Navigation apparatus that may include a radio receiver, at least one directional antenna communicatively coupled to the radio receiver, and a navigation computer including a memory and a processor. The navigation computer may be communicatively coupled to the radio receiver to receive relative bearing information from the directional antenna to a set of known radio transmitters, such as (but not limited to) commercial broadcast radio or television stations. Using a database stored in the memory that includes a record of position information and a record of radio frequency information for the set of known radio transmitters, the apparatus allows for the calculation of one or more reference positions using relative bearing information to the set of known radio transmitters and the stored, known positions of the set of known radio transmitters.