Named only in Metroid Prime Hunters, the Thermal Positioner is a default ability that is primarily responsible for mapping the surrounding areas. When used with the minimap system in the HUD, it will automatically generate a small minimap version of the room Samus currently is in. Another important feature is that it will also show where in the room Samus is. While not named or referred to in any other way in other games, it is possible that this also is part of the minimap system in the 2D games, as well.
Also in Prime games and in Zero Mission, a Hint system points out locations on the larger maps (viewable in the Pause or Map screens) of objectives, suit upgrades, and other important places to go to. Such examples include pointing out elevators in Metroid Prime, upgrades and Temple Key locations in Metroid Prime 2: Echoes, or objective locations in Metroid Prime 3: Corruption. It is possible that this callout mapping system works in tandem with the Thermal Positioner to point to Samus/the player where to go next.
Metroid Prime Hunters
SAMUS' location is tracked by a THERMAL POSITIONER which relays an image of SAMUS and her surroundings. This valuable imaging tool also identifies objects and entities with unique POWER SIGNATURES. Access the THERMAL POSITIONER by pressing START.