CSS technology

CSS is an abbreviation of Chirp Spread Spectrum, translated as chirp spread spectrum. A spread spectrum technique used in

communication systems. If the radio frequency pulse signal is transmitted in a period, the frequency of its carrier frequency changes

linearly, it is called linear frequency modulation. Because its frequency varies over a wide band, the band of the signal is also

broadened. This kind of spread spectrum modulation is mainly used in radar, but it also has applications in communication.

CSS technology is another physical layer technology written into IEEE 802.15.4a with UWB technology. The promotion of this

technology is mainly Germany's Nanotron (http://www.nanotron.com/). CSS technology works at ISM 2.4GHz. Three positioning

modes such as ToF, TDoA and AoA can be supported.

In fact, CSS technology has been mature in 2008, its ranging stability and accuracy is slightly lower than UWB, but in the industry is

also very good, but limited by the Nanotron company's strategy, the final solution is not really widely used.

But it is also characterized by its own characteristics:

1, because it is a narrowband technology, the recognition ability of multi-path is relatively weak;

2, the accuracy of ranging can basically reach 0.5 meters;

3, due to the use of 2.4GHz, the highest bandwidth can be 80MHz, the working distance is relatively far, relatively easy to 500 meters

away, but there are other 2.4GHz equipment in the environment, coexistence is a huge challenge;

4, the ranging efficiency is slightly low, resulting in low system capacity, in addition, because Nanotron does not open the underlying

algorithm of TDoA, and TDoA base station does it itself, and finally plays itself to death.