/// <summary>
/// Ephemeris computation
/// </summary>
/// <param name="Y0"></param>
/// <param name="N_Step"></param>
/// <param name="Step"></param>
/// <param name="p"></param>
/// <param name="Eph"></param>
static void Ephemeris(Geo.Algorithm.Vector Y0, int N_Step, double Step, ForceModelOption p, Geo.Algorithm.Vector[] Eph)
{
int i;
double t, t_end;
double relerr, abserr; // Accuracy requirements
DeIntegrator Orb = new DeIntegrator(Deriv, 6, p); // Object for integrating the eq. of motion
Geo.Algorithm.Vector Y = new Geo.Algorithm.Vector(Y0);
relerr = 1.0e-13;
abserr = 1.0e-6;
t = 0.0;
// Y = Y0;
Orb.Init(t, relerr, abserr);
for (i = 0; i <= N_Step; i++)
{
t_end = Step * i;
var Yresult = Orb.Integ(t_end, Y);
Eph[i] = Yresult;
}
;
//var prevObj = Eph[0];
//Console.WriteLine(prevObj);
//var last = Eph[Eph.Length -1];
//Console.WriteLine(last);
}
/// <summary>
/// 导数、微分
/// Computes the derivative of the state vector .
/// pAux is expected to point to a variable of type AuxDataRecord, which is
/// used to communicate with the other program sections and to hold satData
/// between subsequent calls of this function
/// </summary>
/// <param name="t">历元</param>
/// <param name="y">卫星状态，坐标和速度</param>
/// <param name="pAux">附加选项</param>
static Geo.Algorithm.Vector Deriv(double t, Geo.Algorithm.Vector y, Object pAux)
{
// Pointer to auxiliary satData record
ForceModelOption p = (ForceModelOption)pAux;// static_cast<ForceModelOption*>(pAux);
// Time
double Mjd_TT = p.Mjd0_TT + t / 86400.0;
// State vector components
Geo.Algorithm.Vector r = y.Slice(0, 2);
Geo.Algorithm.Vector v = y.Slice(3, 5);
// Acceleration
AccelerationCalculator calculator = new AccelerationCalculator(p, IERS);
var a = calculator.GetAcceleration(Mjd_TT, r, v);
// State vector derivative
Geo.Algorithm.Vector yp = v.Stack(a);
return(yp);
}
/// <summary>
/// 构造函数。
/// </summary>
/// <param name="option"></param>
/// <param name="IERS"></param>
public AccelerationCalculator(ForceModelOption option, IERS IERS)
{
this.IERS = IERS;
this.Option = option;
}
static void Main0(string[] args)
{
// Constants
const int N_Step = 720; // Maximum number of steps
// Variables
int i;
int N_Step1;
int N_Step2;
double Step;
double Mjd0_UTC;
Geo.Algorithm.Vector Y0 = new Geo.Algorithm.Vector(6);
Geo.Algorithm.Vector Kep = new Geo.Algorithm.Vector(6);
ForceModelOption Aux_ref = new ForceModelOption(), Aux = new ForceModelOption(); // Auxiliary parameters
double Max_J20, Max_J22, Max_J44, Max_J1010;
double Max_Sun, Max_Moon, Max_SRad, Max_Drag;
Geo.Algorithm.Vector[] Eph_Ref = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_J20 = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_J22 = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_J44 = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_J1010 = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_Sun = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_Moon = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_SRad = new Geo.Algorithm.Vector[N_Step + 1];
Geo.Algorithm.Vector[] Eph_Drag = new Geo.Algorithm.Vector[N_Step + 1];
// Initialize UT1-UTC and UTC-TAI time difference
IERS = new IERS(-0.05, -30.00, 0.0, 0.0);
// Epoch state (remote sensing satellite)
Mjd0_UTC = DateUtil.DateToMjd(1999, 03, 01, 00, 00, 0.0);
Kep = new Vector(7178.0e3, 0.0010, 98.57 * OrbitConsts.RadPerDeg, 0.0, 0.0, 0.0);
Y0 = Kepler.State(OrbitConsts.GM_Earth, Kep, 0.0);
// Model parameters
Aux_ref.Mjd0_TT = Mjd0_UTC - IERS.GetTT_UTC(Mjd0_UTC) / 86400.0;
Aux_ref.Area = 5.0; // [m^2] Remote sensing satellite
Aux_ref.Mass = 1000.0; // [kg]
Aux_ref.CoefOfRadiation = 1.3;
Aux_ref.CoefOfDrag = 2.3;
Aux_ref.MaxDegree = 20;
Aux_ref.MaxOrder = 20;
Aux_ref.EnableSun = true;
Aux_ref.EnableMoon = true;
Aux_ref.EnableSolarRadiation = true;
Aux_ref.EnableDrag = true;
// Reference orbit
Step = 120.0; // [s]
N_Step1 = 50; // 100 mins
N_Step2 = 720; // 1 day
Aux = Aux_ref;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Ref);
// J2,0 perturbations
Aux.MaxDegree = 2; Aux.MaxOrder = 0;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J20);
// J2,2 perturbations
Aux.MaxDegree = 2; Aux.MaxOrder = 2;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J22);
// J4,4 perturbations
Aux.MaxDegree = 4; Aux.MaxOrder = 4;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J44);
// J10,10 perturbations
Aux.MaxDegree = 10; Aux.MaxOrder = 10;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J1010);
Aux.MaxDegree = 20; Aux.MaxOrder = 20;
// Solar perturbations
Aux.EnableSun = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Sun);
Aux.EnableSun = true;
// Lunar perturbations
Aux.EnableMoon = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Moon);
Aux.EnableMoon = true;
// Solar radiation pressure perturbations
Aux.EnableSolarRadiation = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_SRad);
Aux.EnableSolarRadiation = true;
// Drag perturbations
Aux.EnableDrag = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Drag);
Aux.EnableDrag = true;
// Find maximum over N_Step1 steps
Max_J20 = Max_J22 = Max_J44 = Max_J1010 = Max_Sun = Max_Moon = Max_SRad = Max_Drag = 0.0;
for (i = 0; i <= N_Step1; i++)
{
var refEph = Eph_Ref[i].Slice(0, 2);
Max_J20 = max(Norm(Eph_J20[i].Slice(0, 2) - refEph), Max_J20);
Max_J22 = max(Norm(Eph_J22[i].Slice(0, 2) - refEph), Max_J22);
Max_J44 = max(Norm(Eph_J44[i].Slice(0, 2) - refEph), Max_J44);
Max_J1010 = max(Norm(Eph_J1010[i].Slice(0, 2) - refEph), Max_J1010);
Max_Sun = max(Norm(Eph_Sun[i].Slice(0, 2) - refEph), Max_Sun);
Max_Moon = max(Norm(Eph_Moon[i].Slice(0, 2) - refEph), Max_Moon);
Max_SRad = max(Norm(Eph_SRad[i].Slice(0, 2) - refEph), Max_SRad);
Max_Drag = max(Norm(Eph_Drag[i].Slice(0, 2) - refEph), Max_Drag);
}
;
// Output
var info = "Exercise 3-4: Orbit Perturbations " + "\r\n" + "\r\n";
info += "Remote sensing satellite: " + "\r\n" + "\r\n";
info += " Maximum position errors within ";
Console.Write(info);
info = String.Format("{0, 8:F}", N_Step1 * Step / 60.0);
info += " min propagation interval " + "\r\n";
info += " J2,0 J2,2 J4,4 J10,10" + " Sun Moon SolRad Drag" + "\r\n";
info += " [m] [m] [m] [m]" + " [m] [m] [m] [m]";
Console.WriteLine(info);
info = String.Format("{0, 8:F}{1, 8:F}{2, 8:F}{3, 8:F}{4, 8:F}{5, 8:F}{6, 8:F}{7, 8:F}", Max_J20, Max_J22, Max_J44, Max_J1010, Max_Sun, Max_Moon, Max_SRad, Max_Drag);
Console.WriteLine(info);
Console.WriteLine();
// Find maximum over N_Step2 steps
for (i = N_Step1 + 1; i <= N_Step2; i++)
{
var refEph = Eph_Ref[i].Slice(0, 2);
Max_J20 = max(Norm(Eph_J20[i].Slice(0, 2) - refEph), Max_J20);
Max_J22 = max(Norm(Eph_J22[i].Slice(0, 2) - refEph), Max_J22);
Max_J44 = max(Norm(Eph_J44[i].Slice(0, 2) - refEph), Max_J44);
Max_J1010 = max(Norm(Eph_J1010[i].Slice(0, 2) - refEph), Max_J1010);
Max_Sun = max(Norm(Eph_Sun[i].Slice(0, 2) - refEph), Max_Sun);
Max_Moon = max(Norm(Eph_Moon[i].Slice(0, 2) - refEph), Max_Moon);
Max_SRad = max(Norm(Eph_SRad[i].Slice(0, 2) - refEph), Max_SRad);
Max_Drag = max(Norm(Eph_Drag[i].Slice(0, 2) - refEph), Max_Drag);
}
;
// Output
info = " Maximum position errors within ";
Console.Write(info);
info = String.Format("{0, 8:F}", N_Step2 * Step / 60.0);
info += " min propagation interval " + "\r\n";
info += " J2,0 J2,2 J4,4 J10,10" + " Sun Moon SolRad Drag" + "\r\n";
info += " [m] [m] [m] [m]" + " [m] [m] [m] [m]";
Console.WriteLine(info);
info = String.Format("{0, 8:F}{1, 8:F}{2, 8:F}{3, 8:F}{4, 8:F}{5, 8:F}{6, 8:F}{7, 8:F}", Max_J20, Max_J22, Max_J44, Max_J1010, Max_Sun, Max_Moon, Max_SRad, Max_Drag);
Console.WriteLine(info);
Console.WriteLine();
// Epoch state (geostationary satellite)
Kep = new Vector(42166.0e3, 0.0004, 0.02 * OrbitConsts.RadPerDeg, 0.0, 0.0, 0.0);
Y0 = Kepler.State(OrbitConsts.GM_Earth, Kep, 0.0);
// Model parameters
Aux_ref.Area = 10.0; // [m^2] Geostationary satellite
// Reference orbit
Step = 1200.0; // [s]
N_Step1 = 72; // 1 day
N_Step2 = 144; // 2 days
Aux = Aux_ref;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Ref);
// J2,0 perturbations
Aux.MaxDegree = 2; Aux.MaxOrder = 0;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J20);
// J2,2 perturbations
Aux.MaxDegree = 2; Aux.MaxOrder = 2;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J22);
// J4,4 perturbations
Aux.MaxDegree = 4; Aux.MaxOrder = 4;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J44);
// J10,10 perturbations
Aux.MaxDegree = 10; Aux.MaxOrder = 10;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_J1010);
Aux.MaxDegree = 20; Aux.MaxOrder = 20;
// Solar perturbations
Aux.EnableSun = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Sun);
Aux.EnableSun = true;
// Lunar perturbations
Aux.EnableMoon = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Moon);
Aux.EnableMoon = true;
// Solar radiation pressure perturbations
Aux.EnableSolarRadiation = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_SRad);
Aux.EnableSolarRadiation = true;
// Drag perturbations
Aux.EnableDrag = false;
Ephemeris(Y0, N_Step2, Step, Aux, Eph_Drag);
Aux.EnableDrag = true;
// Find maximum over N_Step1 steps
Max_J20 = Max_J22 = Max_J44 = Max_J1010 = Max_Sun = Max_Moon = Max_SRad = Max_Drag = 0.0;
for (i = 0; i <= N_Step1; i++)
{
var refEph = Eph_Ref[i].Slice(0, 2);
Max_J20 = max(Norm(Eph_J20[i].Slice(0, 2) - refEph), Max_J20);
Max_J22 = max(Norm(Eph_J22[i].Slice(0, 2) - refEph), Max_J22);
Max_J44 = max(Norm(Eph_J44[i].Slice(0, 2) - refEph), Max_J44);
Max_J1010 = max(Norm(Eph_J1010[i].Slice(0, 2) - refEph), Max_J1010);
Max_Sun = max(Norm(Eph_Sun[i].Slice(0, 2) - refEph), Max_Sun);
Max_Moon = max(Norm(Eph_Moon[i].Slice(0, 2) - refEph), Max_Moon);
Max_SRad = max(Norm(Eph_SRad[i].Slice(0, 2) - refEph), Max_SRad);
Max_Drag = max(Norm(Eph_Drag[i].Slice(0, 2) - refEph), Max_Drag);
}
;
// Output
// Output
info = "Geostationary satellite: " + "\r\n";
info += " Maximum position errors within ";
Console.Write(info);
info = String.Format("{0, 8:F}", N_Step1 * Step / 60.0);
info += " min propagation interval " + "\r\n";
info += " J2,0 J2,2 J4,4 J10,10" + " Sun Moon SolRad Drag" + "\r\n";
info += " [m] [m] [m] [m]" + " [m] [m] [m] [m]";
Console.WriteLine(info);
info = String.Format("{0, 8:F}{1, 8:F}{2, 8:F}{3, 8:F}{4, 8:F}{5, 8:F}{6, 8:F}{7, 8:F}", Max_J20, Max_J22, Max_J44, Max_J1010, Max_Sun, Max_Moon, Max_SRad, Max_Drag);
Console.WriteLine(info);
Console.WriteLine();
// Find maximum over N_Step2 steps
for (i = N_Step1 + 1; i <= N_Step2; i++)
{
var refEph = Eph_Ref[i].Slice(0, 2);
Max_J20 = max(Norm(Eph_J20[i].Slice(0, 2) - refEph), Max_J20);
Max_J22 = max(Norm(Eph_J22[i].Slice(0, 2) - refEph), Max_J22);
Max_J44 = max(Norm(Eph_J44[i].Slice(0, 2) - refEph), Max_J44);
Max_J1010 = max(Norm(Eph_J1010[i].Slice(0, 2) - refEph), Max_J1010);
Max_Sun = max(Norm(Eph_Sun[i].Slice(0, 2) - refEph), Max_Sun);
Max_Moon = max(Norm(Eph_Moon[i].Slice(0, 2) - refEph), Max_Moon);
Max_SRad = max(Norm(Eph_SRad[i].Slice(0, 2) - refEph), Max_SRad);
Max_Drag = max(Norm(Eph_Drag[i].Slice(0, 2) - refEph), Max_Drag);
}
;
// Output
info = " Maximum position errors within ";
Console.Write(info);
info = String.Format("{0, 8:F}", N_Step2 * Step / 60.0);
info += " min propagation interval " + "\r\n";
info += " J2,0 J2,2 J4,4 J10,10" + " Sun Moon SolRad Drag" + "\r\n";
info += " [m] [m] [m] [m]" + " [m] [m] [m] [m]";
Console.WriteLine(info);
info = String.Format("{0, 8:F}{1, 8:F}{2, 8:F}{3, 8:F}{4, 8:F}{5, 8:F}{6, 8:F}{7, 8:F}", Max_J20, Max_J22, Max_J44, Max_J1010, Max_Sun, Max_Moon, Max_SRad, Max_Drag);
Console.WriteLine(info);
Console.WriteLine();
Console.ReadKey();
}
