Rosso Speedometer
文章
关于 GPS 测速原理、单位换算以及安全使用车速表应用的实用笔记。
其他语言的文章
km/h, mph, Knots and m/s: Speed Conversion Chart
Exact formulas and a quick chart for converting km/h, mph, knots and m/s, based on NIST definitions, plus how to turn speed into running pace (min/km).
How Accurate Is GPS Speed? Why It Jumps, Freezes and Wobbles
Phone GPS is typically accurate to about 4.9 m under open sky. Why GPS speed jumps in cities, freezes in tunnels and wobbles at walking pace, and how to help it.
Why Your Car Speedometer and GPS Speed Disagree
Car speedometers must never read below your true speed, so most read a little high. What UN Regulation No. 39 and Japan's rules say, and which speed to follow.