说明：  三个 kalman滤波示例，特点不在于原创（都是百度里能找到的），而在于对源码作了详细的注释和说明，并修改了部份变量或函数名，使源码变得非常易懂。讨厌那些不作任何贡献的简单转贴或重复上传。
(The three examples of Kalman filtering are not original (all can be found in Baidu), but are characterized by detailed annotations and explanations of the source code and modification of some variables or function names to make the source code very easy to understand. I hate simple posts or duplicate uploads that don't make any contributions.)