Measurement system having active target objects

A surveying system comprising:

• a laser measurer transmitting a search beam and a measuring beam;
• a first active target object including a first reflector for reflecting the measuring beam, a first receiver for receiving the search beam, a first transmitter for transmitting a first visible transmission beam, and a first controller for evaluating the received search beam and for controlling the first receiver and first transmitter, and
• a second active target object including a second reflector for reflecting the measuring beam, a second receiver for receiving the search beam, a second transmitter for transmitting a second visible transmission beam, and a second controller for evaluating the received search beam and for controlling the second receiver and second transmitter, a second light color of the second visible transmission beam being different from a first light color of the first visible transmission beam.