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36 Promark2 User’s Guide
To execute this network design, you must perform a direct GPS observation between all points
directly linked. Each link can be viewed as a required GPS vector. Counting the links in this
network design, you will find that 19 GPS vectors are required to execute this design. If the
survey was to be performed using a 2-receiver ProMark2 system, 19 separate data collection
sessions (observations) would be required. For example, you can start with a receiver on point
1 and another on point 2. After this observation, you would move the receiver from point 1 to
point 3 to perform an observation between points 2 and 3, and so on until all vectors were
observed. Now consider the situation where the survey in Figure 3.7 is to be performed using a
3-receiver ProMark2 system. With 3 receivers, each observation session will produce 2
vectors from the network design. For example, you may start by placing one receiver on point
1, the second on point 2, and the third on point 7. These three receivers would simultaneously
collect data on these three points, resulting in the vectors between points 1 and 2, and points 1
and 7. In addition to these two vectors, a third vector is produced between points 2 and 7. At
the end of this first observation, you could move the receiver from point 2 to point 9 and the
receiver from point 1 to point 8. The receiver at point 7 would remain as the pivot point,
connecting the first observation to the second. This would continue until all vectors were
observed. Figure 3.8 shows what the observation plan might look like with a 3-receiver
ProMark2 system.
Figure 3.7 Network Design for 15-Point Control Survey
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