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working on renderableSatellites

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This commit is contained in:
Jonathan Fransson
2019-03-26 14:11:35 -06:00
committed by Elon
parent 5979a59d6a
commit 2c24dcaa32
3 changed files with 213 additions and 201 deletions
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2
data/assets/scene/solarsystem/planets/earth/satellites/satellites_shared.asset
View File

@@ -105,7 +105,7 @@ local addSatelliteGroupObjects = function(group, tleFolder, shouldAddDuplicates)
Identifier = title,
Parent = transforms.EarthInertial.Identifier,
Renderable = {
Type = "RenderableSatellite",
Type = "RenderableSatellites",
Color = color,
Period = per,
Resolution = 160,

407
modules/space/rendering/renderablesatellites.cpp
View File

@@ -21,8 +21,13 @@
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
#include <fstream>
#include <chrono>
#include <vector>
#include <modules/space/rendering/renderablesatellites.h>
#include <modules/space/translation/keplertranslation.h>
#include <modules/base/basemodule.h>
@@ -33,6 +38,7 @@
#include <openspace/util/updatestructures.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/filesystem/file.h>
#include <ghoul/misc/csvreader.h>
// Todo:
@@ -43,7 +49,7 @@
namespace {
constexpr const char* ProgramName = "KeplerTrails";
constexpr const char* KeyFile = "File";
constexpr const char* KeyLineNumber = "LineNumber";
constexpr const char* KeyLineNum = "LineNumber";
static const openspace::properties::Property::PropertyInfo PathInfo = {
@@ -228,210 +234,15 @@ RenderableSatellites::RenderableSatellites(const ghoul::Dictionary& dictionary)
* test
*/
const std::string& file = dictionary.value<std::string(KeyFile);
const std::string& file = dictionary.value<std::string>(KeyFile);
int lineNum = 1;
if (dictionary.hasKeyAndValue)<double>(KeyLineNum) {
if (dictionary.hasKeyAndValue<double>(KeyLineNum)) {
lineNum = static_cast<int>(dictionary.value<double>(KeyLineNum));
}
readTLEFile(file, lineNum);
}
}
void RenderableSatellites::readTLEFile(const std::string& filename, int lineNum){
ghoul_assert(FileSys.fileExists(filename), "The filename must exist");
std::ifstream file;
file.exceptions(std::ofstream::failbit | std::ofstream::badbit);
file.open(filename);
// All of the Kepler element information
struct {
double inclination = 0.0;
double semiMajorAxis = 0.0;
double ascendingNode = 0.0;
double eccentricity = 0.0;
double argumentOfPeriapsis = 0.0;
double meanAnomaly = 0.0;
double meanMotion = 0.0;
double epoch = 0.0;
} keplerElements;
std::string line;
// Loop through and throw out lines until getting to the linNum of interest
for (int i = 1; i < lineNum; ++i) {
std::getline(file, line);
}
std::getline(file, line); // Throw out the TLE title line (1st)
std::getline(file, line); // Get line 1 of TLE format
if (line[0] == '1') {
// First line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 08-08 Classification (U = Unclassified)
// 4 10-11 International Designator (Last two digits of launch year)
// 5 12-14 International Designator (Launch number of the year)
// 6 15-17 International Designator(piece of the launch) A
// 7 19-20 Epoch Year(last two digits of year)
// 8 21-32 Epoch(day of the year and fractional portion of the day)
// 9 34-43 First Time Derivative of the Mean Motion divided by two
// 10 45-52 Second Time Derivative of Mean Motion divided by six
// 11 54-61 BSTAR drag term(decimal point assumed)[10] - 11606 - 4
// 12 63-63 The "Ephemeris type"
// 13 65-68 Element set number.Incremented when a new TLE is generated
// 14 69-69 Checksum (modulo 10)
keplerElements.epoch = epochFromSubstring(line.substr(18, 14));
} else {
throw ghoul::RuntimeError(fmt::format(
"File {} @ line {} does not have '1' header", filename, lineNum + 1
));
}
std::getline(file, line); // Get line 2 of TLE format
if (line[0] == '2') {
// Second line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 09-16 Inclination (degrees)
// 4 18-25 Right ascension of the ascending node (degrees)
// 5 27-33 Eccentricity (decimal point assumed)
// 6 35-42 Argument of perigee (degrees)
// 7 44-51 Mean Anomaly (degrees)
// 8 53-63 Mean Motion (revolutions per day)
// 9 64-68 Revolution number at epoch (revolutions)
// 10 69-69 Checksum (modulo 10)
std::stringstream stream;
stream.exceptions(std::ios::failbit);
// Get inclination
stream.str(line.substr(8, 8));
stream >> keplerElements.inclination;
stream.clear();
// Get Right ascension of the ascending node
stream.str(line.substr(17, 8));
stream >> keplerElements.ascendingNode;
stream.clear();
// Get Eccentricity
stream.str("0." + line.substr(26, 7));
stream >> keplerElements.eccentricity;
stream.clear();
// Get argument of periapsis
stream.str(line.substr(34, 8));
stream >> keplerElements.argumentOfPeriapsis;
stream.clear();
// Get mean anomaly
stream.str(line.substr(43, 8));
stream >> keplerElements.meanAnomaly;
stream.clear();
// Get mean motion
stream.str(line.substr(52, 11));
stream >> keplerElements.meanMotion;
} else {
throw ghoul::RuntimeError(fmt::format(
"File {} @ line {} does not have '2' header", filename, lineNum + 2
));
}
file.close();
// Calculate the semi major axis based on the mean motion using kepler's laws
keplerElements.semiMajorAxis = calculateSemiMajorAxis(keplerElements.meanMotion);
// Converting the mean motion (revolutions per day) to period (seconds per revolution)
using namespace std::chrono;
double period = seconds(hours(24)).count() / keplerElements.meanMotion;
setKeplerElements(
keplerElements.eccentricity,
keplerElements.semiMajorAxis,
keplerElements.inclination,
keplerElements.ascendingNode,
keplerElements.argumentOfPeriapsis,
keplerElements.meanAnomaly,
period,
keplerElements.epoch
);
}
double epochFromSubstring(const std::string& epochString) {
// The epochString is in the form:
// YYDDD.DDDDDDDD
// With YY being the last two years of the launch epoch, the first DDD the day
// of the year and the remaning a fractional part of the day
// The main overview of this function:
// 1. Reconstruct the full year from the YY part
// 2. Calculate the number of seconds since the beginning of the year
// 2.a Get the number of full days since the beginning of the year
// 2.b If the year is a leap year, modify the number of days
// 3. Convert the number of days to a number of seconds
// 4. Get the number of leap seconds since January 1st, 2000 and remove them
// 5. Adjust for the fact the epoch starts on 1st Januaray at 12:00:00, not
// midnight
// According to https://celestrak.com/columns/v04n03/
// Apparently, US Space Command sees no need to change the two-line element
// set format yet since no artificial earth satellites existed prior to 1957.
// By their reasoning, two-digit years from 57-99 correspond to 1957-1999 and
// those from 00-56 correspond to 2000-2056. We'll see each other again in 2057!
// 1. Get the full year
std::string yearPrefix = [y = epochString.substr(0, 2)](){
int year = std::atoi(y.c_str());
return year >= 57 ? "19" : "20";
}();
const int year = std::atoi((yearPrefix + epochString.substr(0, 2)).c_str());
const int daysSince2000 = countDays(year);
// 2.
// 2.a
double daysInYear = std::atof(epochString.substr(2).c_str());
// 2.b
const bool isInLeapYear = std::find(
LeapYears.begin(),
LeapYears.end(),
year
) != LeapYears.end();
if (isInLeapYear && daysInYear >= 60) {
// We are in a leap year, so we have an effective day more if we are
// beyond the end of february (= 31+29 days)
--daysInYear;
}
// 3
using namespace std::chrono;
const int SecondsPerDay = static_cast<int>(seconds(hours(24)).count());
//Need to subtract 1 from daysInYear since it is not a zero-based count
const double nSecondsSince2000 = (daysSince2000 + daysInYear - 1) * SecondsPerDay;
// 4
// We need to remove additionbal leap seconds past 2000 and add them prior to
// 2000 to sync up the time zones
const double nLeapSecondsOffset = -countLeapSeconds(
year,
static_cast<int>(std::floor(daysInYear))
);
// 5
const double nSecondsEpochOffset = static_cast<double>(
seconds(hours(12)).count()
);
// Combine all of the values
const double epoch = nSecondsSince2000 + nLeapSecondsOffset - nSecondsEpochOffset;
return epoch;
}
// The list of leap years only goes until 2056 as we need to touch this file then
// The list of leap years only goes until 2056 as we need to touch this file then
// again anyway ;)
const std::vector<int> LeapYears = {
1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992, 1996,
@@ -552,6 +363,202 @@ double epochFromSubstring(const std::string& epochString) {
// We need the semi major axis in km instead of m
return semiMajorAxis / 1000.0;
}
double epochFromSubstring(const std::string& epochString) {
// The epochString is in the form:
// YYDDD.DDDDDDDD
// With YY being the last two years of the launch epoch, the first DDD the day
// of the year and the remaning a fractional part of the day
// The main overview of this function:
// 1. Reconstruct the full year from the YY part
// 2. Calculate the number of seconds since the beginning of the year
// 2.a Get the number of full days since the beginning of the year
// 2.b If the year is a leap year, modify the number of days
// 3. Convert the number of days to a number of seconds
// 4. Get the number of leap seconds since January 1st, 2000 and remove them
// 5. Adjust for the fact the epoch starts on 1st Januaray at 12:00:00, not
// midnight
// According to https://celestrak.com/columns/v04n03/
// Apparently, US Space Command sees no need to change the two-line element
// set format yet since no artificial earth satellites existed prior to 1957.
// By their reasoning, two-digit years from 57-99 correspond to 1957-1999 and
// those from 00-56 correspond to 2000-2056. We'll see each other again in 2057!
// 1. Get the full year
std::string yearPrefix = [y = epochString.substr(0, 2)](){
int year = std::atoi(y.c_str());
return year >= 57 ? "19" : "20";
}();
const int year = std::atoi((yearPrefix + epochString.substr(0, 2)).c_str());
const int daysSince2000 = countDays(year);
// 2.
// 2.a
double daysInYear = std::atof(epochString.substr(2).c_str());
// 2.b
const bool isInLeapYear = std::find(
LeapYears.begin(),
LeapYears.end(),
year
) != LeapYears.end();
if (isInLeapYear && daysInYear >= 60) {
// We are in a leap year, so we have an effective day more if we are
// beyond the end of february (= 31+29 days)
--daysInYear;
}
// 3
using namespace std::chrono;
const int SecondsPerDay = static_cast<int>(seconds(hours(24)).count());
//Need to subtract 1 from daysInYear since it is not a zero-based count
const double nSecondsSince2000 = (daysSince2000 + daysInYear - 1) * SecondsPerDay;
// 4
// We need to remove additionbal leap seconds past 2000 and add them prior to
// 2000 to sync up the time zones
const double nLeapSecondsOffset = -countLeapSeconds(
year,
static_cast<int>(std::floor(daysInYear))
);
// 5
const double nSecondsEpochOffset = static_cast<double>(
seconds(hours(12)).count()
);
// Combine all of the values
const double epoch = nSecondsSince2000 + nLeapSecondsOffset - nSecondsEpochOffset;
return epoch;
}
void RenderableSatellites::readTLEFile(const std::string& filename, int lineNum){
ghoul_assert(FileSys.fileExists(filename), "The filename must exist");
std::ifstream file;
file.exceptions(std::ofstream::failbit | std::ofstream::badbit);
file.open(filename);
// All of the Kepler element information
struct {
double inclination = 0.0;
double semiMajorAxis = 0.0;
double ascendingNode = 0.0;
double eccentricity = 0.0;
double argumentOfPeriapsis = 0.0;
double meanAnomaly = 0.0;
double meanMotion = 0.0;
double epoch = 0.0;
} keplerElements;
std::string line;
// Loop through and throw out lines until getting to the linNum of interest
for (int i = 1; i < lineNum; ++i) {
std::getline(file, line);
}
std::getline(file, line); // Throw out the TLE title line (1st)
std::getline(file, line); // Get line 1 of TLE format
if (line[0] == '1') {
// First line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 08-08 Classification (U = Unclassified)
// 4 10-11 International Designator (Last two digits of launch year)
// 5 12-14 International Designator (Launch number of the year)
// 6 15-17 International Designator(piece of the launch) A
// 7 19-20 Epoch Year(last two digits of year)
// 8 21-32 Epoch(day of the year and fractional portion of the day)
// 9 34-43 First Time Derivative of the Mean Motion divided by two
// 10 45-52 Second Time Derivative of Mean Motion divided by six
// 11 54-61 BSTAR drag term(decimal point assumed)[10] - 11606 - 4
// 12 63-63 The "Ephemeris type"
// 13 65-68 Element set number.Incremented when a new TLE is generated
// 14 69-69 Checksum (modulo 10)
keplerElements.epoch = epochFromSubstring(line.substr(18, 14));
} else {
throw ghoul::RuntimeError(fmt::format(
"File {} @ line {} does not have '1' header", filename, lineNum + 1
));
}
std::getline(file, line); // Get line 2 of TLE format
if (line[0] == '2') {
// Second line
// Field Columns Content
// 1 01-01 Line number
// 2 03-07 Satellite number
// 3 09-16 Inclination (degrees)
// 4 18-25 Right ascension of the ascending node (degrees)
// 5 27-33 Eccentricity (decimal point assumed)
// 6 35-42 Argument of perigee (degrees)
// 7 44-51 Mean Anomaly (degrees)
// 8 53-63 Mean Motion (revolutions per day)
// 9 64-68 Revolution number at epoch (revolutions)
// 10 69-69 Checksum (modulo 10)
std::stringstream stream;
stream.exceptions(std::ios::failbit);
// Get inclination
stream.str(line.substr(8, 8));
stream >> keplerElements.inclination;
stream.clear();
// Get Right ascension of the ascending node
stream.str(line.substr(17, 8));
stream >> keplerElements.ascendingNode;
stream.clear();
// Get Eccentricity
stream.str("0." + line.substr(26, 7));
stream >> keplerElements.eccentricity;
stream.clear();
// Get argument of periapsis
stream.str(line.substr(34, 8));
stream >> keplerElements.argumentOfPeriapsis;
stream.clear();
// Get mean anomaly
stream.str(line.substr(43, 8));
stream >> keplerElements.meanAnomaly;
stream.clear();
// Get mean motion
stream.str(line.substr(52, 11));
stream >> keplerElements.meanMotion;
} else {
throw ghoul::RuntimeError(fmt::format(
"File {} @ line {} does not have '2' header", filename, lineNum + 2
));
}
file.close();
// Calculate the semi major axis based on the mean motion using kepler's laws
keplerElements.semiMajorAxis = calculateSemiMajorAxis(keplerElements.meanMotion);
// Converting the mean motion (revolutions per day) to period (seconds per revolution)
using namespace std::chrono;
double period = seconds(hours(24)).count() / keplerElements.meanMotion;
setKeplerElements(
keplerElements.eccentricity,
keplerElements.semiMajorAxis,
keplerElements.inclination,
keplerElements.ascendingNode,
keplerElements.argumentOfPeriapsis,
keplerElements.meanAnomaly,
period,
keplerElements.epoch
);
}
/*
* !test
*/

5
modules/space/rendering/renderablesatellites.h
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@@ -52,6 +52,11 @@ public:
void render(const RenderData& data, RendererTasks& rendererTask) override;
void update(const UpdateData& data) override;
void setKeplerElements(double eccentricity, double semiMajorAxis, double inclination,
double ascendingNode, double argumentOfPeriapsis, double meanAnomalyAtEpoch,
double orbitalPeriod, double epoch);
static documentation::Documentation Documentation();