre Corp, Bedford, Ma 13 October 1976.
Topic:
R&D area:
R&D group:
Summary
During the last few years, the Radar Techniques Group at Lincoln Laboratory has been applying digital processing techniques to the problem of automatic detection of moving vehicles in the presence of ground and weather clutter. An outgrowth of this effort is the development of a real-time radar signal processor, the Parallel Microprogrammable Processor, or PMP. Conceptually the PMP consists of a single control unit and an array of identical processing modules. The control unit sequences through a program stored in its control memory, providing identical instructions to each processing module, so that all modules are performing the same operation in parallel, each on its own set of data. The talk will focus on the motivation for, and advantages of such a parallel architecture, as presently implemented with TTL medium-scale integrated circuits. Some examples of parallel computation will be illustrated as well as more general issues relating to programmability of the PMP. Much of the information in the talk will be based on experience with an operational prototype, which has a control unit and one processor module.
Summary
During the last few years, the Radar Techniques Group at Lincoln Laboratory has been applying digital processing techniques to the problem of automatic detection of moving vehicles in the presence of ground and weather clutter. An outgrowth of this effort is the development of a real-time radar signal processor, the...
READ MORE
Radar detection of thunderstorm hazards for air traffic control volume II: radar systems
October 7, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-67,II
Summary
Radar systems are investigated for the acquisition of weather data to support detection and forecasting of hazardous turbulence associated with individual storm cells. Utilization of the FAA Airport Surveillance Radar (ASR) is explored. The issues of antenna polarization and Sensitivity Time Control (STG) that impact on shared operation for aircraft and weather detection are addressed. Candidate system configurations employing a common RF channel and dual orthogonal polarization channels are discussed. Ground clutter discrimination by coherent Doppler and noncoherent (Doppler spread) processing methods is described. An interim procedure is suggested for obtaining fixed reflectivity contour data from a Moving Target Detector for use in the all-digital ARTS. A preliminary design is presented for a new joint-use, long-range weather radar to support enroute air traffic controllers and to meet the data requirements of the National Weather Service and the Air Weather Service.
Summary
Radar systems are investigated for the acquisition of weather data to support detection and forecasting of hazardous turbulence associated with individual storm cells. Utilization of the FAA Airport Surveillance Radar (ASR) is explored. The issues of antenna polarization and Sensitivity Time Control (STG) that impact on shared operation for aircraft...
READ MORE
Radar detection of thunderstorm hazards for air traffic control volume I: storm cell detection
October 7, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-67,I
Summary
A procedure was developed to detect hazardous regions within thunderstorms using weather radar data. The procedure is based upon the hypothesis that convective turbulence occurs within 2-3 km of relative radar reflectivity maxima (cells). The hypothesis was tested using a limited set of simultaneous aircraft and radar data. Good agreement was found between the observed regions of convective turbulence and the cell locations determined by radar. The viability of the hazard detection hypothesis as a basis for automatic warning and forcast depends upon the reliability of the cell detection and tracking algorithms. Analysis of precision radar data revealed that the cells are small in area extent, have a detection probability in excess of 0.9 using multiple radar scans, and are readily tracked for periods between 10 and 20 minutes. The characteristics of radar systems for acquiring data to support cell detection, are discussed. The role of Doppler spectral data is explored, and it is found that practical limitations on radar beamwidth hamper direct observation of turbulence on the scale size hazardous to aircraft.
Summary
A procedure was developed to detect hazardous regions within thunderstorms using weather radar data. The procedure is based upon the hypothesis that convective turbulence occurs within 2-3 km of relative radar reflectivity maxima (cells). The hypothesis was tested using a limited set of simultaneous aircraft and radar data. Good agreement...
READ MORE
Spectra of ionospheric scintillation
May 1, 1976
Journal Article
Published in:
J. Geophys. Res., Vol. 81, No. 13, 1 May 1976, pp. 2041-2050.
Summary
Observation of amplitude and phase scintillation were made at the Millstone Hill radar facility by using phase coherent sources at 150 and 400 MHz on the U.S. Navy navigation system satellites. These observations have been processed to yield power spectra of the fluctuations in the logarithm of the received power (log power) at each frequency and the calculations in phase path length difference (differential phase) between the two frequencies. A theoretical analysis was performed to predict the log power and differential phase power spectra. The theoretical model was based upon weak scatter theory for a thick screen with a three-dimensional power law power spectrum representation for the electron density fluctuations. A -4 exponent for the power law best fit the observed spectra. For weak scintillation (rms fluctuations in log power less than 5 dB or S4 < 0.9) the theroretical calculations were in excellent agreement with the observations. For strong scintillation, saturation was observed, and the measured spectra were broader than those predicted on the basis of weak scatter theory. An increase in electron density fluctuations relative to the value predicted by the power law model was observed at scale sizes smaller than 0.8 km.This increase may be responsible for the anomalous scintillation observations at gigahertz frequencies.
Summary
Observation of amplitude and phase scintillation were made at the Millstone Hill radar facility by using phase coherent sources at 150 and 400 MHz on the U.S. Navy navigation system satellites. These observations have been processed to yield power spectra of the fluctuations in the logarithm of the received power...
READ MORE
Concept and plan for the development of a weather support subsystem for Air Traffic Control
April 16, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-64
Summary
This report summarizes the results of a study to: (1) investigate the primary needs of air traffic controllers, flow controllers, and central flow controllers for weather information, (2) define a cost effective system concept to meet these needs, and (3) lay out a plan for the development of the proposed weather subsystem to support Air Traffic Control. The recommended system will provide rapid geration and dissemination of reliable use oriented observations and very short range severe weather forecasts (up to 30 min.) to facilitate controller planning. This new capability will: 1) reduce weather induced controller work load peaks, 2) permit controllers to coordinate and preplan aircraft rerouting for weather avoidance, 3) achieve an improved balance between the inefficiency of overreaction and the essentials of safety, 4) facilitate controller response to pilot requests for weather data on a work load permitting basis, and 5) enable the issuance of accurate weather advisories. The system will also provide rapid generation and dissemination of reliable short range forecasts (up to 4 hours) to permit early introduction of necessary flow control procedures. This new capability will: 1) decrease problems for controllers, 2) increase acceptance of flow control, and 3) increase traffic flow efficiency without decreasing safety.
Summary
This report summarizes the results of a study to: (1) investigate the primary needs of air traffic controllers, flow controllers, and central flow controllers for weather information, (2) define a cost effective system concept to meet these needs, and (3) lay out a plan for the development of the proposed...
READ MORE
The Airborne Measurement Facility (AMF) system description
March 25, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-60
Topic:
R&D area:
R&D group:
Summary
The Airborne Measurement Facility (AMF) is a data collection and conversion system that provides a means for obtaining recorded data representing pulsed electromagnetic signals received on one of the two ATC radar beacon frequency bands that is selected for a given data collecting mission. The facility consists of two subsystems: (1) an airborne subsystem which collects and records data during flight, and (2) a ground playback facility which processes the data and transcribes it onto computer-compatible tape.
Summary
The Airborne Measurement Facility (AMF) is a data collection and conversion system that provides a means for obtaining recorded data representing pulsed electromagnetic signals received on one of the two ATC radar beacon frequency bands that is selected for a given data collecting mission. The facility consists of two subsystems...
READ MORE
DABS modulation and coding design - a summary
March 12, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-52
Topic:
R&D area:
R&D group:
Summary
The Discrete Address Beacon System (DABS) has been designed as an evolutionary replacement for the Air Traffic Control Radar Beacon System (ATCRBS). As with ATCRBS, DABS is a cooperative Air Traffic Surveillance System utilizing ground based sensors (interrogators) and airborne transponders. In addition to its surveillance function, DABS integrally accommodates ground-to-air and air-to-ground data link communication within the interrogations and replies. In DABS, each aircraft transponder may be individually interrogated, using its unique 24-bit address, giving the ground based interrogators freedom to schedule interrogations and replies to make efficient use of the channels essentially independent of the aircraft traffic distribution. The evolutionary constraint on DABS, requiring the capability for one-for-one replacement of ATCRBS ground sensors and transponders, dictated the need to maximize commonality between the two systems. Thus, the ATCRBS interrogation and reply frequencies (1030 and 1090 MHz) were prime candidates for DABS operating frequencies. This report presents the rationale for the selection of the DABS signalling waveforms and error control techniques. The main issues in arriving at the final link design were (1) affordable transponder cost, (2) electromagnetic compatibility with ATCRBS and TACAN, and (3) adequate performance in the channel environment, which includes interference from ATCRBS transmissions. The resulting DABS that of ATCRBS, and transmits ground-to-air data link messages with high reliability. This is accomplished without noticeably affecting ATCRBS performance, with less channel occupancy per target report than ATCRBS, and with transponders projected to cost approximately 160% of the cost of ATCRBS transponders.
Summary
The Discrete Address Beacon System (DABS) has been designed as an evolutionary replacement for the Air Traffic Control Radar Beacon System (ATCRBS). As with ATCRBS, DABS is a cooperative Air Traffic Surveillance System utilizing ground based sensors (interrogators) and airborne transponders. In addition to its surveillance function, DABS integrally accommodates...
READ MORE
MLS multipath studies volume II: application of multipath model to key MLS performance issues
February 25, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-63,II
Summary
This report summarizes MLS multipath work carried out at Lincoln Laboratory from March 1974 to Sept. 30, 1975. The focus of the program is the development of realistic models for 1) the multipath in representative real world environments and 2) the multipath characteristic of candidate MLS techniques. These multipath and system models are used in a comprehensive computer simulation to predict the strengths and weaknesses of major MLS systems when subjected to representative real world environments. The report is organized into two volumes. Volume I describes the algorithms and validation of various portions of the program. In Volume II, the simulation (or selected portions thereof) is applied to key multipath related MLS issues. Mathematical models are given for the major MLS multipath sources (ground reflections, building and aircraft reflections, and shadowing by objects and humped runways), and it is shown that they agree (Doppler and scanning beam) considered in phase II of the U.S. MLS program are presented together with validation by comparison with theory and bench tests. Also presented are the results of a general study in motion averaging. The (validated) computer simulation (and portions thereof) is then applied to studying 1) the critical areas required by the TRSB system to avoid excessive reflection effects, 2) the expected TRSB performance of a specific TRSB system at Friendship International Airport (MD).
Summary
This report summarizes MLS multipath work carried out at Lincoln Laboratory from March 1974 to Sept. 30, 1975. The focus of the program is the development of realistic models for 1) the multipath in representative real world environments and 2) the multipath characteristic of candidate MLS techniques. These multipath and...
READ MORE
MLS multipath studies volume I: mathematical models and validation
February 25, 1976
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-63,I
Summary
This report summarizes MLS multipath work carried out at Lincoln Laboratory from March 1974 to Sept. 30, 1975. The focus of the program is the development of realistic models for 1) the multipath in representative real world environments and 2) the multipath characteristic of candidate MLS techniques. These multipath and system models are used in a comprehensive computer simulation to predict the strengths and weaknesses of major MLS systems when subjected to representative real world environments. The report is organized into two volumes. Volume I describes the algorithms and validation of various portions of the program. In Volume II, the simulation (or selected portions thereof) is applied to key multipath related MLS issues. Mathematical models are given for the major MLS multipath sources (ground reflections, building and aircraft reflections, and shadowing by objects and humped runways), and it is shown that they agree (Doppler and scanning beam) considered in phase II of the U.S. MLS program are presented together with validation by comparison with theory and bench tests. Also presented are the results of a general study in motion averaging. The (validated) computer simulation (and portions thereof) is then applied to studying 1) the critical areas required by the TRSB system to avoid excessive reflection effects, 2) the expected TRSB performance of a specific TRSB system at Friendship International Airport (MD).
Summary
This report summarizes MLS multipath work carried out at Lincoln Laboratory from March 1974 to Sept. 30, 1975. The focus of the program is the development of realistic models for 1) the multipath in representative real world environments and 2) the multipath characteristic of candidate MLS techniques. These multipath and...
READ MORE