The thing you need to realize is that the sensor isn't telling you that you are near a target, only that you're merely moving in the direction of the target. The better the signal, the more it is directly ahead of you. So if it's beeping at full strength, that means you should start walking straight ahead. If it's not at full but some bars, you should start turning until you could get a better signal. If you have nothing at all, then the target is nowhere near you at all. If you're standing still, then you won't get any feedback, only that the target is somewhere in the area or none at all.
So as you're moving about, keep walking straight as long as the signal is full. If it isn't course correct until it is. You'll eventually reach your target as long as you're able to recognize that you've found it.
there are no targets in the area and you should go elsewhere
a target is in the area but you're not moving or the target is behind you
you are walking toward the target so keep moving straight