RasterProcessTool/SPG4Tool/PassPredict.cpp

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#include <Observer.h>
#include <SGP4.h>
#include <Util.h>
#include <CoordTopocentric.h>
#include <CoordGeodetic.h>
#include <cmath>
#include <iostream>
#include <list>
#include <QDate>
#include <QDateTime>
#include <iomanip>
#include <sstream>
#include "SPG4Function.h"
struct PassDetails
{
libsgp4::DateTime aos;
libsgp4::DateTime los;
double max_elevation;
};
double FindMaxElevation(
const libsgp4::CoordGeodetic& user_geo,
libsgp4::SGP4& sgp4,
const libsgp4::DateTime& aos,
const libsgp4::DateTime& los)
{
libsgp4::Observer obs(user_geo);
bool running;
double time_step = (los - aos).TotalSeconds() / 9.0;
libsgp4::DateTime current_time(aos); //! current time
libsgp4::DateTime time1(aos); //! start time of search period
libsgp4::DateTime time2(los); //! end time of search period
double max_elevation; //! max elevation
running = true;
do
{
running = true;
max_elevation = -99999999999999.0;
while (running && current_time < time2)
{
/*
* find position
*/
libsgp4::Eci eci = sgp4.FindPosition(current_time);
libsgp4::CoordTopocentric topo = obs.GetLookAngle(eci);
if (topo.elevation > max_elevation)
{
/*
* still going up
*/
max_elevation = topo.elevation;
/*
* move time along
*/
current_time = current_time.AddSeconds(time_step);
if (current_time > time2)
{
/*
* dont go past end time
*/
current_time = time2;
}
}
else
{
/*
* stop
*/
running = false;
}
}
/*
* make start time to 2 time steps back
*/
time1 = current_time.AddSeconds(-2.0 * time_step);
/*
* make end time to current time
*/
time2 = current_time;
/*
* current time to start time
*/
current_time = time1;
/*
* recalculate time step
*/
time_step = (time2 - time1).TotalSeconds() / 9.0;
} while (time_step > 1.0);
return max_elevation;
}
libsgp4::DateTime FindCrossingPoint(
const libsgp4::CoordGeodetic& user_geo,
libsgp4::SGP4& sgp4,
const libsgp4::DateTime& initial_time1,
const libsgp4::DateTime& initial_time2,
bool finding_aos)
{
libsgp4::Observer obs(user_geo);
bool running;
int cnt;
libsgp4::DateTime time1(initial_time1);
libsgp4::DateTime time2(initial_time2);
libsgp4::DateTime middle_time;
running = true;
cnt = 0;
while (running && cnt++ < 16)
{
middle_time = time1.AddSeconds((time2 - time1).TotalSeconds() / 2.0);
/*
* calculate satellite position
*/
libsgp4::Eci eci = sgp4.FindPosition(middle_time);
libsgp4::CoordTopocentric topo = obs.GetLookAngle(eci);
if (topo.elevation > 0.0)
{
/*
* satellite above horizon
*/
if (finding_aos)
{
time2 = middle_time;
}
else
{
time1 = middle_time;
}
}
else
{
if (finding_aos)
{
time1 = middle_time;
}
else
{
time2 = middle_time;
}
}
if ((time2 - time1).TotalSeconds() < 1.0)
{
/*
* two times are within a second, stop
*/
running = false;
/*
* remove microseconds
*/
int us = middle_time.Microsecond();
middle_time = middle_time.AddMicroseconds(-us);
/*
* step back into the pass by 1 second
*/
middle_time = middle_time.AddSeconds(finding_aos ? 1 : -1);
}
}
/*
* go back/forward 1second until below the horizon
*/
running = true;
cnt = 0;
while (running && cnt++ < 6)
{
libsgp4::Eci eci = sgp4.FindPosition(middle_time);
libsgp4::CoordTopocentric topo = obs.GetLookAngle(eci);
if (topo.elevation > 0)
{
middle_time = middle_time.AddSeconds(finding_aos ? -1 : 1);
}
else
{
running = false;
}
}
return middle_time;
}
std::list<struct PassDetails> GeneratePassList(
const libsgp4::CoordGeodetic& user_geo,
libsgp4::SGP4& sgp4,
const libsgp4::DateTime& start_time,
const libsgp4::DateTime& end_time,
const int time_step)
{
std::list<struct PassDetails> pass_list;
libsgp4::Observer obs(user_geo);
libsgp4::DateTime aos_time;
libsgp4::DateTime los_time;
bool found_aos = false;
libsgp4::DateTime previous_time(start_time);
libsgp4::DateTime current_time(start_time);
while (current_time < end_time)
{
bool end_of_pass = false;
/*
* calculate satellite position
*/
libsgp4::Eci eci = sgp4.FindPosition(current_time);
libsgp4::CoordTopocentric topo = obs.GetLookAngle(eci);
if (!found_aos && topo.elevation > 0.0)
{
/*
* aos hasnt occured yet, but the satellite is now above horizon
* this must have occured within the last time_step
*/
if (start_time == current_time)
{
/*
* satellite was already above the horizon at the start,
* so use the start time
*/
aos_time = start_time;
}
else
{
/*
* find the point at which the satellite crossed the horizon
*/
aos_time = FindCrossingPoint(
user_geo,
sgp4,
previous_time,
current_time,
true);
}
found_aos = true;
}
else if (found_aos && topo.elevation < 0.0)
{
found_aos = false;
/*
* end of pass, so move along more than time_step
*/
end_of_pass = true;
/*
* already have the aos, but now the satellite is below the horizon,
* so find the los
*/
los_time = FindCrossingPoint(
user_geo,
sgp4,
previous_time,
current_time,
false);
struct PassDetails pd;
pd.aos = aos_time;
pd.los = los_time;
pd.max_elevation = FindMaxElevation(
user_geo,
sgp4,
aos_time,
los_time);
pass_list.push_back(pd);
}
/*
* save current time
*/
previous_time = current_time;
if (end_of_pass)
{
/*
* at the end of the pass move the time along by 30mins
*/
current_time = current_time + libsgp4::TimeSpan(0, 30, 0);
}
else
{
/*
* move the time along by the time step value
*/
current_time = current_time + libsgp4::TimeSpan(0, 0, time_step);
}
if (current_time > end_time)
{
/*
* dont go past end time
*/
current_time = end_time;
}
};
if (found_aos)
{
/*
* satellite still above horizon at end of search period, so use end
* time as los
*/
struct PassDetails pd;
pd.aos = aos_time;
pd.los = end_time;
pd.max_elevation = FindMaxElevation(user_geo, sgp4, aos_time, end_time);
pass_list.push_back(pd);
}
return pass_list;
}
bool PassPredict(std::vector<QDateTime>& aos, std::vector<QDateTime>& los, std::string line1, std::string line2, double startTime, double predictDayLen, double lon, double lat, double ati) {
libsgp4::CoordGeodetic geo(lat, lon, ati);
libsgp4::Tle tle("GALILEO-PFM (GSAT0101) ",
line1,
line2);
libsgp4::SGP4 sgp4(tle);
std::vector<QDateTime> result;
// <20><> double ʱ<><CAB1><EFBFBD><EFBFBD>תΪ QDateTime
QDateTime dateTime = QDateTime::fromSecsSinceEpoch(static_cast<qint64>(startTime*1000));
libsgp4::DateTime start_date(
dateTime.date().year(),
dateTime.date().month(),
dateTime.date().day(),
dateTime.time().hour(),
dateTime.time().minute(),
dateTime.time().second(),
dateTime.time().msec() * 1000);
libsgp4::DateTime end_date(start_date.AddDays(predictDayLen));
std::list<struct PassDetails> pass_list;
pass_list = GeneratePassList(geo, sgp4, start_date, end_date, 180);
if (pass_list.begin() == pass_list.end())
{
return false;
}
else
{
std::stringstream ss;
ss << std::right << std::setprecision(1) << std::fixed;
std::list<struct PassDetails>::const_iterator itr = pass_list.begin();
do
{
ss << "AOS: " << itr->aos
<< ", LOS: " << itr->los
<< ", Max El: " << std::setw(4) << libsgp4::Util::RadiansToDegrees(itr->max_elevation)
<< ", Duration: " << (itr->los - itr->aos)
<< std::endl;
// <20><><EFBFBD><EFBFBD>AOSʱ<53><CAB1>
QDate aosDate(itr->aos.Year(), itr->aos.Month(), itr->aos.Day());
QTime aosTimePart(itr->aos.Hour(), itr->aos.Minute(), itr->aos.Second(), itr->aos.Microsecond());
QDateTime aosDateTime(aosDate, aosTimePart, Qt::UTC); //
// <20><><EFBFBD><EFBFBD>LOSʱ<53><CAB1>
QDate losDate(itr->los.Year(), itr->los.Month(), itr->los.Day());
QTime losTimePart(itr->los.Hour(), itr->los.Minute(), itr->los.Second(), itr->los.Microsecond());
QDateTime losDateTime(losDate, losTimePart, Qt::UTC); //
aos.push_back(aosDateTime);
los.push_back(losDateTime);
} while (++itr != pass_list.end());
std::cout << ss.str();
return true;
}
return false;
}