Radar Range Resolution
Understanding Radar Range Resolution
Range resolution determines how precisely a radar can separate closely spaced targets. It is purely a function of bandwidth, not pulse duration or power. This is why modern radars use wideband waveforms.
Range Resolution
delta_R = c / (2 x B)
Where B = signal bandwidth (Hz)
Examples:
B = 1 MHz: delta_R = 150 m
B = 10 MHz: delta_R = 15 m
B = 100 MHz: delta_R = 1.5 m
B = 1 GHz: delta_R = 15 cm
B = 4 GHz (77 GHz auto radar): 3.75 cm
Frequently Asked Questions
What determines range resolution?
Range resolution = c/(2B). Only bandwidth matters. 10 MHz: 15m resolution. 100 MHz: 1.5m. 1 GHz: 15 cm. Wider bandwidth = finer resolution. Pulse compression achieves wide bandwidth with practical pulse durations.
Why is pulse compression needed?
A short pulse (1 ns = 15 cm resolution) has very little energy, limiting detection range. Pulse compression uses a long, modulated pulse (high energy) and compresses it upon reception to achieve the resolution of a short pulse. Best of both worlds.
What resolution does automotive radar achieve?
77 GHz automotive radar uses 4 GHz bandwidth: range resolution = 3.75 cm. This enables detailed imaging of the driving environment, separating pedestrians, vehicles, and road features.