Specifications

You provide the software with your current location and the

date when you wish to perform your survey. The software then

provides you with multiple ways of examining the satellite

constellation at your location for the given time. Pay particular

attention to satellite availability (number of satellites in view)

and the satellite distribution.

To assist in analyzing the quality of satellite distribution, Di-

lution of Precision (DOP) values are presented. DOP is a qual-

ity analysis value for satellite distribution. The most popular

DOP value is PDOP, which stands for Positional Dilution of

Precision. The PDOP value estimates the impact on the preci

sion of your GPS observations due to satellite geometry. The

smaller the PDOP value the better the satellite distribution

(geometry) and therefore the better the precision of your ob

servations.

With the current constellation of 26+ GPS satellites, it is un-

common to find periods in the day when satellite availability

and distribution are so poor that data collection should be

avoided. Time of poor availability and distribution are usually

short in duration.

When using the static mode of GPS data collection, where ob-

servation times are usually 20+ minutes, short periods of poor

availability and distribution can be tolerated.

When performing an observation during which a period of poor

availability and distribution appears, observation times will

normally need to be extended to compensate for this event.