/// <summary>
/// J2积分器(惯性系中计算，无岁差章动)，右函数采用J2Gravity模型
/// <para>积分变量仅位置、速度</para>
/// <para>给position仅添加J2项右函数</para>
/// <para>RKF7(8)数值积分器，缺省绝对和相对精度皆为1e-13</para>
/// <para>Epoch属性需手动赋值</para>
/// </summary>
/// <param name="position">PropagationNewtonianPoint,单位:m,m/s</param>
/// <param name="centralBody"></param>
/// <param name="gravitationalParameter">引力常数GM(m^3/s^2)</param>
/// <param name="j2UnnormalizedValue">J2</param>
/// <param name="referenceDistance">Re(m)</param>
/// <param name="absTolerance">RKF7(8)的绝对精度</param>
/// <param name="relRolerance">RKF7(8)的相对精度</param>
public PropagatorDefinitionPureJ2(PropagationNewtonianPoint position, CentralBody centralBody, double gravitationalParameter = 3.986004418e14, double j2UnnormalizedValue = 0.001082629989052, double referenceDistance = 6378137.0, double absTolerance = 1e-13, double relRolerance = 1e-13)
{
// 中心天体的J2项引力摄动(含中心引力，中心天体的惯性系中计算)，无岁差章动
J2Gravity gravity = new J2Gravity(position.IntegrationPoint, centralBody, gravitationalParameter, j2UnnormalizedValue, referenceDistance);
// 添加右函数
position.AppliedForces.Clear();
position.AppliedForces.Add(gravity);
// 积分变量
this.IntegrationElements.Add(position);
// RKF7(8)数值积分器
RungeKuttaFehlberg78Integrator integrator = new RungeKuttaFehlberg78Integrator();
integrator.AbsoluteTolerance = absTolerance;
integrator.RelativeTolerance = relRolerance;
integrator.InitialStepSize = 60.0;
integrator.StepSizeBehavior = KindOfStepSize.Relative;
integrator.MaximumStepSize = 200.0;
integrator.MinimumStepSize = 1.0;
//* This is STK's default and truncates each step to 3 decimal places
integrator.StepTruncationOrder = -3;
this.Integrator = integrator;
}
/// <summary>
/// Propagate a Platform using a NumericalPropagator configured with the entered KeplerianElements,
/// ForceModels, NumericalIntegrator, and start and stop dates.
/// </summary>
private void PropagateSatellite()
{
KeplerianElements orbitalElements = m_keplerianOrbitalElementsEntry.KeplerianElementValues;
if (orbitalElements == null)
{
return;
}
Motion <Cartesian> initialMotion = orbitalElements.ToCartesian();
PropagationNewtonianPoint point = new PropagationNewtonianPoint(m_elementID, m_forceModelSettings.CurrentCentralBody.InertialFrame, initialMotion.Value, initialMotion.FirstDerivative);
point.Mass = new ScalarFixed(double.Parse(m_mass.Text));
m_forceModelSettings.SetForceModelsOnPoint(point, new ScalarFixed(double.Parse(m_area.Text)));
CentralBody primaryCentralBody = m_forceModelSettings.CurrentCentralBody;
NumericalPropagatorDefinition state = new NumericalPropagatorDefinition();
state.IntegrationElements.Add(point);
state.Integrator = m_integratorSettings.GetIntegrator();
JulianDate start = new JulianDate(GregorianDate.ParseExact(m_start.Text, DateFormat, null));
JulianDate end = new JulianDate(GregorianDate.ParseExact(m_end.Text, DateFormat, null));
state.Epoch = start;
NumericalPropagator propagator = state.CreatePropagator();
propagator.StepTaken += (sender, args) =>
{
// Telling the propagator to stop if we get too close to the central body
Cartesian position = propagator.Converter.ConvertState <Cartesian>(m_elementID, args.CurrentState).Value;
if (position.Magnitude <= primaryCentralBody.Shape.SemimajorAxisLength + 10000)
{
args.Indication = PropagationEventIndication.StopPropagationAfterStep;
}
};
DateMotionCollection <Cartesian> answer = null;
var backgroundCalculation = new BackgroundCalculation();
backgroundCalculation.DoWork += (sender, e) =>
{
// actually propagate
var result = propagator.Propagate(end.Subtract(start), 1, backgroundCalculation);
answer = result.GetDateMotionCollection <Cartesian>(m_elementID);
};
backgroundCalculation.ProgressChanged += (sender, e) => m_propagationProgress.Value = e.ProgressPercentage;
backgroundCalculation.RunWorkerCompleted += (sender, e) =>
{
// when finished, draw the satellite
DrawSatellite(answer, primaryCentralBody.InertialFrame);
m_propagate.Enabled = true;
};
m_propagate.Enabled = false;
backgroundCalculation.RunWorkerAsync();
}
/// <summary>
/// 构造函数,给定瞬时点、中心天体、引力常数、J2项系数、参考半径
/// <para>缺省：忽略偏微分</para>
/// </summary>
/// <param name="targetPoint">计算引力的瞬时点(位置、速度)</param>
/// <param name="centralBody">中心天体</param>
/// <param name="gravitationalParameter">引力常数</param>
/// <param name="j2UnnormalizedValue">J2项系数</param>
/// <param name="referenceDistance">参考半径</param>
public J2Gravity(Point targetPoint, CentralBody centralBody, double gravitationalParameter, double j2UnnormalizedValue, double referenceDistance)
: base(RoleOfForce.Principal, KindOfForce.NewtonianSpecificForce)
{
this.m_ignorePartials = false;
this.m_targetPoint = targetPoint;
this.m_centralBody = centralBody;
this.m_gravitationalParameter = gravitationalParameter;
this.m_j2ZonalHarmonicCoefficient = j2UnnormalizedValue;
this.m_referenceDistance = referenceDistance;
}
//#########################################################################################
#region 构造函数
/// <summary>
/// 构造函数，缺省使用中心天体：地球(J2项系数为0)
/// </summary>
//public J2Gravity()
// : base(RoleOfForce.Principal, KindOfForce.NewtonianSpecificForce)
//{
// CentralBodiesFacet fromContext = CentralBodiesFacet.GetFromContext();
// this.m_centralBody = fromContext.Earth;
// this.m_gravitationalParameter = WorldGeodeticSystem1984.GravitationalParameter;
// this.J2ZonalHarmonicCoefficient = 0.0;
// this.m_referenceDistance = m_centralBody.Shape.SemimajorAxisLength;
//}
/// <summary>
/// 构造函数，缺省使用中心天体：地球(J2项系数为0)
/// </summary>
/// <param name="targetPoint">计算引力的瞬时点(位置、速度)</param>
//public J2Gravity(Point targetPoint)
// : this()
//{
// this.m_targetPoint = targetPoint;
//}
/// <summary>
/// 构造函数，从已有对象复制
/// </summary>
/// <param name="existingInstance">已有对象</param>
/// <param name="context">A CopyContext that controls the depth of the copy.</param>
protected J2Gravity(J2Gravity existingInstance, CopyContext context)
: base(existingInstance, context)
{
this.m_centralBody = context.UpdateReference <CentralBody>(existingInstance.m_centralBody);
this.m_gravitationalParameter = existingInstance.m_gravitationalParameter;
this.m_ignorePartials = existingInstance.m_ignorePartials;
this.m_targetPoint = context.UpdateReference <Point>(existingInstance.m_targetPoint);
this.m_j2ZonalHarmonicCoefficient = existingInstance.m_j2ZonalHarmonicCoefficient;
this.m_referenceDistance = existingInstance.m_referenceDistance;
}
/// <summary>
/// Positions the camera to view a given extent on the surface from a given azimuth and elevation angle.
/// </summary>
public static void ViewExtent(Insight3D insight3D, CentralBody centralBody,
double west, double south, double east, double north,
double azimuthAngle, double elevationAngle)
{
var camera = insight3D.Scene.Camera;
camera.ViewExtent(centralBody, west, south, east, north);
var offset = new Cartesian(new AzimuthElevationRange(azimuthAngle, elevationAngle, camera.Distance));
camera.Position = camera.ReferencePoint + offset;
}
/// <summary>
/// Positions the camera to view a given bounding sphere from a given azimuth and elevation angle.
/// </summary>
public static void ViewBoundingSphere(Insight3D insight3D, CentralBody centralBody, BoundingSphere sphere,
double azimuthAngle, double elevationAngle)
{
var boundingSphereCenter = new PointFixedOffset(centralBody.FixedFrame, sphere.Center);
var boundingSphereAxes = new AxesEastNorthUp(centralBody, boundingSphereCenter);
var camera = insight3D.Scene.Camera;
var offset = new Cartesian(new AzimuthElevationRange(azimuthAngle, elevationAngle, camera.DistancePerRadius * sphere.Radius));
camera.ViewOffset(boundingSphereAxes, boundingSphereCenter, offset);
}
/// <summary>
/// J2积分器(惯性系中计算，含岁差章动)，右函数采用SphericalHarmonicGravity模型
/// <para>积分变量仅位置、速度</para>
/// <para>给position仅添加J2项右函数</para>
/// <para>RKF7(8)数值积分器，缺省绝对和相对精度皆为1e-13</para>
/// <para>Epoch属性需手动赋值</para>
/// </summary>
/// <param name="position">PropagationNewtonianPoint,单位:m,m/s</param>
/// <param name="centralBody"></param>
/// <param name="gravitationalParameter">引力常数GM(m^3/s^2)</param>
/// <param name="j2UnnormalizedValue">J2</param>
/// <param name="referenceDistance">Re(m)</param>
/// <param name="absTolerance">RKF7(8)的绝对精度</param>
/// <param name="relRolerance">RKF7(8)的相对精度</param>
public PropagatorDefinitionJ2(PropagationNewtonianPoint position, CentralBody centralBody, double gravitationalParameter = 3.986004418e14, double j2UnnormalizedValue = 0.001082629989052, double referenceDistance = 6378137.0, double absTolerance = 1e-13, double relRolerance = 1e-13)
{
// 中心天体的J2项引力摄动(含中心引力，中心天体的惯性系中计算)，含岁差章动
SphericalHarmonicGravity gravity = new SphericalHarmonicGravity();
gravity.TargetPoint = position.IntegrationPoint; //* Will represent the position during propagation
double[][] coe = new double[3][];
coe[0] = new double[1];
coe[1] = new double[2];
coe[2] = new double[3];
SphericalHarmonicGravityModel gravityModel = new SphericalHarmonicGravityModel("WGS84", centralBody.Name, gravitationalParameter, referenceDistance, new double[] { 1.0, 0.0, j2UnnormalizedValue }, coe, coe, false, false);
int degree = 2;
int order = 0;
bool includeTwoBodyForce = true;
gravity.GravityField = new SphericalHarmonicGravityField(gravityModel, degree, order, includeTwoBodyForce, SphericalHarmonicsTideType.None);
// 添加右函数
position.AppliedForces.Clear();
position.AppliedForces.Add(gravity);
// 积分变量
this.IntegrationElements.Add(position);
// RKF7(8)数值积分器
RungeKuttaFehlberg78Integrator integrator = new RungeKuttaFehlberg78Integrator();
integrator.AbsoluteTolerance = absTolerance;
integrator.RelativeTolerance = relRolerance;
integrator.InitialStepSize = 60.0;
integrator.StepSizeBehavior = KindOfStepSize.Relative;
integrator.MaximumStepSize = 200.0;
integrator.MinimumStepSize = 1.0;
//* This is STK's default and truncates each step to 3 decimal places
integrator.StepTruncationOrder = -3;
this.Integrator = integrator;
}
/// <summary>
/// Handles updating the various central body lists if the primary central body changes.
/// </summary>
/// <param name="sender">What fired this event.</param>
/// <param name="e">Additional information about this event.</param>
private void OnPrimaryCBSelectedIndexChanged(object sender, EventArgs e)
{
if (m_primaryCB.SelectedItem.ToString() != m_lastCB)
{
m_thirdBodies.Items.Remove(m_primaryCB.SelectedItem.ToString());
m_thirdBodies.Items.Add(m_lastCB);
m_lastCB = m_primaryCB.SelectedItem.ToString();
if (m_primaryCB.SelectedItem.ToString() != EARTH)
{
// we only have drag models for the earth
m_lastDragChecked = m_useDrag.Checked;
m_useDrag.Checked = false;
m_useDrag.Enabled = false;
}
else
{
m_useDrag.Checked = m_lastDragChecked;
m_useDrag.Enabled = true;
}
CurrentCentralBodysGravitationalParameter = m_gravConstants[m_primaryCB.SelectedItem.ToString()];
CurrentCentralBody = CentralBodiesFacet.GetFromContext().GetByName(m_primaryCB.SelectedItem.ToString());
}
}
/// <summary>
/// Positions the camera to view a given extent on the surface from a given azimuth and elevation angle.
/// </summary>
public static void ViewExtent(Insight3D insight3D, CentralBody centralBody, CartographicExtent extent,
double azimuthAngle, double elevationAngle)
{
ViewExtent(insight3D, centralBody, extent.WestLongitude, extent.SouthLatitude, extent.EastLongitude, extent.NorthLatitude, azimuthAngle, elevationAngle);
}
/// <summary>
/// Positions the camera to view a given bounding sphere.
/// </summary>
public static void ViewBoundingSphere(Insight3D insight3D, CentralBody centralBody, BoundingSphere sphere)
{
ViewBoundingSphere(insight3D, centralBody, sphere, Trig.DegreesToRadians(-90.0), Trig.DegreesToRadians(-30.0));
}
// Edit By: Li Yunfei
// 20161208: 初次编写
// 20170104: 使用Orbitbase中的常数
/// <summary>
/// 中心天体J2项摄动力(含中心引力，惯性系中计算，含岁差章动)，右函数采用SphericalHarmonicGravity模型
/// <para>**缺省单位:m,m/s</para>
/// <para>**Mu,J2,Re默认采用缺省值</para>
/// </summary>
/// <param name="position">PropagationNewtonianPoint,单位:m,m/s</param>
/// <param name="centralBody"></param>
/// <param name="gravitationalParameter">引力常数GM(m^3/s^2)</param>
/// <param name="j2UnnormalizedValue">J2</param>
/// <param name="referenceDistance">Re(m)</param>
public static SphericalHarmonicGravity GetJ2Gravity(PropagationNewtonianPoint position, CentralBody centralBody, double gravitationalParameter = OrbitBase.EarthMu, double j2UnnormalizedValue = OrbitBase.EarthJ2, double referenceDistance = OrbitBase.EarthRe)
{
// 中心天体的J2项引力摄动(含中心引力，中心天体的惯性系中计算)，含岁差章动
SphericalHarmonicGravity gravity = new SphericalHarmonicGravity();
gravity.TargetPoint = position.IntegrationPoint; //* Will represent the position during propagation
// 单位一致性检查
if (gravitationalParameter > 1e10 && (referenceDistance < 1e6 || position.InitialPosition.Magnitude < 1e6))
{
throw new Exception("单位不一致Gm/Re/position!");
}
if (gravitationalParameter < 1e10 && (referenceDistance > 1e6 || position.InitialPosition.Magnitude > 1e6))
{
throw new Exception("单位不一致Gm/Re/position!");
}
double[][] coe = new double[3][];
coe[0] = new double[1];
coe[1] = new double[2];
coe[2] = new double[3];
SphericalHarmonicGravityModel gravityModel = new SphericalHarmonicGravityModel("WGS84", centralBody.Name, gravitationalParameter, referenceDistance, new double[] { 1.0, 0.0, j2UnnormalizedValue }, coe, coe, false, false);
int degree = 2;
int order = 0;
bool includeTwoBodyForce = true;
gravity.GravityField = new SphericalHarmonicGravityField(gravityModel, degree, order, includeTwoBodyForce, SphericalHarmonicsTideType.None);
return(gravity);
}
