Lidar: introduction and usage of ouster OS

Preface

Ouster Company profile

Ouster Inc. Founded on 2015 year , By the lidar field Unicorn Quanergy Former co-founder of Angus Pacala found , Headquartered in San Francisco .

It is a manufacturer of laser radar , Products include OS0、OS1、OS2 Three series 9 Laser radar .

Ouster Committed to building a new generation of lidar sensors for large-scale applications , Committed to improving product resolution 、 Parameters such as visual distance and overall dimension , be based on MBF Multi beam flash basic patent , Combined independence ASIC IP Design implementation capability , Dedicated to unmanned systems 、 Surveying and mapping 、 Security monitoring 、 Industrial Engineering Automation 、 Intelligent transportation / logistics / Industries and scenes such as cities , Higher performance 、 More reliable 、 More cost-effective depth vision products and 3D Perceived solutions .

Unlike traditional lidar, it contains thousands of components ,Ouster There is only a chip level laser array and a CMOS sensor , Greatly reduced the price , Improved performance and reliability .

Ouster Product series introduction

Ouster The product line is very simple and clear , Yes 3 The two series are ：

• OS0
• OS1
• OS2
  
  They have different characteristics
  OS0 Its main feature is the super wide field angle , The vertical field of view angle can reach 90°, But the detection distance is the shortest , by 50m
  OS1 On average , The vertical field angle is 45°, The detection distance is 120m
  OS2 Its main feature is long-distance detection , The minimum vertical field angle is 22.5°, The detection distance is 240m

When using, you can choose different series of products according to the application scenario .

OS1 Detailed introduction

Because of the use of OS1-64 Products , Its parameters are introduced in detail here .
First, let's take a picture of the point cloud of a frame of data ：

You can choose the distribution form of point cloud , There are three kinds of ：

• Uniform distribution
• Central encryption
• Downward distribution
  The schematic diagrams of the three types are as follows ：
  
  Uniform distribution
  
  Central encryption
  
  Downward distribution
  It can be seen that the bus bundle is fixed 64, So the more backward the vertical field of view angle is smaller .

OS1 main parameter

Horizontal resolution	512,1024,2048
Vertical resolution	64 Line
Detection distance	120 m
Vertical field angle	45° (±22.5º)
Vertical angular resolution	0.35º – 2.8º ( Multiple choice )
Measurement accuracy	±0.7 – 5 cm
Points per second	1,310,720
OS1-64	10 Hz,20 Hz
Power waste	14 – 20 W
weight	447 g
Protection level	IP68, IP69K

In addition, the characteristics that laser radar often pays attention to are also summarized below ：

• Optional PTP and NMEA/PPS Time synchronization
• Output ： Detection distance 、 Strength 、 Reflectivity 、 Environmental near infrared 、 azimuth 、 Time stamp
• Dual echo mode , The strongest echo and the second strongest echo

Hardware connection

Hardware connection is not recommended if it is complicated , It is the interface directly connected to the radar sensor .

OS1 It can be operated without an interface box . When using , Conduct wiring according to pin assignment as described below .

The reason why it is not recommended is that there is any equipment damage due to voltage and current , The manufacturer is not responsible .

Let's look at the conventional usage , The manufacturer will also provide a connector .
It's like this

This connection is simple , The interface on the left is connected to radar , The Internet port on the right connects to the computer , There is also a power supply port on the right , Just supply power .
One more GPS Time hardware synchronization port ,

The side view on the right is as follows

Network port and power supply port needless to say , The pins of the clock synchronization port are defined as follows ：

The overall connection diagram is as follows ：

Ouster ROS drive

ROS The version is Kinetic

GitHub Cloned

git clone https://github.com/ouster-lidar/ouster_example.git

Then compile Ouster ROS
After the compilation is successful, you will be prompted as follows ：

If the compilation encounters the following problems ：

fatal error: tclap/CmdLine.h: No such file or directory

It can be done by

sudo apt install libtclap-dev

solve

stay ouster_example/ouster_ros Under the path os1.launch This launch file

roslaunch os1.launch os1_hostname:=< radar IP> os1_udp_dest:=< This machine IP> viz:=true image:=true

Through the above instructions You can run this launch file ,

os1_hostname:=： For radar IP Address 

os1_udp_dest:=： For this machine IP Address 

viz:=：true -  Turn on  Ouster Visualizer  Show point clouds and 2D Ring view , The default is false

image:=：true -  Turn on 2D Ring view node , Can be found in rviz View in , The default is false

lidar_mode:=：  Radar operation mode options , Optional 512x10 | 512x20 | 1024x10 | 1024x20 | 2048x10,  The default is 1024x10

The above instructions are configured as required

And then in rviz You can see some clouds inside