How does Reflectorless Electromagnetic Distance Measurement (REDM) differ from EDM?

Reflectorless Electromagnetic Distance Measurement (REDM) differs from traditional Electronic Distance Measurement (EDM) primarily in the way they interact with the measured object. REDM technology does not require a reflective surface and instead can directly measure the distance to the object by analyzing the return signal that reflects off the surface of the target, even if it does not specifically reflect light back toward the instrument.

In contrast to traditional EDM methods, which depend on a reflective target for accurate readings (often requiring a prism or a special reflective surface to return a signal), REDM allows surveyors to easily measure distances to surfaces without needing a separate reflector. This can significantly enhance efficiency in various surveying situations, particularly when access to a point for placing a reflector is impractical.

Other options do not apply to REDM's capabilities and functions. For instance, measuring the angle of elevation only relates to angular measurements rather than linear distance, and manual calculations are not a distinct requirement of REDM since modern instruments often automate these processes. Additionally, relying on a return signal from the measured object is an inherent feature of many distance measurement technologies, but in this context, it emphasizes the operational difference that REDM presents compared to traditional EDM.