精确性的关键需要：用今天（和明天）的传感器来实现它

　　精确性的关键需要：用今天（和明天）的传感器来实现它

　　最近在传感器技术领域发生了许多事情。自2007年1月9日推出第一款苹果iPhone以来，MEMS在便携式电子产品中的应用激增。在汽车领域，MEMS陀螺仪的成功应用包括动态稳定控制系统、侧翻安全气囊检测系统、乘用车导航和紧急响应系统。

　　其他需要更高位置精度的解决方案，通常与车辆支持系统集成，正在出现用于农业、建筑和起重用途的商用车辆和机器。然而，对于新的传感器，以成功地满足这些应用的挑战，一些重要的传感器精度问题必须首先回答。例如：在传感器范围内的进步是否提高了应用程序的精确度，如果是这样的话，需要多少？在近期内，最有说服力的应用程序性能改进和其他的精度改进在哪里？

　　本文将讨论这些和其他与传感器有关的精度问题，特别强调基于MEMS的传感器系统的准确性。

　　Sensor errors

　　Although the accuracy of sensors is determined through stringent testing and the resulting specs are published on datasheets， several factors either enhance or leave accuracy results hamstrung. All too often the specification will read something like “accuracy within ±1.0 percent”。 My question then is： “Percent of what？” If it is meant to be percent of indicated value， we need to clarify a few things. Let’s take temperature as an example. There are four primary temperature scales in use today： Kelvin and Rankine， which are absolute temperature scales， and Celsius and Fahrenheit， which are not. Let‘s take the freezing point of water in Celsius， for example. What is ±1.0 percent of temperature accuracy at 0°C？ A perfect reading？ Possible， but not likely. If we were reading this in Fahrenheit， the tolerance would be ±0.32°F; in Kelvin， it would be ±2.73°K， which equals ±2.73°C. So which is right？ None of the above. Simply stated， the specification was poorly written; it is acceptable， however， to use percent if you clearly state what the scale will be.