Laser receiver for detecting a relative position

A laser receiver for detecting a relative position of a defined zero point of said laser receiver with respect to an external reference laser beam not from the laser receiver, the laser receiver comprising:

• a laser light photo sensor having a plurality of photo sensitive elements providing an electrical output when illuminated by said external reference laser beam;
• circuitry connected to said photo sensor for determination of said relative position;
• a visible readout for indication of said relative position, wherein the visible readout includes a first laser fan emitter including a laser light source;
• and
• at least one fan-generating optical element for projecting a visible laser line onto a target surface, wherein the visible laser line is from a substantially flat planar fan-shaped laser beam emitted from the first laser fan emitter;
• and
• a housing, wherein at least said housing, said laser light photo sensor, said circuitry, said visible readout and said first laser fan emitter are assembled as unitary apparatus.