CZ32010U1 - A scalable localization system for determination of position in 3D - Google Patents

Description

Technical field

The technical solution relates to a scalable real-time 3D positioning system.

BACKGROUND OF THE INVENTION

Current scalable location systems based on UWB technology use the TDoA principle. By extending them using MEMS inertial sensors, ie the "Micro Electro Mechanical System", it is possible to obtain information about the location of the localized object in addition to the position. It is possible to use fusion of data from accelerometer, gyroscope and magnetometer.

The current limitation of the TDoA location system is 3D position calculation. For this purpose it is necessary to have reference anchors, ie static receivers, located diagonally in the space. Unfortunately, this approach is usually not possible in practical deployment outside the laboratory, because anchors and locators need to have direct visibility on them, and this is usually not possible when placed on the floor. In addition, the antennas used for broadband UWBs, ie "Ultra-Wideband" radio positioning technologies, have good plane radiation, but already significantly lower gain outside of it. Therefore, the diagonal arrangement leads to the necessity of a significantly denser anchor network.

The object of the invention is to overcome the above-mentioned disadvantages of the prior art.

The essence of the technical solution

The above-mentioned deficiencies are remedied to a large extent by the scalable location system, which consists of a locator containing an MEMS inertial unit intended to evaluate their micro-motions, a UWB radio designed to determine its own position and transmit position information and MEMS inertial unit data. to a central server, a Bluetooth module for possible interconnection of the micro-motion unit with external sensors, an NFC interface designed to allow pairing of the micro-motion unit with other digital equipment, a pressure sensor for determining height, power source locators, and a microcontroller designed for preprocessing and reception control; sending data, where MEMS inertial unit, UWB radio, Bluetooth module, NFC interface, pressure sensor, power supply and control microcontroller are interconnected data, and scalable location the system includes an anchor containing UWB radio data interconnected with UWB locator radio for data transmission between them, microcontroller with Ethernet interface designed for preprocessing and control of data receiving and sending, WiFi module and pressure sensor for determination of height, and further scalable location system contains central server for evaluation of measured data, where the locator, anchor and central server are interconnected by data.

Clarification of drawings

The technical solution will be further illustrated by means of a picture representing a block diagram of a scalable location system according to the technical solution.

Example of technical solution implementation

Scalable location system according to the technical solution whose block diagram is presented at

- 1 CZ 32010 U1 Fig. 1, contains:

locator containing

- MEMS, ie the "MicroElectroMechanical System", an inertial unit designed to evaluate their micro-movements, or the person on which the micro-movement unit is located,

- UWB radio designed to detect its own position and to transmit its position information and data from the MEMS inertial unit to the central server,

- Bluetooth module designed to connect the micro-motion unit to external sensors, such as heart rate sensors,

- NFC interface designed to enable the pairing of the micro-motion unit with other digital equipment,

- a power source such as a battery,

- non-wired power circuit,

a control microcontroller designed for the preprocessing and control of data transmission, and

- pressure sensor,

and further comprising an anchor

- UWB radio data-connected to the UWB locator radio, designed to transmit data between them,

- microcontroller with Ethernet interface,

- WiFi module and

- a pressure sensor for determining the height, and a central server for evaluating the measured data.

All of the above locator components are interconnected with each other as well as the locator, anchor and central server.

The locator may preferably include an indicator LED, a button, a beeper, a vibrating motor, etc.

The NFC interface uses close inductive coupling to configure the micro motion unit from another device, such as a mobile phone.

The indicator microcontroller is preferably of the BGM121 type from Silicon Labs, which provides enough processing power to control the microprocessor unit and to preprocess inertial data. At the same time, it allows for deep sleep when the total indicator consumption is only 16 pW.

The UWB indicator chip is preferably a DW1000 type from Decawave, which allows accurate timestamping of received frames and determining its position in decimeter resolution.

The indicator charging wireless circuit is preferably of the BQ5105 type, which combines wireless power transmission according to the WPC standard, and a Li-ion / Li-pol battery charger.

The MEMS inertial unit is preferably Infenion's MPU-9250, which integrates a three-axis accelerometer, magnetometer and gyroscope into a single housing to accurately sense and detect parameters such as person position, acceleration, rotation, swing, step, jump, impact , fall, etc.

The presented technical solution for 3D position calculation combines 2D position calculation using UWB signal together with MEMS barometer for determination of Z axis with accuracy better than one meter, which further allows to have anchors in the plane, see Fig. 2b.

To determine the absolute height, the pressure gauge is located in the locator and in static anchors. Since the position of the anchor is known, it is then possible to determine from the locator coordinate by relative barometric measurement of the locator, and the nearest static anchors in the vicinity. In addition, the surrounding anchors allow to suppress transient pressure changes, for example, when windows or doors are opened in a room.

-2GB 32010 U1

Each anchor and locator have a certain barometer offset from production, which means that the indicated pressure varies on each anchor or locator. This offset can be up to several tens of Pascals. For this reason, the anchors must be calibrated.

The locator pressure sensor is calibrated at the reference anchors. It is controlled from the control software remotely. First of all, for each reference anchor, its real ground level is set and initialized to send the current value of the pressure sensor to the receiver with some redundancy in a defined time interval. The server evaluates the received values and calibrates the barometers on the anchors.

The pressure sensor on the locators is then calibrated. These must be placed static and measure their height from the ground. The calibration process is then started, during which the anchors capture the barometric measurement from the locators and forward it to the server where the locator is calibrated. From this time it is possible to dynamically determine the Z coordinate.

Anchor calibration is performed during initialization and is performed by the RTLS server. The advantage is that we get 40 pressure values from each anchor in 10 seconds. From these 40 values, we choose one final value median. This highly eliminates the effect of sudden pressure changes during measurements such as opening a window, slamming doors, etc.

Subsequently, the RTLS Server will designate any anchor, first for simplicity, as the reference.

Then, for all other anchors, the offset to be added to each pressure value from that anchor is calculated to bring it to the level of the reference anchor. This, of course, creates an absolute error in the system, and the system is only interested in the relevant error, where the output of the system is the height in the room, not the altitude.

If all anchors were at the same height, the offset is calculated as the difference in anchor pressure to the reference anchor. However, the anchors are placed at different heights, so it is necessary to calculate the next offset. The calculation of this offset is based on the equation of J. Babinet to calculate the difference in altitude levels, knowing the pressure at these altitudes.

Anchors are not only located at different heights, but also at different locations. Thus, two anchors with the same Z coordinate but different altitude can occur in the system. To avoid this error, it is necessary to introduce a new parameter for the location, namely height. It is not the absolute height that matters, but the relative difference between the other sites.

The scalable location system according to the invention utilizes a unique 2D UWB connection and Z coordinate determination using a pressure MEMS sensor. Its application is possible mainly in location systems for monitoring elements for real-time sports applications, but also for medical and industrial sensors.

PROTECTION REQUIREMENTS

Claims (4)

A scalable location system, characterized in that it comprises a locator comprising MEMS an inertial unit designed to evaluate their micro-movements, UWB radio designed to detect its own position and to transmit information about this position and to transmit the data measured by the MEMS inertial unit to the central server, a Bluetooth module designed for possible interconnection of the micro-motion unit with external sensors, -3 EN 32010 U1 NFC interface designed to enable pairing of the micro-motion unit with other digital equipment, a pressure sensor for determining height, a power source locators, and 5 - a control microcontroller designed to preprocess and control the reception and transmission of data, where The MEMS inertial unit, UWB radio, Bluetooth module, NFC interface, pressure sensor, power supply and control microcontroller are data interconnected, and the scalable location system includes an anchor containing UWB radio data-connected to UWB locator radio, designed to transmit data between them, 10 - microcontroller with Ethernet interface designed for preprocessing and control of data receiving and sending, The WiFi module and pressure sensor for height determination, and the scalable location system includes a central server for evaluating the measurements 15 where the locator, anchor and the central server are interconnected data.