卫星轨道六根数计算星下点经纬度写出C#代码

以下是C#代码，可以计算卫星轨道六根数并计算星下点经纬度：

using System;

public class SatelliteOrbit
{
    private const double EARTH_RADIUS = 6378.137; // 地球半径
    private const double PI = Math.PI;

    // 卫星轨道六根数
    private double a; // 长半轴
    private double e; // 偏心率
    private double i; // 轨道倾角
    private double Omega; // 升交点赤经
    private double omega; // 近地点幅角
    private double M0; // 初平近点角

    public SatelliteOrbit(double a, double e, double i, double Omega, double omega, double M0)
    {
        this.a = a;
        this.e = e;
        this.i = i;
        this.Omega = Omega;
        this.omega = omega;
        this.M0 = M0;
    }

    // 计算轨道坐标
    public void Calculate(double t, out double x, out double y, out double z)
    {
        double n = Math.Sqrt(398600.4418 / (a * a * a)); // 平均角速度
        double M = M0 + n * t; // 平近点角
        double E = M; // 初值
        double dE = 1;
        double E0 = 0;
        while (Math.Abs(dE) > 1e-8)
        {
            E0 = E;
            E = M + e * Math.Sin(E);
            dE = E - E0;
        }
        double v = 2 * Math.Atan(Math.Sqrt((1 + e) / (1 - e)) * Math.Tan(E / 2)); // 真近点角
        double r = a * (1 - e * Math.Cos(E)); // 距离
        double x1 = r * Math.Cos(v);
        double y1 = r * Math.Sin(v);
        double z1 = 0;
        double x2 = x1 * Math.Cos(omega) - y1 * Math.Sin(omega);
        double y2 = x1 * Math.Sin(omega) + y1 * Math.Cos(omega);
        double z2 = 0;
        x = x2 * Math.Cos(Omega) - y2 * Math.Sin(Omega) * Math.Cos(i);
        y = x2 * Math.Sin(Omega) + y2 * Math.Cos(Omega) * Math.Cos(i);
        z = y2 * Math.Sin(i);
    }

    // 计算星下点经纬度
    public void CalculateSubpoint(double t, out double lon, out double lat)
    {
        double x, y, z;
        Calculate(t, out x, out y, out z);
        double r = Math.Sqrt(x * x + y * y + z * z);
        double lon1 = Math.Atan2(y, x);
        double lat1 = Math.Asin(z / r);
        double N = EARTH_RADIUS / Math.Sqrt(1 - 0.00669437999014 * Math.Sin(lat1) * Math.Sin(lat1));
        lon = lon1 * 180 / PI; // 经度
        lat = lat1 * 180 / PI; // 纬度
    }
}

// 示例
public class Example
{
    public static void Main()
    {
        double a = 7000; // 长半轴
        double e = 0.01; // 偏心率
        double i = 30 * PI / 180; // 轨道倾角
        double Omega = 60 * PI / 180; // 升交点赤经
        double omega = 90 * PI / 180; // 近地点幅角
        double M0 = 0; // 初平近点角
        SatelliteOrbit orbit = new SatelliteOrbit(a, e, i, Omega, omega, M0);
        double t = 0; // 时间
        double lon, lat;
        orbit.CalculateSubpoint(t, out lon, out lat);
        Console.WriteLine("经度：{0}，纬度：{1}", lon, lat);
    }
}
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