import radarsimpy
radarsimpy.__version__

'10.0.0'

FMCW Radar with a Plate

This is an example of using RadarSimPy to simulate an FMCW radar with a plate.

---

Setup FMCW radar

Transmitter

Setup the basic transmitter parameters through Transmitter module.

The following table lists the parameters in this example.

Parameter	Variable in Transmitter	Value
Frequency ($f$)	f	[1e9-50e6, 1e9+50e6] GHz
Time ($T$)	t	80e-6 s
Transmitted power ($P_t$)	tx_power	15 dBm
Pulse repetition period ($PRP$)	prp	0.5 s
Number of pulses	pulses	180

Receiver

Setup the receiver parameters through Receiver module.

The parameters of the receiver are listed in the table below.

Parameter	Variable in Receiver	Value
Sampling rate ($f_s$)	fs	2 Msps
Noise figure ($NF$)	noise_figure	8 dB
RF gain/loss ($G_{rf}$)	rf_gain	20 dB
Load resistor ($R_L$)	load_resistor	500 $\Omega$
Baseband voltage gain ($G_{BB}$)	baseband_gain	30 dB

import numpy as np
from radarsimpy import Radar, Transmitter, Receiver

tx_channel = dict(
    location=(0, 0, 0),
)

tx = Transmitter(f=[1e9-50e6, 1e9+50e6],
                 t=[0, 80e-6],
                 tx_power=15,
                 prp=0.5,
                 pulses=180,
                 channels=[tx_channel])

rx_channel = dict(
    location=(0, 0, 0),
)

rx = Receiver(fs=2e6,
              noise_figure=8,
              rf_gain=20,
              load_resistor=500,
              baseband_gain=30,
              channels=[rx_channel])

radar = Radar(transmitter=tx, receiver=rx)

Plate model

The plate model is with .stl. It can be imported by using meshio module.

target_1 = {
    'model': '../models/plate5x5.stl',
    'location': (200, 0, 0),
    'speed': (0, 0, 0),
    'rotation_rate': (1, 0, 0),
}

targets = [target_1]

Plot the 3D mesh of the plate

import meshio

import plotly.graph_objs as go
from IPython.display import SVG, display

mesh_data = meshio.read('../models/plate5x5.stl')

fig = go.Figure()

fig.add_trace(go.Mesh3d(x=mesh_data.points[:, 0],
                        y=mesh_data.points[:, 1],
                        z=mesh_data.points[:, 2],
                        i=mesh_data.cells[0].data[:, 0],
                        j=mesh_data.cells[0].data[:, 1],
                        k=mesh_data.cells[0].data[:, 2],
                        intensity=mesh_data.points[:, 2],
                        colorscale='Viridis'
                        ))

# fig.show()
display(SVG(fig.to_image(format='svg', scale=1)))

Raytracing

from radarsimpy.rt import scene
import time

tic = time.time()
data = scene(radar, targets, density=1, noise=False, level='pulse')

baseband = data['baseband']
toc = time.time()

print('Exec time:', toc-tic, 's')

Exec time: 0.6394860744476318 s

Radar signal processing

Range processing

from scipy import signal
import radarsimpy.processing as proc

range_window = signal.chebwin(radar.samples_per_pulse, at=60)
range_profile = proc.range_fft(baseband, range_window)

Plot range profiles

import plotly.express as px

fig = px.imshow(
    20 * np.log10(np.abs(range_profile[0, :, :]) + 0.0001), color_continuous_scale='hot')
fig.update_xaxes(title='Range bin')
fig.update_yaxes(title='Chirp index')
display(SVG(fig.to_image(format='svg', scale=1)))

Peak amplitude versus observation angle

obs_angle = np.arange(0, 90, 0.5)

fig = px.line(x=obs_angle, y=20 *
              np.log10(np.abs(range_profile[0, :, :]) + 0.0001)[:, 133])

fig.update_xaxes(title='Observation angle (deg)')
fig.update_yaxes(title='Peak amplitude (dB)')
display(SVG(fig.to_image(format='svg', scale=1)))