Location via time of flight is very accurate in terms of distance but not angle. It will require at least two septated devices to accurately pinpoint a third unknown device. And if those two baseline devices are moving then the accuracy is reduced. Android has support for location via wifi time of flight (802.11mc) where the baseline devices are your existing wifi access points. It makes much more sense indoors however it has two disadvantages: it won't work outside wifi range and it is much more difficult to make low power wifi devices.
I wonder whether you can fix this by using the positional tracking they developed for Augmented Reality (ARkit). If your device is moving, even a little, and the thing you are looking for is stationary, it should be possible to figure out exactly where it is.
