FOXTECH LD-24 24GHz Millimeter-Wave Radar User Manual

LD-24 24GHz Millimeter-Wave
Radar Manual

LD-24 24GHz Millimeter-Wave Radar

Disclaimer:
Please read the contents of this manual carefully to ensure that you can use this product correctly and safely. Once used, it is deemed to be an acknowledgement and acceptance of the contents of this statement. Please strictly follow the manual to install and use this product . If there is any damage or damage caused by incorrect use, Foxtech will not be responsible for the corresponding loss and compensation. In line with the principle of continuous improvement and continuous development, the company reserves the right to modify and improve any product details described in the document without prior notice. The content in this manual is provided as of the time of manufacture, and unless otherwise required by applicable law , no warranty of any kind, express or implied, is made as to the accuracy, reliability, and content of this document. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, IN NO EVENT WILL THE COMPANY AND ITS SUPPLIERS BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INCIDENTAL , OR CONSEQUENTIAL DAMAGES, HOWEVER CAUSED. This product is copyrighted by Foxtech. Reproduction in any form is not permitted without permission. This manual contains important information, please keep it for future reference.

Product Overview

LD-24 is a compact 24GHz millimeter-wave radar altimeter specially designed for NAGA series multirotor. The size of the PCBA is only 45*45mm and the weight is 6.5g.
We adopts unique antenna design, through high efficient signal processing algorithm and high sensitive real-time signal processing method based on time domain, frequency domain and phase, which can greatly reduce the physical size of radar module and facilitate the integration of radar module into the UAV fuselage, thus satisfying height determination demands required by UAV.
The millimeter-wave radar can achieve accurate altitude measurement in the height range of 0.2~50m (long time hovering is not recommended below 0.5m), which provides great convenience for UAV hovering and terrain-following flight.

Product Technical Parameters

2.1 System Characteristics

• Transmission Frequency：24.0 ~ 24.25GHz
• Transmit Power (EIRP)：20dBm
• Modulation Mode：FMCW
• Hardware interface: UART-TTL
• Size: 45456mm （PCBA ）
• Weight: 6.5g
• Working voltage: 4~5.5V；Typical value: 5V ( independent power supply )
• Working Current: 200~275mA； Typical Value: 220mA@5V
• Storage Temperature: -40~85 ℃
• Working Temperature: -40~80 ℃

2.2 Ranging Characteristics

• Distance Arrangement ~ 50m（over the ground ）
• Refresh Rate：50Hz

2.3 Antenna characteristics
Transmitting antenna

• Elevation beamwidth：20°

• Azimuth beamwidth：31°

• Sidelobe Level: -19dB
  Receiving antenna

• Elevation beamwidth：31°

• Azimuth beamwidth：20°

• Sidelobe Level: -19dB

2.4 Product Pin Definition

Figure 1 Product Pin Diagram

Table 1 Pin Definition

2.5 Data Interface Protocol
The radar adopts UART-TTL interface, using the preset default transmission rate of 115200 bit/s , the start of the frame is indicated by the space character of ASCII value for each datagram ( hexadecimal 0X2 0 )，at the same time, the end of the frame is indicated by a line feed and carriage return in the ASCII code value. LD24 radar sensor data frame refresh rate is 50Hz .
The radar uses an inquiry communication method. When the controller sends an inquiry command once, the radar returns the current distance information once. The query command sent by the controller is shown in Table 1 .
Table 1 : Controller Command List

| Comment
---|---
‘d’ or ‘D’| Query the distance information of the radar

A complete data frame of UART-TTL communication has 7-8 bytes according to the current measured distance of the radar. If the measured distance is greater than 10m , use 5 bytes to represent the distance information, if it is less than 10m , use 4 bytes to represent the distance information . The data of each byte is character type, and the data frame is shown in Table 2 below.
Table 2 : Data Frame Format

The starting sequence Frame header is a fixed value：0X20< space > , and the ending sequence Frame Tail is a fixed value：
OX0D OX0A . An example of data analysis is shown in Table 3 :
Table 3 : Data Parsing Example
Target Info Data Frame：
0X20 0X31 0X32 0X2E 0X33 0X34 0X0D 0X0A or 0X20 0X31 0X2E 0X33 0X34 0X0D 0X0A Eg 1：0X20 0X31 0X32 0X2E 0X33 0X34 0X0D 0X0A
Frame header = 0X20———-
Distance Data = 0X31 0X32 0X2E 0X33 0X34——— 12.34
Frame Tail：= 0X0D 0X0A———-
The analysis is as follows:
Indicates that the distance information returned by the current radar sensor is 12.34m
Example 2 : 0X20 0X31 0X2E 0X33 0X34 0X0D 0X0A
Frame header = 0X20 ———< space >
Distance Data = 0X31 0X2E 0X33 0X34 ——– 1.34
Frame Tail : = 0X0D 0X0A ——–
The analysis is as follows:
Indicates that the distance information returned by the current radar sensor is 1.34m

Joint Test of Ground Station

3.1 Overall Functional Description
The altimeter radar can display data in conjunction with the ground station, which helps customers to more accurately debug and test the radar .
3.2 Operating Environment
The operation of 1.3.74 Mission planner software requires the following software and hardware environments as shown in Table 4 :
Table 4 Software and Hardware Environment Requirements

serial cable (Note: Please make sure that the length of the cable does not exceed 2m when upgrading the firmware )
Operating System| support Windows 7 8 10 32 bit/64 bit

The testing tools or software are as follow:

• LD-24 Radar
• Notebook/PC
• Independent Power Supply ( 5V power supply)
• Mission Planner Software
• Open Source Flight Controller ( if the firmware is missing, you can download it from the Ardupilot website)
• USB Cable / Datalink

LD-24 radar is connected to the open source flight control and power input(the radar module should not be powered directly by the flight control power supply, please ensure that it is powered by an independent power supply), open the ground station Mission planner software and connect to flight controller ( USB cable / datalink ). The software operation steps are as follows: ” Configuration / Debug ” – ” All Parameter List “- configure the following parameters:

• EK2_ALT_SOURCE=1
• RNGFND1_TYPE=8
• RNGFND1_ORIENT=25
• SER1_BAUD=115200 (other SER ports can also be selected)
• SER1_PROTOCOL=9

After configuration,operate as follow:

• Click ” Flight Data ” to return to the main interface
• Double-click the red box in Figure 3 to pop up the “Display This” interface shown in Figure 3, and cancel other options, only check “sonarrange” , “sonar range” will be displayed here , which is the actual height of the radar.

Cautions

4.1 Shipping, Storage and Use Precautions
It is necessary to fully do a good job of electrostatic protection during the process of radar transportation, storage, working. When dealing with non- integrated independent modules, users must pay attention: when the module is taken out of the sealed anti-electrostatic package, it is necessary to start the electrostatic protection work; do not touch or grab the surface of the radar antenna and the connector pins, only touch its corners. It is recommended to wear anti-electrostatic gloves whenever possible when handling all radar sensors.

• Do not wrap antennas with foil or partial metal parts; do not use CFK sheet (conductive ) wrapping the antenna;
•  Do not spray the antenna structure with any kind of paint or varnish;
• Do not let the plastic material come into direct contact with the antenna structure ( which has the effect of a higher dielectric constant on the resonant frequency of the patch ).
• When the radar is installed, it is necessary to ensure that the module is vertically downward, so as to ensure the accuracy of the detection data.
• When the radar is installed, the radar should be kept away from electromagnetic interference sources such as motors and suspended metal shells.

4.2 Shell design parameters and installation requirements
The radar shell will have a great influence on the actual effect of the radar, which mainly depends on the shell material, thickness and the distance between the inner surface of the radar module. LD-24 radar is equipped with a wear- resistant, firm and beautiful shell structure. If you need to customize the shell, our company can provide relevant consultation.

Application scenarios

The fixed altitude mode is the most important mode in the UAV flight control, and the high-precision altimeter radar is the basis for the stable flight of the fixed altitude mode. As we all know, fine-tuning the throttle to ensure the lift and weight balance of the drone consumes a lot of energy for the pilot, and the fixed altitude mode of the drone realized by the altimeter radar can greatly reduce the difficulty of the pilot’s operation. After the drone enters the fixed altitude mode, the pilot can only control the flight direction of the drone , which can greatly liberate the pilot and reduce the risk of bombing. In addition, with the help of altimeter radar to achieve fixed height hovering, you can get better photo effects. Not only that, the altimeter radar also helps to achieve stable terrain-follow flight, improving the applicability of UAVs in specific application scenarios such as line patrol.

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