GPS signals

High school (ages 12+)
Science & Technology

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/gps-signals

1. How high is GPS signals?
2. What is the daily relativistic drift correction?
3. What are GPS signals and how do they help my phone find its location?
4. Why do GPS satellites need atomic clocks and how does relativity affect them?

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. How high is GPS signals?Approximately 20,200 kilometers (12,550 miles) above Earth
2. What is the daily relativistic drift correction?Approximately 38 microseconds per day to account for Einstein's theories of relativity
3. What are GPS signals and how do they help my phone find its location?GPS satellites send radio waves that a phone receives. By measuring how long the waves take to arrive, the phone calculates its distance from each satellite and finds its position.
4. Why do GPS satellites need atomic clocks and how does relativity affect them?Atomic clocks keep the timing extremely precise. Because the satellites move fast and are farther from Earth, their clocks tick a little faster, and this difference is corrected so GPS stays accurate.

Ephemeris Data: Precise orbital information for each GPS satellite, transmitted in its signal.
Pseudorange: The calculated distance between a GPS satellite and a receiver, including receiver clock errors.
Dilution of Precision (DOP): A measure of the geometric strength of the satellite constellation relative to the receiver, affecting accuracy.
Multipath Interference: Signal reflections from surfaces that cause errors in the receiver's position calculation.