AIDT 온디바이스 국방 MUM-T 대레이더 미사일(ARM) 밀리미터파/광대역 패시브 RF 복합 시커 Home-on-Jam 및 사이드로브 기만 분리 서보 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Defense.AntiRadiationMissile
{
    /// <summary>
    /// ARM 이중 모드 RF 시커 텔레메트리 계측 상태
    /// </summary>
    public readonly ref struct DualSeekerTelemetryState
    {
        public readonly double PassiveAoaAzimuthDeg;    // 패시브 시커 방위각 오차 [deg]
        public readonly double PassiveAoaElevationDeg;  // 패시브 시커 고저각 오차 [deg]
        public readonly double MmwEstimatedRangeMeters; // 밀리미터파 능동 거리 [m]
        public readonly double ReceivedRfPowerDbm;      // 수신 RF 신호 강도 [dBm]
        public readonly double JammerCorrelationCoeff;  // 사이드로브 기만 상관 계수 (0~1)
        public readonly bool IsRadarTransmitting;       // 적 레이더 주파수 송신 여부
        public readonly double MissileClosingSpeedMps;  // 접근 상대 속도 [m/s]

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public DualSeekerTelemetryState(
            double az, double el, double range, double pwr, double jamCorr, bool transmitting, double vClose)
        {
            PassiveAoaAzimuthDeg = az;
            PassiveAoaElevationDeg = el;
            MmwEstimatedRangeMeters = range;
            ReceivedRfPowerDbm = pwr;
            JammerCorrelationCoeff = jamCorr;
            IsRadarTransmitting = transmitting;
            MissileClosingSpeedMps = vClose;
        }
    }

    /// <summary>
    /// 시커 짐벌 및 유도 명령
    /// </summary>
    public readonly ref struct ArmSeekerGimbalCommand
    {
        public readonly double GimbalAzimuthRateDegPerSec;   // 짐벌 방위각 회전속도 [deg/s]
        public readonly double GimbalElevationRateDegPerSec; // 짐벌 고저각 회전속도 [deg/s]
        public readonly double GuidanceAccelerationG;        // 비례항법 유도 가속도 [G]
        public readonly bool IsHomeOnJamActive;              // HOJ 역추적 활성화 여부
        public readonly bool TargetDecoyDiscriminated;       // 기만 디코이 분리 성공 여부

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public ArmSeekerGimbalCommand(double azRate, double elRate, double accelG, bool hoj, bool disc)
        {
            GimbalAzimuthRateDegPerSec = azRate;
            GimbalElevationRateDegPerSec = elRate;
            GuidanceAccelerationG = accelG;
            IsHomeOnJamActive = hoj;
            TargetDecoyDiscriminated = disc;
        }
    }

    /// <summary>
    /// 10,000Hz 주기 ARM 이중 모드 시커 HOJ 표적 지향 서보 엔진
    /// </summary>
    public ref struct ArmDualSeekerTargetingServoEngine
    {
        private const double NavigationGain = 4.0;
        private double _prevLosAzimuth;
        private double _prevLosElevation;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public ArmSeekerGimbalCommand CalculateGuidanceCommand(
            in DualSeekerTelemetryState state, double dtSeconds)
        {
            bool isJamming = state.JammerCorrelationCoeff > 0.65;
            bool hojActive = isJamming || (!state.IsRadarTransmitting && state.ReceivedRfPowerDbm > -50.0);

            // 1. 시선 각속도(LOS Rate) 산출
            double losAzRate = (dtSeconds > 1e-9) ? (state.PassiveAoaAzimuthDeg - _prevLosAzimuth) / dtSeconds : 0.0;
            double losElRate = (dtSeconds > 1e-9) ? (state.PassiveAoaElevationDeg - _prevLosElevation) / dtSeconds : 0.0;
            _prevLosAzimuth = state.PassiveAoaAzimuthDeg;
            _prevLosElevation = state.PassiveAoaElevationDeg;

            // 2. 짐벌 추적 루프 (비례 이득 제어)
            double gimbalAzRate = 18.0 * state.PassiveAoaAzimuthDeg + 0.45 * losAzRate;
            double gimbalElRate = 18.0 * state.PassiveAoaElevationDeg + 0.45 * losElRate;
            gimbalAzRate = Math.Clamp(gimbalAzRate, -120.0, 120.0);
            gimbalElRate = Math.Clamp(gimbalElRate, -120.0, 120.0);

            // 3. 비례항법 유도 가속도 a = N' * V_c * dot(lambda)
            double totalLosRateRad = Math.Sqrt(losAzRate * losAzRate + losElRate * losElRate) * (Math.PI / 180.0);
            double cmdAccelMps2 = NavigationGain * state.MissileClosingSpeedMps * totalLosRateRad;
            double cmdAccelG = cmdAccelMps2 / 9.80665;
            cmdAccelG = Math.Clamp(cmdAccelG, -35.0, 35.0);

            // 기만원 분리 성공 판정
            bool decoyDiscriminated = !isJamming || (state.MmwEstimatedRangeMeters < 2000.0);

            return new ArmSeekerGimbalCommand(
                gimbalAzRate,
                gimbalElRate,
                cmdAccelG,
                hojActive,
                decoyDiscriminated
            );
        }
    }
}