Ultra Wideband (UWB) Technology
| ResellersUltra wideband (WB) signals have been used for decades in geophysical characteristic applications. When UWB signals are employed in geophysical analysis systems, the sensor is moved in order to detect and map underground stationary objects. When used in UVSS’s UltraSensor™, the sensor is stationary to detect motion.
UWB signals are generally defined as electromagnetic transmitters whose bandwidth is at least 25% of the nominal center frequency. UWB operates in the time domain; almost all other transmitters operate in the frequency domain.
Geophysical analysis instruments are moved across a surface and transmit very short bursts of electromagnetic energy into the ground. Reflections from buried targets or subsurface anomalies (fixed objects) are received at another antenna. This technology can detect targets such as plastic pipes and voids underground, and even targets inside walls and floors. Any change in dielectric property of materials will cause a reflection. Echoes from targets will arrive at different times depending on their distance from the antenna (and will also vary depending on the type of material through which the signal passes).
For UltraVision’s UltraSensor™, the transmitted and reflected signals are passing through solid objects: pavement, landscaping material, roadbed, building walls and ceilings, etc. The sensor is stationary and detects moving objects. As with geophysical analysis, the approximate distance of the object causing the reflected signal can be determined by the particular time delay in the signal return. The velocity of the target can also be determined in either feet or meters per second through the detection field. There may be concrete walls or other structures and obstacles in the radiation path.
- Total average power is transmitted is ~1% of a cell phone
- Working in the time domain, distance to the motion can be measured
The reason for using a UWB signal instead of a single frequency transmitter (like microwave) is improved motion resolution, distance measurement and obstacle penetration. Lower frequencies within the transmitted pulse carry farther especially when looking through walls and floors; however resolution deteriorates with lower frequencies. Since the resolution is actually a function of the total length of the RF (radio frequency) burst, then having the fewest number of cycles of the waveform will maximize it. In the simplest terms, the wide spectrum of the transmitted signal accommodates most motion and obstacle types. In essence, a maximum number of frequencies are transmitted (both low and high frequencies) with the notion that some frequency will be reflected and sent back to the receiver.