"Not long ago, Infineon launched a new generation of 24GHz radar solution - position2go development kit. I was lucky to get it and have a practical experience. Position2go adopts a new RF transceiver and main control MCU, which not only improves the performance, but also increases the angle detection function of objects. Let's have a look!
Unpack
The package of the position2go kit is packaged in a white paper case with a simple introduction and detailed information access link printed on the position2go kit, which can be described as simple and environmentally friendly.
After unpacking, in addition to the paper shell lining, there is a small circuit board, a micro USB data cable and a folded triangular scattering board. Let's learn more about Infineon's position2go radar suite from the aspects of hardware composition, software development and actual testing.
Introduction to position2go
Based on the RF transceiver of bgt24mtr12 and xmc4700 32-bit arm cortex-m4 MCU, the position2go radar sensor development kit obtains the angle, distance, speed and direction of motion by using fast chirp FMCW and two receiving antennas. These functions make it suitable for various applications, such as tracking people, presence detection, collision avoidance and so on.
So far, Infineon has launched three industrial xensiv radar demonstration kits: sense2gol, distance2go and position2go, which support different applications - from basic motion detection to advanced motion detection and sensing.
The position2go module provides a complete radar system evaluation platform, including demonstration software and graphical user interface (GUI), which can be used to display and analyze the collected data in time domain and frequency domain. On board is a removable debugger with segger licensed firmware, which can be easily debugged via USB. Dave through Infineon's powerful free tool chain ™ Program xmc4700 MCU. The board also integrates microstrip patch antenna on PCB, including design data, so as to eliminate the complexity of antenna design at the user end.
characteristic
The main radar technology used on the position2go board is FMCW (frequency modulated continuous wave). The distance to the target is measured by the time delay between the transmitted and received chirp signals. Since bgt24mtr12 has two receivers, phase monopulse comparison technology is used to determine AOA. The transmitted and received signals are mixed and then quantized for further processing. Multiple chirp signals (up to 16) are processed to create a 2D range Doppler map, which can estimate the range and velocity of the target.
Based on the above principles, the main functions of the position2go board are as follows:
Detect and track the location of multiple targets in the outdoor environment.
Measure the distance (1 to 50 meters) of multiple targets within a user configurable range.
Detect the movement, presence, speed and moving direction (approach or retreat) of human targets.
It can operate under different weather conditions, such as rain, fog and so on.
It can be hidden in terminal applications and can be detected through non-metallic materials.
Let's take a look at the video introduction of unpacking and testing of position2go:
Hardware description
The board is small, only 5cm x 4.5cm. Let's learn more about the main hardware configuration of the position2go module.
Front of board
Back of board
As shown in the figure above, the position2go board mainly includes the following four important parts:
RF part: bgt24mtr12 - highly integrated 24 GHz transceiver IC, single transmit dual receive channel, and conical microstrip patch antenna for TX and Rx parts.
Analog amplifier part: provide the interface between RF part and digital part of circuit board, with programmable gain amplifier (PGA), which can be programmed through SPI to provide variable gain for different use conditions.
Digital part: MCU xmc4700 based on 32-bit arm cortex-m4 is used to sample and process analog data from the radar front end. Bgt24mtr12, PLL and PGA can also be configured through SPI.
Frequency control part: contains a low noise fractional frequency PLL.
Xmc4200 onboard debugger: for serial line debugging (SWD), with built-in segger licensed firmware.
The following block diagram describes the hardware structure of the position2go evaluation board in detail.
The structure is very similar to the previous generation product distance2go evaluation board. The main changes are that the RF transceiver is upgraded to bgt24mtr12, and the main controller is upgraded to 32-bit arm cortex-m4 core MCU xmc4700. The microstrip patch antenna is integrated on the board, and the Wilkinson combiner combines the output power of the differential transmitter of the radar IC with the antenna. Each receiver channel is connected to a two-stage analog amplifier at its if output. The built-in 12 bit ADC of xmc4700 32-bit arm cortex-m4 MCU samples and processes the analog down conversion signal from the baseband amplifier. The user can also control the radar chip through SPI, set the output power of the radar chip and the gain of the receiving part, or read out different sensor outputs. The low noise fractional phase locked loop (PLL) IC is used to perform frequency control and modulation wave generation. The output of the / 16 integrated prescaler on the radar IC is connected to the RF input pin of the PLL, and the output voltage of the PLL charge pump is connected to the tuning port of bgt24mtr12 through the loop filter to form a closed-loop system. This process is used to lock the transmission signal of the module to the output frequency in the ISM band. The integrated 1 / 65536 prescaler generates a low frequency output signal (23 kHz), which is connected to the comparison and acquisition unit (ccu4) of xmc4700 for monitoring.
The module is powered by micro USB and uses multiple low-noise LDOS to provide regulated power supply for different building modules. The bgt24mtr12 MMIC is powered by the PMOS switch and can operate the sensor in the duty cycle mode.
Position2go has a detachable on-board debugger pre installed with segger licensed firmware for debugging and communicating with the main radar MCU through UART pins. In addition, the pins on both sides of the PCB can realize the interface connection between the sensor module and the external processor.
Let's focus on the main parameters of two core devices of position2go: bgt24mtr12 RF transceiver and xmc4700 controller.
Bgt24mtr12 is one of Infineon 24GHz ISM band radar transceiver series products. At present, bgt24m / L series products are bgt24mtr11 (single transmit and single receive channel), bgt24mtr12 (single transmit and dual receive channel) and bgtmr2 (dual receiver channel chip, which can be integrated with two chipsets).
The main features of bgt24mtr12 are as follows:
24GHz ISM band transceiver MMIC, single transmit and dual receive channels
Fully integrated low phase noise VCO
Switchable prescaler with 1.5GHz and 23khz outputs
On chip power and temperature sensor
Homodyne quadrature receiver based on Gilbert
Single ended RF and lo terminals
Low noise figure nfssb: 12 dB
High conversion gain: 26 DB
High 1 dB input compression point: - 12 dBm
Single supply voltage 3.3 v
Power consumption in continuous operation mode 690mw
200ghz bipolar SiGe: C technology b7hf200
Fully ESD protected equipment
Vqfn-32-9 package
Xmc4700 32-bit arm cortex-m4 MCU is mainly used to sample and process signals. It can also control radar chip through SPI. Its main characteristics are as follows:
ARM ® Cortex ®- M4 @ 144mhz, 2048kb flash memory, 352kb RAM
Data and IP protection on flash
Power supply voltage range: 3.13 - 3.63v
6 x can nodes
Ethernet MAC, USB-OTG, SD/MMC
6-channel usic (configurable to SPI, UART, IIC, IIS)
External bus unit
4x12 bit ADC, 26 input channels, 4x parallel sampling and conversion
2-channel 12 bit ADC, 4-channel ∆ Σ Demodulator
24 x 16 bit dedicated timer, dead time generation
2X position interface
Watchdog timer, real-time clock
Xmc4000 functional safety package
Package: lqfp144, temperature range: - 40 - 85 ° C, safe package, support SIL-2 / 3
Application Demo
The position2go evaluation board is used immediately after unpacking, together with the PC application radar GUI, to display and analyze the collected data in time domain and frequency domain. The radar time domain signal can be extracted through the GUI, allowing advanced debugging and algorithm development. In addition, the Dave development tool of Infineon can be used for programming. Let's experience the development process of the position2go evaluation board. Follow the first five steps listed below to download and install some supporting tools. If you want to deeply experience the development of position2go, you need to install other development tools.
1. Prepare development kit
Position2go development board
Micro USB cable
Folding corner reflector
2. Download and install Infineon toolbox
Download Infineon toolbox from Infineon official website
Run "infineon-toolboxlauncher-setup-win-x86. Exe" to complete the installation
3. Install position2go Kit: XMC flasher + radar GUI
Open the Infineon toolbox
Select the manage tools option
Enter position2go kit in the search box
Installing the position2go Kit
4. (optional) Download SW + HW package
Download and run p2g_ sw_ setup_ V1.0.0.exe file
Install XMC serial driver (win10 does not need to be installed separately)
5. Run radar GUI to read data
Use micro USB cable to connect position2go motherboard and PC
Open the Infineon toolbox – radar GUI
Observation real-time data
6. (optional) update firmware using XMC flasher
7. (optional) use Dave ide to edit the source file and debug
8. (optional) use matlab interface to read data to Matlab
The preparation and software installation in steps 1-4 above will not be repeated here. After installation, use the micro USB cable to connect the position2go motherboard and PC, and open the Infineon toolbox – radar GUI to display and analyze the collected data in time domain and frequency domain. The process is shown in the following figure.
Connect the position2go motherboard to the computer
Open the Infineon toolbox radar GUI
Radar GUI application window
Firmware burning
The firmware of position2go is burned in advance. XMC flasher can be used to reprogram the xmc4700 of position2go.
Use two micro USB cables to connect the on-board debugger of PC and position2go and the USB port of the motherboard. The USB port of the debugger is used for downloading and the USB port of the motherboard is used for power supply. Open Infineon toolbox – XMC flasher.
Click the "connect" button and select xmc4700-2048 from the device list
After the device is successfully connected, select "select file", and there is optional firmware in. Hex format under the debug folder in the "position2go kit" directory. After selecting firmware, click "program" to burn xmc4700.
Use the Dave ide to edit source files and debug
Dave IDE is a free eclipse based ide of Infineon. Using GNU C compiler, you can edit, compile programs and debug Infineon XMC microcontroller.
Dave ide can be downloaded from Infineon's official website https://www.infineon.com/DAVE 。
The software is an installation free version, which can be used after downloading and decompressing. After opening, it is a very familiar eclipse environment. In the Dave project folder of the "position2go kit" directory, there are Dave projects that can be developed by users. After importing Dave project, you can edit, compile and debug the program, which will not be repeated here.
performance testing
Compared with the previous generation of products, the performance of position2go is greatly improved. The system performance specifications under specific conditions are given in Infineon's official manual.
Since there is no professional radar reflector on hand, in order to experience the performance of position2go, we set up a simple test environment outdoors. On the open square, a pile point is calibrated every 1m. People stop at different pile points and record the data. Since the position of the pile point is measured with a tape measure, and the standing position of people is not consistent, the following measurement data is not very accurate, but it can still reflect the measurement performance of position2go.
In addition, the configuration information used in ranging is shown in the figure below.
The test results are as follows:
From the above results, position2go's outdoor positioning of people is still very accurate, and the error is also within the scope of the data manual. However, because people's radar reflection cross section is relatively small, people can't detect after standing 10m, but objects with large reflection cross section such as cars can still be detected.
We also measured the velocity of moving objects by position 2Go when a person approached and moved away from the radar board at different speeds. In addition, three people approached the radar board with an S-shaped route to test the measurement of the angle of the object. Through the test, position2go can accurately measure the results within the measurement range.
summary
The position2go development kit allows users to implement and test a variety of transmission sensors in the 24 GHz ISM band
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