Signal-to-Noise Ratio

SNR (Signal to Noise Ratio) is the fundamental metric used to evaluate the performance of a radar system.

This ratio compares the received signal power from a target against the background noise,

that originates within the system itself, primarily from thermal and phase noise.

1. Impact of SNR

A high SNR is critical to minimize false alarms and enhance measurement precision.

If the SNR is too low, the target signal becomes indistinguishable from the noise floor,

leading to missed detections or increased False Alarm Rates.

	A higher SNR reduces detection errors and enhances measurement precision.
	False alarms occur when time-varying noise exceeds the detection threshold, leading to target misidentification.
	Raising the detection threshold to suppress false alarms makes target detection less sensitive

2. Supplementary: SCNR

SCNR (Signal-to-Clutter-plus-Noise Ratio) is a more realistic performance metric than SNR.

In real-world applications, the system is limited not just by internal noise, but by clutter.

Clutter refers to unwanted reflections from stationary objects like walls, furniture, or appliances.

3. SNR Calculation Example

Parameter	Symbol	Value	Converted Value	Descritpion
Transmit Power	P_t	10 dBm	0.1 W
TX Antenna Gain	G_t	8 dBi	6.31	Conversion to Linear Gain
RX Antenna Gain	G_r	8 dBi	6.31	Conversion to Linear Gain
Wavelength	λ	12.4 mm	0.0124 m
Target RCS	σ	0.5 m²		Estimated RCS of Stationary human
Range	R	8 m		Target Distance

Parameter	Symbol	Value	Converted Value	Description
Thermal Noise Density	k•T	-174 dBm/Hz
IF/Baseband Bandwidth	B	1 MHz	60 dB-Hz	Conversion to dB
Noise Figure	F	10 dB