Radar-Range-Equation 2025.11.21.dev1

A Radar Range Equation Package

2025.10.27

Main updates include support for theta_B and calculations for spheres, RCS and radius from RCS.

New: Plotting capabilities for visualizing radar signals including pulsed radar, CW Doppler, CWFM, pulse compression, range profiles, and Doppler spectra.

Radar Range Equation

A compact toolbox for deriving and evaluating radar range equations. It exposes a small programmatic API for setting physical variables, performing common radar-related calculations, converting units, and visualizing radar signals.

Install

pip install radar-range-equation

## Quick start

```python
import radar_range_equation as RRE

# Set common variables
RRE.vars.c = 3.0e8        # speed of light (m/s)
RRE.vars.f = 430e6        # frequency (Hz)
RRE.vars.eta = 0.6        # antenna efficiency (unitless)

# Because `lambda` is a reserved word in Python, access it with getattr/setattr
setattr(RRE.vars, 'lambda', RRE.vars.c / RRE.vars.f)
print('wavelength (m):', getattr(RRE.vars, 'lambda'))

# Compute effective aperture (circular antenna example)
RRE.vars.D = RRE.convert_ft_to_m(60)  # antenna diameter in meters
RRE.vars.A_e = RRE.solve.A_e_circ()
print('A_e (m^2):', RRE.vars.A_e)

# Visualize a pulsed radar signal
RRE.plot.pulsed_radar_signal(
    amplitude=20,
    frequency=0.5e6,  # 0.5 MHz
    pulse_width=15e-6,  # 15 microseconds
    pri=50e-6,  # 50 microseconds
    num_pulses=3
)

Public API (short)

• vars — namespace-like container of variables (speed of light c, frequency f, wavelength lambda, gains, power, sigma, etc.). Use getattr/setattr for lambda.
• solve — helper functions for computing aperture, gain, R_max, P_t and other routine expressions (e.g., solve.wavelength(), solve.G_t()).
• equations — symbolic SymPy expressions representing the radar equations used by solve.
• plot — plotting utilities for visualizing radar signals (pulsed radar, CW Doppler, CWFM, pulse compression, range profiles, Doppler spectra).
• redefine_variable(name, value) — convenience to set attributes on the vars namespace.
• convert — unit conversion helpers (e.g., convert.ft_to_m(), convert.lin_to_db(), convert.hz_to(), etc.).

Plotting Capabilities

The package now includes comprehensive plotting functions for visualizing radar signals:

Pulsed Radar Signal

import radar_range_equation as RRE

# Visualize a pulsed radar transmit signal
t, signal, fig = RRE.plot.pulsed_radar_signal(
    amplitude=20,           # Peak amplitude
    frequency=0.5e6,        # 0.5 MHz carrier
    pulse_width=15e-6,      # 15 µs pulse width
    pri=50e-6,              # 50 µs pulse repetition interval
    num_pulses=3,           # 3 pulses
    time_span=150e-6        # 150 µs total time
)

Other Plotting Functions

• plot.cw_doppler_signal() — CW radar with Doppler shift
• plot.cwfm_signal() — Continuous Wave Frequency Modulated radar
• plot.pulse_compression_signal() — Chirp pulse and compressed output
• plot.range_profile() — Target detections at various ranges
• plot.doppler_spectrum() — Velocity distribution of targets

See python/example_plotting.py for complete examples of all plotting capabilities.

Testing

After installing the package you can run the included smoke test:

python python/test_package.py

The test script checks basic import and example calculations.

To test the plotting functionality:

python python/test_plotting.py

To see examples of all plotting capabilities:

python python/example_plotting.py

Notes and gotchas

• lambda is a reserved Python keyword; use getattr(vars, 'lambda') and setattr(vars, 'lambda', value) when reading/writing the wavelength variable.
• The package mixes symbolic (SymPy) and numeric (NumPy/Scipy) approaches. The equations module provides symbolic forms while solve returns numeric results based on values in vars.

Contributing

Small, focused improvements (tests, docs, type hints) are welcome. The repository uses Hatch in CI for packaging; see .github/workflows/python-package.yml for the build/test flow.

License

See the repository LICENSE file for licensing details.

Radar Range Equation

A basic toolbox for solving radar range equations

Testing

After building and installing the package, you can run the test script to verify functionality:

python python/test_package.py

This test script verifies that:

• The package can be imported successfully
• Variables can be set dynamically (e.g., c, f, lambda)
• The redefine_variable function works correctly
• Calculations work as expected (e.g., lambda = c/f)

Example Usage

import radar_range_equation as RRE

# Set the speed of light (m/s)
RRE.vars.c = 3.00 * 10**8

# Set the frequency (Hz)
RRE.vars.f = 10

# Calculate and set wavelength (m)
# Note: 'lambda' is a reserved keyword in Python, so use setattr/getattr
setattr(RRE.vars, 'lambda', RRE.vars.c / RRE.vars.f)

# Print the wavelength
print(getattr(RRE.vars, 'lambda'))  # Output: 30000000.0