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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Omega Data Bank Report: Winter 1980 Through Spring 1981</title>
      <link>https://trid.trb.org/View/2714185</link>
      <description><![CDATA[The International Bank for Airborne-Omega Data continued operation at the Federal Aviation Administration (FAA) Technical Center. This report, issued by the Data Bank, is based upon 355 flight data hours covering flights in the North and South Atlantic, parts of the Caribbean, Central and South America, Canada, and the North Pacific. These data were collected during the winter 1980 through spring 1981. There were three major contributors to the Omega Data Bank during this period operating the same equipment types. Operationally usable signals corresponded quite well with Omega signal coverage prediction diagrams published by Omega Navigation System Operational Detail (ONSOD). Exceptions were noted from Ellesmere Island over the Arctic Ocean for the Liberia, Hawaii, North Dakota, and Japan signals for the specific months and times of the data flights. During the months when the above flights were made, there were 114 solar flares (of magnitude M2 or greater), 10 were coincident with recorded flight data. Several large magnetic solar flares peaked during aircraft data recording; however, no effects were discernible on observed signal-to-noise ratios (SNR's) values.]]></description>
      <pubDate>Tue, 07 Jul 2026 17:29:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2714185</guid>
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    <item>
      <title>Omega Data Bank Report (Spring and Fall 1980)</title>
      <link>https://trid.trb.org/View/2709289</link>
      <description><![CDATA[The International Bank for Airborne Omega Data continued operation at the Federal Aviation Administration (FAA) Technical Center. This report, issued by the Data Bank, is based upon 427 flight data hours covering flights in the North Atlantic, parts of the Continental United States (U.S.) and the Caribbean, South America, and Canada. These data were collected during the spring and fall of 1980; no flights were made during the summer. There were four major contributors to the Omega Data Bank during this period with three different equipment types. Operationally usable signals corresponded quite well with the Omega signal coverage prediction diagram published by the Omega Navigation System Operational Detail (ONSOD). Exceptions were noted near Ellesmere Island for the La Reunion signal, and the continental U.S. for the Argentina signal for the specific months and times of the data flights. Several operational differences were noted between two different Omega sets flown side by side in an FAA aircraft during flights in South America and the South Atlantic. Nonetheless, for both sets, Omega positions were within 2 nautical miles of the Inertial Navigation System position (95 percent probability) during normal flight conditions.]]></description>
      <pubDate>Mon, 22 Jun 2026 12:22:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2709289</guid>
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      <title>SYSTEM DESCRIPTION FOR THE AIRBORNE-OMEGA DATA BANK</title>
      <link>https://trid.trb.org/View/162091</link>
      <description><![CDATA[The Airborne-Omega Data Bank has been established at the Federal Aviation Administration (FAA) Technical Center. Its main objective is to provide a centralized repository for operational airborne-Omega data so that performance which is representative of the majority of production airborne-Omega navigation equipments under various ionospheric conditions (including high solar activity) may be evaluated. Details of the methods developed for data collection, processing, and reporting are documented in this report. Current status and plans for the near future are discussed. (Author)]]></description>
      <pubDate>Wed, 19 Nov 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/162091</guid>
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    <item>
      <title>AVIONICS CERTIFICATION REQUIREMENTS AND PROCEDURES ERROR BUDGETS FOR VOR/DME RNAV, LORAN-C, OMEGA AND GPS INCLUDING FLIGHT TECHNICAL ERROR</title>
      <link>https://trid.trb.org/View/177343</link>
      <description><![CDATA[This study assessed the availability and applicability of error budget data for avionics certification requirements. The investigation includes a review of data for both station oriented (VOR/DME-RNAV) navigation systems and wide area (Loran-C, Omega and GPS) navigation systems. The primary thrust of the analysis was to determine the operational capabilities of the various navigation systems currently being certified. A secondary objective was to examine the viability of current certification procedures, techniques and accuracy criteria to any advanced navigation system. To accomplish these objectives, a detailed assessment of error budget data, error combination techniques and functional performance standards was performed.]]></description>
      <pubDate>Sat, 30 Aug 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/177343</guid>
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    <item>
      <title>EVALUATION OF VARIOUS NAVIGATION SYSTEM CONCEPTS</title>
      <link>https://trid.trb.org/View/177234</link>
      <description><![CDATA[The purpose of this study is to identify the capabilities and limitations of a particular set of navigation systems and evaluate their performance in the current airspace environment. The navigation systems evaluated are Loran-C, Omega, VHF Omnidirectional Range/Distance Measuring Equipment (VOR/DME), Global Positioning System (GPS), Doppler navigation system, and inertial navigation system (INS). In addition to detailed technical and operational analyses of each navigation system, consideration is also given to the constraints imposed by and the deficiencies existing in the standards by which accuracy and effectiveness of navigation systems are measured. (Author)]]></description>
      <pubDate>Mon, 30 Jun 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/177234</guid>
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    <item>
      <title>PROPOSED ATC SYSTEM FOR THE GULF OF MEXICO, HELICOPTER OPERATIONS DEVELOPMENT PROGRAM</title>
      <link>https://trid.trb.org/View/162256</link>
      <description><![CDATA[A helicopter ATC system for the Gulf of Mexico is set forth. It embodies a concept of evolutionary growth in four phases: (1) The Present System (period of use: 1980) -- IFR navigation is obtained primarily with Loran-C, or VLF/OMEGA. Back-up systems are ADF and Airborne Weather Radar. VOR/DME is used over land. ATC is by procedural control and separation standards because no radar or other surveillance system is available off shore; (2) LOFF (Loran-C Flight Following) (Period of Evaluation: 1981) -- The LOFF system is placed in operation for experimentation and evaluation. While ATC is still performed by procedural control, LOFF will assist ground controllers by reducing workload, improving flexibility, etc. Experiments will also be performed on secondary radar systems (ATCRBS & VLATME) to provide surveillance; (3) Augmented LOFF (Period of use: 1983 and beyond) -- IFR helicopters will be able to fly direct, offset or segmented RNAV routes. ATC will be essentially equivalent to the NAS. Navigation by Loran-C will expand. Surveillance will be by LOFF and/or secondary radar. Area of control will be 1,500' to 10,000' over entire Gulf, and (4) RNAV Traffic Control (Period of use: 1985 and beyond) -- IFR helicopters will be able to use any of a number of certified navigation systems. ATC systems will adapt to varying accuracies of these systems. ATC will be based on surveillance provided by aircraft reporting of position information and/or secondary radar. Separation standards will be reduced and be equivalent to Northeast Corridor.]]></description>
      <pubDate>Mon, 30 Dec 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/162256</guid>
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      <title>INITIAL DATA BANK REPORT (FALL 1978; WINTER/SPRING/SUMMER/FALL 1979; WINTER 1980)</title>
      <link>https://trid.trb.org/View/162196</link>
      <description><![CDATA[The International Bank for airborne-Omega data has begun operation at the Federal Aviation Administration (FAA) Technical Center. This first report issued by the Data Bank is based upon preliminary data for Pacific flights in fall 1978 and winter/spring 1979 and upon data from North Atlantic flights in summer/fall 1979 and winter 1980. At least three Omega stations were received during all phases of these flights. No significant seasonal variations or effects due to solar activity were noted in the signal-to-noise values. These values were highly repeatable (under the same conditions) with major drops due to ice cap attenuation and operation in areas of normally high very low frequency (VLF) noise. Differences in signal-to-noise between signals traversing daylight/night ice cap (for both Greenland and Antarctica) were noted. (Author)]]></description>
      <pubDate>Wed, 11 Dec 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/162196</guid>
    </item>
    <item>
      <title>THE DISTRESS ALERTING AND LOCATING SYSTEM (DALS). SUMMARY OF DEVELOPMENT AND DOCUMENTATION</title>
      <link>https://trid.trb.org/View/56538</link>
      <description><![CDATA[This report documents the evolution of a Distress Alerting and Locating System (DALS) based on the retransmission of radio navigational aid signals. This equipment, developed from balloon tracking and meterological data gathering equipment manufactured by Beukers Laboratories, progressed through a test and development cycle culminating in a system that could: automatically alert search and rescue forces of a distress situation; identify the distressed vessel; automatically indicate the distress site location to within 1/2 mile; automatically plot the distressed vessel's location; track multiple vessels simultaneously; and operate at extended ranges by using aircraft-mounted telemetry equipment. Ancillary developments include a VHF-FM marine-band distress beacon whose radio signal includes identification information, a plasma-display-based SAR Command and Control Console, and techniques for narrow-band retransmission of the Omega navigation system signals over a telemetry link. Budgetary limitations and cost effectiveness studies resulted in termination of the DALS development prior to installation and testing of an operational system. (Author)]]></description>
      <pubDate>Tue, 29 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/56538</guid>
    </item>
    <item>
      <title>WORLDWIDE OMEGA AND VERY LOW FREQUENCY (VLF) TRANSMITTER OUTAGES, JANUARY TO DECEMBER 1980</title>
      <link>https://trid.trb.org/View/170425</link>
      <description><![CDATA[An investigation of worldwide OMEGA and very low frequency (VLF) transmitter outages during 1980 was conducted with emphasis on simultaneous outages. Data includes frequency and duration of simultaneous outages and total yearly percentage shutdown for each transmitter. Scheduled outages are specifically noted. The most significant dual OMEGA outage lasted 4.9 hours when the Argentina transmitter was shutdown to correct tower structural problems while La Reunion was down for annual maintenance. (Author)]]></description>
      <pubDate>Mon, 28 Oct 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/170425</guid>
    </item>
    <item>
      <title>OMEGA TRANSMITTER OUTAGES JANUARY TO DECEMBER 1979</title>
      <link>https://trid.trb.org/View/162754</link>
      <description><![CDATA[An investigation of Omega transmitter outages during 1979 was conducted with emphasis on the occurrence of simultaneous downtimes. Data presented includes frequency and duration of outages and total yearly percentage shutdown for each transmitter, with scheduled outages specifically noted. The most significant dual outage lasted more than 5 days when Norway antenna repairs were coincident with Argentina annual maintenance. (Author)]]></description>
      <pubDate>Mon, 15 Apr 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/162754</guid>
    </item>
    <item>
      <title>DIFFERENTIAL OMEGA IN THE ALASKA/YUKON REGION: AN ANALYTIC ASSESSMENT</title>
      <link>https://trid.trb.org/View/144176</link>
      <description><![CDATA[This report presents an analytic evaluation of the differential Omega experiment being conducted by the Federal Aviation Administration in the Alaska/Yukon region. An error model for Omega propagation prediction residuals is used to predict performance achievable with an equipment suite consisting of a TRACOR 599R Omega monitor receiver and associated ground station equipment built by Transport Canada, and an airborne suite which includes a modified TRACOR 7620 Omega navigation set and special-purpose differential Omega equipment built by Systems Control, Inc. (Vt.). Predictions are made for use of the equipment as a non-precision approach aid within the differential Omega coverage area and for use as an enroute navigation aid between areas serviced by a differential Omega ground station. (Author)]]></description>
      <pubDate>Sun, 31 Mar 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/144176</guid>
    </item>
    <item>
      <title>DIFFERENTIAL OMEGA SYSTEM DEVELOPMENT AND EVALUATION</title>
      <link>https://trid.trb.org/View/171654</link>
      <description><![CDATA[This report describes a development and evaluation program for Differential Omega in general aviation. The program was a cooperative venture between the FAA and Transport Canada. SCT performed system design, program management, and flight test on behalf of the FAA. Tracor, Inc. provided modified Omega airborne receivers under subcontract to SCT. Flight tests took place in Alaska aboard a Convair 580 provided by the FAA. Monitor stations were located in Anchorage and at Deadhorse. The most definitive results were obtained from flight tests conducted in October 1980 and February 1981. Important results included: (a) data-link range varied from 44 nm to 198 nm, (b) random component of navigation error was 0.25 nm, 2-D RMS, (c) range decorrelation error was about 2 nm over a distance of 550 nm, (d) transient response of the system-following aircraft procedure turns was characterized by a positional overshoot of about 1.5 nm, followed by a monotonically decreasing error with a two-minute time constant. Recommendations are made for improving system performance. (Author)]]></description>
      <pubDate>Wed, 27 Feb 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/171654</guid>
    </item>
    <item>
      <title>TESTING THE FEASIBILITY OF DIFFERENTIAL OMEGA FOR AIRBORNE USE</title>
      <link>https://trid.trb.org/View/77790</link>
      <description><![CDATA[This report outlines the testing conducted at the National Aviation Facilities Experimental Center (NAFEC) in order to determine the critical characteristics of one airborne feasibility model Differential Omega System. Through static testing, dynamic simulation, and actual test flights in the Atlantic City, New Jersey area, Differential Omega was compared to Skywave-corrected and Uncorrected Omega. These experiments provided data to determine the operating range, accuracy, the limits of system performance, and an accuracy comparison using three different phase correction techniques. It was found that Differential Omega was the most accurate system with no noticeable decrease in accuracy up to 150 nautical miles. This analysis outlines further improvements to the Differential Omega system which may be incorporated into later units to improve their capability. (Author)]]></description>
      <pubDate>Sun, 13 Jan 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/77790</guid>
    </item>
    <item>
      <title>INTEGRATED RUSSIAN VLF/OMEGA RECEIVER DESIGN; FINAL REPT</title>
      <link>https://trid.trb.org/View/406102</link>
      <description><![CDATA[With recent statements from Russian officials indicating their VLF navigation system may be operated in the future for worldwide civil use, its potential use in conjunction with the existing Omega system is of renewed interest. The design of an Integrated Russian VLF/Omega Receiver implemented on a Texas Instruments TMS320C25 microprocessor based Ariel DSP16 plug-in board installed in a PC- compatible portable computer is presented. The system also requires an external antenna, pre-amp, and frequency reference. The DSP16 board digitizes the RF signal to 16 bits and then digitally mixes with the sines and cosines of the three Soviet frequencies plus 10.2, 11 1/3, and 13.6 kHz. The mixer outputs are lowpass filtered and the comb filters implemented for the respective epoches. The PC compatible computer accesses and processes the comb filter outputs, calculating and logging signal phase and amplitude. The design allows for easy future expansion to include unique and VLF communication frequencies.]]></description>
      <pubDate>Mon, 03 Oct 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/406102</guid>
    </item>
    <item>
      <title>PROBABILITY OF CYCLE JUMPS IN OMEGA RECEIVERS AND OTHER PHASE LOCKED LOOP APPLICATIONS; TECHNICAL REPT</title>
      <link>https://trid.trb.org/View/406138</link>
      <description><![CDATA[A study of cycle jumps in phase locked loops with a particular emphasis on Omega receivers is presented. Theoretical predictions using numerical integration of the probability density functions of the phase estimates for both Gaussian and more accurate atmospheric noise models are presented. These theoretical results are validated through computer and hardware simulations using both Gaussian and atmospheric noise.  Hard limited and linear receivers are considered along with various methods of phase estimate averaging. In addition, the combined effect of noise and errors in the velocity or phase estimate are presented.  The results relating the probability of cycle jumps to signal to noise ratio (SNR) show very pronounced thresholding in Gaussian Noise, i.e.  very small changes in SNR can mean the difference between acceptable and unacceptable probability of cycle jumps. This was found not to be true for atmospheric noise due to the significant number of outliers even for large SNR's. The data supports a conclusion that the lower limit on acceptable SNR for receiver operation is due to the probability of receiver cycle errors and not merely fix inaccuracy due to noise in lines of position.]]></description>
      <pubDate>Mon, 03 Oct 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/406138</guid>
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