Increase the distance and confusion rains supreme. In the literature over a decade ago, the debate surrounded object detectors versus environmental sensors. However, most of the aids I described above are not truly object detectors only. The Mowat, for example, can tell a thoughtful user much more than that there is something ahead. By scanning, you also know something about its size.
Proprioceptive feedback provides information about the exact direction of the object.
That is, the user is, in my view, ideally taking an active part in deducing what is ahead and making appropriate decisions accordingly. One of the problems, it seems to me, is that very few people really appreciate the potential of the sort of information provided by existing ETAs. I have read in formal studies of the SonicGuide, for example, that it will not detect low objects. It will not always do so, especially in cluttered areas. However, even in unfamiliar areas, I often do not use the cane to locate ascending single steps or flights of stairs.