This program uses the "PSA" solar positioning algorithm calculating the sun position, based on longitude, latitude, and time zone. Then Mbed chip controls the two digital servos to rotate the solar panel to the correct azimuth and zenith angle.
Dependencies: 4DGL-uLCD-SE AX12 NetServices mbed spxml
Fork of AX12-HelloWorld by
Helios.cpp
- Committer:
- conantina
- Date:
- 2016-04-25
- Revision:
- 2:2a3493799f03
File content as of revision 2:2a3493799f03:
/* Helios.cpp- Copyright (c) 2011 Hannes Hassler. All rights reserved. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA This library can be used for calculating the solar position on Arduino. The algorithm is an adaption from the "PSA" solar positioning algorithm, as documented in: Blanco-Muriel et al.: Computing the Solar Vector. Solar Energy Vol 70 No 5 pp 431-441. http://dx.doi.org/10.1016/S0038-092X(00)00156-0 According to the paper, "The algorithm allows .. the true solar vector to be determined with an accuracy of 0.5 minutes of arc for the period 1999–2015. The original code has been downloaded from http://www.psa.es/sdg/sunpos.htm Adaptions: Modified calculation of number of Days since 1.Jan 2000 (dJulianDate-2451545.0) Neccessary because of the limited double precision on Arduino (double has the same precision as float on the current Arduino (2011)) It should be used only for dates between 1.1.2000 and 31.12.2100 (PSA itself has garantueed accuracy only until 2015) */ #include "Helios.h" #include <math.h> Helios::Helios(){} void Helios::calcSunPos( int iYear, int iMonth, int iDay, double dHours, double dMinutes, double dSeconds, double dLongitude, double dLatitude) { // Calculate difference in days between the current Julian Day // and JD 2451545.0, which is noon 1 January 2000 Universal Time { //double dJulianDate; //long int liAux1; //long int liAux2; // Calculate time of the day in UT decimal hours dDecimalHours = dHours + (dMinutes + dSeconds / 60.0 ) / 60.0; // Calculate current Julian Day /* original calculation; does not work for Arduino, because double precision is the same same as float. liAux1 =(iMonth-14)/12; liAux2=(1461*(iYear + 4800 + liAux1))/4 + (367*(iMonth - 2-12*liAux1))/12- (3*((iYear + 4900 + liAux1)/100))/4+iDay-32075; dJulianDate=(double)(liAux2)-0.5+dDecimalHours/24.0; // Calculate difference between current Julian Day and JD 2451545.0 dElapsedJulianDays = dJulianDate-2451545.0; */ long int iYfrom2000=iYear-2000; long int iA=(14-(iMonth))/12; long int iM=(iMonth)+12*iA-3; long int liAux3=(153*iM+2)/5; long int liAux4=365*(iYfrom2000-iA); long int liAux5=(iYfrom2000-iA)/4; dElapsedJulianDays=(double)(iDay+liAux3+liAux4+liAux5+59)+ -0.5+dDecimalHours/24.0; } // Calculate ecliptic coordinates (ecliptic longitude and obliquity of the // ecliptic in radians but without limiting the angle to be less than 2*Pi // (i.e., the result may be greater than 2*Pi) { /*double dMeanLongitude; double dMeanAnomaly; double dOmega;*/ dOmega=2.1429-0.0010394594*dElapsedJulianDays; dMeanLongitude = 4.8950630+ 0.017202791698*dElapsedJulianDays; // Radians dMeanAnomaly = 6.2400600+ 0.0172019699*dElapsedJulianDays; dEclipticLongitude = dMeanLongitude + 0.03341607*sin( dMeanAnomaly ) + 0.00034894*sin( 2*dMeanAnomaly )-0.0001134 -0.0000203*sin(dOmega); dEclipticObliquity = 0.4090928 - 6.2140e-9*dElapsedJulianDays +0.0000396*cos(dOmega); } // Calculate celestial coordinates ( right ascension and declination ) in radians // but without limiting the angle to be less than 2*Pi (i.e., the result may be // greater than 2*Pi) { dSin_EclipticLongitude= sin( dEclipticLongitude ); double dY1 = cos( dEclipticObliquity ) * dSin_EclipticLongitude; double dX1 = cos( dEclipticLongitude ); dRightAscension = atan2( dY1,dX1 ); if( dRightAscension < 0.0 ) dRightAscension = dRightAscension + twopi; dDeclination = asin( sin( dEclipticObliquity )*dSin_EclipticLongitude ); } // Calculate local coordinates ( azimuth and zenith angle ) in degrees { dGreenwichMeanSiderealTime = 6.6974243242 + 0.0657098283*dElapsedJulianDays + dDecimalHours; dLocalMeanSiderealTime = (dGreenwichMeanSiderealTime*15 + dLongitude)*rad; dHourAngle = dLocalMeanSiderealTime - dRightAscension; dLatitudeInRadians = dLatitude*rad; dCos_Latitude = cos( dLatitudeInRadians ); dSin_Latitude = sin( dLatitudeInRadians ); dCos_HourAngle= cos( dHourAngle ); dZenithAngle = (acos( dCos_Latitude*dCos_HourAngle *cos(dDeclination) + sin( dDeclination )*dSin_Latitude)); double dY = -sin( dHourAngle ); double dX = tan( dDeclination )*dCos_Latitude - dSin_Latitude*dCos_HourAngle; dAzimuth=atan2( dY, dX ); if ( dAzimuth < 0.0 ) dAzimuth = dAzimuth + twopi; dAzimuth = dAzimuth/rad; // Parallax Correction dParallax=(dEarthMeanRadius/dAstronomicalUnit) *sin(dZenithAngle); dZenithAngle=(dZenithAngle + dParallax)/rad; dElevation=90-dZenithAngle; } }