Which combination of factors are typical sources of radar errors?

• A. Ionosphere delay, atmosphere/troposphere attenuation, and noise
• B. Ionosphere delay only
• C. Ground clutter and multipath
• D. Thermal noise only

Answer: (A)

Radar errors mainly come from how the signal is altered as it travels through the atmosphere and how the receiver handles the signal. The ionosphere can slow down and change the phase of the wave, causing timing and phase errors in range measurements. The troposphere can absorb or attenuate the signal, especially at higher frequencies, which reduces received power and can skew interpretation of the return. On top of that, the receiver itself has thermal noise, a fundamental random fluctuation that limits how accurately you can detect and measure the signal. When you combine these propagation-related effects with the unavoidable receiver noise, you have a realistic set of typical radar error sources that affect most systems.

Ground clutter and multipath are indeed real error contributors, but they depend a lot on the environment around the radar and the specific scene being scanned. Thermal noise alone is not sufficient to explain the range of errors seen, since propagation effects like ionospheric delay and atmosphere-induced attenuation also play a crucial role.