SPSx20, SPSx30, total station EDM

The Trimble SPSx20 and SPSx30 Total Station EDM is a pulsed laser distance unit that determines distances by precisely measuring the flight time of the transmitted light pulse. The distance unit generates many short laser pulses, which are transmitted through the telescope to the target. The pulses reflect off the target surface and return to the instrument where the unit determines the time difference between the transmitted pulses and the received pulses. The unit uses the time difference to calculate the distance to the target.

The distance unit includes additional functions that allow you to control the accuracy and precision of a DR measurement through the field application software.

Field application software includes:

• Standard Deviation. This allows you to configure the required precision of the DR measurement before the distance will be accepted. The distance measurement process will be carried out by the instrument until the preset standard deviation value has been achieved. The default standard deviation value is 0.003m. Setting this value to a higher number gives shorter measurement time but is less accurate, especially when measuring to surfaces at greater distances or at oblique angles to the line of sight.

• Weak Signal. This allows you to accept a DR measurement that is below the normal instrument specification. This is useful when measuring to poor reflective surfaces, or when trying to achieve the maximum range of the instrument.

• Min.-Max Range. This allows you to specify the DR measurement interval. For example, when you measure to a small object at 50 m with a background object at 200 m, set the min.-max range from 2 m to 100 m. The distance meter is then tuned to provide a distance within the specified range and to ignore any signal from outside the defined range. By default, the min.-max range is 2–300 m1.5–600 m.