base station GPS provides correctional data to rover GPS data, usually accurate inbetween 1/10 and 1/100 of a foot.

base station can support several rovers

base station radio drastically reduces line of sight limitations, doesn't need to be moved until rovers exceed radio range

laser increases accuracy and frequency of z data, for the most accurate positional data commercially possible

optical equipment is vulnerable to environmental interference (rain, dust, snow, thermals, etc.), requires line of sight

laser only works within the height of the receiver mast

laser and laser mast are mechanical devices, suffer from wear and tear

rotating laser consumes a lot of power - operation requires a deep cell battery charged daily to run

Lasers are potentially unstable - windy conditions easily make a laser tripod sway in the wind, affecting accuracy. In high winds, the laser may even cause the laser to shutdown and reset itself. Bad soil conditions may also make a laser unstable, such as placement on frozen ground when the air temperature is above 32 degrees.

Extra time is required to set up a rotating laser and calibrate the mast.

works for staking and surveying (which doesn't require rapid positional information)

GCS software accommodates for some level of latency with vector calculations

works where satellite communication is not possible

Slow refresh rate, very high latency, may be inappropriate for machine control

optical equipment is vulnerable to environmental interference (rain, dust, snow, thermals, etc.), requires line of sight

Robotic transits are mechanical devices that must be properly maintained and calibrated. They suffer from wear and can be quite easily damaged if dropped or bounced too hard. This wear and tear can result in excessive down time.

Relatively short range device. Typically the target can not be further than 1500 feet from the transit to still be tracked.

Glass reflectors are quite fragile and susceptable to dirt or finger prints on the surfaces.

Robotic transits are mechanical devices that must be properly maintained and calibrated. They suffer from wear and can be quite easily damaged if dropped or bounced too hard. This wear and tear can result in excessive down time.

Relatively short range device. Typically the target can not be further than 1500 feet from the transit to still be tracked.

Glass reflectors are quite fragile and susceptable to dirt or finger prints on the surfaces.

see GPS and Laser - Cons

very high refresh rate

works where satellite communication is not possible

capable only of planar control - only gives Z information, no X,Y data

optical equipment is vulnerable to environmental interference (rain, dust, snow, thermals, etc.), requires line of sight

laser only works within the height of the receiver mast

laser and laser mast are mechanical devices, suffer from wear and tear

rotating laser consumes a lot of power - operation requires a deep cell battery charged daily to run

Lasers are potentially unstable - windy conditions easily make a laser tripod sway in the wind, affecting accuracy. In high winds, the laser may even cause the laser to shutdown and reset itself. Bad soil conditions may also make a laser unstable, such as placement on frozen ground when the air temperature is above 32 degrees.

also see GPS and Laser - Cons