nanoradar CAR28T User manual

CAR28T Millimeter Wave Radar
User manual

Hunan Nanoradar Science and Technology Co., Ltd.
Disclaimers
Thanks to purchase this product. There is web pages about NRA24 altimeter in our
official website (www.nanoradar.cn).You can find the latest product information and
user manual on the pages. The user manual is subject to change without notice.
Please read this manual carefully before using this product. Once used, it is deemed to
have recognized and accepted the content of this manual. Please strictly follow the
manual to install and use the product. Any improper use may cause damage or injury,
and Nanoradar would not bear the corresponding loss and liability.
Product copyright is retained by Nanoradar. Reproduction in any form shall not be done
without permission. The use of this product and manual shall not be pursued liability for
the patent.
Version history
Date
Version
Version description
2017-05-05
1.0
the 1st version of CAR28T user manual

Contents
1 Brief introduction of CAR28T................................................................................ 4
2 Matters needing attention in use............................................................................. 4
3 Shipping list......................................................................................................... 5
3 Quick-to-use steps...................................................................................................5
4.1 Cables installation............................................................................................ 5
4.2 The installation and coordinate system of CAR28T........................................ 5
4.3 Test and use...................................................................................................... 7
4.4 Online upgrade for product firmware.................................................................. 9
5. Data parsing for CAN interface........................................................................... 10
5.1 CAR28T configuration (Sensor Configuration).............................................11
5.2 Radar back (Sensor Feedback).......................................................................15
5.3 Radar status (Radar Status)............................................................................ 16
5.5 Target output information (Target Info)............................................................. 18
6. Data parsing examples......................................................................................... 19
7 Installation and notes for risks.............................................................................. 20
7.1Installation principles...................................................................................... 20
7.2Notes for risks in use.......................................................................................21
9 References............................................................................................................. 22

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1 Brief introduction of CAR28T
CAR28T is a lightweight 24GHz car millimeter-wave radar sensor in the industry. It can
accurately detect the distance, speed, angle and other information of the target using of radio
waves and echo.
CAR28T compacts 96 × 57 × 20mm, detection range is 50 meters. With its leading performance,
cost-effective feature, integrated peripheral interface (CAN interface), BSD, FCTA, RCTA,
EAF and other functions, car28T can meet the rapid growth of the automotive industry safety
support driving demand.
Fig1.CAR28T outlook
Note:
CAN wiring is the 4-core RVV line, with 4 meters long.
2 Matters needing attention in use
(1) The module antenna surface (convex surface) should face the detection area, and should
not to be covered by any metal objects;
(2) Must carry out the test in open space outdoors.

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Any problem in installation, please feel free to contact Nanoradar
3 Shipping list
The shipping list includes：CAR28T sensor 1x，as in figure2，cable 1x，as in figure3.
Fig2.CAR28T sensor Fig3.CAR28T cables
Note:
CAR28T can be fixed with 4 M2.5 screws or magic stickers.
3 Quick-to-use steps
4.1 Cables installation
The definition for CAR28T sensor interface pins are as shown in table1：
Table 1 The definition for CAR28T pin interface
No.
Definition
Range
Cable colors
1
CAN_H
-58~58V DC
yellow
2
CAN_L
-58~58V DC
blue
3
GND
black
4
POWER IN
5~32V DC
red
4.2 The installation and coordinate system of CAR28T
In the blind spot detection and related applications, there should be an installation height of
500 ~ 1200mm to the ground for CAR28T, and a 25 ° angle between the radar antenna surface
and the car body. The installation diagram is as follows:

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Fig4. Module backward installation diagram
The installation parameters are as follows：
Table 2 Module installation parameters
Note:
In forward applications, the coverage width of the blind area on both sides is higher. It will be
recommended to adjust the installation azimuth to 45°. However, in backward applications, it
has a higher requirement for the longitudinal coverage in the BSD / LCA and others. And the
recommended installation angle and the body angle (azimuth) is typically 25°.
Radar directions are specified as shown in the following figure.
Fig5. The sign of angle direction is
specified as positive(+)
Fig6. The sign of angle direction is
specified as negative(+)

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Note:
CAR28T uses Cartesian Coordinates. When installed, the antenna face (convex face) of
CAR28T is facing the target direction, and the CAN port is facing the right direction (+) as
shown in the left figure (recommended mounting direction), while CAN port is facing the left
direction (-) as shown in the right figure.
As shown in the left figure, the dotted line indicates the origin of the target angle, and the
distance from the dotted line to the left border is 26 mm. The target angle of CAR28T test is the
azimuth distance from the radial distance (linear distance). The speed is positive when the target
is near the radar sensor, and the speed is negative when the target is far from the sensor.
4.3 Test and use
CAR28T sensor data can be acquired and parsed by the "MMW Radar general Management
Tool" testing software, which is used to visually display the observation results. The tool is
helpful in the use of CAR28T sensor.
First of all, the "millimeter-wave radar general management tool" (PC test software), user
manual, Micro USB drive shall be provided by Nanoradar. According to the user manual, install
and configure the PC test software.
Note:
"MMW Radar General Management Tool" utilizes the USB2CAN adapter shown in Figure 8
to communicate with the CAR28T. Other types of USB2CAN adapters are not supported at this
time. The shipping list does not include USB2CAN adapters by default. Customers can get to
Nanoradar's customer service to obtain CAN adapter link address to buy it. Or Nanoradar can
also help customers purchase it.
Fig7. CAN box for test
Test procedures are as follows：
1) Test tools and software are as the following table：

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Table 3 Product test and use tools
No.
Device name
Qty
1
CAR28T
1
2
PC
1
3
Cables
2
4
12V DC power supply
1
5
PC test software
1
6
USBCAN box
1
2) Connect the PC and CAR28T radar sensor via USBCAN adapter, and the connection
diagram is as follows:
Fig8. CANBUS connection and test diagram
Note:
When the connection is correct and CAR28T is started for the first time, CAR28T will give a
1-second "beep" tone. When CAR28T is connected to the 12VDC power supply, the green light
(POWER) in the USBCAN will continue to light, and yellow light will continue to flash when
the CAR28T is operating normally.
3) Start to test.
USBCAN adapter connects to PC, and radar antenna surface (convex surface) faces to the target,
with CAN port to the right. Then Open the host computer software, first select the radar model,
select and set the CAN connection type, as shown in the red part of figure 10, while the blue
part is the adjusted coordinate range according to the test distance. After setting, clicking "save"
on the bottom to save settings. Then click the button "Connect to Device" on the right. When
exiting the test, click the right "stop device "button.
In Figure 10, this interface shows there are two moving targets detected by the radar. A
represents the azimuth of angle, and R represents the radial distance of the target.
Note:
CAR28T is required for the radar type in the millimeter-wave radar general management tool
when testing CAR28T.

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Fig9. CAR28T test interface
In Figure 9 at this point, the interface shows that the radar detects two moving targets, where the
parameter A represents the target angle, R represents the radial distance of the target (the
distance from the target to the radar)
Note:
Check "save data" in the page to the local check box, and the target data captured by radar will
be stored in text format under the Data folder in the millimeter-wave radar general management
tool installation path folder.
The suggested test sites：
CAR28T should be tested in open areas outdoors, due to that there are many interference for the
indoor test, which will lead to the discontinuous target track.
4.4 Online upgrade for product firmware
CAR28T support online upgrade. After customers purchase products, if the product program
needs to be upgraded, you can turn to Nanoradar's customer service or Nanoradar's official
website to obtain Nanoradar's millimeter wave radar upgrade tool and upgrade program. The
upgrade tool interface is as shown below. And the use method of PC software please refers to
the user manual of Nanordar's Radar Upgrade Tool.

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Fig10. CAR28T radar upgrade tool interface
5. Data parsing for CAN interface
CAR28T radar supports CAN interface. The communication network of CAN Bus complies
with ISO11898-2 standard, with the transmission rate of 500bit/s. CAR28T transmits radar
signals to the surroundings and processes the received signals in multiple steps, to collect the
targets groups and target tracks. The relative velocity and position of targets could be
transmitted via CAN interface.
The CAN message of CAR28T is defined as follows.
Table 4 Definition of frame message

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Note:
The specific ID calculation format: Each radar message ID=radar ID*10+basic message ID Due
to that multiple devices could be mounted in the CAN bus, and each device has its own ID. In
the above table, the default radar ID is 0 and the underlying message IDs are 0x200, 0x400,
0x60A, 0x28TB and 0x28TC. If the radar ID is configured as 1, then its Message ID is 0x210,
0x410, 0x61A, 0x71B, 0x71C, and so on.
5.1 CAR28T configuration (Sensor Configuration)
CAR28T radar is configured through 0x200 messages. And the structure of radar configuration
message is as the following table：
Table 5 the structure of radar configuration message
The description for each field in the structure of radar configuration message is as the
followings.
Table 6 the description of the structure of radar configuration message

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For reading or writing parameters, CAR28T will reply a message that contains the results of
writing parameters or the returning of the parameters to read. RadarFeedback defines the format
of the replied message. When configuring CAR28T, the definition of Parameter is different for
different DataType. The definition is as follows:
1) Configuration of radar ID
The format of radar ID configuration is as follows.
Table 7 The format of radar ID configuration
When reading Radar ID, R / W is 0, and the ID_Number value is invalid; when writing Radar
ID, R / W is 1, and ID_Number is the ID number of radar.
2) Obtain radar version
The frame format for obtaining radar version is as follows：
Table 8 Format for obtaining radar version

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When the obtained radar version is read-only, in getting the radar version, do not fill any value
in the Master Version, Second Version, Step Version, and CAR28T ignore these values. When
CAR28T receives a message of obtained radar version, the current radar version information
will fill up the fields in the reply message of 0x400.
3) Start/stop the output of target information
Format for start/stop target information data output is as follows：
Table 9 Format for start/stop target information data output
4) Distance filtering
【Reserve】
5) Mode configuration
CAR28T can switch between different modes to meet the requirements of different scenarios.
The mode configuration format is shown in the following table.
Table 10 Format of mode configuration

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6) Configuration of radar installation direction
The installation direction of CAR28T affects the angle calibration in the algorithm. After
installing the CAR28T, the installation direction field of the radar needs to be configured, and
the program will be calibrated according to the installation direction. The radar installation
direction configuration format is shown in the following table:
Table 11 Configuration format of radar installation direction
7) Target output option
CAR28T can output processed target data (for example, output the target data within the set
distance range), or directly output the original target data (all the target data in the detection
range).And the current default output is the original target data. The format of target output
option is shown in the following table.
Table 12 Format of target output option
8) For internal test
【Reserve】
9) Save parameters
To save the configured parameters, you need to run the command of saving parameters. Then
after reboot, the last configuration takes effect and it does not need to be re-configured.
Otherwise, it needs to be re-configured in the next startup. The format for saving the parameters
(i.e. 0xFF00000000000000) is shown in the following table:
Table 13 Format of saving parameters

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5.2 Radar back (Sensor Feedback)
Each time the host computer or other MCU sends the configuration signal to CAR28T, CAR28T
will immediately return the execution result. The reply format of the reply is shown in the
following table. In the radar reply, only Bit7 is different. Bit7 in RadarConfiguration is defined
as R / W, and RadarFeedback is defined as the result of the configured execution. The Parameter
field RadarConfiguration is used to write the parameter, which is used in the RadarFeedback to
return the current value of the parameter.
Table 14 the structure of radar back message
The definition for the description of each field in radar reply is as follows:
Table 15 the description of each field in radar reply

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5.3 Radar status (Radar Status)
The message 0x60A includes radar status message. And the structure of radar configuration
message is as follows.
Table 16 the structure of radar status message（0x60A）
The description for each filed in radar status message is as follows.
Table 17 the description for radar status message（0x60A）

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The target output status data message format for CAR28T system is as shown in the table,
which NoOfCluster represents the number of detected targets, and the value of RollCount value
lies between successive cycles of 0-1-2-3-0-1-2-3 ••••••. When the host computer or an external
MCU cannot process the output data of CAR28T sensor in time, it will cause the received
RollCount value to be discontinuous. At this time you should find a faster moving and handling
method to solve this problem.
Table 18 target status（0x28TB）
The description for each field in target status is as follows.
Table 19 the description for target status（0x28TB）

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5.5 Target output information (Target Info)
The message format for Car28T target output is as follows.
Table 20 the structure of target information (0x28TC)
Message 0x28TC contains the target's distance, angle, speed and other information. When the
radar sensor is working and the target is detected, the target output state message appears after
the CAR 28T system status message, and finally there will be the target output information
message.
The description of each field in the target message is described in the following table:
Table 21 the description for target information（0x28TC）
Note:
The value of each field in the table is not the true value of the target information. The true value
needs to be calculated by the following formula:
- Index = IndexValue
- Rcs = RcsValue*0.5 – 50

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- Range = (RangeHValue*256 + RangeLValue)*0.01
- Azimuth = AzimuthValue*2 – 90
- RollCount = RollCountValue
- Verl = (VrelHValue*256 + VrelLValue) *0.05-35
- SNR = Value-127
The reflection Radar-Cross Section (RCS), the target range (Range), the target velocity (Verl),
the target azimuth (Azimuth), and the Signal Noise Ratio (SNR) can be obtained by these
calculations, therefore to accurately detect the target.
Note:
The target speed is the relative movement velocity. When the target is close to the radar sensor,
the target speed value (Verl) is negative; when the target is far away from the radar sensor, the
target speed value (Verl) is a positive number.
6 Data parsing examples
Take Message ID as the target output information (Target Info) as an example, there is a frame
of the Target Info data message as follows:
Message ID:
0x28TC
Data Payload:
0x01 0xC8 0x07 0xD0 0x32 0x02 0xEE 0x96
Interpretation：
Message ID =0x28TC
Data Payload =0x01 0xC8 0x07 0xD0 0x32 0x02 0xEE 0x96
Each field of Data Payload is parsed as following：
Index = 1
Rcs = 0xC8*0.5 – 50 = 50
Range = (0x07*0x100 +0xD0)*0.01 = 20
Azimuth = 0x32*2-90 = 10 Rsvd1 = 0
RollCount = (0x0 & 0xE0) >> 5 = 0
Verl = (0x02*0x100 + 0xEE) *0.05-35 = 2.5
SNR = 0x96 – 127 = 23

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Note:
The user needs to program to parse the sensor output data (hexadecimal). The data
before being parsed is hexadecimal, and is decimal after being parsed. 0x2AF51
hexadecimal is converted to decimal:
10997=5*16^0+F*16^1+A*16^2+2*16^3。
7 Installation and notes for risks
7.1Installation principles
Radar installation principles：
1. Keep away from the antenna within the body of the signal as far as possible when installing;
2. Keep away from the location of the large frequently started electrical equipment when
installing;
3. Keep away from the motor actuator and drive.
Installation position：
The CAR28T radar sensor is recommended for installation in the position of the vehicle bumper.
Same as the radome, the bumper material will also have a greater impact on radar performance.
In essence, there are three aspects of impact on radar performance. Firstly, radar cannot
penetrate completely through the radome, which will reduce the effective radiated radar power,
including reflection loss and dielectric loss; Secondly, the distortion of radar antenna beam
causes the change of radar's effective areas, which may lead to the interference of the backward
targets; Thirdly, the radome makes radar’s standing wave worse. Radar radome will reduce the
detection sensitivity and coverage of radar.
When installing the rear bumper, try to follow the following guidelines:
1. Select the smooth surface area;
2. To avoid the corner or areas with the changes of thickness;
3. Avoid chrome plating or any other additional area with "the design of special decorative
shape ".