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AP_Declination: added inclination and intensity tables 

moved from SITL/SIM_Aircraft.h
This commit is contained in:
Andrew Tridgell 2017-08-17 19:09:00 +10:00
parent 1f76f69d80
commit 252fc9c757
2 changed files with 157 additions and 176 deletions
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303
libraries/AP_Declination/AP_Declination.cpp
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@ -29,187 +29,160 @@
#include <AP_Common/AP_Common.h>
#include <AP_Math/AP_Math.h>
// 1 byte - 4 bits for value + 1 bit for sign + 3 bits for repeats => 8 bits
struct row_value {
// Offset has a max value of 15
uint8_t abs_offset : 4;
// Sign of the offset, 0 = negative, 1 = positive
uint8_t offset_sign : 1;
// The highest repeat is 7
uint8_t repeats : 3;
/* table data containing magnetic declination angle in degrees */
const float AP_Declination::declination_table[13][37] = {
{47.225,46.016,44.6,43.214,41.929,40.625,38.996,36.648,33.246,28.649,22.973,16.599,10.096,4.0412,-1.2113,-5.7129,-9.9239,-14.505,-19.992,-26.538,-33.881,-41.531,-48.995,-55.908,-62.043,-67.26,-71.433,-74.32,-75.32,-72.759,-61.089,-22.66,24.673,41.679,46.715,47.77,47.225},
{30.663,30.935,30.729,30.365,30.083,29.989,29.903,29.306,27.493,23.864,18.229,11.012,3.2503,-3.7771,-9.1638,-12.793,-15.299,-17.753,-21.275,-26.491,-33.098,-40.129,-46.619,-51.911,-55.576,-57.256,-56.482,-52.464,-44.092,-30.765,-14.236,1.4682,13.543,21.705,26.727,29.465,30.663},
{22.141,22.67,22.786,22.665,22.457,22.365,22.478,22.512,21.659,18.814,13.22,5.1441,-3.8724,-11.749,-17.208,-20.303,-21.777,-22.354,-23.04,-25.422,-30.143,-35.947,-41.114,-44.536,-45.603,-43.943,-39.28,-31.541,-21.622,-11.631,-3.1023,3.9413,9.8774,14.757,18.445,20.858,22.141},
{16.701,17.175,17.415,17.473,17.283,16.943,16.689,16.566,15.935,13.436,7.8847,-0.52637,-9.7982,-17.399,-22.182,-24.63,-25.544,-24.89,-22.583,-20.489,-21.371,-25.128,-29.294,-31.76,-31.569,-28.686,-23.466,-16.487,-9.2421,-3.5196,0.52944,4.0043,7.5112,10.847,13.654,15.633,16.701},
{13.062,13.307,13.488,13.647,13.552,13.138,12.644,12.281,11.511,8.9083,3.288,-4.9363,-13.534,-20.108,-23.761,-24.943,-24.267,-21.633,-16.975,-11.895,-9.3052,-10.608,-14.22,-17.235,-17.896,-16.21,-12.734,-7.944,-3.1917,-0.09448,1.5925,3.3685,5.7977,8.374,10.643,12.277,13.062},
{10.819,10.774,10.744,10.873,10.857,10.513,10.051,9.6504,8.6623,5.7203,-0.00103,-7.7113,-15.239,-20.543,-22.747,-22.021,-19.117,-14.884,-10.06,-5.4668,-2.2918,-1.8711,-4.2049,-7.1881,-8.7089,-8.4387,-6.7419,-3.8048,-0.7327,0.90936,1.399,2.3853,4.3796,6.6682,8.7425,10.241,10.819},
{9.6261,9.4267,9.2035,9.2862,9.3524,9.1115,8.7204,8.235,6.8708,3.4733,-2.2704,-9.2885,-15.646,-19.575,-20.227,-17.864,-13.663,-9.1469,-5.2757,-2.071,0.49345,1.5251,0.29098,-2.0644,-3.6913,-4.1179,-3.5596,-1.9862,-0.1684,0.55548,0.42539,1.019,2.8249,5.1073,7.319,8.9998,9.6261},
{8.9369,8.9745,8.8157,9.0087,9.2615,9.1408,8.6708,7.7842,5.7199,1.6936,-4.0873,-10.373,-15.479,-17.961,-17.333,-14.207,-9.8358,-5.6345,-2.4989,-0.22009,1.7216,2.8156,2.1698,0.36849,-1.0742,-1.6949,-1.7318,-1.1504,-0.42435,-0.50061,-1.1161,-0.88856,0.69851,3.0638,5.6417,7.8392,8.9369},
{8.0661,8.9128,9.3097,9.8875,10.445,10.466,9.7864,8.2288,5.1818,0.28672,-5.7524,-11.438,-15.264,-16.348,-14.841,-11.596,-7.5597,-3.7288,-0.91243,0.96946,2.51,3.5079,3.1926,1.8339,0.62026,-0.01417,-0.36046,-0.53631,-0.84781,-1.8165,-3.0616,-3.3677,-2.1514,0.22612,3.1996,6.0876,8.0661},
{6.6045,8.7101,10.209,11.491,12.418,12.553,11.622,9.3409,5.2254,-0.73322,-7.3408,-12.717,-15.505,-15.494,-13.422,-10.206,-6.4719,-2.8539,-0.05159,1.8185,3.2182,4.1923,4.2452,3.4363,2.5284,1.8671,1.1902,0.25353,-1.1684,-3.2141,-5.2908,-6.2436,-5.4483,-3.1334,0.11904,3.6145,6.6045},
{4.8686,8.2538,11.062,13.264,14.651,14.898,13.714,10.725,5.4958,-1.7139,-9.1709,-14.568,-16.765,-16.116,-13.666,-10.317,-6.5773,-2.906,0.14042,2.3482,3.9956,5.2703,5.9678,5.9805,5.5419,4.7751,3.4951,1.4836,-1.3442,-4.7282,-7.762,-9.283,-8.7476,-6.4234,-2.9491,1.0086,4.8686},
{3.5965,7.9367,11.797,14.893,16.888,17.409,16.035,12.22,5.5033,-3.468,-12.144,-17.817,-19.749,-18.751,-15.97,-12.268,-8.1724,-4.1017,-0.46224,2.551,5.0589,7.2268,8.9817,10.082,10.298,9.416,7.21,3.5705,-1.2522,-6.3856,-10.448,-12.313,-11.73,-9.1743,-5.367,-0.9513,3.5965},
{3.0633,8.0696,12.667,16.527,19.239,20.252,18.783,13.765,4.4393,-7.6723,-18.2,-24.093,-25.554,-23.984,-20.61,-16.25,-11.425,-6.5023,-1.759,2.6571,6.7294,10.458,13.708,16.148,17.3,16.587,13.441,7.6143,-0.14961,-7.7957,-13.103,-15.143,-14.253,-11.262,-6.9868,-2.0631,3.0633}
};
// 730 bytes
static const uint8_t exceptions[10][73] = {
{150,145,140,135,130,125,120,115,110,105,100,95,90,85,80,75,70,65,60,55,50,45,40,35,30,25,20,15,10,5,0,4,9,14,19,24,29,34,39,44,49,54,59,64,69,74,79,84,89,94,99,104,109,114,119,124,129,134,139,144,149,154,159,164,169,174,179,175,170,165,160,155,150},
{143,137,131,126,120,115,110,105,100,95,90,85,80,75,71,66,62,57,53,48,44,39,35,31,27,22,18,14,9,5,1,3,7,11,16,20,25,29,34,38,43,47,52,57,61,66,71,76,81,86,91,96,101,107,112,117,123,128,134,140,146,151,157,163,169,175,178,172,166,160,154,148,143},
{130,124,118,112,107,101,96,92,87,82,78,74,70,65,61,57,54,50,46,42,38,34,31,27,23,19,16,12,8,4,1,2,6,10,14,18,22,26,30,34,38,43,47,51,56,61,65,70,75,79,84,89,94,100,105,111,116,122,128,135,141,148,155,162,170,177,174,166,159,151,144,137,130},
{111,104,99,94,89,85,81,77,73,70,66,63,60,56,53,50,46,43,40,36,33,30,26,23,20,16,13,10,6,3,0,3,6,9,13,16,20,24,28,32,36,40,44,48,52,57,61,65,70,74,79,84,88,93,98,103,109,115,121,128,135,143,152,162,172,176,165,154,144,134,125,118,111},
{85,81,77,74,71,68,65,63,60,58,56,53,51,49,46,43,41,38,35,32,29,26,23,19,16,13,10,7,4,1,1,3,6,9,13,16,19,23,26,30,34,38,42,46,50,54,58,62,66,70,74,78,83,87,91,95,100,105,110,117,124,133,144,159,178,160,141,125,112,103,96,90,85},
{62,60,58,57,55,54,52,51,50,48,47,46,44,42,41,39,36,34,31,28,25,22,19,16,13,10,7,4,2,0,3,5,8,10,13,16,19,22,26,29,33,37,41,45,49,53,56,60,64,67,70,74,77,80,83,86,89,91,94,97,101,105,111,130,109,84,77,74,71,68,66,64,62},
{46,46,45,44,44,43,42,42,41,41,40,39,38,37,36,35,33,31,28,26,23,20,16,13,10,7,4,1,1,3,5,7,9,12,14,16,19,22,26,29,33,36,40,44,48,51,55,58,61,64,66,68,71,72,74,74,75,74,72,68,61,48,25,2,22,33,40,43,45,46,47,46,46},
{6,9,12,15,18,21,23,25,27,28,27,24,17,4,14,34,49,56,60,60,60,58,56,53,50,47,43,40,36,32,28,25,21,17,13,9,5,1,2,6,10,14,17,21,24,28,31,34,37,39,41,42,43,43,41,38,33,25,17,8,0,4,8,10,10,10,8,7,4,2,0,3,6},
{22,24,26,28,30,32,33,31,23,18,81,96,99,98,95,93,89,86,82,78,74,70,66,62,57,53,49,44,40,36,32,27,23,19,14,10,6,1,2,6,10,15,19,23,27,31,35,38,42,45,49,52,55,57,60,61,63,63,62,61,57,53,47,40,33,28,23,21,19,19,19,20,22},
{168,173,178,176,171,166,161,156,151,146,141,136,131,126,121,116,111,106,101,96,91,86,81,76,71,66,61,56,51,46,41,36,31,26,21,16,11,6,1,3,8,13,18,23,28,33,38,43,48,53,58,63,68,73,78,83,88,93,98,103,108,113,118,123,128,133,138,143,148,153,158,163,168}
/* table data containing magnetic inclination angle in degrees */
const float AP_Declination::inclination_table[13][37] = {
{-77.62,-75.621,-73.703,-71.805,-69.84,-67.703,-65.317,-62.69,-59.968,-57.429,-55.437,-54.313,-54.191,-54.921,-56.118,-57.329,-58.214,-58.643,-58.712,-58.692,-58.934,-59.74,-61.257,-63.461,-66.211,-69.329,-72.657,-76.065,-79.441,-82.661,-85.506,-87.208,-86.36,-84.237,-81.951,-79.73,-77.62},
{-71.644,-69.722,-67.862,-66.038,-64.191,-62.202,-59.91,-57.194,-54.113,-51.035,-48.639,-47.697,-48.625,-51.137,-54.39,-57.488,-59.821,-61.085,-61.237,-60.574,-59.768,-59.618,-60.616,-62.761,-65.711,-69.044,-72.416,-75.556,-78.175,-79.936,-80.593,-80.201,-79.054,-77.45,-75.591,-73.62,-71.644},
{-64.379,-62.435,-60.505,-58.564,-56.621,-54.665,-52.574,-50.107,-47.083,-43.756,-41.093,-40.479,-42.721,-47.229,-52.537,-57.471,-61.513,-64.379,-65.669,-65.164,-63.395,-61.672,-61.269,-62.55,-65.012,-67.881,-70.533,-72.526,-73.547,-73.61,-73.075,-72.251,-71.191,-69.844,-68.201,-66.334,-64.379},
{-54.946,-52.868,-50.792,-48.616,-46.372,-44.193,-42.1,-39.8,-36.829,-33.264,-30.385,-30.266,-34.046,-40.628,-47.854,-54.358,-59.856,-64.283,-67.119,-67.68,-65.968,-63.1,-60.894,-60.535,-61.761,-63.584,-65.189,-66.021,-65.775,-64.769,-63.698,-62.826,-61.898,-60.654,-59.023,-57.056,-54.946},
{-42.121,-39.754,-37.516,-35.153,-32.626,-30.14,-27.828,-25.343,-22.028,-18.017,-15.062,-15.744,-21.265,-30.112,-39.56,-47.788,-54.306,-59.187,-62.247,-63.04,-61.444,-58.163,-54.854,-53.154,-53.207,-54.092,-55.004,-55.267,-54.381,-52.801,-51.562,-50.874,-50.1,-48.81,-46.97,-44.643,-42.121},
{-25.138,-22.301,-19.912,-17.531,-14.951,-12.37,-9.9146,-7.1192,-3.3525,0.86465,3.4285,1.8632,-4.8485,-15.374,-26.858,-36.666,-43.599,-47.78,-49.783,-49.893,-48.024,-44.445,-40.638,-38.414,-38.009,-38.508,-39.247,-39.498,-38.5,-36.768,-35.692,-35.432,-34.911,-33.532,-31.323,-28.369,-25.138},
{-4.9962,-1.7126,0.71401,2.8847,5.219,7.5873,9.91,12.689,16.306,19.897,21.553,19.47,12.842,2.3904,-9.4406,-19.56,-26.119,-29.178,-29.919,-29.286,-27.194,-23.471,-19.459,-17.133,-16.698,-17.132,-17.899,-18.371,-17.66,-16.255,-15.708,-16.114,-16.082,-14.846,-12.422,-8.9145,-4.9962},
{14.869,18.185,20.462,22.293,24.256,26.334,28.442,30.896,33.762,36.172,36.784,34.538,28.924,20.356,10.616,2.2154,-3.0793,-5.0649,-4.8917,-3.7875,-1.7639,1.5757,5.1722,7.2324,7.5774,7.2059,6.5718,6.0595,6.3467,7.0334,6.8289,5.7043,4.9959,5.5796,7.5845,10.93,14.869},
{31.164,34.006,36.041,37.647,39.383,41.332,43.382,45.569,47.716,49.104,48.9,46.613,42.181,36.116,29.611,24.084,20.599,19.485,20.056,21.274,22.956,25.416,28.017,29.529,29.786,29.536,29.184,28.895,28.929,28.95,28.145,26.531,25.104,24.717,25.695,28.042,31.164},
{43.422,45.479,47.235,48.815,50.558,52.55,54.665,56.761,58.528,59.374,58.753,56.548,53.102,49.074,45.208,42.092,40.16,39.643,40.248,41.324,42.606,44.197,45.811,46.815,47.078,47.021,46.948,46.916,46.893,46.555,45.437,43.596,41.72,40.533,40.438,41.516,43.422},
{53.102,54.356,55.814,57.449,59.331,61.427,63.597,65.639,67.216,67.832,67.107,65.133,62.449,59.699,57.346,55.602,54.591,54.397,54.884,55.703,56.613,57.588,58.539,59.25,59.652,59.904,60.137,60.33,60.32,59.812,58.553,56.66,54.639,53.044,52.229,52.294,53.102},
{61.877,62.601,63.785,65.363,67.255,69.332,71.425,73.313,74.675,75.099,74.352,72.651,70.529,68.494,66.843,65.687,65.049,64.919,65.198,65.705,66.286,66.893,67.525,68.165,68.802,69.44,70.041,70.469,70.5,69.901,68.591,66.775,64.856,63.228,62.144,61.699,61.877},
{70.565,71.043,71.969,73.282,74.89,76.669,78.458,80.035,81.082,81.248,80.439,78.963,77.256,75.651,74.334,73.378,72.792,72.544,72.57,72.785,73.123,73.565,74.13,74.845,75.713,76.683,77.618,78.289,78.419,77.836,76.61,75.025,73.414,72.04,71.067,70.568,70.565}
};
// 100 bytes
static const uint8_t exception_signs[10][10] = {
{0,0,0,1,255,255,224,0,0,0},
{0,0,0,1,255,255,240,0,0,0},
{0,0,0,1,255,255,248,0,0,0},
{0,0,0,1,255,255,254,0,0,0},
{0,0,0,3,255,255,255,0,0,0},
{0,0,0,3,255,255,255,240,0,0},
{0,0,0,15,255,255,255,254,0,0},
{0,3,255,255,252,0,0,7,252,0},
{0,127,255,255,252,0,0,0,0,0},
{0,0,31,255,254,0,0,0,0,0}
/* table data containing magnetic intensity in Gauss */
const float AP_Declination::intensity_table[13][37] = {
{0.62195,0.60352,0.58407,0.56378,0.54235,0.5192,0.49375,0.46596,0.43661,0.40734,0.38017,0.35689,0.33841,0.32458,0.31447,0.30707,0.302,0.29983,0.30197,0.31023,0.32606,0.35005,0.38167,0.41941,0.4611,0.50431,0.54648,0.58515,0.61805,0.64341,0.66031,0.66875,0.6695,0.66384,0.65315,0.6388,0.62195},
{0.58699,0.56471,0.54222,0.51977,0.49699,0.47285,0.44606,0.4159,0.38299,0.3495,0.31875,0.29401,0.2771,0.26745,0.26251,0.25941,0.25657,0.25431,0.25469,0.26104,0.27676,0.30379,0.34157,0.38741,0.43751,0.48812,0.53602,0.57843,0.61292,0.63771,0.65218,0.65693,0.65331,0.64296,0.62744,0.6083,0.58699},
{0.54115,0.51716,0.49337,0.47003,0.44701,0.42359,0.39839,0.37018,0.33882,0.30605,0.27573,0.25265,0.23995,0.23673,0.23869,0.24146,0.24284,0.24258,0.24188,0.24416,0.25504,0.27952,0.31847,0.36815,0.42238,0.47534,0.52306,0.56286,0.59276,0.61199,0.62133,0.62218,0.61584,0.60338,0.58585,0.56455,0.54115},
{0.48901,0.46546,0.44226,0.41941,0.39712,0.37544,0.35375,0.33083,0.30548,0.27808,0.25206,0.23294,0.22466,0.22623,0.23284,0.24043,0.24771,0.25392,0.25756,0.2592,0.26416,0.28046,0.31301,0.35947,0.41201,0.4626,0.5061,0.53933,0.56053,0.57088,0.5738,0.57145,0.56393,0.55115,0.53361,0.51231,0.48901},
{0.43275,0.41204,0.39186,0.37191,0.35253,0.33441,0.31775,0.3017,0.28442,0.26511,0.24603,0.23176,0.22605,0.22892,0.2372,0.24818,0.2613,0.27524,0.28613,0.2912,0.29315,0.29999,0.32028,0.35581,0.39969,0.44294,0.47952,0.50496,0.51672,0.51792,0.51496,0.51028,0.50215,0.48957,0.47314,0.45367,0.43275},
{0.37936,0.36387,0.34916,0.33493,0.32156,0.30968,0.29963,0.29094,0.28194,0.27119,0.25923,0.24862,0.24246,0.2429,0.25003,0.26227,0.27786,0.29465,0.30882,0.3168,0.31873,0.3201,0.32969,0.35219,0.38333,0.41554,0.44325,0.46129,0.46614,0.4614,0.45461,0.44801,0.43895,0.4265,0.41178,0.39569,0.37936},
{0.34151,0.33271,0.3248,0.31786,0.31251,0.30889,0.30674,0.30563,0.30411,0.30005,0.29252,0.28275,0.27347,0.26836,0.27051,0.27963,0.29265,0.30666,0.31919,0.32782,0.33164,0.33341,0.33926,0.35308,0.37271,0.39367,0.41222,0.42402,0.42574,0.41956,0.41085,0.40143,0.39009,0.37701,0.36387,0.35184,0.34151},
{0.32861,0.32598,0.32444,0.32451,0.32723,0.33225,0.33844,0.34476,0.34925,0.34892,0.34232,0.33071,0.31718,0.30603,0.30142,0.30408,0.3115,0.32118,0.33137,0.34024,0.34686,0.35275,0.36068,0.37146,0.38401,0.39715,0.40907,0.41682,0.418,0.41256,0.40201,0.38791,0.37189,0.35616,0.34293,0.33373,0.32861},
{0.34027,0.34127,0.34464,0.3507,0.36038,0.37294,0.3865,0.39917,0.40815,0.4099,0.40274,0.38831,0.37072,0.3552,0.34582,0.34316,0.34566,0.35218,0.36135,0.37089,0.37971,0.38903,0.39965,0.41036,0.42049,0.43072,0.44044,0.44743,0.44945,0.44455,0.43158,0.41195,0.38966,0.369,0.35302,0.34348,0.34027},
{0.37253,0.3743,0.38082,0.39172,0.4068,0.42456,0.44274,0.45904,0.47046,0.47349,0.4662,0.45016,0.43012,0.41204,0.39986,0.39392,0.39314,0.39717,0.40505,0.41434,0.42357,0.43356,0.44488,0.45654,0.46802,0.47977,0.49115,0.5,0.50357,0.49896,0.48426,0.46097,0.43398,0.40879,0.38917,0.37703,0.37253},
{0.42232,0.42361,0.43153,0.44511,0.46277,0.48222,0.50102,0.51697,0.52763,0.53021,0.5231,0.50749,0.48759,0.46872,0.4545,0.44574,0.44202,0.44314,0.44829,0.45556,0.46359,0.47278,0.48398,0.49721,0.51197,0.52753,0.54226,0.5536,0.55855,0.55434,0.53968,0.51634,0.489,0.46299,0.44215,0.4284,0.42232},
{0.48297,0.48409,0.49144,0.50386,0.51947,0.53592,0.55104,0.56298,0.57002,0.57048,0.5635,0.54997,0.53268,0.51524,0.50048,0.48973,0.48333,0.48125,0.48294,0.48735,0.49374,0.50234,0.51385,0.52856,0.54583,0.56407,0.58089,0.59345,0.59903,0.5957,0.58321,0.56356,0.54058,0.51853,0.50058,0.4885,0.48297},
{0.53888,0.53954,0.54416,0.55185,0.5613,0.57099,0.5795,0.58558,0.58818,0.58651,0.58029,0.57006,0.55723,0.54365,0.53109,0.52078,0.51346,0.50946,0.50872,0.51103,0.51624,0.52445,0.53585,0.55027,0.56682,0.58384,0.59914,0.61041,0.61575,0.61419,0.60607,0.59307,0.5778,0.563,0.55086,0.54264,0.53888}
};
// 76 bytes
static const uint8_t declination_keys[2][37] = {
// Row start values
{36,30,25,21,18,16,14,12,11,10,9,9,9,8,8,8,7,6,6,5,4,4,4,3,4,4,4},
// Row length values
{39,38,33,35,37,35,37,36,39,34,41,42,42,28,39,40,43,51,50,39,37,34,44,51,49,48,55}
};
// 1056 total values @ 1 byte each = 1056 bytes
static const row_value declination_values[] = {
{0,0,4},{1,1,0},{0,0,2},{1,1,0},{0,0,2},{1,1,3},{2,1,1},{3,1,3},{4,1,1},{3,1,1},{2,1,1},{3,1,0},{2,1,0},{1,1,0},{2,1,1},{1,1,0},{2,1,0},{3,1,4},{4,1,1},{3,1,0},{4,1,0},{3,1,2},{2,1,2},{1,1,1},{0,0,0},{1,0,1},{3,0,0},{4,0,0},{6,0,0},{8,0,0},{11,0,0},{13,0,1},{10,0,0},{9,0,0},{7,0,0},{5,0,0},{4,0,0},{2,0,0},{1,0,2},
{0,0,6},{1,1,0},{0,0,6},{1,1,2},{2,1,0},{3,1,2},{4,1,2},{3,1,3},{2,1,0},{1,1,0},{2,1,0},{1,1,2},{2,1,2},{3,1,3},{4,1,0},{3,1,3},{2,1,1},{1,1,1},{0,0,0},{1,0,1},{2,0,0},{4,0,0},{5,0,0},{6,0,0},{7,0,0},{8,0,0},{9,0,0},{8,0,0},{6,0,0},{7,0,0},{6,0,0},{4,0,1},{3,0,0},{2,0,0},{1,0,0},{2,0,0},{0,0,0},{1,0,0},
{0,0,1},{1,0,0},{0,0,1},{1,1,0},{0,0,6},{1,0,0},{1,1,0},{0,0,0},{1,1,1},{2,1,1},{3,1,0},{4,1,3},{3,1,0},{4,1,0},{3,1,1},{2,1,0},{1,1,7},{2,1,0},{3,1,6},{2,1,0},{1,1,2},{0,0,0},{1,0,0},{2,0,0},{3,0,1},{5,0,1},{6,0,0},{7,0,0},{6,0,2},{4,0,2},{3,0,1},{2,0,2},{1,0,1},
{0,0,0},{1,0,0},{0,0,7},{0,0,5},{1,1,1},{2,1,1},{3,1,0},{4,1,5},{3,1,1},{1,1,0},{2,1,0},{1,1,0},{0,0,0},{1,1,0},{0,0,1},{1,1,0},{0,0,0},{2,1,2},{3,1,1},{2,1,0},{3,1,0},{2,1,1},{1,1,0},{0,0,1},{1,0,0},{2,0,1},{4,0,1},{5,0,4},{4,0,0},{3,0,1},{4,0,0},{2,0,0},{3,0,0},{2,0,2},{1,0,2},
{0,0,0},{1,0,0},{0,0,7},{0,0,5},{1,1,2},{2,1,0},{4,1,0},{3,1,0},{5,1,0},{3,1,0},{5,1,0},{4,1,1},{3,1,0},{2,1,1},{1,1,2},{0,0,2},{1,0,0},{0,0,1},{1,1,0},{2,1,2},{3,1,0},{2,1,1},{1,1,1},{0,0,0},{1,0,0},{2,0,1},{3,0,1},{4,0,0},{5,0,0},{4,0,0},{5,0,0},{4,0,0},{3,0,1},{1,0,0},{3,0,0},{2,0,4},{1,0,3},
{0,0,1},{1,0,0},{0,0,7},{1,1,0},{0,0,4},{1,1,0},{2,1,1},{3,1,0},{4,1,2},{5,1,0},{4,1,0},{3,1,1},{2,1,1},{1,1,1},{0,0,2},{1,0,1},{2,0,0},{1,0,0},{0,0,0},{1,1,1},{2,1,3},{1,1,1},{1,0,2},{2,0,0},{3,0,1},{4,0,2},{3,0,1},{2,0,0},{1,0,0},{2,0,1},{1,0,0},{2,0,1},{1,0,0},{2,0,0},{1,0,3},
{0,0,2},{1,0,0},{0,0,5},{1,1,0},{0,0,4},{1,1,2},{2,1,0},{4,1,0},{3,1,0},{4,1,1},{5,1,0},{4,1,0},{3,1,1},{2,1,0},{1,1,1},{0,0,2},{1,0,0},{2,0,0},{1,0,0},{3,0,0},{2,0,0},{1,0,0},{0,0,1},{2,1,2},{1,1,0},{2,1,0},{0,0,1},{1,0,1},{2,0,1},{3,0,2},{4,0,0},{2,0,1},{1,0,2},{2,0,0},{1,0,1},{2,0,0},{1,0,5},
{0,0,0},{1,0,0},{0,0,7},{0,0,1},{1,1,0},{0,0,2},{1,1,2},{3,1,2},{4,1,3},{3,1,0},{2,1,1},{1,1,0},{0,0,2},{1,0,1},{2,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,0},{1,0,0},{0,0,0},{1,1,0},{2,1,0},{1,1,0},{2,1,1},{0,0,0},{1,1,0},{1,0,2},{2,0,1},{3,0,1},{2,0,1},{1,0,1},{0,0,0},{1,0,2},{2,0,0},{1,0,5},
{0,0,4},{1,0,0},{0,0,3},{1,1,0},{0,0,3},{1,1,0},{0,0,0},{1,1,0},{2,1,1},{3,1,1},{4,1,3},{3,1,0},{2,1,0},{1,1,0},{0,0,2},{1,0,0},{2,0,3},{3,0,0},{2,0,0},{3,0,0},{1,0,1},{1,1,1},{2,1,0},{1,1,0},{2,1,0},{1,1,0},{0,0,2},{1,0,0},{2,0,0},{1,0,0},{2,0,0},{3,0,0},{2,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,0},{1,0,7},{1,0,1},
{0,0,7},{0,0,5},{1,1,0},{0,0,1},{2,1,0},{1,1,0},{3,1,3},{4,1,1},{3,1,1},{1,1,1},{0,0,1},{1,0,0},{2,0,3},{3,0,0},{2,0,3},{0,0,2},{2,1,0},{1,1,0},{2,1,0},{1,1,0},{0,0,0},{1,1,0},{1,0,0},{0,0,0},{1,0,0},{2,0,0},{1,0,0},{2,0,1},{0,0,0},{1,0,0},{0,0,1},{1,0,0},{0,0,0},{1,0,7},
{0,0,6},{1,0,0},{0,0,0},{1,1,0},{0,0,4},{1,1,0},{0,0,0},{2,1,0},{1,1,0},{3,1,0},{2,1,0},{4,1,0},{3,1,0},{4,1,1},{2,1,2},{0,0,1},{1,0,0},{2,0,7},{2,0,0},{1,0,1},{0,0,1},{1,1,1},{2,1,0},{1,1,0},{0,0,0},{1,1,0},{0,0,0},{1,0,0},{0,0,0},{1,0,1},{2,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,2},{1,0,1},{0,0,0},{2,0,0},{1,0,2},{0,0,0},{1,0,0},
{0,0,7},{0,0,3},{1,1,0},{0,0,2},{1,1,0},{2,1,0},{1,1,0},{3,1,0},{2,1,0},{4,1,0},{3,1,0},{4,1,0},{3,1,0},{2,1,1},{1,1,0},{0,0,0},{1,0,1},{2,0,1},{3,0,0},{2,0,2},{1,0,0},{2,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,0},{1,1,0},{0,0,0},{2,1,0},{1,1,0},{0,0,0},{1,1,0},{0,0,1},{1,0,0},{0,0,0},{1,0,2},{0,0,3},{1,0,0},{0,0,0},{1,0,6},{0,0,0},{1,0,0},
{0,0,2},{1,1,0},{0,0,1},{1,0,0},{0,0,3},{1,1,0},{0,0,2},{1,1,2},{2,1,0},{3,1,0},{2,1,0},{3,1,0},{4,1,0},{3,1,1},{2,1,0},{1,1,1},{0,0,0},{1,0,0},{2,0,2},{3,0,0},{2,0,1},{1,0,0},{2,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,2},{1,1,0},{0,0,0},{1,1,1},{0,0,0},{1,1,0},{0,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,5},{1,0,7},{0,0,0},{1,0,0},
{0,0,5},{1,0,0},{0,0,4},{1,1,0},{0,0,1},{1,1,1},{2,1,2},{3,1,4},{2,1,0},{1,1,0},{0,0,0},{1,0,1},{2,0,6},{1,0,1},{0,0,0},{1,0,1},{0,0,2},{1,1,1},{0,0,0},{1,1,0},{0,0,1},{1,1,0},{0,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,7},{1,0,7},
{0,0,3},{1,0,0},{0,0,7},{1,1,0},{0,0,0},{1,1,0},{2,1,3},{3,1,3},{2,1,0},{1,1,1},{0,0,0},{1,0,1},{2,0,2},{3,0,0},{1,0,0},{2,0,0},{1,0,0},{2,0,0},{0,0,1},{1,0,1},{0,0,2},{1,1,0},{0,0,0},{1,1,0},{0,0,1},{1,1,0},{0,0,3},{1,0,0},{0,0,2},{1,1,0},{0,0,3},{1,0,0},{0,0,0},{1,0,0},{2,0,0},{1,0,1},{2,0,0},{0,0,0},{1,0,0},
{0,0,1},{1,0,0},{0,0,2},{1,0,0},{0,0,5},{1,1,2},{2,1,1},{3,1,0},{2,1,0},{3,1,2},{2,1,1},{1,1,0},{0,0,1},{1,0,0},{2,0,0},{1,0,0},{2,0,4},{1,0,1},{0,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,0},{1,1,0},{0,0,0},{1,1,1},{0,0,7},{0,0,0},{1,1,0},{0,0,0},{1,1,0},{0,0,3},{1,0,1},{0,0,0},{1,0,0},{2,0,0},{1,0,0},{2,0,0},{1,0,0},{1,0,0},
{0,0,0},{1,0,1},{0,0,1},{1,0,0},{0,0,0},{1,0,0},{0,0,3},{1,1,0},{0,0,0},{1,1,0},{2,1,2},{3,1,0},{2,1,0},{4,1,0},{3,1,0},{2,1,2},{1,1,0},{0,0,0},{1,0,2},{2,0,4},{1,0,0},{2,0,0},{0,0,0},{1,0,0},{0,0,0},{1,0,1},{0,0,2},{1,1,0},{0,0,0},{1,1,0},{0,0,0},{1,1,0},{0,0,5},{1,1,0},{0,0,0},{1,1,1},{0,0,0},{1,1,0},{0,0,1},{1,0,4},{2,0,1},{1,0,0},{1,0,0},
{0,0,0},{2,0,0},{1,0,0},{0,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,3},{1,1,0},{0,0,0},{2,1,2},{3,1,0},{2,1,0},{3,1,0},{4,1,0},{3,1,0},{2,1,1},{1,1,1},{1,0,0},{0,0,0},{2,0,0},{1,0,0},{2,0,1},{1,0,0},{2,0,2},{1,0,0},{0,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,0},{1,0,0},{1,1,0},{0,0,1},{1,1,0},{0,0,0},{1,1,0},{0,0,1},{1,1,0},{0,0,2},{1,1,3},{0,0,0},{1,1,0},{0,0,2},{1,0,0},{2,0,0},{1,0,1},{2,0,0},{1,0,0},{2,0,0},{1,0,0},
{0,0,0},{1,0,1},{2,0,0},{1,0,1},{0,0,0},{1,0,0},{0,0,0},{1,0,0},{0,0,0},{1,1,0},{0,0,0},{2,1,0},{1,1,0},{2,1,0},{3,1,1},{2,1,0},{4,1,1},{3,1,0},{2,1,1},{1,1,0},{0,0,1},{1,0,0},{2,0,0},{1,0,0},{2,0,2},{1,0,0},{2,0,1},{1,0,0},{0,0,0},{1,0,2},{0,0,0},{1,0,0},{0,0,3},{1,1,0},{0,0,1},{1,1,0},{0,0,0},{1,1,0},{0,0,0},{1,1,0},{0,0,0},{1,1,2},{2,1,0},{1,1,1},{0,0,1},{1,0,3},{2,0,0},{1,0,0},{2,0,1},{2,0,0},
{0,0,0},{2,0,0},{1,0,0},{2,0,0},{1,0,4},{0,0,1},{1,1,0},{0,0,0},{2,1,0},{1,1,0},{3,1,3},{4,1,1},{3,1,0},{2,1,1},{1,1,0},{0,0,0},{1,0,2},{2,0,0},{1,0,0},{2,0,4},{1,0,0},{0,0,0},{1,0,3},{0,0,0},{1,0,0},{0,0,4},{1,1,0},{0,0,0},{1,1,0},{0,0,0},{1,1,4},{2,1,1},{1,1,1},{0,0,2},{1,0,1},{2,0,2},{1,0,0},{2,0,0},{2,0,0},
{0,0,0},{2,0,3},{1,0,3},{0,0,2},{1,1,0},{2,1,2},{4,1,0},{3,1,0},{4,1,2},{3,1,1},{1,1,1},{0,0,0},{1,0,2},{2,0,4},{1,0,0},{2,0,1},{0,0,0},{1,0,0},{2,0,0},{0,0,0},{1,0,2},{0,0,0},{1,0,0},{0,0,3},{1,1,4},{2,1,0},{1,1,0},{2,1,2},{1,1,2},{0,0,1},{1,0,0},{2,0,1},{1,0,0},{3,0,0},{1,0,0},{2,0,0},{2,0,0},
{0,0,0},{2,0,4},{1,0,3},{0,0,0},{1,1,2},{3,1,1},{4,1,2},{5,1,0},{4,1,0},{3,1,1},{1,1,1},{0,0,0},{1,0,1},{2,0,0},{1,0,0},{2,0,1},{3,0,0},{2,0,2},{1,0,2},{2,0,0},{1,0,5},{0,0,4},{1,1,1},{2,1,4},{3,1,0},{2,1,1},{1,1,1},{0,0,0},{1,0,2},{2,0,1},{3,0,0},{2,0,0},{1,0,0},{3,0,0},
{0,0,0},{2,0,1},{3,0,0},{2,0,1},{1,0,0},{2,0,0},{1,0,0},{0,0,2},{1,1,0},{2,1,0},{3,1,1},{5,1,4},{3,1,1},{1,1,1},{1,0,0},{0,0,0},{2,0,1},{1,0,0},{3,0,0},{2,0,2},{3,0,0},{2,0,1},{1,0,1},{2,0,1},{1,0,0},{2,0,0},{1,0,3},{0,0,0},{1,0,0},{1,1,0},{0,0,0},{1,1,0},{2,1,2},{3,1,0},{2,1,0},{3,1,2},{2,1,0},{1,1,1},{0,0,0},{1,0,2},{2,0,1},{3,0,0},{2,0,1},{3,0,0},
{0,0,0},{3,0,1},{2,0,0},{3,0,0},{2,0,0},{1,0,0},{2,0,0},{1,0,1},{0,0,1},{2,1,1},{3,1,0},{4,1,0},{6,1,0},{5,1,0},{7,1,0},{6,1,0},{5,1,0},{3,1,1},{1,1,0},{0,0,1},{1,0,0},{2,0,3},{3,0,0},{2,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,1},{1,0,0},{2,0,5},{1,0,2},{0,0,2},{1,1,0},{2,1,0},{3,1,2},{4,1,0},{3,1,0},{4,1,0},{3,1,0},{2,1,1},{1,1,0},{1,0,0},{0,0,0},{2,0,0},{1,0,0},{2,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,0},{2,0,0},
{0,0,0},{2,0,0},{3,0,1},{2,0,0},{3,0,0},{2,0,1},{1,0,1},{0,0,1},{2,1,1},{4,1,0},{6,1,0},{7,1,1},{8,1,0},{7,1,0},{5,1,0},{3,1,0},{2,1,0},{1,1,0},{0,0,0},{1,0,1},{2,0,1},{3,0,0},{2,0,0},{3,0,2},{2,0,0},{3,0,2},{1,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,4},{1,0,1},{0,0,1},{1,1,0},{2,1,0},{3,1,0},{4,1,0},{5,1,0},{4,1,1},{5,1,0},{4,1,0},{2,1,1},{1,1,0},{0,0,0},{1,0,0},{2,0,3},{3,0,1},{2,0,0},{3,0,0},
{0,0,0},{3,0,2},{2,0,0},{3,0,0},{2,0,2},{1,0,0},{0,0,1},{2,1,0},{3,1,0},{5,1,0},{8,1,0},{9,1,0},{10,1,1},{7,1,0},{5,1,0},{3,1,0},{1,1,0},{0,0,0},{1,0,1},{2,0,0},{3,0,0},{2,0,0},{3,0,3},{4,0,0},{3,0,7},{2,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,0},{1,0,0},{2,0,0},{0,0,2},{2,1,0},{3,1,0},{4,1,0},{5,1,0},{7,1,0},{5,1,0},{6,1,0},{4,1,1},{2,1,0},{0,0,1},{1,0,1},{2,0,1},{3,0,2},{2,0,0},{3,0,0},
{0,0,0},{3,0,5},{2,0,1},{1,0,0},{0,0,0},{1,1,0},{2,1,0},{5,1,0},{8,1,0},{12,1,0},{14,1,0},{13,1,0},{9,1,0},{6,1,0},{3,1,0},{1,1,0},{0,0,0},{2,0,0},{1,0,0},{3,0,0},{2,0,0},{3,0,0},{4,0,0},{3,0,1},{4,0,0},{3,0,0},{4,0,1},{3,0,0},{4,0,0},{3,0,2},{4,0,0},{3,0,1},{4,0,0},{3,0,0},{2,0,0},{3,0,0},{2,0,2},{0,0,1},{1,1,0},{2,1,0},{4,1,0},{5,1,0},{7,1,0},{8,1,0},{6,1,1},{5,1,0},{3,1,0},{1,1,1},{1,0,1},{2,0,0},{3,0,0},{2,0,0},{3,0,1},{2,0,0},{3,0,0},
};
float
AP_Declination::get_declination(float lat, float lon)
/*
calculate magnetic field intensity and orientation
*/
bool AP_Declination::get_mag_field_ef(float latitude_deg, float longitude_deg, float &intensity_gauss, float &declination_deg, float &inclination_deg)
{
int16_t decSW, decSE, decNW, decNE, lonmin, latmin;
uint8_t latmin_index,lonmin_index;
float decmin, decmax;
/* set this always to the sampling in degrees for the table below */
const float SAMPLING_RES = 10.0f;
const float SAMPLING_MIN_LAT = -60.0f;
const float SAMPLING_MAX_LAT = 60.0f;
const float SAMPLING_MIN_LON = -180.0f;
const float SAMPLING_MAX_LON = 180.0f;
// Constrain to valid inputs
lat = constrain_float(lat, -90, 90);
lon = constrain_float(lon, -180, 180);
bool valid_input_data = true;
latmin = floorf(lat/5)*5;
lonmin = floorf(lon/5)*5;
/* round down to nearest sampling resolution */
int32_t min_lat = static_cast<int32_t>(static_cast<int32_t>(latitude_deg / SAMPLING_RES) * SAMPLING_RES);
int32_t min_lon = static_cast<int32_t>(static_cast<int32_t>(longitude_deg / SAMPLING_RES) * SAMPLING_RES);
latmin_index= (90+latmin)/5;
lonmin_index= (180+lonmin)/5;
/* for the rare case of hitting the bounds exactly
* the rounding logic wouldn't fit, so enforce it.
*/
decSW = get_lookup_value(latmin_index, lonmin_index);
decSE = get_lookup_value(latmin_index, lonmin_index+1);
decNE = get_lookup_value(latmin_index+1, lonmin_index+1);
decNW = get_lookup_value(latmin_index+1, lonmin_index);
/* limit to table bounds - required for maxima even when table spans full globe range */
if (latitude_deg <= SAMPLING_MIN_LAT) {
min_lat = static_cast<int32_t>(SAMPLING_MIN_LAT);
valid_input_data = false;
}
/* approximate declination within the grid using bilinear interpolation */
decmin = (lon - lonmin) / 5 * (decSE - decSW) + decSW;
decmax = (lon - lonmin) / 5 * (decNE - decNW) + decNW;
return (lat - latmin) / 5 * (decmax - decmin) + decmin;
if (latitude_deg >= SAMPLING_MAX_LAT) {
min_lat = static_cast<int32_t>(static_cast<int32_t>(latitude_deg / SAMPLING_RES) * SAMPLING_RES - SAMPLING_RES);
valid_input_data = false;
}
if (longitude_deg <= SAMPLING_MIN_LON) {
min_lon = static_cast<int32_t>(SAMPLING_MIN_LON);
valid_input_data = false;
}
if (longitude_deg >= SAMPLING_MAX_LON) {
min_lon = static_cast<int32_t>(static_cast<int32_t>(longitude_deg / SAMPLING_RES) * SAMPLING_RES - SAMPLING_RES);
valid_input_data = false;
}
/* find index of nearest low sampling point */
uint32_t min_lat_index = static_cast<uint32_t>((-(SAMPLING_MIN_LAT) + min_lat) / SAMPLING_RES);
uint32_t min_lon_index = static_cast<uint32_t>((-(SAMPLING_MIN_LON) + min_lon) / SAMPLING_RES);
/* calculate intensity */
float data_sw = intensity_table[min_lat_index][min_lon_index];
float data_se = intensity_table[min_lat_index][min_lon_index + 1];;
float data_ne = intensity_table[min_lat_index + 1][min_lon_index + 1];
float data_nw = intensity_table[min_lat_index + 1][min_lon_index];
/* perform bilinear interpolation on the four grid corners */
float data_min = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_se - data_sw) + data_sw;
float data_max = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_ne - data_nw) + data_nw;
intensity_gauss = ((latitude_deg - min_lat) / SAMPLING_RES) * (data_max - data_min) + data_min;
/* calculate declination */
data_sw = declination_table[min_lat_index][min_lon_index];
data_se = declination_table[min_lat_index][min_lon_index + 1];;
data_ne = declination_table[min_lat_index + 1][min_lon_index + 1];
data_nw = declination_table[min_lat_index + 1][min_lon_index];
/* perform bilinear interpolation on the four grid corners */
data_min = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_se - data_sw) + data_sw;
data_max = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_ne - data_nw) + data_nw;
declination_deg = ((latitude_deg - min_lat) / SAMPLING_RES) * (data_max - data_min) + data_min;
/* calculate inclination */
data_sw = inclination_table[min_lat_index][min_lon_index];
data_se = inclination_table[min_lat_index][min_lon_index + 1];;
data_ne = inclination_table[min_lat_index + 1][min_lon_index + 1];
data_nw = inclination_table[min_lat_index + 1][min_lon_index];
/* perform bilinear interpolation on the four grid corners */
data_min = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_se - data_sw) + data_sw;
data_max = ((longitude_deg - min_lon) / SAMPLING_RES) * (data_ne - data_nw) + data_nw;
inclination_deg = ((latitude_deg - min_lat) / SAMPLING_RES) * (data_max - data_min) + data_min;
return valid_input_data;
}
int16_t
AP_Declination::get_lookup_value(uint8_t x, uint8_t y)
/*
calculate magnetic field intensity and orientation
*/
float AP_Declination::get_declination(float latitude_deg, float longitude_deg)
{
// return value
int16_t val = 0;
float declination_deg=0, inclination_deg=0, intensity_gauss=0;
// These are exception indices
if(x <= 6 || x >= 34)
{
// If the x index is in the upper range we need to translate it
// to match the 10 indices in the exceptions lookup table
if(x >= 34) x -= 27;
get_mag_field_ef(latitude_deg, longitude_deg, intensity_gauss, declination_deg, inclination_deg);
// Read the unsigned value from the array
val = exceptions[x][y];
// Read the 8 bit compressed sign values
uint8_t sign = exception_signs[x][y/8];
// Check the sign bit for this index
if(sign & (0x80 >> y%8))
val = -val;
return val;
}
// Because the values were removed from the start of the
// original array (0-6) to the exception array, all the indices
// in this main lookup need to be shifted left 7
// EX: User enters 7 -> 7 is the first row in this array so it needs to be zero
if(x >= 7) x -= 7;
// If we are looking for the first value we can just use the
// row start value from declination_keys
if (y == 0) {
return declination_keys[0][x];
}
// Init vars
row_value stval;
int16_t offset = 0;
// These will never exceed the second dimension length of 73
uint8_t current_virtual_index = 0, r;
// This could be the length of the array or less (1075 or less)
uint16_t start_index = 0, i;
// Init value to row start
val = declination_keys[0][x];
// Find the first element in the 1D array
// that corresponds with the target row
for(i = 0; i < x; i++) {
start_index += declination_keys[1][i];
}
// Traverse the row until we find our value
for(i = start_index; i < (start_index + declination_keys[1][x]) && current_virtual_index <= y; i++) {
// Pull out the row_value struct
memcpy((void*) &stval, (const char *)&declination_values[i], sizeof(struct row_value));
// Pull the first offset and determine sign
offset = stval.abs_offset;
offset = (stval.offset_sign == 1) ? -offset : offset;
// Add offset for each repeat
// This will at least run once for zero repeat
for(r = 0; r <= stval.repeats && current_virtual_index <= y; r++) {
val += offset;
current_virtual_index++;
}
}
return val;
return declination_deg;
}

30
libraries/AP_Declination/AP_Declination.h
View File

@ -1,20 +1,28 @@
#pragma once
#include <inttypes.h>
/*
* Adam M Rivera
* With direction from: Andrew Tridgell, Jason Short, Justin Beech
*
* Adapted from: http://www.societyofrobots.com/robotforum/index.php?topic=11855.0
* Scott Ferguson
* scottfromscott@gmail.com
*
magnetic data derived from WMM
*/
class AP_Declination
{
public:
static float get_declination(float lat, float lon);
/*
* Calculates the magnetic intensity, declination and inclination at a given WGS-84 latitude and longitude.
* Assumes a WGS-84 height of zero
* latitude and longitude have units of degrees
* declination and inclination are returned in degrees
* intensity is returned in Gauss
* Boolean returns false if latitude and longitude are outside the valid input range of +-60 latitude and +-180 longitude
*/
static bool get_mag_field_ef(float latitude_deg, float longitude_deg, float &intensity_gauss, float &declination_deg, float &inclination_deg);
/*
get declination in degrees for a given latitude_deg and longitude_deg
*/
static float get_declination(float latitude_deg, float longitude_deg);
private:
static int16_t get_lookup_value(uint8_t x, uint8_t y);
static const float declination_table[13][37];
static const float inclination_table[13][37];
static const float intensity_table[13][37];
};