대한민국 해군 손원일급(KSS-II) 잠수함 측면배열소나(FAS) 어뢰 접근 탐지 및 1,000Hz 0-Alloc C# 음향대항(TACM) 회피기동 엔진

using System;
using System.Numerics;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Defense.Navy.Submarine
{
    public readonly record struct TorpedoThreatTrack(
        float BearingDeg,
        float EstimatedRangeMeters,
        float ClosingSpeedMps,
        float ActivePingFreqKhz,
        bool IsHomingLocked
    );

    public readonly record struct SubmarineOwnState(
        float HeadingDeg,
        float SpeedKnots,
        float DepthMeters,
        float RudderAngleDeg
    );

    public ref struct TorpedoEvasionPlan
    {
        public float CommandedHeadingDeg;
        public float CommandedDepthMeters;
        public byte LaunchDecoyTubeIndex;
        public bool DeployMobileDecoy;
        public bool DeployAcousticJammer;
        public float TimeToImpactSec;
    }

    public static class SonwonilFasTacmTorpedoEvasionEngine
    {
        private const float KnotsToMps = 0.514444f;
        private const float MaxSubmarineSpeedKnots = 20.0f;
        private const float MaxEvasionDepthMeters = 250.0f;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void GenerateEvasionManeuver(
            ref readonly TorpedoThreatTrack threat,
            ref readonly SubmarineOwnState own,
            out TorpedoEvasionPlan plan)
        {
            plan = default;
            float ttc = threat.ClosingSpeedMps > 1.0f ? threat.EstimatedRangeMeters / threat.ClosingSpeedMps : 999.0f;
            plan.TimeToImpactSec = ttc;

            // 1. 최적 탈출 침로각 계산 (어뢰 방위각에서 110도 외측 선회)
            float escapeHeading = threat.BearingDeg + 110.0f;
            while (escapeHeading >= 360.0f) escapeHeading -= 360.0f;

            // 2. 심도 급강하 제어 (수온약층 아래로 80m 추가 침강)
            float targetDepth = Math.Min(own.DepthMeters + 80.0f, MaxEvasionDepthMeters);

            // 3. TACM 기만기 사출 판정 (TTC < 35초일 때 기만기+방해기 연동 사출)
            bool launchDecoy = false;
            bool launchJammer = false;
            byte tube = 0;

            if (ttc <= 35.0f && threat.IsHomingLocked)
            {
                launchDecoy = true;
                launchJammer = true;
                tube = 1; // 1번 TACM 사출관
            }
            else if (ttc <= 50.0f)
            {
                launchDecoy = true;
                tube = 2; // 선행 기만기 단독 사출
            }

            plan.CommandedHeadingDeg = escapeHeading;
            plan.CommandedDepthMeters = targetDepth;
            plan.LaunchDecoyTubeIndex = tube;
            plan.DeployMobileDecoy = launchDecoy;
            plan.DeployAcousticJammer = launchJammer;
        }
    }
}