NTIA-REPO RT -79 -15

An Additional Catalog

of Programs and Data

for 100 MHz -100 GHz

Radio System Predictions

J.T. Collins

F.K. Steele

u.s. DEPARTMENT OF COMMERCE

Juanita M. Kreps, Secretary

Henry Geller, Assistant Secretary

for Communications and Information

January 1979

PREFACE

The sole purpose of this publication is to provide the

public with a list of existing computer aids for the

evaluation of radio systems which operate in any part of the

radio spectrum. Consequently, neither the Department of

Commerce (DoC), nor the National Telecommunications and

Information Administration (NTIA) approves of, recommends,

or endorses any particular proprietary product or service

mentioned in this publication. Accordingly, no reference

should be made to NTIA, DOC, or this publication that (1)

implies or states the contrary, or (2) has as its purpose

the recommendation, directly or indirectly, for the purchase

of any particular proprietary product or service listed in

this publication.

iii

TABLE OF CONTENTS

Page

ABSTRACT 1

1.

2.

INTRODUCTION

COMPUTER PROGRAMS AND DATA BASES

2

2

Category 1. Computations of Transmission

Loss and Radar Returned Power 4

1-1 COSPEM, Communication System Performance

Model. 4

1-2 ION, The Bent Ionospheric Model. 6

1-3 AMAP, Atmospheric Microwave Analysis Program 7

1-4 SPHERE 9

1-5 CSPM, Communication System Performance

Model. 10

1-6 SLAM, Slant-Path Absorption Model. 12

1-7 MRRPR, Microwave Radio Relay Path

Propagation Reliability Models for

Overland Multipath Fading. 14

1-8 RMRRPP, Reliability of Microwave Radio

Relay Paths with Precipitation. 15

1-9 PCTDCP, Partially Correlated Tropo

Diversity Calculation Program. 16

1-10 SELSP, Satellite to Earth Location Signal

Power. 17

1-11 LCP, Link Calculator Program. 19

1-12 RADREF, Radar Refraction. 20

Category 2. computations on Desired-to-Undesired

Signal Ratios 22

2-1 TSPD, Terrestrial Surface Power Flux

Density Limits for Services Using

Satellites.

2-2 IMP, Interference Modeling Program.

v

22

23
TABLE OF CONTENTS (cont.)

Page

Category 3. Computations of Atmospheric and

Precipitation Parameters 25

3-1 FAP, Frequency Analysis Program. 25

3-2 MWPE, Millimeter Wave Propagation

Experiment Central Data Reduction Program. 26

3-3 RPP, Rain Propagation Prediction. 27

Category 4. Data Bases and Associated Programs 28

4-1 ZPRARS, Z Profile and Rain Attenuation

from Rain Scatter.

4-2 RAT, Rain Attenuation vs Time.

28

29

Category 5. Performance of Digital Communication

Systems 30

5-1 DTCM, Digital Telecommunication Conversion

Model. 30

5-2 DTGTAP, Digital Tropo Generalized Time

Availability Program 31

Category 6. Miscellaneous Programs 33

6-1 MAIM, Multipath Analysis of ILS and MLS. 33

6-2 Y, Earth Coverage Footprints from

Geostationary Satellite Antennas. 34

6-3 JRWOOl, Transionospheric Ray Tracing with

Interactive Homing. 35

6-4 RAYTRA, A versatile three-dimensional ray

tracing computer program for radio waves

in the ionosphere. 36

6-5 WTC-MBA/LASL. 37

vi
An Additional Catalog of Programs and Data

for 100 MHz - lOOGHz Radio System Predictions

Jack T. Collins* and F. K. Steele**

Analysis aids and data bases for predicting

the performance of 100 MHz - 100 GHz communication

systems are presented and briefly described. They

are loosely grouped into the following functional

catagories:

1) Computations of transmission loss and

radar returned power.

2) Computations of desired-to-undesired

signal ratios.

3) Computations of atmospheric and

precipitation parameters.

4) Data bases and associated programs.

5) Performance of digital communication

systems.

6) Miscellaneous programs.

Sources are given for the analysis aids, data

bases, and additional information.

ey Words: atmosphere: computer programs: data

bases: desired signal: digital

communications: precipitation:

propagation prediction; radar

power: transmission -loss:

undesired signal.

* Mr. Collins is with Potomac Research, Inc., Denver Office,

Lakewood, Colorado 80228.

** Mr. Steele is with the u.s. Department of Commerce, National

Telecommunications and Information Administration, Institute

for Telecommunication Sciences, Boulder, Colorado 80303.
1. INTRODUCTION

This catalog is the second publication in a continuing

effort to compile a comprehensive set of computer programs

and data bases to predict the performance of radio systems.

The first catalog, published in March 1978 as OT Report

78-141, concentrated on the 10 - 100 GHz portion of the

spectrum. Additional catalogs are planned, so that

eventually the entire radio spectrum will be covered.

Most of the programs in OT Report 78-141 were developed

at the National Telecommunications and Information

Administration, Institute for Telecommunication Sciences.

For this report, programs have been solicited from

universities and private industry as well as various

government agencies. These reports should be viewed as

complementing each other since many of the programs in the

previous publication cover the frequency range of this

report, but have not been listed in this catalog.

2. COMPUTER PROGRAMS AND DATA BASES

Each catalog entry contains brief information about the

program's function or content, user inputs, limitations,

current status, references, and information contacts for

that program. This information is supplied so that

searchers can rapidly identify analysis aids or data bases

of interest which they can pursue through the given

information contact.

The entries have been arranged alphabetically within

the following catagories:

1) Computations of transmission loss and radar

returned power.

2) Computations of desired-to-undesired signal ratio.

2
3) Computations of atmospheric and precipitation

parameters.

4) Data bases and associated programs.

5) Performance of digital communication systems.

6) Miscellaneous programs.

3
Category 1

Computations of Transmission Loss

and Radar Returned Power

Item: 1-1

Title: COSPEM, Communication System Performance Model

Computes: This is a communication system performance model

that computes the probability of successful communications,

(ps)' versus range or other variables (e.g., transmitter

power, antenna gain or height, etc.). The model also

computes operational range of a radio system for a specified

required probability of success, p sr . It will compute for

up to three systems simultaneously, with graphics and line

printer output.

Input: The required input consists of system parameters

(transmitter power, antenna gains, transmission line losses,

receiver noise figure, and modulation information);

propagation parameters (Longley-Rice input plus vegetation

and urbanization information); noise environment category;

and operational parameters (required channel quality and

reliability, fixed or mobile).

Limitations: This program has the basic limitations of the

1977 version of the Longley-Rice model.

(Frequency 20 MHz). CCIR Reports 258 and 322 noise models

limit the frequency to 300 MHz, although the noise model

can be extended to 20 GHz. Antenna heights are permitted

from I m to 3 km.

Current Status: The program is operational and available to

the public by contract with SRI International. It is

written in FORTRAN for the CDC 6400, but can be converted

for use on other computers. Its output agrees well with

measured data for FM voice systems from Fort Hood, TX, and

Fulda, FRG (30-76 MHz).

4
References:

Tupper, B. C., and G. H. Hagn (1978), Nap-of-the-earth

communication program for u.s. Army helicopters, final

report, SRI Project 4979, Contract DAAB07-76-C-0868, SRI

International, Menlo Park, CA,

For more information contact: G. H. Hagn, SRI

International, 1611 N. Kent Street, Arlington, VA 22209,

(703)524-2053; B. C. Tupper, SRI International, 333

Ravenswood Avenue, Menlo Park, CA 94025, (415) 326-6200,

ext. 3821.

5
Item: 1-2

Title: ION, The Bent Ionospheric Model.

computes: For a given condition consisting of station,

satellite, date, and time information, the electron density

versus height profile is computed from which range, rangerate, and angular refraction correction, as well as vertical

and total angular electron content, are obtained. The model

has the additional capability of improving its predictions

by updating with actual ionospheric observations.

Input: The required input parameters are transmission

frequency, station latitude and longitude, elevation angle

to satellite, azimuth angle, satellite height, elevation

rate, altitude rate, year, month, day, time, daily solar

flux for month, 12-month running average of sunspot number

and of solar flux. Optional input consists of the same

information for updating with actual ionospheric

observations.

Limitations: The program removes only between 75% and 90%

of the ionospheric effects under solar maximum conditions.

Current Status: The program is well documented and has been

used extensively on a Sigma 7 computer. Slight

modifications may be necessary for other machines. The

program is written in FORTRAN.

References:

Llewellyn, S. K., and R. B. Bent (1973), Documentation

and description of the Bent ionospheric model, Atlantic

Science Corporation.

For more information contact: Judy Lipofsky, Atlantic

Science Corp., P.O. Box 3201, Indialantic, FL 32903, (305)

773-1300.

6
Item: 1-3

Title: AMAP, Atmospheric Microwave Analysis Program.

computes: The program computes attenuation, refraction, and

dispersion for ground-to-aircraft or ground-to-satellite

paths. It includes the effects of water vapor (both

uncondensed and condensed), molecular oxygen, clouds, and

rain. The MSFC 4-D Atmospheric Model is used for

temperature, humidity, and density profiling from the ground

to 25 km height. Above 25 km, exponential atmosphere is

assumed. The user may choose any of nine standard cloud

models or may specify his own model. Precipitation rates

may be specified, or the program will default to values

typical of the cloud model. The location of the cloud with

respect to the ground terminal must be specified.

Attenuations due to uncondensed water vapor, molecular

oxygen, condensed water, and rain are printed separately and

summed, so that an evaluation of contributions can be made.

The path length is computed both along the line of sight and

along the ray path for listing of both range errors and

apparent refraction. DeLay excess is printed.

Input: The required input parameters are latitude and

longitude of ground station; month of year; frequency; cloud

type; distance to storm center and storm radius; height of

rain cell and precipitation rate; satellite or aircraft

height; thickness of ~tmospheric slices; starting value and

number of increments of ray takeoff elevation; and choice of

mean or best/worst case analysis.

Limitations: The frequency range is 0.5 - 100 GHz,

although the accuracy above 30 GHz has not been evaluated.

The graphic output requires CDC DD280 plot routines and

hardware.

7
Current Status: The program is operational on the CDC 6500

at Martin Marietta Company/Denver Division. The program

source listing is proprietary.

For more information contact: D. Lund, Martin Marietta

Aerospace, P.O. Box 179, Denver, CO 80201, (303) 973-3326.

8
Item: 1-4

Title: SPHERE

computes: The program computes the basic transmission loss

over the earth for microwaves.

Input: The required input parameters are station

separation, station heights, and wavelength.

Limitations: The program accounts for reflection,

refraction, diffraction, but not tropospheric scatter or

ionosphere refraction. It also assumes perfect

conductivity.

Current Status: The published version assumes a "4/3

earth;" other earth factors can be obtained by scaling the

distances and the wavelength. The in-house version has an

input for earth factor.

References:

1976 Microwave Engineers Handbook, Microwave Journal,

1976. The program evaluates the solution given by V. Fock,

Electromagnetic diffraction and propagation problems,~ 1965,

Chap. 12.

For more information contact: Dr. Ira Gilbert or Dr. J. J.

G. McCue, Lincoln Laboratory, MIT, Lexington, MA 02173.

9
Item: 1-5

Title: CSPM, Communication System Performance Model.

Computes: This automated model uses the point-to-point

version of the Longley-Rice propagation loss model to

estimate communication system performance throughout a

defined geographical area. The model calculates radio path

terrain profiles and statistically characterized basic

transmission loss, power density, received signal level, and

ultimately, communication reliability for a large number of

specific paths within the geographical area. All computed

data are available in either tabulated or plotted forms, at

the option of the user.

Input: The required input are the coordinates of a fixed

antenna and the coordinates of the bounds of a geographical

area. Opportunity is provided for specifying a large number

of other parameters which characterize the technical aspects

of the problem and define the desired mode for running the

model and the desired form of the output data. The

technical data which may be specified as input include

frequency, antenna heights and gains, polarization,

transmitter output power, threshold 'received signal level,

ground dielectric constant and conductivity, surface

refractivity, climate code, and coordinates defining the

geographical area bounds. When not specified, nominal or.

computed values are assigned to these parameters.

Limitations: Radio frequencies must be between 20 MHz and

20 GHz. Antenna heights are restricted to 0.5 to 3000 m and

only vertical or horizontal polarizations may be specified.

Current Status: The program is operational on CDC 6000

series computer systems. Documentation is complete and

available from the NTIS. The program can be provided on

magnetic tape.

10
References:

Jennings, R. D., and S. J. Paulson (1977),

Communication system performance model for VHF and higher

frequencies, OT Report 77-128, (NTIS PB274-458/AS).

For more information contact: R. D. Jennings, NTIA/ITS,

u.s. Dept. of Commerce, Boulder, CO 80303, (303) 499-1000,

ext. 3233 or FTS 323-4303 or 323-3233; S. J. Paulson,

NTIA/ITS, u.S. Dept. of Commerce, Boulder, CO 80303 1 (303)

499-1000, ext. 3874 or FTS 323-3874.

11
Item: 1-6

Title: SLAM, Slant-Path Absorption Model.

computes: The program computes the molecular attenuation of

microwave and submillimeter waves in earth's atmosphere.

For a fixed frequency (ern-I) and a given atmospheric model,

it computes horizontal (dB/km) and upward- and downwardlooking vertical (dB) attenuations vs altitude. The

complete exponential term for induced emission is employed.

Input: Required are a modified binary tape version of AFCRL

(AFGL) line parameter compilation; constituent molecule(s);

atmospheric model (from 1966 supplement to 1962 u.s.

Standard); line profile (Van Vleck-Weisskopf, Gross,

Lorentz, Voight-type); frequency range; and "bound." This

determines furthest lines used.

Limitations: The program computes molecular attenuation

only (no aerosol or clouds). It computes fixed-frequency

calculations at intervals of 0.001 cm-l (~ 30 MHz). There

is no continuum correction included, and "interference" is

neglected. The Voigt-type approximation is only

approximately valid above 40 km. The AFCRL data out to

550 cm- 1 (= 16.5 THz) is employed.

Current Status: The FORTRAN program and associated binary

data is stored on magnetic tape. It is immediately usable

on disc-oriented XDS Sigma-series computers, but is

straightforwardly convertible for other computers with

FORTRAN IV compilers.

References:

Greenebaum, M., and D. Koppel (1975), A study of

millimeter and submillimeter wave attenuation and dispersion

in the earth's atmosphere, final report F-l/306-3-14,

Riverside Research Institute, New York, NY 10023

(AD-A015544) •

12
Koppel, D. (1976), Present status of the RRI slant-path

absorption model (SLAM) computer program, Tech. Rept.

T-2/306-3-14, Riverside Research Institute, New York, NY

10023.

For more information contact: Dr. Michael Greenebaum, RRI,

80 West End Avenue, New York, NY 10012, (212) 873-4000, ext.

347.

13
Item: 1-7

Title: MRRPR, Microwave Radio Relay Path Propagation

Reliability Models for Overland Multipath Fading.

Computes: The program computes median fade duration and

time distribution; overland earth and atmospheric multipath

fading outage in accordance with the Bell and CCIR criteria

4, 5-ms-mean distributions; and CCIR criteria 3, I-min-mean

distributions; and fade margin difference for a given

outage. In addition, the program computes space and

frequency diversity improvement factors, path roughness

factors, and minimum path lengths at which multipath fading

can be expected.

Input: The required input parameters are frequency, fade

margin, path distance and roughness, geographic factors, and

annual mean temperature.

Limitations: The applicab,le frequency range is from 4 to

18 GHz.

Current Status: The program is operational on the HP 67

calculator.

References: No published references.

For more information contact: H. J. Sartori, Collins

Commercial Telecommunications Group, P.O. Box 10462, Dallas,

TX 75201, (214) 690-5000.

14
Item: 1-8

Title: RMRRPP, Reliability of Microwave Radio Relay Paths

with Precipitation.

Computes: The program computes the annual rainfall outage

time and cumulative rainfall time distribution as a function

of path distance and surfaee point rainfall rate.

Input: The required input parameters are frequency, fade

depth, path distance, annual rainfall, and thunderstorm

ratio.

Limitations: The applicable frequency range is from 4 to

18 GHz.

Current status: The program is operational on the HP 67/97

calculator.

References: No published references.

For more information contact: H. J. Sartori, Collins

Commercial Telecommunications Group, P.O. Box 10462, Dallas,

TX 75201, (214) 690-5000.

15
Item: 1-9

Title: PCTDCP, Partially Correlated Tropo Diversity

Calculation Program.

Computes: This program computes the probability that the

output of a maximal ratio combiner will be above some

threshold value as a function of the signal power in a given

channel.

Input: The program requires a complex correlation matrix of

the tropo system. This matrix has elements relating the

fading on each diversity branch to all other diversity

branches. The correlation matrix is square and is, at most,

4 by 4. The elements may be written in the form PIJ where P

is the complex correlation coefficient between the amplitude

fluctuations (fading) on the ith and jth diversity branch.

If the complex correlation coefficient is not available, it

may be approximated by the square root of the envelope

correlation coefficient, which is the correlation commonly

measured experimentally.

Limitations: The program is limited to making calculations

for dual or quad diversity systems.

Current Status: The program is in FORTRAN and is

operational on an IBM 370.

References:

Pierce, J~ N., and S. Stein (1960), Multiple diversity

with nonindependent fading, Proc. IRE, No.1.

For more information contact: Dr. J. Wick, Mail Stop A160,

The MITRE Corporation, Bedford, MA 01730, (617) 271-4590 or

AUTOVON 478-1001, ext. 75-4590.

16
Item: 1-10

Title: SELSP, Satellite to Earth Location Signal Power.

computes: The program computes the following data for

satellites in earth orbit, for any given ground point:

Slant range in kilometers.

Satellite cone angle in degrees.

Satellite clock angle in degrees.

Ground point location elevation to satellite.

Ground point location azimuth to satellite.

Power flux density at ground point location in dBw/m 2•

Path loss in dB.

Elapsed time in seconds.

The program was primarily intended for the analysis of

potential interference between satellites and earth stations

of different services, but it can be used in a generalized

manner without modification. The program performs an orbit

inclination test and informs the user if the orbit

inclination and ground point location preclude any view

periods. The program also retains information used in the

computations, which can easily be accessed by a trained

operator. Once initialized, the program runs until

commanded to stop by the user. Typical run times vary from

a few minutes upward depending on the quantity of output

required. Data is output at time increments determined by

the user.

Input: An interactive segment of the program leads the user

through the necessary input steps.

Required input parameters are:

Orbit altitude at perigee.

Orbit inclination.

Longitude of ascending node.

17
Angle between ascending node and perigee.

Orbit ellipticity.

GMT at ascending node.

Time increment for data during track.

Ground station longitude and latitude.

Ground station minimum elevation angle.

Transmitter frequency.

E.I.R.P.

Initial elliptical angle.

Limitations: Atmospheric effects are not included.

Earth radius is assumed constant (6378.16 km). Calculates

data only for one satellite and one ground point per run.

Current Status: The program is operational and available.

It is written for HP 9815A desk top computer, but could be

converted for use on other machines.

For more information contact: Dennis Nightingale, Jet

Propulsion Laboratory, California Institute of Technology,

4800 Oak Grove Drive, Pasadena, CA 91103, (213) 354-6326 or

FTS 792-6326.

18
Item: 1-11

Title: LCP, Link Calculator Program.

Computes: This program computes the path loss, modulation

losses, threshold parameters, Doppler, as well as link

margins for FM, AM, and PM systems.

Input: The required input parameters are antenna gains,

system temperature, losses, modulation-type, modulation

parameters, range, frequency, and accuracy required.

Limitations: The program uses only a simplified model for

atmospheric efforts that is custom designed for NASA STDN

links for VHF and S-band frequencies.

Current Status: The program is currently operational.

References:

STDN Link Analysis Handbook, Volumes I, II, and III,

June 1977, November 1977.

For more information contact: Frank Stocklin, Goddard Space

Flight Center, Code 861.3, Greenbelt, MD 20071, (301) 982-

5712.

19
Item: 1-12

Title: RADREF, Radar Refraction.

Computes: The program computes radar angular deviation and

range inaccuracies which occur when electromagnetic waves

traverse the earth's atmosphere. Both the troposphere and

the ionosphere are considered in the program. The outputs

are primarily the errors in elevation angle and range as

functions of apparent elevation and apparent range, but

various types of associated data can be broken down into the

various components resulting from retardation and bending,

from both the troposphere and the ionosphere. The program

is available in both a double-precision version and a

single-precision version.

Input: Program input consist primarily of data parameters

which define the refractive profile of the earth's

atmosphere (troposphere and ionosphere), plus radar

frequency, and various computational control and output

selection parameters. The indices of refraction in the

troposphere can be either input directly or computed as a

function of surface temperature, pressure, and water vapor

pressure, as well as height. The indices of refraction in

the ionosphere are computed as a function of the latitude

and either the electron density or the plasma frequency.

Limitations: Primary limitations of the program are that

the program assumes a spherically symmetric atmosphere.

Computations are also currently accomplished using a

"stratified layer method," in which the vertical profile of

the atmosphere is approximated by a series of thin layers

each of constant refractivity. The program currently

assumes that the radar site is on the ground; there is no

provision for air- or space-borne sensors. Studies have

indicated that the single-precision version of the program

provides good computational results (i.e., truncation errors

20
are not the dominant accuracy limitation) when the program

is run on a computer with 48 or more bits per word; however,

the double-precision version of the program is recommended

for machines with 36 or fewer bits per word. Usable

frequency is from 30 MHz thru 3 GHz.

Current status: The current version of the program (RADREF

IV) is in the final stages of debugging and testing. The

program is written in standard FORTRAN IV. It has been used

on the Honeywell 6080 and 6060 and the Philco 212 computers,

but is easily convertible for use on other computers which

have a FORTRAN IV compiler.

References:

Technical Memorandum, 78-1, RADREF IV Documentation by

St Clair Hultsman, Directorate of Analysis DCS/Plans and

Programs Headquarters NORAD/ADCOM.

For more information contact: St Clair Hultsman or Preston

M. Landry, HQ ADCOM, Peterson AFB CO 80914, (303) 635-8911,

ext. 3535.

21
Category 2

Computations on Desired-to-Undesired

Signal Ratios

Item: 2-1

Title: TSPD, Terrestrial Surface Power Flux Density Limits

for Services Using Satellites.

Computes: The program computes the probable impact of

various levels of power flux density at the earth's surface

upon terrestrial systems as a function of percentage of

terrestrial systems affected.

Input: The Government Master File provides terminal

locations and required equipment parameters.

Limitations: The program is limited to the information

available on the Government Master File.

Current Status: The program is currently running on the DOC

CDC 6600 computer.

References:

Haydon, G. W., and R. K. Rosich (1973), Technical

considerations in the efficient use of the spectrum: Part 1

- terrestrial surface power flux density limits for services

using satellites, OT Report 73-19 (NTIS, COM75-10863/AS).

For more information contact: George W. Haydon, NTIA/ITS,

U.S. Dept. of Commerce, Boulder, CO 80303, (303) 499-1000,

ext. 3583 or FTS 323-3583; Dr. Rayner K. Rosich, NTIA/ITS,

U.S. Dept. of Commerce, Boulder, CO 80303, (303) 499-1000,

ext. 3109 or FTS 323-3109.

22
Item: 2-2

Title: IMP, Interference Modeling Program.

Computes: The program computes the following data for

interference at DSN ground stations tracking real-time

mission spacecraft from either satellites or from other

active spacecraft not being tracked:

Elapsed time in seconds.

Satellite azimuth and elevation.

Angle off boresight between sun and mission spacecraft.

Angle off boresight between satellite and mission

spacecraft.

Satellite power flux density at ground station.

Power from satellite in dBW.

Signal to interference ratio in dB.

The output is tabularized by ground station - a maximum of

three can be used - and by satellite and mission spacecraft.

Output is directly to the user terminal in demand mode or to

a line printer in batch mode. Future plans call for

selected output to go to data files, which may be used for

plotting.

Input: The program requires responses to prompting for some

input and accesses other parameter files for additional

data. Some of this additional data is stored on tape,

principally that concerning future potential space missions

for deep space research. The required input parameters are:

Operating frequency band.

Satellite name(s).

Mission spacecraft ID and operating parameters.

Names of ground stations (three maximum).

Start time of run.

Time increment for data (for mission to mission

interference only, otherwise fixed by program).

23
Limi tat ions: Not all known satell ites ar.e cur rently filed.

The output data format is presently limited to 80 characters

per line to allow direct extraction into 8-1/2 x 11 pages.

Thus, not all available computed data are printed. Also,

the effect of weather, sun, planets, etc., on system noise

temperatures is ignored.

Current Status:' Program is still under development for use

on Univac 1108 computer e (Note that "canned" data available

at JPL's 1108 computers are essential). It is written in

FORTRAN IV.

References:

Newton, R. R. (1960), Astronomy for the non-astronomer,

IRE TRANS. on Space Electronics and Telemetry, 1-16.

For more information contact: Dennis Nightingale, Jet

Propulsion Laboratory, California ~nstitute of Technology,

4800 Oak Grove Drive, Pasadena, CA 91103, (213) 354-6326 or

FTS 792-6326.

24
Category 3

Computations of Atmospheric and

Precipitation Parameters

Item: 3-1

Title: FAP, Frequency Analysis Program.

Computes: The program computes and tabulates the frequency

of occurrence of 10 weather classes with clear and dry at

one extreme and heavy rain at the other.

Input: The program is designed to operate on the Rand

collection of weather data called RAWDAB. There are

approximately 90 stations in the collection covering the

Northern Hemisphere. Data is most dense in Central Europe.

Limitations: The chief limitation is data input. Some

stations have poor observations and a limited length of

record.

Current Status: Operating.

References:

Deirmendjian, D. (1969), Electromagnetic Scattering on

Spherical Polydispersions, American Elsevier Publishing Co.,

Inc., New York.

Deirmendjian, D. (1975), Far-infrared and submillimeter

wave attenuation by clouds and rain, J. Appl. Meteor., Vol.

14, No.8, 1584-1593.

For more information contact: Charles Schutz or Jeanine

Lamar, Rand Corp., 1700 Main Street, Santa Monica, CA

90406, (213) 393-0411.

25
Item: 3-2

Title: MWPE, Millimeter Wave Propagation Experiment Central

Data Reduction Program.

Computes: The program computes rain attenuation and related

statistics (rain rate, radar backscatter, radiometric

temperture, etc.) from measurements on an earth-space

propagation path using satellite beacons.

Input: The required input parameters are received signal

levels (calibrated), rain gauge tips, ambient temperature

and pressure, radar reflectivity, etc. - all from ground

station equipment.

Limitations: The program is designed for the specific

requirements of the NASA terminals at Rosman, N. C., and

GSFC, Greenbelt, MD. Approximately 36 inputs are used to

develop 24 plots and printouts.

Current Status: The program has been operatinal since 1969

at GSFC. It has been used (with modifications) on the

ATS-S, ATS-6, CTC, and COMSTAR satellite programs.

References:

Numerous reports and references in open literature -

available on request.

For more information contact: Louis J. Ippolito, NASA

Goddard Space Flight Center, Code 953, Greenbelt, MD, (301)

982-6716.

26
Item: 3-3

Title: RPP, Rain Propagation Prediction.

Computes: The program computes the attenuation, isolation,

and phase shift of millimeter wave signals passing through a

rain/ice medium.

Input: The required input parameters are frequency,

elevation angle, transmit/receive antenna polarization

states, and rain/ice parameters. The rain medium can be

divided into 10 segments with different characteristics.

Limitations: The program has been designed for use at 11,

19, 30 GHz with rain rate from 1 to 300 mm/hr.

Current Status: The program is operational on an IBM 370 and

is written in FORTRAN IV.

For more information contact: Dr. W. L. Stutzman, Virginia

Tech, Electrical Engineering Dept., Blacksburg, VA. 24061,

(703) 951-6834.

27
Computes:

over each

The

The

The

The

The

The

The

The

Category 4

Data Bases and Associated Programs

Item: 4-1

Title: ZPRARS, Z Profile and Rain Attenuation from Rain

Scatter.

This program computes the following parameters

adjacent radar range bin:

height of the pulse volume (km),.

range of the pulse volume (km).

received power (dBm).

number of tape units.

reflectivity factor of rain (mm 6/m3 and dBZ).

attenuation coefficient (dB/km) at a frequency, f.

cumulative attenuation (dB) at a frequency, f.

Marshall-Palmer rain rate (mm/hr).

Input: The input parameters are radar constant, calibration

slope and intercept, number of range bins to be processed,

drop size distribution parameters, file number to be

processed, and time.

Limitations: This program is written for a PDP-8-IBM

compatible format. The PDP-8 minicomputer controls the

radar and injects the output on line onto an IBM tape.

Current Status: This program is operational.

References:

Goldhirsh, J. (1977), Analysis of single and multiple

wavelength radar systems for estimating slant path

attenuation through rain at frequencies greater than 10 GHz,

APL/JHU internal memo SlR77U-036.

For more information contact: J. Goldhirsh, Applied Physics

Laboratory, The Johns Hopkins University, Johns Hopkins

Road, Laurel, MD 20810, (301) 953-7100, ext. 2779.

28
Item: 4-2

Title: RAT, Rain Attenuation vs Time.

computes: This program computes the estimated attenuation

due to rain for three arbitrary frequencies depending upon

the drop size distributions assumed. These attenuations

correspond to the path along the radar beam where the

attenuation contribution due to each adjacent range bin is

considered.

Input: The input parameters are radar constant, calibration

slope and intercept, number of range bins to be processed,

drop size distribution parameters, file numbers, time

interval to be processed, and sampling interval.

Limitations: This program is written for a PDP-8-IBM

compatible format. The PDP-8 minicomputer controls the

radar and injects the output on line onto an IBM tape.

Current Status: This program is operational.

References:

Goldhirsh, J. (1978), Prediction of attenuation of the

28 GHz COMSTAR beacon signal using radar and measured rain

drop spectra, APL/JHU internal memo SlR78U-009.

For more information contact: J. Goldhirsh, Applied Physics

Laboratory, The Johns Hopkins University, Johns Hopkins

Road, Laurel, MD 20810, (301) 953-7100, ext. 2779.

29
Category 5

Performance of Digital Communication 'Systems

Item: 5-1

Title: DTCM, Digital Telecommunication Conversion Model.

Computes: The program computes the mean, standard

deviation, and probability functions of the number of

bits/message for message mixtures which arrive at a digital

telecommunication network station for conversion to

electronic messages.

Input: The required input parameters are the percentages of

digital data on magnetic tape or cards, the percentage of

alphanumeric messages on paper, the percentage of graphic

messages on paper, data compression ratios, and lines per

inch facsimile scanning ratios.

Current Status: The program is operational. The program is

docum~nted and described in the two references given below.

The program is written in FORTRAN IV for a CDC 6600.

References:

McManamon, P. (1975), A digital telecommunication

conversion model for electronic message mixtures, u.S.

Postal Service Report, (NTIS PB252-183).

Miles, M. (1975), Analysis of a digital

telecommunications message model, u.S. Postal Service

Report, (NTIS PB252-184).

For more information contact: Dr. P. McManamon, NTIA/ITS,

U.S. Dept. of Commerce, Boulder, CO 80303, (303) 499-1000,

ext. 3570 or FTS 323-3570; R. Marcotte, USPSR&D Center,

11711 Park1awn Drive, Rockville, MD 20853, (301) 443-6100

or FTS 443-6100.

30
Item: 5-2

Title: DTGTAP, Digital Tropo Generalized Time Availability

Program.

computes: This program computes the generalized time

availability of a digital troposcatter system at a given

service probability.

Input: The program requires the following input data:

A. The mean and variance of the energy-per-bit to noise

ratio (Eb/No) supplied to the modem.

B. The mean and variance of the distribution of

multipath spread characterized by its two sigma width.

C. Fifteen samples from the modem performance curve.

This is the plot of required mean Eb/No vs mean multipath

spread for which the digital troposcatter modem will produce

a given average bit error rate.

Limitations: The accuracy of the program degrades when the

modem is operated under multipath conditions where its

performance is significantly degraded by intersymbol

interference. The computational problem is a consequence of

the steep slope of typical modem performance curves in this

region.

Current Status: The program is operational. Running time

could be significantly reduced by refinement of the two

dimensional integration algorithm used.

References:

Sherwood, A., S. Wenglin, and J. Wick, An experimental

program leading to development of a tactical digital

troposcatter system, to be published in the proceedings of

the AGARD EPP symposium on "Aspects of Electromagnetic

Scattering in Radio Communication," 3-7 October, Cambridge,

MA.

31
For more information contact: Dr. J. Wick, Mail Stop A160,

The MITRE Corporation, Bedford, MA 01730, (617) 271-4590, or

AUTOVON 478-1001, ext. 75-4590.

32
Category 6

Miscellaneous Programs

Item: 6-1

Title: MAIM, Multipath Analysis of ILS and MLS.

Computes: This program computes the position error of ILS

and MLS due to multipath from the environment. The

environment is modeled as a number of flat triangles with a

given roughness. Specular and diffuse components are

computed.

Input: Required input parameters are the geometrical and

electrical properties of each triangle, coordinates of the

ground system and the aircraft, antenna radiation pattern,

and frequency band, as well as type of ILS or MLS.

Limitations: The program is limited to systems for which

computer models exist, such as Scanning Beam MLS, Doppler

Scan MLS, Interferometry MLS and ILS.

Current Status: The program is operational.

References:

Breien, T. (1976), Computer analysis of MLS in

multipath environment, lEE Conf. Publ. No. 147.

For more information contact: T. Breien, ELAB, N-7034

TRONDHEIM - NTH, NORWAY.

33
Item: 6-2

Title: Y, Earth Coverage Footprints from Geostationary

Satellite Antennas.

Computes: The program contains an algorithm for generating

on microfilm output, earth coverage footprints from

geostationary satellite antennas. Also, a separate

algorithm is included for determining whether given

coordinates or ground points are included in or excluded

from a particular footprint. The antenna beam can be

elliptic in cross-section with an arbitrary orientation of

semi-minor and semi-major axes.

Input: The required inputs are data giving latitude and

longitudes of continental u.s. plus state boundaries or

latitude and longitude of political boundaries on world map,

longitude of satellite and distance from earth center,

latitude and longitude of antenna aim point, semi-minor and

semi-major axes, and rotation angle of elliptic pattern.

Current Status: The program is operating and available on

request.

References:

Ott, R. H. (1975), A numerical method for generating

earth coverage footprints from geostationary antennas,

report prepared for Advanced Mail Systems Directorate, U.S.

Postal Service, Rockville, MD 20852.

For more information contact:

Dept. of Commerce, Boulder, CO

3353.

Dr. R. H. Ott, NTIA/ITS, U.S.

80303, (303) 499-1000, ext.

34
Item: 6-3

Titl~.: JRWOOl, Transionospheric Ray Tracing with Iterative

Homing.

Computes: This program is designed to perform ray tracing

of radio waves through a spherically-stratified model

ionosphere, using Snell's Law iterated at each layer. A

homing capability is included so that the actual path which

will connect transmitter and receiver will be determined to

whatever accuracy is specified. 0 and X waves are traced

separately and Faraday Rotation obtained from their phase

path length difference. Various model ionospheres can be

used, including profiles derived from ionosondes. Different

models of the geomagnetic field can be specified.

Input: The required input parameters are frequency, transmitter location, receiver location, parameters to define

ionosphere profile (N(h», and parameters to define geomagnetic field model.

Limitations: The program uses a spherically stratified

ionosphere. There are no frequency limits: although, of

course, it is assumed that the rays do penetrate the

ionosphere.

Current Status: Program was converted to run on the

NOAA/ERL CDC 6600 in November 1976. Due to the number of

subroutines used, this would be a very difficult program to

convert to run on other computers.

References:

Lawrence, R. S., and D. J. Posakony (1961), A digital

ray-tracing program for ionospheric research, SPACE RESEARCH

II, Proc. Second International Space Science Symposium.

For more information contact: Judy Stephenson, NOAA/SEL,

u.S. Dept. of Commerce, Boulder, CO 80303, (303) 499-1000,

ext. 3997: R. B. Fritz, NOAA/SEL, u.S. Dept. of Commerce,

Boulder, CO 80303, (303) 499-1000, ext. 6523.

35
Item: 6-4

Title: RAYTRA, A versatile three-dimensional ray tracing

computer program for radio waves in the ionosphere.

computes: Th~s program will trace rays through an

anisotropic medium whose index of refraction varies

continuously in three dimensions. The program can represent

the refractive index by either the Appleton-Hartree or the

Sen-Wyller formula, and has several ionospheric models for

electron density, perturbations to the electron density, the

earth's magnetic fi~ld, and electron collision frequency.

For each path, the program can calculate group path length,

phase path length, absorption, Doppler shift due to a timevarying ionosphere, and geometrical path length. In

addition to printing these parameters and the direction of

the wave normal at various points along the ray path, the

program can plot the projection of the ray path on any

vertical plane or on the ground and punch the main

characteristics of each ray path on cards.

Input: The input parameters are transmitter location

(longitude, latitude, and height above the ground), the

frequency of the wave, the direction of transmission (both

elevation and azimuth), the receiver height, and the maximum

number of hops desired.

Limitations: The program has no homing capability.

Current Status: The program is written in FORTRAN, is on

cards, and is operational on a CDC 6600.

Reference: Jones, R. M., and J. J. Stephenson (1975), A

versatile three-dimensional ray tracing computer program for

radio waves in the ionosphere, OT Report 75-76.

For more information contact: R. M. Jones, NOAA/SEL, u.S.

Dept. of Commerce, Boulder, CO 80303, (303) 499-1000, ext.

6494 or J. J. Stephenson~ NOAA/SEL, u.S. Dept. of Commerce,

Boulder, CO 80303, (303) 499-1000, ext. 3997.

36
Item: 6-5

Title: WTC-MBA/LASL.

computes: The program computes the transient response of

thin-wire antennas or scatterers connected to circuits. The

solution is obtained by timestepping. The circuit may

contain nonlinear elements. The program was designed to

analyze the transient response of wire objects. Wideband

frequency domain results are also available through a

Fourier transform. structures modeled by grids of wires can

also be handled. The current on each wire segment and the

voltage of each node of the circuit is available for all

tirnesteps. Far field electric field intensities can be found

also.

Input: The required input parameters are antenna geometry,

antenna loading, circuit element values, exciting fields or

voltages, and the desired timestep increment. The desired

far field observation direction and polarization can also be

input.

Limitations: Approximately 12 wire segments per wavelength

are required to model the wire structure. This limits the

structure complexity to approximately 300 segments for a

CDC 7600. The ratio of the wire segment length to diameter

must be greater than one. The time-step increment must be

approximately equal to the length of the longest wire

segment divided by the velocity of light.

Current Status: This program is operational and will be

available when documentation is complete. It is written in

FORTRAN for a CDC 7600.

References:

Landt, J. A., E. K. Miller, and M. Van Blavicum (1974),

WT-MBA/LLLIB: A computer program for the time-domain

electromagnetic response of thin-wire structures,

37
UCRL-51585, Lawrence Livermore Laboratory, Livermore, CA

(Same as WTC-MBA/LASL except for circuit loading).

Miller, E. K., and J. A. Landt (1976), Direct timedomain techniques for transient radiation and scattering,

UCRL-52315, Lawrence Livermore Laboratory, Livermore, CA.

For more information contact: J. A. Landt, MS-429, Los

Alamos Scientific Laboratory, Los Alamos, NM 87545, (505)

667-7558 or FTS 843-7558.

38
FORM OT-29

(3-73)

u.s. DEPARTMENT OF COMMERCE

OFFICE OF TELECOMMUNICATIONS

BIBLIOGRAPHIC DATA SHEET

1. PUBLICATION OR REPORT NO.2. Gov't Accession No.3. Recipient's Accession No.

NTIA Report 79-15

4. TITLE AND SUBTITLE 5. Publication Date

January 1979

6. Performing Organization Code

An Additional Catalog of Programs and Data 1

-----------------1 for 100 MHz - 100 GHz Radio System Predictions

7. AUTHOR(S)

Jack T. Collins and F. K. Steele

9•. Project/Task/Work Unit No.

8. PERFORMING ORGANIZATION NAME AND ADDRESS

U.S. Department of Commerce

NTIA/ITS

325 Broadway

Boulder, CO 80303

10. Contract/Grant No.

11. Sponsoring Organization Name and Address

U.S. Department of Commerce

NTIA/ITS

325 Broadway

Boulder, CO 80303

12. Type of Report and Period Covered

13.

14. SUPPLEMENTARY NOTES

15. A!3S!RACT (A 2?O-word or less factual summary of most significant information. If document includes a significant

bIblIography of lIterature survey, mention it here.) Analysis aids and data bases for predicting the performance of

100 MHz - 100 GHz communication systems are presented and briefly

described. They are loosely grouped into the following functional

catagories:

1) Computations of transmission loss and radar returned power.

2) Computations of desired-to-undesired signal ratios.

3) Computations of atmospheric and precipitation parameters.

4) Data bases and associated programs.

5) Perfor,mance of digital communication systems.

6) Miscellaneous programs.

Sources are given for the analysis aids, data bases, and additional information.

16. Key Words (Alphabetical order, separated by semicolons)

atmosphere; computer programs; data bases; desired signal; digital

communications; precipitation; propagation prediction; radar power;

transmission loss; undesired signal.

17. AVAILABILITY STATEMENT 18. Sec uri ty Class (This report) 20. Number of pages

QS UNLIMITED. UNCLASSIFIED 48

o FOR OFFICIAL DISTRIBUTION.

19. Security Class (This page)

UNCLASSIFIED

21. Price:

~u.s. GOVERNMENT PRINTING OFFICE: 1979-0-678-684/328 L'SCOMM-DC 29716-P73