In this paper we propose two algorithms, called DIR and OMNI, for precisely localizing terrestrial objects, or more simply sensors, using a drone. DIR is based on the observation that, by using directional antennas, it is possible to precisely localize terrestrial sensors just applying a single trilateration. We extend this approach to the case of a regular omnidirectional antenna and formulate the OMNI algorithm. Both DIR and OMNI plan a static path for the drone over the deployment area, which includes a set of waypoints where distance measurements between the drone and the sensors are taken. Differently from previously proposed best-effort approaches, our algorithms prove that a guaranteed precision can be achieved by considering a set of waypoints, for each sensor, that are at a distance above a certain threshold and that surround the sensor with a certain layout. We perform extensive simulations to validate the performance of our algorithms. Results show that both approaches provide a comparable localization precision, but DIR exhibits a shorter path compared to OMNI, being able to exploit the directional antennas.