C#与Matlab实现卫星星下点经纬度计算算法详解

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double EARTH_RADIUS_METER = 6378137;
double ee2 = 0.00669437999013;
double ex = 0.0000001;
        

        public void satposition_earth(float x, float y, float z,ref double lat,ref double lng)
        {
            double nb = 0;
            double hb = 0;
            double bb = 0;

            double N = EARTH_RADIUS_METER ;
            double H = Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2) + Math.Pow(z, 2)) - 6367437.02f;
            double B = Math.Atan2(z, (Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2))) / (1 - ee2 * N / (N + H)));

            for (int i = 1; i < 50; i++)
            {
                nb = N;
                hb = H;
                bb = B;

                N = EARTH_RADIUS_METER / (Math.Sqrt(1 - ee2 * Math.Pow(Math.Sin(B), 2)));
                H = Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2)) / Math.Cos(B) - N;
                B = Math.Atan2(z, Math.Sqrt(Math.Pow(x, 2) + Math.Pow(y, 2)) / (1 - ee2 * N / (N + H)));

                if (Math.Abs(hb - H) < ex && Math.Abs(B - bb) < ex)