Android Automotive Implementations
## Android Automotive Implementations
* Android Auto
* Android Automotive OS
* Exterior View System (EVS) stack
## Android Auto
* CarPlay和Android Auto上的应用程序并没有直接安装在车载系统上，而是在你的移动设备上运行并投影至车载屏幕上。如果你在手机上安装了一个适配车载系统的应用程序，那么应用程序将会显示在车载系统上。
* 它包含了Google地图、电话、信息（以及Hangouts）和Google Play Music（以及第三方音乐/播客服务）。
* Android Auto可以使用屏幕上的按钮或方向盘上的专用按钮来激活Google Now从而进行语音控制。
* Announced in Google I/O June, 2014. API supports: Android 5.0 (L) API level 21.
* Hyundai Sonata first supported Android Auto in 2015.
* 缺点:
(1)分辨率和反应速度还远达不到手机端的流畅和易用。
(2)车载系统的处理器和感应器没有统一的技术规范，
不同的规格给适配带来了难度。
## Android Automotive OS
* Android Automotive is tightly integrated with the features of a car Android-based operating system designed for use directly on vehicle head units as part or all of the vehicle system and/or infotainment functionality (e.g. VMS - Vehicle Map Service , EVS - Exterior View System, IVI - In-Vehicle Infotainment, HVAC - Heating, ventilation, and air conditioning etc.)
* Features:
*Google 智能助理、Google 地图等应用程序，甚至还可以通过 OTA 更新下载新系统，也可以从 Google Play 下载更多应用程序。
*全局夜间模式.所有子菜单都将支持纯黑色显示，并且支持按自然时间/用户自定义时间段自动切换。
*全新的导航通知栏.如果驾驶员在导航的过程中接了个电话，那么新版的导航通知栏将会在系统最上方固定显示通话的相关按钮, 所有导航按钮都被移到了屏幕的左下角，也就是最接近驾驶员的位置。
*支持屏幕尺寸自适应调节
*谷歌在汽车行业并没有选择做得尽量多，与之相反的是，谷歌选择了做得尽量好
*Supported after Android 8.0 (O), API level 26.
*2017 Google 宣布Audi及Volvo将以Android作为车载信息娱乐系统的平台
*2019 Google I/O open 3rd party app development. Volvo Polestar 2 demonstrated Android Automotive OS
*2018 Starting with the cars manufactured from 2021, the three brands that make up the Renault-Nissan-Mitsubishi alliance will be using Google’s Android to power their infotainment systems.
*2019 April, FCA、谷歌、三星合作研发车机系统，在2022年之前让旗下全部车型搭载Android Auto车机系统和三星电子云服务。
## UI
##Android Automotive OS Architecture
*Car API: CarxxxManager interfaces directly called by APPS.
*Car Service: Functionalities for HVAC, Car info, media playback…
*VehicleNetworkService: Controls vehicle HAL with built-in security.
*Vehicle HAL: Interface that defines the vehicle properties OEMS can implement.
## Car Services
*Located at packages/services/Car/service/src/com/android/car
## Car App and Car API
*Car App located at packages/apps/Car/
*Car API located at packages/services/Car/car-lib/src/android/car
##EVS
*An automotive HIDL Hardware Abstraction Layer (HAL) that provides for imagery capture and display very early in the Android boot process and continues functioning for the life of the system.
*Evs app: located at packages/services/Car/evs
*App: evs应用层，负责初始化操作，监听倒车状态，OpenGL 显示, 倒车UI更新等逻辑处理
Name: evs_app
*Manager: evs管理器，负责与HAL层的交互，实现HAL层的一些接口，例如openDisplay()，openCamera()等操作。
Name: [email protected]
*SampleDriver:驱动层实现，基于v4l2实现的一个驱动Demo程序，供HAL层调用，Camera操作和display操作核心，涉及到摄像头设备操作和display设备操作。
Name: [email protected]
*Evs HAL: hardware\interfaces\automotive\evs\1.0
- default：提供一个模拟倒车测试，显示静态图片模拟倒车；用于测试功能逻辑，不是真实的倒车；
- Types.hal文件：提供了hal接口，供驱动层实现；
## Automotive OSPros
* Minimize developing efforts. Focus on our specializations.
* Leverage Android latest technology: e.g., google access, map, multi-screens, Bluetooth
* Unified user interfaces and behavior on all IVI.
* Features collected from all eco system.
* Well tested and approved framework from world wide.
* Allow applications from third party.
* Easy maintenance. Fast to update to latest Android AOSP.
## Automotive OS Cons
* Less uniqueness to other IVI solution providers .
* Existed features and future new features may conflict with Automotive OS framework.
* Is it safe to install 3rd party App?
##Conclusions
* EVS is independent of Automotive OS framework. It can be deployed separately for fast rear-view camera or surround view displays in an Android-based IVI system.
* Apply Automotive OS to reduce lag to latest Android version and take advantage of its new features.
* Seamless and tightly integrate with vehicle related functions: HVAC, cabin, engine, energy.
* Minimize customization for easy upgrade. For example, skin, launcher.
* Well control and manage 3rd party App.
* Value-added services: cloud, membership, shopping, customer services…
##References
Hyundai car demo https://player.youku.com/embed/XODM3NjMzNDEy
https://www.autoevolution.com/news/google-android-to-power-nissan-renault-and-mitsubishi-cars-from-2021-128702.html
https://chejiahao.autohome.com.cn/info/3779942/
https://source.android.google.cn/devices/automotive