Milestone-Proposal:Longley-Rice Model
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Docket #:2022-13
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To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has the IEEE Section(s) in which the plaque(s) will be located agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
1960 - 1983
Title of the proposed milestone:
Longley-Rice Irregular Terrain Model, 1960
Plaque citation summarizing the achievement and its significance; if personal name(s) are included, such name(s) must follow the achievement itself in the citation wording: Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons.
Development and testing of tropospheric propagation models for transmission loss predictions for communication circuits over irregular terrain, and effects of climate on long-term variability used in: frequency planning in television broadcasting, channel allocation tables for VHF/UHF broadcasting, military and non-military government, for reliable mobile telephones, radio navigation, improved international shortwave, operation of radar, marine communications, air traffic control, air navigation, and weather forecasting by the National Oceanic and Atmospheric Administration.
200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.
The Longley-Rice Model predicts tropospheric radio transmission loss over irregular terrain for a radio link (from transmitter to receiver) and is referred to as the Irregular Terrain Model (ITM). It was designed for frequencies between 20 MHz and 20 GHz and for path lengths between 1 km and 2000 km. [2] The model marries an empirical model (based on electromagnetic theory) with measured data (terrain features and radio measurements) and has two prediction modes: point-to-point (requires terrain profile between transmitter and receiver) and area prediction (estimates the impact of terrain by empirical and statistical methods). The result of the model is the median attenuation of a radio signal as a function of distance and the variability of the signal in time and in space.[3]
The model was designed to provide a means by which terrain roughness could be factored into the determination of signal strength. [4] The quantitative estimates of propagation characteristics help to determine how well proposed radio systems will meet requirements for satisfactory service, free from harmful interference. This was, at the time of the model’s development and today remains, an important step toward more efficient use of the radio frequency spectrum. [5]
The allocations of commercial, non-federal, and federal spectrum rely on computer models that incorporate the rapidly evolving technology developments of the last fifty years. Many of the more sophisticated computer models in the 21st century that take advantage of satellite data and advanced programming languages for determination of radio transmission loss have the basic Longley-Rice methodology embedded in their programming. [7]
[2] “Longley-Rice Model: Irregular Terrain Model (ITM), http://www.awe-communications.com/Propagation/Rural/ITM/index.htm.
[3] G.A. Hufford, A.G. Longley and W.A. Kissick, A Guide to the Use of the ITS Irregular Terrain Model in the Area Prediction Mode, U.S. Department of Commerce, National Telecommunications and Information Administration, NTIA Report 82-100, April 1982, pp. 1-9.
[4] Lee G. Petro, “FCC Re-affirms Availability of Longley-Rice Analysis, But Imposes New Limitations on its Use.” Fletcher, Heald & Hildreth, PLC. August 2002, p.1. http://www.fhhlaw.com/resources/Memo/2002/august/0802_5.pdf.
[5] P.L.Rice, A.G. Longley, K.A. Norton and A.P. Barsis, Transmission Loss Predictions for Tropospheric Communication Circuits, National Bureau of Standards, Technical Note 101, January 1, 1967 revision. pp. 2-3, 1-1, I-7. I-29, Volumes I and II.
[7] Shumate, S.E., Givens & Bell, Inc., “Longley-Rice and ITU-P.1546 Combined: A New International Terrain-Specific Propagation Model,” IEEE Vehicular Technology Conference, Fall 2010, abstract.
IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.
Antennas & Propagation - Society, Communications Society, Computer Society, Computational Analytics,
In what IEEE section(s) does it reside?
Denver
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: IEEE Denver Section
Senior Officer Name: James Sipes
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: IEEE Denver Section
Senior Officer Name: James Sipes
IEEE section(s) monitoring the plaque(s):
IEEE Section: IEEE Denver Section
IEEE Section Chair name: James Sipes
Milestone proposer(s):
Proposer name: Katherine Grace August, PhD
Proposer email: Proposer's email masked to public
Proposer name: Thomas M Willis, III PhD
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):
U.S. Department of Commerce, National Telecommunications and Information Administration, Institute for Telecommunication Sciences its.ntia.gov 325 Broadway, Boulder, CO 80305 The street address of the Radio Building (Building 1 on the campus of the Department of Commerce Boulder Laboratories) is 325 S. Broadway, Boulder CO 80305. Coordinates are (from Google Earth) Latitude: 39.995967° Longitude: -105.26195°. It is on the National Register of Historic Places (NRHP). Building 1, including the Front of the House, the Spine, and Wings 1 through 4, was completed in 1954, and Wings 5 and 6 were completed in 1962 and 1959, respectively. The site is still owned by NIST (formerly NBS).
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. NTIA which is the location where Anita Longely conducted her work. The street address of the Radio Building (Building 1 on the campus of the Department of Commerce Boulder Laboratories) is 325 S. Broadway, Boulder CO 80305. Coordinates are (from Google Earth) Latitude: 39.995967° Longitude: -105.26195°. It is on the National Register of Historic Places (NRHP). Building 1, including the Front of the House, the Spine, and Wings 1 through 4, was completed in 1954, and Wings 5 and 6 were completed in 1962 and 1959, respectively. The site is still owned by NIST (formerly NBS).
Are the original buildings extant?
Yes
Details of the plaque mounting:
There is a hall with memorials and awards displayed.
How is the site protected/secured, and in what ways is it accessible to the public?
The campus is currently a worksite with all appropriate security and access.
Who is the present owner of the site(s)?
NTIA
What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include detailed support at the end of this section preceded by "Justification for Inclusion of Name(s)". (see section 6 of Milestone Guidelines)
Anita Longley provided a legacy still widely used today, 50 years later. Her main research focus was tropospheric propagation model testing and development. Models she worked on have important applications to propagation over irregular terrain, and she further examined the effects of climate on long-term variability. Longley co-authored Tech Note 101, and described the concept of the “urban factor” in propagation. She expanded and refined the predictions in Tech Note 101 to create the Irregular Terrain Model (ITM or Longley-Rice) computer program in 1968. In 1982 she undertook an extensive revision to the model and it was re-released. Her publications were always backed up by extensive measurements. The validation that Anita Longley and Rita Reasoner did in 1982 became the gold standard for comparing models to measured data. The ITM model has lasting importance in enabling the communications applications we enjoy and rely on every day. This model is one of the top downloads from the ITS website, and updates of her work continue in many ITS modeling and prediction projects today.
What obstacles (technical, political, geographic) needed to be overcome?
Typically calculations were conducted using measurements and physics; Anita Longley created computer models with physics measurements, terrain mapping, and additional measurements such as weather. In this way, even before systems are built, engineers and regulators can determine propagation necessary for research, planning, licensing, and commercialization.
What features set this work apart from similar achievements?
Economic impact of ITM — FCC frequently specifies ITM for determining separation distances for spectrum assignments or unlicensed use—recently, unlicensed use of the 6 GHz band (opened in 2020, estimated $153.75 billion in economic value to US economy over 5 years) and the CBRS band (1st round of PAL auction licenses netted $4.58B to the Treasury in 2020, is expected to generate $1 billion in investment over five years).
Why was the achievement successful and impactful?
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
The mathematical algorithms are published and the physics explained in Philip L. Rice; Anita G. Longley; Kenneth A. Norton; Albrecht P. Barsis, "Transmission Loss Predictions for Tropospheric Communication Circuits: Volume I", Technical Note TN-101 vol. I and vol. II, January 1967. That was a tremendous achievement. But the following year ITS published Anita G. Longley; Philip L. Rice, "Prediction of Tropospheric Radio Transmission Loss Over Irregular Terrain: A Computer Method - 1968", Technical Report ERL 79-ITS 67, July 1968. This report actually presents the flow charts that demonstrate how to computerize the algorithms and gives the Fortran code—and establishes the template for computerizing propagation models. After ERL 79-ITS 67, Anita and Rita Reasoner, then Anita and George Hufford published three more reports that compare measurements to predicted values, then in 1982 she co-authored George A. Hufford; Anita G. Longley; William A. Kissick, "A Guide to the Use of the ITS Irregular Terrain Model in the Area Prediction Mode", NTIA Technical Report TR-82-100, April 1982, which is still frequently downloaded. It explains how to use ITM for real applications, including limitations on using the model and sample problems. The last publication she co-authored at ITS was George A. Hufford; William A. Kissick; Anita G. Longley; H. T. Dougherty, "The Use of Burst Transmission to Increase Communication Range – A Feasibility Study", NTIA Technical Report TR-83-130, August 1983, which continues the focus on using an iterative cycle of measurement and modeling to improve propagation prediction, in this case for the purpose of increasing robustness in communications systems.
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.
Media:TN101v1.pdf
Media:TN101v2.pdf
Media:82-100_ocr.pdf
Media:83-130_ocr.pdf
Media:AnitaLongley06586676.pdf
Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to ieee-history@ieee.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).
Please recommend reviewers by emailing their names and email addresses to ieee-history@ieee.org. Please include the docket number and brief title of your proposal in the subject line of all emails.
