gcb-1.07.orig/0000755000175000017500000000000010411016120011405 5ustar pg4ipg4igcb-1.07.orig/README0000644000175000017500000000066406221261066012312 0ustar pg4ipg4iI used this program a lot to give me a quick and dirty bearing and range to a location. It is command-line oriented, and very easy to remember syntax. This version builds on the last version by incorporating the information in the ARRL Satellite Experimenters Handbook. Particularly the short path, long path, and antipodal data. If you have any questions, feel free to email me any time. Steve Sampson, N5OWK ssampson@oklahoma.net gcb-1.07.orig/gc.c0000644000175000017500000001460606221261066012170 0ustar pg4ipg4i/* * gc.c * * Great Circle. This program is used to determine bearing * and range to two stations given latitude and longitude. * * Ver 1.07 By S. R. Sampson, N5OWK * Public Domain (p) June 1993 * * Ref: "Air Navigation", Air Force Manual 51-40, 1 February 1987 * Ref: "ARRL Satellite Experimenters Handbook", August 1990 * * Usage examples: * * gc n 35.19n97.27w 0s0e (Moore to Prime/Equator) * gc n 35.19N97.27W 38.51n77.02W (Moore to Washington D.C., mixed case) * gc n 33.56n118.24w 55.45n37.35e (L.A. to Moscow) * gc n 35N70W 35N71W (No decimal points used, all uppercase) * * Modified the program to incorporate short and long path information * from the Satellite Handbook. This version also takes into consideration * the two points being close enough to be in the near-field, and the * antipodal points, which are easily calculated. These last points were * made in discussions with John Allison who makes the nice MAPIT program. * * Compile GNU C with: cc -O gc.c -o gc -lm */ /* Includes */ #include #include #include #include #include /* Defines */ #define RADIAN (180.0 / M_PI) /* Globals */ struct { double miles; /* arc length for 1 degree, various units of measure */ char *text; } Units[] = { { 60.0, "Nautical Miles"}, { 111.2, "kilometers"}, { 69.1, "Statute Miles"} }; /* Simple Declare, No Prototypes */ /* * Error routine */ void err(type) int type; { switch(type) { case 1: printf("\007Latitude Out of Range (90N to 90S)\n"); break; case 2: printf("\007Longitude Out of Range (180W to 180E)\n"); break; case 3: printf("\007Minutes Out of Range (0 to 59)\n"); } exit(-1); } /* * Convert Degrees and Minutes to Decimal */ double dm2dec(n) double n; { double t; t = (int)n; n -= t; n /= .60; if (n >= 1.0) err(3); return (n + t); } /* * Parse the input line * * dd(.mm)[NnSs]ddd(.mm)[EeWw] */ void parse(s, lat, lon) char *s; double *lat, *lon; { register char *i, *t, *e; e = s + strlen(s); for (i = s; i < e; ++i) { switch (*i) { case 'n': case 'N': *i = '\0'; t = i + 1; *lat = atof(s); break; case 's': case 'S': *i = '\0'; t = i + 1; *lat = -atof(s); break; case 'e': case 'E': *i = '\0'; *lon = -atof(t); break; case 'w': case 'W': *i = '\0'; *lon = atof(t); } } *lat = dm2dec(*lat); *lon = dm2dec(*lon); if (*lat > 90.0 || *lat < -90.0) err(1); if (*lon > 180.0 || *lon < -180.0) err(2); /* Prevent ACOS() Domain Error */ if (*lat == 90.0) *lat = 89.9; if (*lat == -90.0) *lat = -89.9; } void main(argc, argv) int argc; char **argv; { double tmp, arc, cosaz, az, azsp, azlp, distsp, distlp; double QTH_Lat, QTH_Long, DEST_Lat, DEST_Long, Delta_Long; int units; if (argc != 4) { fprintf(stderr, "\nUsage: gc units station1 station2\n\n" \ "This program computes Great Circle Bearing and Range\n" \ "given the latitude and longitude (degrees and minutes).\n\n" \ "You must input the lat/long of the two stations.\n" \ "The output will then be relative from station1 to station2.\n\n" \ "Input the two station lat/longs using the following format:\n\n" \ "\tdd.mmHddd.mmG lead/lagging zeros can be left out.\n\n" \ "d = Degrees, m = Minutes, H = Hemisphere (N or S), " \ "G = Greenwich (W or E)\n\n" \ "units is 'n' for Nautical, 'k' for kilometers, and 's' for " \ "Statute.\n\n"); exit(1); } /* Process the command line data */ switch (argv[1][0]) { case 'k': case 'K': units = 1; break; case 's': case 'S': units = 2; break; case 'n': case 'N': default: units = 0; } parse(argv[2], &QTH_Lat, &QTH_Long); parse(argv[3], &DEST_Lat, &DEST_Long); QTH_Lat /= RADIAN; /* Convert variables to Radians */ QTH_Long /= RADIAN; DEST_Lat /= RADIAN; DEST_Long /= RADIAN; Delta_Long = DEST_Long - QTH_Long; tmp = (sin(QTH_Lat) * sin(DEST_Lat)) + (cos(QTH_Lat) * cos(DEST_Lat) * cos(Delta_Long)); if (tmp > .999999) { printf("Station points coincide, use an Omni!\n\n"); exit(0); } else if (tmp < -.999999) { /* * points are antipodal, he's straight down. * So take 180 Degrees of arc times 60 nm, * and you get 10800 nm, or whatever units... */ printf("Station is equal distance in all Azimuths " \ "(antipodal)\n%.0f %s\n\n", (Units[units].miles) * 180.0, Units[units].text); exit(0); } else { arc = acos(tmp); /* * One degree of arc is 60 Nautical miles * at the surface of the earth, 111.2 km, or 69.1 sm * This method is easier than the one in the handbook */ /* Short Path */ distsp = (Units[units].miles) * (arc * RADIAN); /* Long Path */ distlp = ((Units[units].miles) * 360.0) - distsp; } cosaz = (sin(DEST_Lat) - (sin(QTH_Lat) * cos(arc))) / (sin(arc) * cos(QTH_Lat)); if (cosaz > .999999) az = 0.0; else if (cosaz < -.999999) az = 180.0; else az = acos(cosaz) * RADIAN; /* * Handbook had the test ">= 0.0" which looks backwards?? */ if (sin(Delta_Long) < 0.0) { azsp = az; azlp = 180.0 + az; } else { azsp = 360.0 - az; azlp = 180.0 - az; } /* Computations complete, show answer */ printf("Short Path Bearing is %03.0f Degrees for %.0f %s\n", azsp, distsp, Units[units].text); printf(" Long Path Bearing is %03.0f Degrees for %.0f %s\n", azlp, distlp, Units[units].text); exit(0); }