Which data are included in satellite ephemeris data?

• A. Orbital data only
• B. Atmospheric propagation data only
• C. Satellite clock error data only
• D. Orbital data, atmospheric propagation data, and satellite clock error data

Answer: (D)

Satellite ephemeris data is the information broadcast by a satellite that lets a receiver determine where the satellite is and what time it reads, so you can compute accurate position fixes. It includes orbital data to describe the satellite’s precise path, satellite clock error data to correct the satellite’s onboard time, and atmospheric propagation data to account for the delays the signal experiences as it travels through the ionosphere and troposphere. Together these pieces enable precise pseudorange measurements. That’s why all three types of data are included.