57 lines
2 KiB
C++
57 lines
2 KiB
C++
/*
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MinIMU-9-Arduino-AHRS
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Pololu MinIMU-9 + Arduino AHRS (Attitude and Heading Reference System)
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Copyright (c) 2011 Pololu Corporation.
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http://www.pololu.com/
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MinIMU-9-Arduino-AHRS is based on sf9domahrs by Doug Weibel and Jose Julio:
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http://code.google.com/p/sf9domahrs/
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sf9domahrs is based on ArduIMU v1.5 by Jordi Munoz and William Premerlani, Jose
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Julio and Doug Weibel:
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http://code.google.com/p/ardu-imu/
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MinIMU-9-Arduino-AHRS is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your option)
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any later version.
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MinIMU-9-Arduino-AHRS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License along
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with MinIMU-9-Arduino-AHRS. If not, see <http://www.gnu.org/licenses/>.
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*/
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void Compass_Heading()
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{
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float MAG_X;
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float MAG_Y;
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float cos_roll;
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float sin_roll;
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float cos_pitch;
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float sin_pitch;
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cos_roll = cos(roll);
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sin_roll = sin(roll);
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cos_pitch = cos(pitch);
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sin_pitch = sin(pitch);
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// adjust for LSM303 compass axis offsets/sensitivity differences by scaling to +/-0.5 range
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c_magnetom_x = (float)(magnetom_x - SENSOR_SIGN[6]*M_X_MIN) / (M_X_MAX - M_X_MIN) - SENSOR_SIGN[6]*0.5;
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c_magnetom_y = (float)(magnetom_y - SENSOR_SIGN[7]*M_Y_MIN) / (M_Y_MAX - M_Y_MIN) - SENSOR_SIGN[7]*0.5;
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c_magnetom_z = (float)(magnetom_z - SENSOR_SIGN[8]*M_Z_MIN) / (M_Z_MAX - M_Z_MIN) - SENSOR_SIGN[8]*0.5;
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// Tilt compensated Magnetic filed X:
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MAG_X = c_magnetom_x*cos_pitch+c_magnetom_y*sin_roll*sin_pitch+c_magnetom_z*cos_roll*sin_pitch;
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// Tilt compensated Magnetic filed Y:
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MAG_Y = c_magnetom_y*cos_roll-c_magnetom_z*sin_roll;
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// Magnetic Heading
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MAG_Heading = atan2(-MAG_Y,MAG_X);
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}
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