Design And Implementation Of ADAS Video Node Based On AVB

In complicated driving environment,ADAS(Advanced Driver Assistance Systems)generates traffic assistance information by integrating sensor data to reduce the burden on the driver,thereby enhancing the safety of driving.The most important information is the video collected by multiple cameras.To ensure the ADAS can quickly respond to a varity of unexpected conditions,the data transmission technology used by ADAS must meet the demands of latency,bandwidth,scalability and synchronization in transmitting multiple video streams.At present,the solution using MOST as the in-vehicle network in ADAS can't satisfy the demands,so the need of a new transmission technology to solve the problem faced by ADAS is quite urgent.In this thesis,a video node of ADAS,which transmits data by AVB technology,is designed.AVB combines the precise time synchronization,stream reservation,queue queuing and forwarding technology to complete the low delay transmission of HD video stream which is captured by ADAS video node and meet the requirements of maximum end to end delay of video data in ADAS.The main work done in this thesis is as follows:(1)To meet the requirements of data transmission in ADAS,AVB is used as the transmission technology.A simulation to test the performance of the AVB is made,the result shows that AVB is feasible as transmission technology in ADAS.(2)To minimize the response time of ADAS system,an AVB supported professional vehicle multimedia chip is used to reduce data transfer delay and video encode/decode delay;Using PoE technology to simplify the design of the video node and deduce the difficulty of deployment in the car.(3)In order to running video service and command interactive service at same time,uC3/Compact real time micro operating system is transplanted to the input port of video node and embedded Linux system with graphic user interface is transplanted to receive port of the video node.After the transplantation work done,the sotaware of video function and command interactive function is developed.To verify that the video node using AVB transmission technology meets the needs of the ADAS,a stress test is made by injecting jam traffic into the data transfer link.Test results show that even in the case of high-load network,the video transmit delay of ADAS video node is still kept in 30 ms and meets the demand of max end-to-end delay less than 45 ms.The test result shows that the AVB technology is feasible on ADAS systems.