How UWB calculates location

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How UWB calculates location [Copy link]

The application of UWB is also very clear. There are three main applications: imaging, communication and measurement, and vehicle-mounted radar systems. Looking at it from a macro perspective, the high-precision positioning accuracy of Precision Technology's UWB is up to 10cm, which can be divided into three scenarios: positioning, communication and imaging.

Positioning: I would like to borrow my previous answer here. The UWB positioning system also needs to use the UWB base station as coordinates. If we talk about base station positioning, there are these types:

a. Trilateration:

Solve the geometry problem through the received signal. Since the base station location is known, the only unknown number is the distance between the user and the base station. In order to solve the distance between the user and the base station, the signal propagation time in the air is required, that is, several types of information may be used: time of arrival (ToA); time difference of arrival (TDoA) or received signal strength (RSS).

b. Triangulation:

When the base station location is known, the distance information between the base station and the user can be replaced by angle information. If we know the angle of arrival (AoA) of the signal, we can also get the same result as trilateration.

c. Approximate:

If we have only one known base station, we can roughly estimate the distance and angle between the user and the base station based on ToA or AoA and signal strength, and then we can approximate the user's location. In fact, this is also the most common base station positioning method in 2G systems. The problem here is that there is usually a lot of interference on the ground, and the estimate of a single base station will not be very accurate.

d.Scenario analysis:

We can store the signal characteristics of some typical locations (such as RSS, delay spread or channel spread) in the database, and then compare them with the signals at that time to estimate the distance and direction between the user and the base station.

Communications:

Because of its large bandwidth, UWB was once considered a wireless alternative to USB data transmission. The problem with Bluetooth is that the transmission speed is too slow. UWB is also often used for military confidential communications, mainly because the energy of UWB pulses is very low, which can easily fall below the noise threshold and is not easily monitored by other radio systems.

Imaging:

The bandwidth of the UWB system is very wide. Currently, UWB through-the-wall radar is widely used. The specific method is to use narrow pulses to pass through the wall, obtain the echo on the other side of the wall, and then obtain an image with very low imaging error. So if Apple opens the underlying interface one day, maybe the iPhone can be used to spy on neighbors.

As we have analyzed before, trilateration is very suitable for UWB because of its high distance resolution and high ToA accuracy. In fact, this is also the most mainstream positioning method in UWB radio. AoA, an angle estimation method that requires an antenna array, is not as suitable for UWB as ToA.