126 lines
5.2 KiB
C#
126 lines
5.2 KiB
C#
/*
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* 版本历史：
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* 1.0.0 (2024-10-13): 初始版本，实现大气湍流对光传输影响的计算模型。作者：田建勇
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* 1.1.0 (2024-10-18): 改进版本，考虑目标位置关系和大气参数分布。作者：田建勇
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*/
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namespace AirTransmission
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{
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/// <summary>
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/// 大气湍流模型类，用于计算大气湍流对光传输的影响
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/// </summary>
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public class AtmosphericTurbulenceModel
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{
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// 波数，假设波长为1.06微米（常用的激光波长）
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private const double k = 2 * Math.PI / 1.06e-6;
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/// <summary>
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/// 计算大气湍流对光传输的综合影响
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/// </summary>
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/// <param name="distance">传输距离（米）</param>
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/// <param name="height">传输高度（米）</param>
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/// <param name="windSpeed">风速（米/秒）</param>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <returns>湍流效应（0到1之间的值，1表示无影响，0表示完全衰减）</returns>
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public static double CalculateTurbulenceEffect(double distance, double height, double windSpeed, double C2n)
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{
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double r0 = CalculateFriedParameter(C2n, distance);
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double sigmaI2 = CalculateScintillationIndex(C2n, k, distance);
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double beamWander = CalculateBeamWander(C2n, distance, height);
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// 修改综合湍流效应计算
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double turbulenceEffect = Math.Exp(-sigmaI2) * (1 - Math.Exp(-r0 / beamWander));
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// 增加一个缩放因子，使效应更明显
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double scalingFactor = 0.8;
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turbulenceEffect = 1 - scalingFactor * (1 - turbulenceEffect);
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return turbulenceEffect;
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}
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/// <summary>
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/// 使用修改后的 Hufnagel-Valley 模型计算大气折射率结构常数
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/// </summary>
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/// <param name="height">高度（米）</param>
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/// <param name="windSpeed">风速（米/秒）</param>
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/// <returns>大气折射率结构常数</returns>
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public static double CalculateC2n(double height, double windSpeed)
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{
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// 修改 Hufnagel-Valley 模型，增加湍流强度
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double A = 1.7e-13; // 增加了一个数量级
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double v = windSpeed;
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return A * Math.Pow(v / 27, 2) * Math.Pow(height * 1e-5, 10) * Math.Exp(-height / 1000)
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+ 2.7e-15 * Math.Exp(-height / 1500);
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}
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/// <summary>
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/// 计算弗里德参数（Fried parameter）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="L">传输距离（米）</param>
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/// <returns>弗里德参数（米）</returns>
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private static double CalculateFriedParameter(double C2n, double L)
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{
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return Math.Pow(0.423 * k * k * C2n * L, -3.0 / 5.0);
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}
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/// <summary>
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/// 计算闪烁指数（Scintillation Index）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="k">波数</param>
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/// <param name="L">传输距离（米）</param>
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/// <returns>闪烁指数（无量纲）</returns>
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private static double CalculateScintillationIndex(double C2n, double k, double L)
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{
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return 1.23 * C2n * Math.Pow(k, 7.0 / 6.0) * Math.Pow(L, 11.0 / 6.0);
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}
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/// <summary>
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/// 计算光束漂移（Beam Wander）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="L">传输距离（米）</param>
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/// <param name="h">传输高度（米）</param>
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/// <returns>光束漂移（弧度）</returns>
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private static double CalculateBeamWander(double C2n, double L, double h)
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{
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return 2.87 * Math.Pow(C2n * L * Math.Pow(h, 5.0/3.0), 1.0/3.0);
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}
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/// <summary>
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/// 计算相干长度（Coherence Length）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="L">传输距离（米）</param>
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/// <returns>相干长度（米）</returns>
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private static double CalculateCoherenceLength(double C2n, double L)
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{
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return Math.Pow(1.46 * k * k * C2n * L, -3.0 / 5.0);
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}
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/// <summary>
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/// 计算到达角（Angle of Arrival）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="L">传输距离（米）</param>
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/// <param name="D">接收器口径（米）</param>
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/// <returns>到达角（弧度）</returns>
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public static double CalculateAngleOfArrival(double C2n, double L, double D)
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{
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return 2.91 * Math.Pow(C2n * L / Math.Pow(D, 1.0/3.0), 0.6);
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}
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/// <summary>
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/// 计算等晕角（Isoplanatism Angle）
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/// </summary>
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/// <param name="C2n">大气折射率结构常数</param>
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/// <param name="L">传输距离（米）</param>
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/// <returns>等晕角（弧度）</returns>
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public static double CalculateIsoplanatismAngle(double C2n, double L)
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{
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return 0.314 * Math.Pow(C2n * k * k * L, -3.0 / 5.0);
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}
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}
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}
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