十万个为什么·科学启蒙30篇（2）

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GPS设备如何知道你的精确位置？

GPS devices receive signals from at least four satellites orbiting Earth at 20,000 kilometers high.
Each signal carries precise time data from atomic clocks aboard the satellites.
The device calculates distance to each satellite by measuring how long the signal took to arrive.
Using trilateration, it pinpoints your location where three imaginary spheres intersect.
Tiny timing errors—even one-millionth of a second—can cause position mistakes of hundreds of meters.
Ground stations constantly monitor and correct satellite orbits and clock drifts.
Your phone combines GPS with Wi-Fi and cell tower data to speed up and refine location fixes.
Atmospheric delays slow down signals, so advanced receivers apply real-time correction models.
Military GPS uses encrypted signals for higher accuracy than civilian versions.
That’s how your map app knows whether you’re on the left or right side of the street.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

Using trilateration, it pinpoints your location where three imaginary spheres intersect. 利用三边测量法，它在三个假想球体的交汇处精确定位你的位置。
Ground stations constantly monitor and correct satellite orbits and clock drifts. 地面站持续监测并校正卫星轨道和时钟漂移。
Military GPS uses encrypted signals for higher accuracy than civilian versions. 军用GPS使用加密信号，精度高于民用版本。

这篇中文题目最接近哪一句？ GPS设备如何知道你的精确位置？一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？ GPS设备接收至少四颗距地表2万公里高空绕地球运行的卫星发来的信号。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） How Do GPS Devices Know Your Exact Location? How to cook noodles A maths worksheet

Using trilateration, it pinpoints your location where three imaginary spheres intersect.

Using trilateration, it pinpoints your location where three imaginary spheres intersect.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：Using trilateration, it pinpoints your location where three imaginary spheres intersect.