gsdi.cxx

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// gsdi.cxx - Ground Speed Drift Angle Indicator (known as GSDI or GSDA)
// Written by Melchior FRANZ, started 2006.
//
// Copyright (C) 2006  Melchior FRANZ - mfranz#aon:at
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif
 
#include <simgear/sg_inlines.h>
#include <simgear/constants.h>
 
#include <Main/fg_props.hxx>
#include "gsdi.hxx"
 
 
/*
 * Failures or inaccuracies are currently not modeled due to lack of data.
 * The Doppler based GSDI should output unreliable data with increasing
 * pitch, roll, vertical acceleration and altitude-agl.
 */
 
 
GSDI::GSDI(SGPropertyNode *node) :
        _name(node->getStringValue("name", "gsdi")),
        _num(node->getIntValue("number", 0))
{
}
 
 
GSDI::~GSDI()
{
}
 
 
void GSDI::init()
{
  std::string branch;
        branch = "/instrumentation/" + _name;
        SGPropertyNode *n = fgGetNode(branch, _num, true);
        _serviceableN = n->getNode("serviceable", true);
 
        // input
        _ubodyN = fgGetNode("/velocities/uBody-fps", true);
        _vbodyN = fgGetNode("/velocities/vBody-fps", true);
 
        // output
        _drift_uN = n->getNode("drift-u-kt", true);
        _drift_vN = n->getNode("drift-v-kt", true);
        _drift_speedN = n->getNode("drift-speed-kt", true);
        _drift_angleN = n->getNode("drift-angle-deg", true);
}
 
 
void GSDI::update(double /*delta_time_sec*/)
{
        if (!_serviceableN->getBoolValue())
                return;
 
        double u = _ubodyN->getDoubleValue() * SG_FPS_TO_KT;
        double v = _vbodyN->getDoubleValue() * SG_FPS_TO_KT;
 
        double speed = sqrt(u * u + v * v);
        double angle = atan2(v, u) * SGD_RADIANS_TO_DEGREES;
 
        _drift_uN->setDoubleValue(u);
        _drift_vN->setDoubleValue(v);
        _drift_speedN->setDoubleValue(speed);
        _drift_angleN->setDoubleValue(angle);
}
 
 
// Register the subsystem.
#if 0
SGSubsystemMgr::InstancedRegistrant<GSDI> registrantGSDI(
    SGSubsystemMgr::FDM,
    {{"instrumentation", SGSubsystemMgr::Dependency::HARD}});
#endif
 
// end of gsdi.cxx