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ardupilot/libraries/AP_Declination/AP_Declination.cpp

222 lines
17 KiB
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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* 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
*
*/
#include <AP_Common.h>
#include <AP_Progmem.h>
#include <AP_Math.h>
#include <AP_Declination.h>
#include <AP_Progmem.h>
#include <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;
};
// 730 bytes
static const uint8_t exceptions[10][73] PROGMEM = \
{ \
{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} \
};
// 100 bytes
static const uint8_t exception_signs[10][10] PROGMEM = \
{ \
{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} \
};
// 76 bytes
static const uint8_t declination_keys[2][37] PROGMEM = \
{ \
// 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[] PROGMEM = \
{ \
{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}, \
};
#define PGM_UINT8(p) pgm_read_byte_far(p)
float
AP_Declination::get_declination(float lat, float lon)
{
int16_t decSW, decSE, decNW, decNE, lonmin, latmin;
uint8_t latmin_index,lonmin_index;
float decmin, decmax;
// Constrain to valid inputs
lat = constrain_float(lat, -90, 90);
lon = constrain_float(lon, -180, 180);
latmin = floorf(lat/5)*5;
lonmin = floorf(lon/5)*5;
latmin_index= (90+latmin)/5;
lonmin_index= (180+lonmin)/5;
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);
/* 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;
}
int16_t
AP_Declination::get_lookup_value(uint8_t x, uint8_t y)
{
// return value
int16_t val = 0;
// These are exception indicies
if(x <= 6 || x >= 34)
{
// If the x index is in the upper range we need to translate it
// to match the 10 indicies in the exceptions lookup table
if(x >= 34) x -= 27;
// Read the unsigned value from the array
val = PGM_UINT8(&exceptions[x][y]);
// Read the 8 bit compressed sign values
uint8_t sign = PGM_UINT8(&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 indicies
// 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 PGM_UINT8(&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 = PGM_UINT8(&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 += PGM_UINT8(&declination_keys[1][i]);
}
// Traverse the row until we find our value
for(i = start_index; i < (start_index + PGM_UINT8(&declination_keys[1][x])) && current_virtual_index <= y; i++) {
// Pull out the row_value struct
memcpy_P((void*) &stval, (const prog_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;
}
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