精確性的關鍵需要：用今天（和明天）的傳感器來實現(xiàn)它

　　精確性的關鍵需要：用今天（和明天）的傳感器來實現(xiàn)它

　　最近在傳感器技術領域發(fā)生了許多事情。自2007年1月9日推出第一款蘋果iPhone以來，MEMS在便攜式電子產(chǎn)品中的應用激增。在汽車領域，MEMS陀螺儀的成功應用包括動態(tài)穩(wěn)定控制系統(tǒng)、側翻安全氣囊檢測系統(tǒng)、乘用車導航和緊急響應系統(tǒng)。

　　其他需要更高位置精度的解決方案，通常與車輛支持系統(tǒng)集成，正在出現(xiàn)用于農(nóng)業(yè)、建筑和起重用途的商用車輛和機器。然而，對于新的傳感器，以成功地滿足這些應用的挑戰(zhàn)，一些重要的傳感器精度問題必須首先回答。例如：在傳感器范圍內(nèi)的進步是否提高了應用程序的精確度，如果是這樣的話，需要多少？在近期內(nèi)，最有說服力的應用程序性能改進和其他的精度改進在哪里？

　　本文將討論這些和其他與傳感器有關的精度問題，特別強調(diào)基于MEMS的傳感器系統(tǒng)的準確性。

　　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.