Methods and systems for estimating the position of an object such (as a vehicle) are disclosed. The method comprises transmitting a first V2X message from the object to a plurality of spaced apart units; and receiving a set of V2X response messages from at least two units in response to the first V2X message. Each response message comprises an identifier of the object, an identifier of the unit from which the response message was sent, and temporal information associated with the times of receiving a previous V2X message at the unit and transmitting a previous V2X response message from the unit. The position of the object is estimated based on the information contained in the set of V2X response messages and the times of transmitting the previous V2X message from the object and receiving the previous set of V2X response messages at the object.