A Position and Orientation Measurement Engine (POME) is a mobile camera system that can be used for accurate indoor measurement (e.g., at a construction site). The POME uses a plurality of cameras to acquire images of a plurality of targets. If locations of the plurality of targets are precisely known, images of the targets can be used to determine a position of the POME in relation to the plurality of targets. However, to precisely determine locations of the plurality of targets can be time consuming and/or use expensive equipment. This disclosure discusses how to use the POME itself to determine locations of the plurality of targets.