대한민국 공군 E-737 피스아이(Peace Eye) MESA 다기능 전자주사식 레이더 360도 해상·공중 표적 추적 및 1,000Hz 0-Alloc C# JPDA 다중표적 추적 필터 엔진

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

namespace ZeliDesk.Defense.AirForce.AewMesaRadar
{
    public readonly record struct RadarMeasurement(
        Vector3 PositionMeters,
        float RadialVelocityMps,
        float SignalSnrDb,
        bool IsClutterSuspect
    );

    public ref struct TrackFilterState
    {
        public Vector3 EstimatedPosition;
        public Vector3 EstimatedVelocity;
        public float TrackConfidenceScore; // 0.0 ~ 1.0
        public bool TrackFirmlyLocked;
    }

    public static class MesaJpdaTrackerCore
    {
        private const float GateThresholdSq = 16.0f; // 4-sigma 게이팅
        private const float AlphaGain = 0.65f;
        private const float BetaGain = 0.38f;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void UpdateTrackWithJpda(
            ref TrackFilterState track,
            ReadOnlySpan plots,
            float dtSec)
        {
            // 1. 상태 외삽 (등속 모델)
            Vector3 predictedPos = track.EstimatedPosition + (track.EstimatedVelocity * dtSec);

            // 2. 게이팅 및 소프트 가중치 연산
            Vector3 combinedResidual = Vector3.Zero;
            float totalWeight = 0.001f; // 클러터 바이어스

            for (int i = 0; i < plots.Length; i++)
            {
                ref readonly var plot = ref plots[i];
                if (plot.IsClutterSuspect && plot.SignalSnrDb < 10.0f) continue;

                Vector3 diff = plot.PositionMeters - predictedPos;
                float distSq = diff.LengthSquared();

                if (distSq < (GateThresholdSq * 400.0f)) // 80m 오차 게이트
                {
                    float weight = (float)Math.Exp(-distSq / 800.0f) * (plot.SignalSnrDb / 20.0f);
                    combinedResidual += diff * weight;
                    totalWeight += weight;
                }
            }

            // 3. 결합 가중치 정규화 및 추적 갱신
            Vector3 avgResidual = combinedResidual / totalWeight;
            track.EstimatedPosition = predictedPos + (avgResidual * AlphaGain);
            track.EstimatedVelocity = track.EstimatedVelocity + (avgResidual * (BetaGain / Math.Max(dtSec, 0.001f)));

            // 4. 신뢰도 평가
            track.TrackConfidenceScore = Math.Clamp(totalWeight / 3.0f, 0.0f, 1.0f);
            track.TrackFirmlyLocked = track.TrackConfidenceScore >= 0.7f;
        }
    }
}