Module 1 : Modern Surveying Equipment
 Lecture 3 : Total Station (TS)
 

Storage : Most TS have on-board storage of records using PCMCIA memory cards of different capacity. The card memory unit can be connected to any external computer or to a special card reader for data transfer (Figure 3.5). The observations can also be downloaded directly into intelligent electronic data loggers. Both systems can be used in reverse to load information into the instruments. Some instruments and/or data loggers can be interfaced directly with a computer for immediate processing and plotting of the data (Kavanagh, 2003).

 

Figure 3.5 Topcon GTS 800 TS with internal data collector (Wolf and Ghilani, 2002)

  • Friction clutch and endless drive: This eliminates the need for horizontal and vertical circle clamps plus the problem of running out of thread on slow motion screws.
  • Guide light or Lumi-guide tracking light : This arrangement is fitted above the telescope objective lens and enables the target operator to maintain alignment when setting-out points. This system emits two visible beams of coherent red light, one steady and one blinking, enabling the rodman to locate the correct line quickly and easily by finding the position where both are visible (Figure 3.6). This light changes colour when the operator moves off-line. With the instrument in the tracking mode, taking measurements every 0.3 s, the guide light speeds up the setting-out process. It can also be used as a convenient signal to the rodman, assists in one-man clearing of lines and work as a prism illuminator in night surveying.

Figure 3.6 Principle of Guide light or Lumi-guide system (Nikon TS instruments)
 
1