UWB technology

UWB (Ultra-Wide Band) is actually a general term, generally refers to ultra-wide band, the general Bandwidth (Bandwidth) more

than 500MHz can be called ultra-wide band, the higher the frequency, such as 60GHz radar, its single channel bandwidth can also

reach more than 1GHz, the future ultra-wide band more and more popular.

Around 2006, IEEE planned to use UWB for data transmission, and later did not land due to normative reasons, and later developed

IEEE 8015.4a and 4z specifications, UWB is used in the field of positioning; In addition, UWB can also be widely used in radar to

achieve presence detection, ranging, imaging, breathing, heart rate detection, etc. Now the most popular is based on IR-UWB (Impulse

Radio-UWB) ranging and positioning technology.

Compared with other positioning technologies, IR-UWB has several main features:

1. High bandwidth

Up to 500MHz, according to Shannon's theorem, the wider the bandwidth, the more accurate the time sampling. The minimum

granularity of clock sampling in UWB reaches 15.6ps.

2, multi-path resolution is strong

IR-UWB adopts pulse mode, the time of a pulse is about 2ns, if the distance between the direct path and the multi-path reaches 0.6

meters, it can be effectively distinguished. Due to the many factors of multi-path, the base station needs to be paid special attention

to if it wants to achieve good accuracy when it is set up.

3. Data sampling is based on time

In UWB based positioning system, whether based on distance measurement or based on the way to reach the time difference, it is

based on the time stamp of receiving or transmitting, and finally calculate the position. The distance is calculated using the method

of time * the speed of light, so the human body occlusion will lead to inaccurate sampling, because the transmission speed of the

battery wave is much lower than the speed of light.

4, low output power

UWB in the global legal power is basically in -41.3dBm/MHz, calculated according to 500MHz, its output power is -14.3dBm, the

general Wi-Fi AP output power is calculated according to 20dBm, 34dBm higher than UWB, is more than 2000 times of UWB power;

5. Security

Two aspects, one is based on the pulse mode, the duration is very short, and the other aspect is related to time, because when the

two terminals communicate, the relative distance relationship can be determined by time, which is difficult to simulate;

6. Bandwidth

Compared with other wireless positioning technologies, UWB bandwidth is much higher than other narrowband communication

technologies, the typical communication rate can reach 6.8Mbps, or even 27Mbps, in terms of power consumption and speed advantages

are unmatched by other wireless technologies.

Based on the above characteristics of UWB, it can be obtained in the positioning system

1, better accuracy, in the best case, can reach 5cm

2, higher reliability, due to its strong anti-multipath ability, the factory environment, can reach 0.5 meters positioning accuracy;

3, strong anti-interference ability, suitable for application in the scene with a certain block.