Initial ARSS. Need to improve and add functions.

2026-03-02 14:48:21 +09:00
commit 775668afdb
20 changed files with 1610 additions and 0 deletions
@@ -0,0 +1,59 @@
+function ChannelOut = apply_channel_effects(RadarParams)
+    Target = RadarParams.Target;
+    TxPos = RadarParams.Antenna.TxPos;
+    RxPos = RadarParams.Antenna.RxPos;
+    NumChirps = RadarParams.Waveform.NumChirps;
+    Timing = RadarParams.Waveform.Timing;
+    fs_adc = RadarParams.Waveform.fs_adc;
+    f_start = RadarParams.Waveform.f_start;
+    Slope = RadarParams.Waveform.Slope;
+    c = RadarParams.Basic.c;
+    NumTx = size(TxPos, 2);
+    NumRx = size(RxPos, 2);
+    NumTargets = Target.NumTargets;
+    T_pri = RadarParams.Waveform.PRI;
+    
+    t_adc = 0 : 1/fs_adc : (Timing.AdcSampTime - 1/fs_adc);
+    N_adc = length(t_adc);
+    
+    % [핵심] 처프 내 샘플별 순시 주파수 및 파장 계산
+    % t_adc에 따라 주파수가 변하므로 파장(lambda)도 샘플마다 변함
+    f_inst = f_start + Slope * t_adc; 
+    lambda_t = c ./ f_inst;          
+    
+    ChannelOut.tau = zeros(NumTargets, NumRx, NumTx, NumChirps, N_adc);
+    ChannelOut.space_loss_amp = zeros(NumTargets, NumRx, NumTx, NumChirps, N_adc);
+    
+    ref_point = (TxPos(:,1) + RxPos(:,1)) / 2;
+    
+    for k = 1:NumTargets
+        az_rad = deg2rad(Target.az(k));
+        el_rad = deg2rad(Target.el(k));
+        rel_pos0 = Target.R(k) * [cos(el_rad)*sin(az_rad); cos(el_rad)*cos(az_rad); sin(el_rad)];
+        target_world_pos0 = ref_point + rel_pos0;
+        v_vec = Target.v(k) * (rel_pos0 / norm(rel_pos0));
+        
+        sigma = 10^(Target.rcs(k)/10);
+        
+        for m = 0:NumChirps-1
+            % 처프 간 이동 반영
+            target_pos_at_chirp = target_world_pos0 + v_vec * (m * T_pri);
+            
+            for tx = 1:NumTx
+                for rx = 1:NumRx
+                    % 처프 내 샘플별 이동 반영
+                    curr_target_pos = target_pos_at_chirp + v_vec * t_adc;
+                    d_tx = sqrt(sum((curr_target_pos - TxPos(:,tx)).^2, 1));
+                    d_rx = sqrt(sum((curr_target_pos - RxPos(:,rx)).^2, 1));
+                    
+                    % TTD 지연 시간 저장
+                    ChannelOut.tau(k, rx, tx, m+1, :) = (d_tx + d_rx) / c;
+                    
+                    % [가변 파장 적용] 주파수 대역폭에 따른 공간 감쇠 변화 반영
+                    denom = (4*pi)^3 * (d_tx.^2 .* d_rx.^2);
+                    ChannelOut.space_loss_amp(k, rx, tx, m+1, :) = sqrt((lambda_t.^2 * sigma) ./ denom);
+                end
+            end
+        end
+    end
+end