function [ target_list_RDA, target_map ] = rda_detection(stat_RD, P_fa)
% Target detection, estimating distance, velocity, and angle intervals
%
% Usage: 
% [target_list_RDA, target_map] = rda_detection(stat_RD, P_fa)
%
% Inputs:
%   stat_RD:            Range-Doppler statistics
%   P_fa:               Probability of false alarm
%
% Outputs:
%   target_list_RDA:    Target list include range, doppler and angle information
%   target_map:         Show targets in RD map


    % parameters
    [lenA, lenR, lenP] = size(stat_RD);
    target_map = zeros(lenR, lenP);
    
    % detection threshold
    d_thd = chi2inv(1 - P_fa, 2) / 2;
    
    % find target
    target_list_RD = [];
    for i = 1: lenA
        RD_map = squeeze(stat_RD(i, :, :));
        detect_map = zeros(size(RD_map));
        detect_map(RD_map > d_thd) = 1;
%         target_map(i, :, :) = detect_map;
        [r, c] = find(detect_map);
        temp_node = [r, c];
        target_list_RD = [target_list_RD; temp_node];
    end
    target_list_RD_new = unique(target_list_RD, 'rows');
    
    % estimate target angle interval
    target_list_angle = [];
    for i = 1: size(target_list_RD_new, 1)
        tgt = target_list_RD_new(i, :);
        stat_vct = stat_RD(:, tgt(1), tgt(2));
        [v, idx] = max(stat_vct);
        target_map(tgt(1), tgt(2)) = idx;
        target_list_angle = [target_list_angle; idx];
    end
    target_list_RDA = [target_list_RD_new, target_list_angle];
    
end