There are several measuring techniques that can be applied when surveying with Carrier-Phase GPS. A brief description of the more commonly used is given below:

Static

Used for high accuracy (about 5mm + 1ppm), measuring long distances. It requires data to be collected for several hours on two receivers simultaneously to achieve the best results. The time of data collection is relative to the length of the baseline between the receivers.

Rapid Static

A form of static GPS which requires minutes instead of hours for satellite observation due to special ambiguity resolution techniques which use extra information. Accuracy can reach the centimetre on baselines less than 20km.

Real Time Kinematic

This technique uses a radio to link so that the reference station broadcasts the data obtained from the satellites to the rover instantaneously. As data is transferred by radio, it limits baseline lengths and accuracy will be in the range of 1-5cm. Nevertheless, it is becoming the most popular technique as results are fast and co-ordinates are displayed in real time.
*NB: Source of material: www.souterrain.biz

GPS-Ltd can utilize and incorporate any of the measurements techniques mention above in your project to ensure that your control network meet your project specifications.