汽车整车OTA测试研究

Test Study of Automotive OTA

随着智能网联汽车应用推广,各种智能终端被集成在汽车上,车载天线的数量呈几何增长,由于受到车辆外壳、车窗、底板等影响,对低增益通信天线、WIFI天线,整车天线性能与单体天线存在较大差异,进而影响整车通信OTA性能。为更准确的测量整车通信OTA性能,建议将整车作为通信终端一起参与OTA测试。OTA测试有远场测试和近场测试,根据天线方向性、增益等,近场测试又可以细化为球面近场、柱面近场、平面近场等。由于车辆尺寸较大,采用远场测试需要十分巨大的暗室(或反射面),造价昂贵,测试效率提升困难。对低增益通信天线,业内多采用多探头球面近场测试,满足MIMO OTA测试基础上,还可最大化提升测试效率。本文从车联网标准体系、整车天线测试难点、车载天线测试环境要求、远近场测试比较等方面探讨整车OTA测试研究。

With the application and promotion of intelligent networked vehicles,various intelligent terminals are integrated in automobiles,and the number of vehicle antennas increases geometrically,due to the influence of vehicle shells,windows,bottom plates,etc..There is a great difference between the performance of low-gain communication antennas,WIFI antennas,and vehicle antennas and single antennas,which in turn affects the OTA performance of vehicle communication.In order to more accurately measure the OTA performance of vehicle communication,it is recommended to participate in OTA testing together with the vehicle as a communication terminal.OTA test includes far-field test and nearfield test,according to antenna directionality,gain,etc.,near-field test can be refined into spherical near-field,cylindrical near-field,plane nearfield,etc.Due to the large size of the vehicle,the use of far-field testing requires a very large anechoic chamber(or reflective surface),which is expensive and difficult to improve test efficiency.For low-gain communication antennas,the industry mostly adopts multi-probe spherical nearfield testing,which can meet the MIMO OTA test and maximize the test efficiency.This paper discusses the research of vehicle OTA testing from the aspects of vehicle networking standard system,vehicle antenna test difficulties,vehicle antenna test environment requirements,and comparison of far and near field tests.