GPS, How does it work? | ICT #12
GPS Technology Explained
This section provides an overview of GPS technology, its applications, and the basic principles behind it.
Introduction to GPS
- GPS is an integral part of our lives and has various useful applications.
- GPS uses a system of 24 satellites orbiting the Earth and requires at least four satellites to track location.
- Albert Einstein's theory of relativity plays a role in GPS technology.
Understanding Trilateration
- Trilateration is a mathematical technique used in GPS to locate someone's position.
- At least two satellites are required for two-dimensional trilateration.
- Satellites measure the distance between the user and themselves to determine position.
- The intersection points of circles formed by satellite distances indicate the user's location.
Three-Dimensional Trilateration
- In three-dimensional trilateration, three satellites are needed to narrow down the user's location to two points.
Measuring Distance Between User and Satellite
- Satellites send radio signals containing time information and their positions.
- By calculating the time difference between sent and received signals, the distance between user and satellite can be determined.
Time Offset Challenge
- The accuracy of time measurement is crucial in GPS calculations. Mobile devices have less accurate clocks compared to atomic clocks used by satellites.
- The time offset between the user's device and the satellites must be solved to accurately determine location.
Four Satellites for Location Measurement
- Four satellites are required to measure the user's location, including solving for the time offset.
- At any given time, at least four satellites can see the user's location.
The transcript is already in English, so there is no need to translate it.
New Section The Importance of Einstein's Theory of Relativity in GPS Systems
In this section, the speaker discusses the significance of Einstein's theory of relativity in GPS systems and how it affects the accuracy of location tracking.
Einstein's Theory of Relativity and Time
- Even with advanced technologies, GPS systems may not provide accurate location information due to the theory of relativity.
- Time is not absolute and depends on various factors.
- According to the theory of special relativity, a fast-moving clock will slow down.
- Atomic clocks in GPS satellites, moving at high speeds, experience time dilation and slow down by seven microseconds every day.
Gravity and Clocks in Satellites
- Satellites at an altitude of 20,000 kilometers above Earth experience one-quarter of Earth's gravity.
- According to Einstein's general relativity theory, clocks in satellites tick slightly faster at this altitude.
- This results in a net offset of 38 microseconds every day in atomic clocks used for GPS.
Compensation with Theory of Relativity Equation
- To compensate for the time dilation effects, computer chips integrated into GPS devices use a theory of relativity equation.
- The equation adjusts the rates of atomic clocks to ensure accurate positioning.
- Without this application of the theory of relativity, GPS would have produced an error rate as high as 10 kilometers per day.
New Section How GPS Works and Assisted GPS
This section provides an overview of how GPS works and introduces assisted GPS as a more accurate alternative.
Introduction to GPS
- GPS is a navigation system developed by the US Department of Defense that is free for public use.
- Modern receivers utilize both GPS and other navigation systems to obtain the most accurate position.
Internet Connection and GPS
- GPS does not require an internet or cell phone signal for basic functionality.
- However, an internet connection can greatly speed up the GPS startup process.
- Assisted GPS systems allow satellite location information to be downloaded via the internet, improving speed compared to direct satellite downloads.
Timestamps are provided in seconds for each section.