Positioning is an indispensable part of drone technology. Outdoors, GPS is often used as positioning technology, but in indoor environments, GPS cannot provide more accurate positioning data. In indoor positioning technology solutions, there are The SLAM positioning and mapping technology of lidar, the vision-based SLAM positioning and mapping technology, the positioning technology solution of optical flow module combined with ultrasonic sensor, and the positioning technology solution of motion capture system. These positioning technology solutions have their own advantages and disadvantages. In accuracy, Price and stability have their own advantages.
Today, we bring you an indoor positioning system called "small satellite"—LinkTrack based on UWB technology. Compared with other technical solutions, its accuracy, stability, and price are relatively balanced, and it is a low cost. , But it can also provide technical solutions with better positioning effects.
The principle of UWB positioning technology:
When it comes to UWB positioning technology, you need to first understand how UWB is ranging. UWB ranging uses two way-time of flight (TW-TOF, two way-time of flight). TOF ranging is a two-way ranging technology. The flight time between two asynchronous transceivers (Transceiver) is mainly used to measure the distance between nodes. If the distance between the nodes can be obtained, then we can perform positioning. The principle of UWB positioning technology is similar to the principle of GPS satellite navigation and positioning. Both are distance measurement between the tags on the drone and the four base stations. The location data of the UAV can be calculated through the algorithm.
LinkTrack introduction:
LinkTrack is a PNTC (positioning, navigation, timing and communication) local positioning system based on UWB technology. Support 1D, 2D, 3D positioning, 1D, 2D typical positioning accuracy 10cm, 3D typical positioning accuracy 30cm; support 40 tags, 120 base station positioning. Supports distributed ranging and data transmission, realizing cluster formation without geographical restrictions; supports pure data transmission mode with a bandwidth of up to 3Mbps.
There are two issues to pay attention to when using LinkTrack for indoor positioning. One is that there should be no obstacles between LinkTracks. From the principle of UWB ranging technology, it can be understood that when there is no direct propagation path between two points, only signal reflection The sum diffraction component can reach the receiving end. At this time, the time of the first arriving pulse cannot represent the true value, and there is a non-line-of-sight error. Second, the calibration data of the base station must be accurate.
LinkTrack is also very convenient in use. For the calibration data mentioned above, the software provided by LinkTrack can realize the function of one-key calibration, and the calibration data can be written in only a few simple operations.
The same is true when LinkTrack is connected to the flight controller. You only need to set the tag to NMEA format, and then connect the tag to the flight controller to use the positioning data directly.
Indoor positioning effect display:
In an indoor 3 X 3 meter square environment, after setting up the base station, place the UAV with LinkTrack installed in it. Observing the data in it, you can find that the accuracy of the UAV positioning data under static conditions is about 5CM Around, we have repeatedly tested and found that the accuracy can basically be maintained within 10CM, but it should be noted that there must be no obstacles between the base stations of LinkTrack and the base station calibration data must be accurate.
Finally, please take a look at the effect of indoor positioning!