KG-access/RADAR_system_analysis
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KG-access
2025-07-29 21:45:44 +09:00
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commit 90231d49ae
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Functions/03. FMCW radar design/SNR_cal.m
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clear all
close all
clc
c0 = physconst('LightSpeed');
fc = 76.5e9;
lambda_c = c0 / fc;
k_c = 2 * pi / lambda_c;
num_tgt = 2;
Ntar_sample = 300;
tar_loc_x = linspace(-2.5, 2.5, num_tgt);
tar_loc_y = linspace(18, 350, Ntar_sample);
tar_loc_z = zeros(1, num_tgt);
for tidx = 1 : num_tgt
tar_xyz(:,:,tidx) = [tar_loc_x(tidx)*ones(Ntar_sample,1) tar_loc_y' tar_loc_z(tidx)*ones(Ntar_sample,1)];
[azimuth, elevation, r] = cart2sph(tar_xyz(:,1,tidx), tar_xyz(:,2,tidx), tar_xyz(:,3,tidx));
tar_scs(:,:,tidx) = [rad2deg(pi/2 - azimuth) rad2deg(elevation) r];
end
Pt = 13; % [dBm]
Pt = Pt - 30; % [dBW]
NF = 12; % [dB]
T0 = 300; % [K]
kb = physconst('Boltzmann');
BW_int = 40e6; % [Hz] instantaneous Bandwidth
% Target RCS
rcs = 10; % [dBsm]
% Noise & Quantization error power
%[~, Qnf] = quanttemp(T0, 12, 'DynamicRange', 52); % ADC bit : 12 [bits], Dynamic Range : 52 [dB] (NXP chip)
%Qnf = 0;
N_bits = 12;
Qnf = -1 * (6.02*N_bits + 10*log10(BW_int) + 1.76) - 30;
Pnq = pow2db(kb * T0) + NF + Qnf + pow2db(BW_int); % [dBW]
% Antenna patter loading
load('azi_ant_pat.mat');
% azi_ant_pat(:,2) = azi_ant_pat(:,2) -16.3 + 15;
load('elev_ant_pat.mat');
% elev_ant_pat(:,2) = elev_ant_pat(:,2) -16.3 + 15;
for tidx = 1 : num_tgt
tar_ant_gain(:, tidx) = interp1(azi_ant_pat(:,1), azi_ant_pat(:,2), tar_scs(:,1,tidx));
tar_elev_ant_gain_reduction = interp1(elev_ant_pat(:,1), elev_ant_pat(:,2), 0) - interp1(elev_ant_pat(:,1), elev_ant_pat(:,2), tar_scs(:,2,tidx));
tar_ant_gain(:, tidx) = tar_ant_gain(:,tidx) - tar_elev_ant_gain_reduction;
end
% Losses & SP gains
L_sf = 3; % [dB] secondary surface loss
L_ant = 2.5; % [dB] Feeder and Radome loss
L_win = 2.38 + 1.36; % [dB] loss by windowing in 2D
L_straddle = 2.88; % [dB] straddle loss(worst)
L_q = 1; % [dB] Quantization loss
L_sp = 1; % [dB] Other signal processing losses
L_total = L_sf + L_ant + L_win + L_straddle + L_q + L_sp;
NFFT_R = 512;
NFFT_D = 256;
G_sp = pow2db(NFFT_R * NFFT_D); % [dB] Signal processing gain by 2D-FFT
% SNR calculation
for tidx = 1 : num_tgt
SNR_set(:,tidx) = Pt + pow2db((lambda_c^2) / (4*pi)^3) + pow2db(1./tar_scs(:,3,tidx).^4) + tar_ant_gain(:,tidx) + tar_ant_gain(:,tidx) + rcs - L_total + G_sp - Pnq;
end
Functions/03. FMCW radar design/azi_ant_pat.mat
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Functions/03. FMCW radar design/beat2rng.m
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function [rng] = beat2rng(f_beat, f_slope, c0)
% Objective : Converting beat frequency [Hz] to range [m]
if isempty(c0)
c0 = physconst('LightSpeed');
end
rng = c0 * f_beat / f_slope / 2;
end
Functions/03. FMCW radar design/bw2rngsep.m
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function [rng_sep] = bw2rngsep(TxBw, rb, c0)
% Objective : Converting range resolution to required 3-dB bandwidth needed to distinguish two targets separated by the range specified in r [m]
if isempty(c0)
c0 = physconst('LightSpeed');
end
rng_sep = (c0 * rb) ./ (2*TxBw);
end
Functions/03. FMCW radar design/cal_nf.m
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function [total_nf, total_gain, total_temp] = cal_nf(nf_set, gain_set, reftemp)
% Check inputs
narginchk(2,3);
% Validate
validateattributes(nf_set,{'double'}, {'nonnan','nonempty','real', ...
'vector','nonnegative'}, 'noisefigure', 'NF');
numNF = numel(nf_set);
validateattributes(gain_set,{'double'}, {'nonnan','nonempty','real', ...
'vector','numel',numNF}, 'noisefigure', 'G');
NFcol = db2pow(nf_set(:));
Gcol = db2pow(gain_set(:));
% Check for temperature input
if nargin < 3
reftemp = 290; % Standard noise temperature (Kelvin)
else
validateattributes(reftemp,{'double'}, {'finite','nonempty','real', ...
'nonnegative','scalar'}, 'noisefigure', 'REFTEMP');
end
% Calculate total gain
total_gain = sum(gain_set(:),1); % dB
% Calculate cascaded noise figure
if numel(NFcol) > 1
cnfLinear = NFcol(1) + sum((NFcol(2:end) - 1)./cumprod(Gcol(1:end-1),1),1); % Linear
total_nf = 10*log10(cnfLinear); % dB
else
cnfLinear = NFcol(1);
total_nf = nf(1);
end
% Calculate cascaded noise temperature
total_temp = reftemp*(cnfLinear); % Kelvin
end
Functions/03. FMCW radar design/cal_rdcoupling.m
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function [deltaR] = cal_rdcoupling(dop, f_slope, c0)
% Objective : Calculating range offset [m] due to Doppler shift [Hz] in a LFM signal
if isempty(c0)
c0 = physconst('LightSpeed');
end
deltaR = -c0 * dop / (2 * f_slope);
end
Functions/03. FMCW radar design/cal_rtmcoupling.m
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function [deltaR] = cal_rtmcoupling(spd, PRI, m)
% Objective : Calculating range offset [m] due to Target Motion during sweeps in a LFM signal
deltaR = -m * PRI * spd;
end
Functions/03. FMCW radar design/dechirping.m
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function [sig_out] = dechirping(sig_in, sig_ref)
% Objecrtive : Mixing the incoming signal, sig_in, with the reference
% signal, sig_ref.
sig_ref = cast(sig_ref, class(sig_in));
sig_out = bsxfun(@times, conj(sig_ref), sig_in);
end
Functions/03. FMCW radar design/dop2spd.m
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function [spd] = dop2spd(dop, lambda)
% Objective : Converting Doppler shift [Hz] to Radial Speed [m/s] for one-way propagation
spd = dop * lambda;
end
Functions/03. FMCW radar design/elev_ant_pat.mat
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Functions/03. FMCW radar design/gen_fastramp_fmcw.m
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function [waveform_seq] = gen_fastramp_fmcw(timing_struct, fs, f0, TxBw, NumChirps, prop_delay, phase_initial, opt)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Generating Fast Ramp Linear FMCW waveform
% Start : 23.12.22
% End : xx.xx.xx
% developed by Kwanggoo Yeo
%
% Description
% - Input
% - 1) timing_struct [struct], [-] : Timing information for one chirp
% - 1-1) T_dwell [scalar], [sec] : Time length for idle
% - 1-2) T_settle [scalar], [sec] : Time length for ramp start but not acquisition
% - 1-3) T_jumpback [scalar], [sec] : Time length for go back to the start frequency
% - 1-4) T_reset [scalar], [sec] : Time length for reset
% - 1-5) T_acq [scalar], [sec] : Time length for acqusition
% - 2) fs [scalar], [Hz] : Sampling rate
% - 3) f0 [scalar], [Hz] : Start frequency
% - 4) TxBw [scalar], [Hz] : Waveform Bandwidth
% - 5) NumChirps [scalar], [-] : The number of chirps in one frame
% - 6) prop_delay [scalar], [sec] : Time delay by range between radar and target
% - 7) phase_ini [scalar], [deg] : Initial phase of Tx waveform in deg
%
% - Output
% - 1) waveform_seq [struct], [-] : Struct containing waveform information
% - 1-1) T_chirp [scalar], [sec] : Time length for one chirp
% - 1-2) T_frame [scalar], [sec] : Time length for one frame
% - 1-3) timeline [vec], [sec] : Time index for Fast ramp Linear FMCW sequence
% - 1-4) waveform [matrix], [-] : Fast ramp Linear FMCW sequence
%
% History
% (23.12.22) Start
%
% Referece
% -
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
T_dwell = timing_struct.T_dwell;
T_settle = timing_struct.T_settle;
T_acq = timing_struct.T_acq;
T_jumpback = timing_struct.T_jumpback;
T_reset = timing_struct.T_reset;
T_idle = timing_struct.T_idle;
waveform_seq.T_chirp = T_dwell + T_settle + T_acq + T_jumpback + T_reset + T_idle;
waveform_seq.T_frame = waveform_seq.T_chirp * NumChirps;
waveform_seq.f_slope = TxBw / T_acq;
waveform_seq.timeline = (0 : 1/fs : (T_acq - 1/fs)) + T_dwell + T_settle + prop_delay;
if opt == 0
waveform_seq.waveform = cos(2 * pi * f0 * waveform_seq.timeline + 2 * pi * (waveform_seq.f_slope/2 * waveform_seq.timeline.^2) + phase_initial);
waveform_seq.waveform = waveform_seq.waveform / sqrt(norm(waveform_seq.waveform)^2 / length(waveform_seq.waveform));
elseif opt == 1
waveform_seq.waveform = exp(1i * 2 * pi * f0 * waveform_seq.timeline + 1i * 2 * pi * (waveform_seq.f_slope/2 * waveform_seq.timeline.^2) + 1i* phase_initial);
waveform_seq.waveform = waveform_seq.waveform / sqrt(norm(waveform_seq.waveform)^2 / length(waveform_seq.waveform));
else
disp('Opt error! : Real waveform(opt = 0) or Complex waveform(opt = 1)')
return;
end
end
Functions/03. FMCW radar design/gen_fastramp_fmcw2.m
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function [waveform_seq] = gen_fastramp_fmcw2(timing_struct, fs, f0, TxBw, ChirpIndex, NumChirps, prop_delay, phase_initial, opt)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Generating m-th Fast Ramp Linear FMCW waveform with considering different PRI
% Start : 23.12.22
% End : xx.xx.xx
% developed by Kwanggoo Yeo
%
% Description
% - Input
% - 1) timing_struct [struct], [-] : Timing information for one chirp
% - 1-1) T_dwell [scalar], [sec] : Time length for idle
% - 1-2) T_settle [scalar], [sec] : Time length for ramp start but not acquisition
% - 1-3) T_jumpback [scalar], [sec] : Time length for go back to the start frequency
% - 1-4) T_reset [scalar], [sec] : Time length for reset
% - 1-5) T_acq [scalar], [sec] : Time length for acqusition
% - 2) fs [scalar], [Hz] : Sampling rate
% - 3) f0 [scalar], [Hz] : Start frequency
% - 4) TxBw [scalar], [Hz] : Waveform Bandwidth
% - 5) ChirpIndex [scalar], [-] : m-th chirp index ( m= 1, 2, 3, ..., M )
% - 6) NumChirps [scalar], [-] : The number of chirps in one frame
% - 7) prop_delay [scalar], [sec] : Time delay by range between radar and target
% - 8) phase_ini [scalar], [deg] : Initial phase of Tx waveform in deg
%
% - Output
% - 1) waveform_seq [struct], [-] : Struct containing waveform information
% - 1-1) T_chirp [scalar], [sec] : Time length for one chirp
% - 1-2) T_frame [scalar], [sec] : Time length for one frame
% - 1-3) timeline [vec], [sec] : Time index for Fast ramp Linear FMCW sequence
% - 1-4) waveform [matrix], [-] : Fast ramp Linear FMCW sequence
%
% History
% (23.12.22) Start
%
% Referece
% -
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
T_dwell = timing_struct.T_dwell;
T_settle = timing_struct.T_settle;
T_acq = timing_struct.T_acq;
T_jumpback = timing_struct.T_jumpback;
T_reset = timing_struct.T_reset;
T_idle = timing_struct.T_idle;
waveform_seq.T_chirp = T_dwell + T_settle + T_acq + T_jumpback + T_reset + T_idle;
waveform_seq.T_frame = waveform_seq.T_chirp * NumChirps;
waveform_seq.f_slope = TxBw / T_acq;
waveform_seq.timeline = T_dwell + T_settle + (0 : 1/fs : (T_acq - 1/fs)) + ((ChirpIndex-1) * waveform_seq.T_chirp) + prop_delay;
if opt == 0
waveform_seq.waveform = cos(2 * pi * f0 * waveform_seq.timeline + 2 * pi * (waveform_seq.f_slope/2 * waveform_seq.timeline.^2) + phase_initial);
waveform_seq.waveform = waveform_seq.waveform / sqrt(norm(waveform_seq.waveform)^2 / length(waveform_seq.waveform));
elseif opt == 1
waveform_seq.waveform = exp(1i * 2 * pi * f0 * waveform_seq.timeline + 1i * 2 * pi * (waveform_seq.f_slope/2 * waveform_seq.timeline.^2) + 1i* phase_initial);
waveform_seq.waveform = waveform_seq.waveform / sqrt(norm(waveform_seq.waveform)^2 / length(waveform_seq.waveform));
else
disp('Opt error! : Real waveform(opt = 0) or Complex waveform(opt = 1)')
return;
end
end
Functions/03. FMCW radar design/rng2beat.m
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function [f_beat] = rng2beat(rng, f_slope, c0)
% Objective : Converting the range [m] of a dechirped linear FMCW signal to
% its corresponding range, beat frequency [Hz]
%
% f_beat = (2 * f_slope * rng) / c0
%
if isempty(c0)
c0 = physconst('LightSpeed');
end
f_beat = 2 * rng / c0 * f_slope;
end
Functions/03. FMCW radar design/rng2time.m
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function [t] = rng2time(r, c0)
% Objective : Calculating the time that a signal takes to propagate given range, r
if isempty(c0)
c0 = physconst('LightSpeed');
end
t = r / c0;
end
Functions/03. FMCW radar design/rngres2bw.m
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function [req_bw] = rngres2bw(rng_res, rb, c0)
% Objective : Converting range resolution to required 3-dB bandwidth needed to distinguish two targets separated by the range specified in r [m]
if isempty(c0)
c0 = physconst('LightSpeed');
end
req_bw = (c0 * rb) ./ (2*rng_res);
end
Functions/03. FMCW radar design/spd2dop.m
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function [dop] = spd2dop(spd, lambda)
% Objective : Converting the speed [m/s] to the corresponding Doppler frequency shift [Hz] for one-way propagation
dop = spd / lambda;
end