Which set of parameters correctly summarizes key characteristics of GPS satellites in the NAVSTAR constellation (medium Earth orbit, plane inclination, and transmitted L-band signals)?

Introduction / Context:
GPS (NAVSTAR) satellites operate in medium Earth orbit (MEO) and broadcast precise timing and navigation signals on multiple L-band frequencies. Knowing their altitude, inclination, and signal frequencies helps practitioners understand coverage, dilution of precision, and receiver compatibility.

Given Data / Assumptions:

• Constellation uses ~20,200 km circular MEO orbits.
• Orbital inclination is approximately 55 degrees.
• Legacy civil signals are on L1 (1575.42 MHz) and L2 (1227.60 MHz), with newer signals on L2C and L5.

Concept / Approach:
Altitude determines orbital period (~12 hours sidereal) and coverage footprint. Inclination affects latitude reach and satellite sky geometry. Multiple L-band signals allow dual-frequency ionospheric correction and improved robustness for precision applications.

Step-by-Step Solution:
Select the MEO altitude closest to 20,200 km.Confirm the standard GPS inclination near 55°.Identify the canonical L1 and L2 center frequencies: 1575.42 and 1227.60 MHz.Choose the option that lists all three correctly.

Verification / Alternative check:
GPS Interface Control Documents (ICDs) and satellite almanacs list these parameters; field receivers routinely use L1/L2 for dual-frequency positioning.

Why Other Options Are Wrong:

• Geostationary altitude (~36,000 km) and 0° inclination do not describe GPS MEO satellites.
• Inclinations like 45° or polar sun-sync (98°) are not applicable to GPS.
• Signal sets limited to one band or other bands (e.g., S-band) do not match GPS.

Common Pitfalls:
Confusing GPS with augmentation systems (e.g., SBAS on GEO) or with other GNSS that use similar but not identical parameters.

Final Answer:
Nominal altitude about 20,200 km; orbital inclination ~55°; L1 at 1575.42 MHz and L2 at 1227.60 MHz