Module 1 : Modern Surveying Equipment
 Lecture 3 : Total Station (TS)
Total Station (TS)
  • These instruments can record horizontal and vertical angles together with slope distance and can be considered as combined EDM plus electronic theodolite. The microprocessor in TS can perform various mathematical operations such as averaging, multiple angle and distance measurements, horizontal and vertical distances, X, Y, Z coordinates, distance between observed points and corrections for atmospheric and instrumental corrections.
  • Due to the versatility and the lower cost of electronic components, future field instruments will be more like total stations that measure angle and distance simultaneously having:
    • all capabilities of theodolites
    • electronic recording of horizontal and vertical angles
    • storage capabilities of all relevant measurements (spatial and non-spatial attribute data) for manipulation with computer.
  • Nowadays surveying systems are available which can be use in an integrated manner with Global Positioning System (GPS). Hence, future theodolites/total stations may have integrated GPS receivers as part of the measurement unit.
  • Generally following types of total stations are available in the market:
    • Mechanical/manual
    • Motorized
    • Autolock
    • Robotic/automatic
  • Mechanical/manual TS: The conventional multipurpose manual TS are used for routine works with powerful built-in applications program and are cheaper than the other types TS.
  • Motorized TS: The motorized TS are equipped with servo to allow for fast, smooth and accurate aiming. This increases the productivity by about 30%. The servo technology enables automated measurement. For example, during angle measurement one can simply aim the instrument at each point. The instrument can then repeat the measurements automatically as may times as required. Servo equipped TS act as base for autolock and robotic surveying.
  • Autolock TS: Autolock TS allow for a semi-automatic measurement where measuring and recoding takes place at the TS. In this case the instrument searches for an active remote positioning target (RMT), locks to it and follows the target as it moves to different points. Autolock technology eliminates the need for time-consuming error prone focusing and allows you to work effectively even in poor and low visibility environment. It improves the time efficiency by up to 50%.
  • Automatic/Robotic TS: This a true one person surveying TS and is ideal for surveying and stakeout operations. In this TS, the control unit can be taken to the prism to record measurements and collect other data. Generally a radio communication is used between TS and the prism. The control unit, battery, antenna and radio modem are integrated to allow full control over instrument and its operation. The prism used may be omni-directional (usually for short distance up to 500 m) which is always aligned to the instrument or directional for longer distances. During stakeout, the control unit is used to move to point of interest. It improves the time efficiency by up to 80%.
 
 
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