+#!/usr/bin/perl -w
+# A perl Minimuf calculator, nicked from the minimuf program written in
+# C.
+#
+# Translated and modified for my own purposes by Dirk Koopman G1TLH
+#
+# Copyright (c) 1999 Dirk Koopman G1TLH
+#
+# The original copyright:-
+#/***********************************************************************
+# * *
+# * Copyright (c) David L. Mills 1994-1998 *
+# * *
+# * Permission to use, copy, modify, and distribute this software and *
+# * its documentation for any purpose and without fee is hereby *
+# * granted, provided that the above copyright notice appears in all *
+# * copies and that both the copyright notice and this permission *
+# * notice appear in supporting documentation, and that the name *
+# * University of Delaware not be used in advertising or publicity *
+# * pertaining to distribution of the software without specific, *
+# * written prior permission. The University of Delaware makes no *
+# * representations about the suitability this software for any *
+# * purpose. It is provided "as is" without express or implied *
+# * warranty. *
+# * *
+# ***********************************************************************
+#
+# MINIMUF 3.5 from QST December 1982
+# (originally in BASIC)
+#
+# $Id$
+#
+#
+
+package Minimuf;
+
+use strict;
+use POSIX;
+use vars qw($pi $d2r $r2d $halfpi $pi2 $VOFL $R $hE $hF $GAMMA $LN10
+ $MINBETA $BOLTZ $NTEMP $DELTAF $MPATH $GLOSS $SLOSS
+ $noise);
+
+$pi = 3.141592653589;
+$d2r = ($pi/180);
+$r2d = (180/$pi);
+$halfpi = $pi/2;
+$pi2 = $pi*2;
+$VOFL = 2.9979250e8; # velocity of light
+$R = 6371.2; # radius of the Earth (km)
+$hE = 110; # mean height of E layer (km)
+$hF = 320; # mean height of F layer (km)
+$GAMMA = 1.42; # geomagnetic constant
+$LN10 = 2.302585; # natural logarithm of 10
+$MINBETA = (10 * $d2r); # min elevation angle (rad)
+$BOLTZ = 1.380622e-23; # Boltzmann's constant
+$NTEMP = 290; # receiver noise temperature (K)
+$DELTAF = 2500; # communication bandwidth (Hz)
+$MPATH = 3; # multipath threshold (dB)
+$GLOSS = 3; # ground-reflection loss (dB)
+$SLOSS = 10; # excess system loss
+$noise = 10 * log10($BOLTZ * $NTEMP * $DELTAF) + 30;
+
+# basic SGN function
+sub SGN
+{
+ my $x = shift;
+ return 0 if $x == 0;
+ return ($x > 0) ? 1 : -1;
+}
+
+#
+# MINIMUF 3.5 (From QST December 1982, originally in BASIC)
+#
+
+sub minimuf
+{
+ my $flux = shift; # 10-cm solar flux
+ my $month = shift; # month of year (1 - 12)
+ my $day = shift; # day of month (1 - 31)
+ my $hour = shift; # hour of day (utc) (0 - 23)
+ my $lat1 = shift; # transmitter latitude (deg n)
+ my $lon1 = shift; # transmitter longitude (deg w)
+ my $lat2 = shift; # receiver latitude (deg n)
+ my $lon2 = shift; # receiver longitude (deg w)
+
+ my $ssn; # sunspot number dervived from flux
+ my $muf; # maximum usable frequency
+ my $dist; # path angle (rad)
+ my ($a, $p, $q); # unfathomable local variables
+ my ($y1, $y2, $y3);
+ my ($t, $t4, $t9);
+ my ($g0, $g8);
+ my ($k1, $k6, $k8, $k9);
+ my ($m9, $c0);
+ my ($ftemp, $gtemp); # volatile temps
+
+ # Determine geometry and invariant coefficients
+ $ssn = spots($flux);
+ $ftemp = sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) *
+ cos($lon2 - $lon1);
+ $ftemp = -1 if ($ftemp < -1);
+ $ftemp = 1 if ($ftemp > 1);
+ $dist = acos($ftemp);
+ $k6 = 1.59 * $dist;
+ $k6 = 1 if ($k6 < 1);
+ $p = sin($lat2);
+ $q = cos($lat2);
+ $a = (sin($lat1) - $p * cos($dist)) / ($q * sin($dist));
+ $y1 = 0.0172 * (10 + ($month - 1) * 30.4 + $day);
+ $y2 = 0.409 * cos($y1);
+ $ftemp = 2.5 * $dist / $k6;
+ $ftemp = $halfpi if ($ftemp > $halfpi);
+ $ftemp = sin($ftemp);
+ $m9 = 1 + 2.5 * $ftemp * sqrt($ftemp);
+ $muf = 100;
+
+ # Loop along path
+ for ($k1 = 1 / (2 * $k6); $k1 <= 1 - 1 / (2 * $k6); $k1 += abs(0.9999 - 1 / $k6)) {
+ $gtemp = $dist * $k1;
+ $ftemp = $p * cos($gtemp) + $q * sin($gtemp) * $a;
+ $ftemp = -1 if ($ftemp < -1);
+ $ftemp = 1 if ($ftemp > 1);
+ $y3 = $halfpi - acos($ftemp);
+ $ftemp = (cos($gtemp) - $ftemp * $p) / ($q * sqrt(1 - $ftemp * $ftemp));
+ $ftemp = -1 if ($ftemp < -1);
+ $ftemp = 1 if ($ftemp > 1);
+ $ftemp = $lon2 + SGN(sin($lon1 - $lon2)) * acos($ftemp);
+ $ftemp += $pi2 if ($ftemp < 0);
+ $ftemp -= $pi2 if ($ftemp >= $pi2);
+ $ftemp = 3.82 * $ftemp + 12 + 0.13 * (sin($y1) + 1.2 * sin(2 * $y1));
+ $k8 = $ftemp - 12 * (1 + SGN($ftemp - 24)) * SGN(abs($ftemp - 24));
+ if (cos($y3 + $y2) <= -0.26) {
+ $k9 = 0;
+ $g0 = 0;
+ } else {
+ $ftemp = (-0.26 + sin($y2) * sin($y3)) / (cos($y2) * cos($y3) + 0.001);
+ $k9 = 12 - atan($ftemp / sqrt(abs(1 - $ftemp * $ftemp))) * 7.639437;
+ $t = $k8 - $k9 / 2 + 12 * (1 - SGN($k8 - $k9 / 2)) * SGN(abs($k8 - $k9 / 2));
+ $t4 = $k8 + $k9 / 2 - 12 * (1 + SGN($k8 + $k9 / 2 - 24)) * SGN(abs($k8 + $k9 / 2 - 24));
+ $c0 = abs(cos($y3 + $y2));
+ $t9 = 9.7 * pow($c0, 9.6);
+ $t9 = 0.1 if ($t9 < 0.1);
+
+ $g8 = $pi * $t9 / $k9;
+ if (($t4 < $t && ($hour - $t4) * ($t - $hour) > 0.) || ($t4 >= $t && ($hour - $t) * ($t4 - $hour) <= 0)) {
+ $ftemp = $hour + 12 * (1 + SGN($t4 - $hour)) * SGN(abs($t4 - $hour));
+ $ftemp = ($t4 - $ftemp) / 2;
+ $g0 = $c0 * ($g8 * (exp(-$k9 / $t9) + 1)) * exp($ftemp) / (1 + $g8 * $g8);
+ } else {
+ $ftemp = $hour + 12 * (1 + SGN($t - $hour)) * SGN(abs($t - $hour));
+ $gtemp = $pi * ($ftemp - $t) / $k9;
+ $ftemp = ($t - $ftemp) / $t9;
+ $g0 = $c0 * (sin($gtemp) + $g8 * (exp($ftemp) - cos($gtemp))) / (1 + $g8 * $g8);
+ $ftemp = $c0 * ($g8 * (exp(-$k9 / $t9) + 1)) * exp(($k9 - 24) / 2) / (1 + $g8 * $g8);
+ $g0 = $ftemp if ($g0 < $ftemp);
+ }
+ }
+ $ftemp = (1 + $ssn / 250) * $m9 * sqrt(6 + 58 * sqrt($g0));
+ $ftemp *= 1 - 0.1 * exp(($k9 - 24) / 3);
+ $ftemp *= 1 + 0.1 * (1 - SGN($lat1) * SGN($lat2));
+ $ftemp *= 1 - 0.1 * (1 + SGN(abs(sin($y3)) - cos($y3)));
+ $muf = $ftemp if ($ftemp < $muf);
+ }
+ return $muf;
+}
+
+#
+# spots(flux) - Routine to map solar flux to sunspot number.
+#
+# THis routine was done by eyeball and graph on p. 22-6 of the 1991
+# ARRL Handbook. The nice curve fitting was done using Mathematica.
+#
+sub spots
+{
+ my $flux = shift; # 10-cm solar flux
+ my $ftemp; # double temp
+
+ return 0 if ($flux < 65);
+ if ($flux < 110) {
+ $ftemp = $flux - 200.6;
+ $ftemp = 108.36 - .005896 * $ftemp * $ftemp;
+ } elsif ($flux < 213) {
+ $ftemp = 60 + 1.0680 * ($flux - 110);
+ } else {
+ $ftemp = $flux - 652.9;
+ $ftemp = 384.0 - 0.0011059 * $ftemp * $ftemp;
+ }
+ return $ftemp;
+}
+
+# ion - determine paratmeters for hop h
+#
+# This routine determines the reflection zones for each hop along the
+# path and computes the minimum F-layer MUF, maximum E-layer MUF,
+# ionospheric absorption factor and day/night flags for the entire
+# path.
+
+sub ion
+{
+ my $h = shift; # hop index
+ my $d = shift; # path angle (rad)
+ my $fcF = shift; # F-layer critical frequency
+ my $ssn = shift; # current sunspot number
+ my $daynight = shift; # ref to daynight array one per hop
+
+ # various refs to arrays
+ my $mufE = shift;
+ my $mufF = shift;
+ my $absorp = shift;
+
+ my $beta; # elevation angle (rad)
+ my $psi; # sun zenith angle (rad)
+ my $dhop; # hop angle / 2 (rad)
+ my $dist; # path angle (rad)
+ my $phiF; # F-layer angle of incidence (rad)
+ my $phiE; # E-layer angle of incidence (rad)
+ my $fcE; # E-layer critical frequency (MHz)
+ my $ftemp; # double temp
+
+
+ # Determine the path geometry, E-layer angle of incidence and
+ # minimum F-layer MUF. The F-layer MUF is determined from the
+ # F-layer critical frequency previously calculated by MINIMUF
+ # 3.5 and the secant law and so depends only on the F-layer
+ # angle of incidence. This is somewhat of a crock; however,
+ # doing it with MINIMUF 3.5 on a hop-by-hop basis results in
+ # rather serious errors.
+
+
+ $dhop = $d / ($h * 2);
+ $beta = atan((cos($dhop) - $R / ($R + $hF)) / sin($dhop));
+ $ftemp = $R * cos($beta) / ($R + $hE);
+ $phiE = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
+ $ftemp = $R * cos($beta) / ($R + $hF);
+ $phiF = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
+ $$mufF->[$h] = $fcF / cos($phiF);;
+ for ($dist = $dhop; $dist < $d; $dist += $dhop * 2) {
+
+ # Calculate the E-layer critical frequency and MUF.
+
+ $fcE = 0;
+ $psi = zenith($dist);
+ $ftemp = cos($psi);
+ $fcE = .9 * pow((180. + 1.44 * $ssn) * $ftemp, .25) if ($ftemp > 0);
+ $fcE = .005 * $ssn if ($fcE < .005 * $ssn);
+ $ftemp = $fcE / cos($phiE);
+ $mufE->[$h] = $ftemp if ($ftemp > $mufE->[$h]);
+
+ # Calculate ionospheric absorption coefficient and
+ # day/night indicators. Note that some hops along a
+ # path can be in daytime and others in nighttime.
+
+ $ftemp = $psi;
+ if ($ftemp > 100.8 * $d2r) {
+ $ftemp = 100.8 * $d2r;
+ $daynight->[$h] |= 2;
+ } else {
+ $daynight->[$h] |= 1;
+ }
+ $ftemp = cos(90. / 100.8 * $ftemp);
+ $ftemp = 0. if ($ftemp < 0.);
+ $ftemp = (1. + .0037 * $ssn) * pow($ftemp, 1.3);
+ $ftemp = .1 if ($ftemp < .1);
+ $absorp->[$h] += $ftemp;
+ }
+}
+
+
+#
+# pathloss(freq, hop) - Compute receive power for given path.
+#
+# This routine determines which of the three ray paths determined
+# previously are usable. It returns the hop index of the best of these
+# or zero if none are found.
+
+sub pathloss
+{
+ my $hop = shift; # minimum hops
+ my $freq = shift; # frequency
+ my $txpower = shift || 20; # transmit power
+ my $rsens = shift || -123; # receiver sensitivity
+ my $antgain = shift || 0; # antenna gain
+
+ my $daynight = shift; # ref to daynight array one per hop
+ my $beta = shift;
+ my $path = shift;
+ my $mufF = shift;
+ my $mufE = shift;
+ my $absorp = shift;
+ my $dB2 = shift;
+
+ my $h; # hop number
+ my $level; # max signal (dBm)
+ my $signal; # receive signal (dBm)
+ my $ftemp; # double temp
+ my $j; # index temp
+
+ #
+ # Calculate signal and noise for all hops. The noise level is
+ # -140 dBm for a receiver bandwidth of 2500 Hz and noise
+ # temperature 290 K. The receiver sensitivity is assumed -123
+ # dBm (0.15 V at 50 Ohm for 10 dB S/N). Paths where the signal
+ # is less than the noise or when the frequency exceeds the F-
+ # layer MUF are considered unusable.
+
+ $level = $noise;
+ $j = 0;
+ for ($h = $hop; $h < $hop + 3; $h++) {
+# $daynight->[$h] &= ~(P_E | P_S | P_M);
+ if ($freq < 0.85 * $mufF->[$h]) {
+
+ # Transmit power (dBm)
+
+ $signal = $txpower + $antgain + 30;
+
+ # Path loss
+
+ $signal -= 32.44 + 20 * log10($path->[$h] * $freq) + $SLOSS;
+
+ # Ionospheric loss
+
+ $ftemp = $R * cos($beta->[$h]) / ($R + $hE);
+ $ftemp = atan($ftemp / sqrt(1 - $ftemp * $ftemp));
+ $signal -= 677.2 * $absorp->[$h] / cos($ftemp) / (pow(($freq + $GAMMA), 1.98) + 10.2);
+
+ # Ground reflection loss
+
+ $signal -= $h * $GLOSS;
+ $dB2->[$h] = $signal;
+
+ # Paths where the signal is greater than the
+ # noise, but less than the receiver sensitivity
+ # are marked 's'. Paths below the E-layer MUF
+ # are marked 'e'. When comparing for maximum
+ # signal, The signal for these paths is reduced
+ # by 3 dB so they will be used only as a last
+ # resort.
+
+
+ $daynight->[$h] |= 4 if ($signal < $rsens);
+ if ($freq < $mufE->[$h]) {
+ $daynight->[$h] |= 8;
+ $signal -= $MPATH;
+ }
+ if ($signal > $level) {
+ $level = $signal;
+ $j = $h;
+ }
+ }
+ }
+
+ # We have found the best path. If this path is less than 3 dB
+ # above the RMS sum of the other paths, the path is marked 'm'.
+
+ return 0 if ($j == 0);
+
+ $ftemp = 0;
+ for ($h = $hop; $h < $hop + 3; $h++) {
+ $ftemp += exp(2 / 10 * $dB2->[$h] * $LN10) if ($h != $j);
+ }
+ $ftemp = 10 / 2 * log10($ftemp);
+ $daynight->[$j] |= 16 if ($level < $ftemp + $MPATH);
+
+ return $j;
+}
+
+# zenith(dist) - Determine sun zenith angle at reflection zone.
+
+sub zenith
+{
+ my $dist = shift; # path angle
+ my $txlat = shift; # tx latitude (rad)
+ my $txlong = shift; # tx longitude (rad)
+ my $txbearing = shift; # tx bearing
+ my $pathangle = shift; # 'b1'
+ my $lats = shift; # subsolar latitude
+ my $lons = shift; # subsolar longitude
+
+ my ($latr, $lonr); # reflection zone coordinates (rad)
+ my $thetar; # reflection zone angle (rad)
+ my $psi; # sun zenith angle (rad)
+
+ # Calculate reflection zone coordinates.
+
+ $latr = acos(cos($dist) * sin($txlat) + sin($dist) * cos($txlat) * cos($txbearing));
+ $latr += $pi if ($latr < 0);
+ $latr = $halfpi - $latr;
+ $lonr = acos((cos($dist) - sin($latr) * sin($txlat)) / (cos($latr) * cos($txlat)));
+ $lonr += $pi if ($lonr < 0);
+ $lonr = - $lonr if ($pathangle < 0);
+ $lonr = $txlong - $lonr;
+ $lonr -= $pi2 if ($lonr >= $pi);
+ $lonr += $pi2 if ($lonr <= -$pi);
+ $thetar = $lons - $lonr;
+ $thetar = $pi2 - $thetar if ($thetar > $pi);
+ $thetar -= $pi2 if ($thetar < - $pi);
+
+ # Calculate sun zenith angle.
+
+ $psi = acos(sin($latr) * sin($lats) + cos($latr) * cos($lats) * cos($thetar));
+ $psi += $pi if ($psi < 0);
+ return($psi);
+}
+
+
+
+1;
projects / spider.git / commitdiff