Which instrument can provide precise location info in search and rescue operations?

A GPS unit is highly effective in providing precise location information during search and rescue operations due to its ability to receive signals from satellites orbiting the Earth. These signals allow the GPS unit to determine its exact coordinates—longitude, latitude, and altitude—often with an accuracy of a few meters, which is critical for effective navigation and communication between rescue teams.

By using a GPS unit, rescuers can quickly and reliably pinpoint their location or the location of a victim in distress, making it an invaluable tool in environments where landmarks may be obscured or where traditional navigation methods may fail. This access to real-time location data helps to streamline searches and improve overall operational efficiency.

In contrast, while a barometer can provide information about atmospheric pressure, which can indicate changes in weather, it does not provide direct location data. A topographic map offers useful spatial information about the terrain but requires interpretation and the use of additional tools for navigation. Compasses are essential for determining direction but need to be used with other navigational aids like maps to establish precise location. Thus, the GPS unit stands out as the most reliable choice for accurate location information in search and rescue contexts.