2002-09-27 18:27:58 +00:00
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// altimeter.cxx - an altimeter tied to the static port.
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// Written by David Megginson, started 2002.
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//
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// This file is in the Public Domain and comes with no warranty.
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#include <simgear/math/interpolater.hxx>
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#include "altimeter.hxx"
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#include <Main/fg_props.hxx>
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2002-09-27 22:04:21 +00:00
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#include <Main/util.hxx>
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2002-09-27 18:27:58 +00:00
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// Altitude based on pressure difference from sea level.
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// pressure difference inHG, altitude ft
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static double altitude_data[][2] = {
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-8.41, -8858.27,
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0.00, 0.00,
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3.05, 2952.76,
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5.86, 5905.51,
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8.41, 8858.27,
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10.74, 11811.02,
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12.87, 14763.78,
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14.78, 17716.54,
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16.55, 20669.29,
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18.13, 23622.05,
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19.62, 26574.80,
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20.82, 29527.56,
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21.96, 32480.31,
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23.01, 35433.07,
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23.91, 38385.83,
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24.71, 41338.58,
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25.40, 44291.34,
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26.00, 47244.09,
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26.51, 50196.85,
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26.96, 53149.61,
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27.35, 56102.36,
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27.68, 59055.12,
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27.98, 62007.87,
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29.62, 100000.00 // just to fill it in
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-1, -1,
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};
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Altimeter::Altimeter ()
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: _altitude_table(new SGInterpTable)
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{
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for (int i = 0; altitude_data[i][0] != -1; i++)
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_altitude_table->addEntry(altitude_data[i][0], altitude_data[i][1]);
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}
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Altimeter::~Altimeter ()
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{
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delete _altitude_table;
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}
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void
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Altimeter::init ()
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{
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_serviceable_node =
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fgGetNode("/instrumentation/altimeter/serviceable", true);
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_setting_node =
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fgGetNode("/instrumentation/altimeter/setting-inhg", true);
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_pressure_node =
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fgGetNode("/systems/static/pressure-inhg", true);
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_altitude_node =
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fgGetNode("/instrumentation/altimeter/indicated-altitude-ft", true);
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}
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void
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Altimeter::bind ()
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{
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}
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void
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Altimeter::unbind ()
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{
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}
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void
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Altimeter::update (double dt)
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{
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if (_serviceable_node->getBoolValue()) {
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double pressure = _pressure_node->getDoubleValue();
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double setting = _setting_node->getDoubleValue();
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2002-09-27 22:04:21 +00:00
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double altitude =
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fgGetLowPass(_altitude_node->getDoubleValue(),
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_altitude_table->interpolate(setting - pressure),
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dt * 10);
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_altitude_node->setDoubleValue(altitude);
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2002-09-27 18:27:58 +00:00
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}
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}
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// end of altimeter.cxx
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