Which of the following are conditions that would cause a fixed target to appear to have a true speed greater than zero?

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In ARPA tracking, a stationary target can seem to have a nonzero true speed because the system’s measured position is shaped by how the radar image is formed and how the tracker assigns detections over time. Centroid shift happens when the center of the target’s radar echo moves on the display due to changes in the echo’s shape, aspect, or surrounding clutter. Even if the target isn’t moving, this shift changes the reported position from update to update, creating an artificial drift that looks like motion. Target swap occurs when the tracker mistakenly switches between two nearby echoes or targets that resemble each other. Each update then corresponds to a different physical point on the screen, which can produce jumps in the target’s reported position. When both effects happen together, the combination can produce a sequence of position updates that mimics forward motion, making a fixed target appear to have a positive true speed. The scenario where both centroid shift and target swap occur is the one that best explains this spurious speed reading.