Terminology » Difference between UWB Ranging Vs. Sensing

Difference between UWB Ranging Vs. Sensing

Introduction : There are various wireless technologies around us mainly offering unique service such as wifi connects us to the internet, bluetooth connects with our peripherals and so on. On the other end, UWB (Ultra-WideBand) transmits ultra short pulses over broad frequency spectrum and are used for two completely different physical functions such as ranging and sensing. Let us understand how UWB Ranging and UWB Sensing operate, why they matter and most importantly when to use one over the other for optimal performance.

UWB Ranging

It leveraging UWB for accurate distance measurement and positioning. UWB Ranging is based on carefully timed pulses and protocols like two way ranging or time of flight. It requires two active devices viz. anchor and tag. Let us understand its working.

UWB Ranging vs UWB Radar Sensing Figure-1 : UWB Ranging Versus Sensing

It is co-operative communication between two active electronic devices. It is based on time of flight (ToF) measurement. In this set up, both the ends of the link must have UWB chip and power source.

Device A (e.g. UWB anchor installed in car) sends a radio pulse to device e.g. smartphone.
Device B processes the pulse and sends a reply.
Device A calculates precise time of flight when it receives response from the device-B as shown in the figure-2.
The output is precise distance measurement with centimete level accuracy.

UWB signal Figure-2 : Time of Flight Measurement

Applications : Indoor navigation, asset tracking, secure device proximity detection and any scenario where knowing exactly how far apart two entities are is crucial.

UWB Sensing

It uses UWB like radar to detect motion, presence or even subtle changes in the environment. It turns UWB chip into a monostatic radar. It does not talk to another chip; instead talks to the environment. It requires only One Active Device. The “target” can be anything (a person, a pet, a hand) and does not need a chip. Let us understand its working.

UWB devices shoots out radio pulses into the empty air.
These pulses bounces off passive objects such as walls, furniture or human chest.
The device listens for the echo. It analyzes Channel Impulse Response (CIR). If the echo changes slightly over time (micro-Doppler effect), it knows something moved.
The output is Presence detection or motion data (e.g., “Movement detected,” or “Respiration rate is 20 breaths/min”).

Applications : Occupancy detection (e.g. child presence detection), gesture recognition, vital sign monitoring or object detection through obstacles and low visibility conditions.

Comparison between UWB Ranging Vs. Sensing

Feature	UWB Ranging	UWB Radar Sensing
Primary Physics	Cooperative (Device to Device)	Monostatic Radar (Device to Environment)
Hardware required	Two active UWB chips i.e. Tag and Anchor	One Active UWB Chip
Target Type	Must be Electronic i.e. Phone, Tag or Fob	Any Physical Object i.e. Human, Pet, Wall
Measurement Method	Time of Flight (ToF) Calculation as explained	Doppler Shift and Signal Reflection
Main Output	Distance/Location (X, Y, Z)	Presence / Motion / Vital Signs
Privacy	Tracks specific ID (Who is there)	Anonymous (Something is there)
Typical Use Case	Unlocking a car with a phone	Detecting a baby breathing in the car

Summary:

Ultimately, the choice between UWB Ranging and UWB Sensing depends on the needs of your project. For precise positioning, go for Ranging. For environmental awareness or presence detection, Sensing often makes more sense. And in many advanced systems, the two can be combined (or used alongside other sensing modalities) to deliver both spatial precision and environmental intelligence.