科学素养与生活应用·英语30篇（1）

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为何手机GPS需要四颗卫星，而非一颗

GPS calculates position by measuring how long signals take to travel from satellites.
Because light speed is constant, timing errors translate directly into distance mistakes.
Three satellites give you latitude, longitude, and altitude—but only if your clock is perfect.
Your phone’s internal clock isn’t accurate enough, so a fourth satellite helps correct timing drift.
This process, called trilateration, works in three dimensions, not just on a flat map.
Engineers designed the system to handle atmospheric delays and signal reflections too.
Even tiny timing errors—just one microsecond—would misplace you by 300 meters.
So precision engineering, physics, and real-time computation all work together silently.

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

Even tiny timing errors—just one microsecond—would misplace you by 300 meters. 哪怕仅1微秒的计时误差，也会导致300米的位置偏差。
So precision engineering, physics, and real-time computation all work together silently. 因此，精密工程、物理学与实时计算在幕后协同运作。
Because light speed is constant, timing errors translate directly into distance mistakes. 由于光速恒定，计时误差会直接转化为距离误差。

这篇中文题目最接近哪一句？为何手机GPS需要四颗卫星，而非一颗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通过测量信号从卫星传播所需时间来计算位置。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） Why Your Phone’s GPS Needs Four Satellites—Not Just One How to cook noodles A maths worksheet

Even tiny timing errors—just one microsecond—would misplace you by 300 meters.

Even tiny timing errors—just one microsecond—would misplace you by 300 meters.

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：Even tiny timing errors—just one microsecond—would misplace you by 300 meters.