Orientation of TS using various Methods.

 

Orientation means setting the correct direction (bearing/azimuth) in the Total Station so all measured points have correct coordinates.

Here are some methods with simple steps to do Orientation of Total Station (TS) for accurate data collection:

Method 1: Backsighting  

A backsight is a location that has a known value - it has a Northing, Easting, and elevation; or Latitude, Longitude, and elevation. In Backsighting method, The total station is set up on a known point, and a prism is set up on a backsight. This will give the instrument an orientation so that future points can be mapped.

Step 1: Set up Total Station on Known Point

• Fix tripod firmly
• Mount Total Station
• Do centering (over control point like BM or CP)
• Do leveling (bubble centered)

Step 2: Enter Station Data

• Open Survey / Station Setup in TS
• Enter:
• Station coordinates (E, N, RL)
• Instrument height (HI)

Step 3: Set Backsight Point

• Place prism on known backsight point (BS)
• Ensure clear visibility
• Enter BS coordinates (E, N)
• Enter prism height (HR)

Step 4: Sight the Backsight

• Aim telescope at prism
• Focus clearly
• Align crosshair exactly at center

Step 5: Set Orientation (Set Angle / Set 0)

• Press “Set” or “0 Set” button
• Horizontal angle becomes 0°00'00" (or known azimuth)

Now your TS is oriented correctly

Step 6: Check Orientation

• Re-sight backsight again
• Angle should still be 0°

Step 7: Start Data Collection

• Now measure new points
• All coordinates will be accurate and correctly oriented

Method 2 : Resection (Free Station Method)

Free station means you can set up the Total Station at any unknown point, and find its coordinates by observing 2 or more known control points. Resection/Free Stationing method is adopted when we cannot set up TS on a known point.

Step 1: Set up Total Station at Unknown Point

• Fix tripod firmly
• Mount TS
• Do leveling carefully
• No need for exact centering (approximate is okay)

Step 2: Open Free Station / Resection Mode

• Go to Program → Free Station / Resection in TS
• Select method:
• Angle + Distance (recommended)
• Angle only (less accurate)

Step 3: Input Known Points (Control Points)

• Choose at least 2 points (better 3 or more)
• Enter their coordinates (E, N, RL)
• Place prism on those known points
• Enter prism height (HR)

Step 4: Observe Each Known Point

• Aim at first point → take reading
• Then second point → take reading
• Then third point (if available)

Step 5: Compute Position

• Press Calculate / Compute
• TS will give:

1. Station Coordinates (E, N, RL)
2. Orientation (angle)
3. Residual error

Step 6: Check Accuracy

• Re-sight one known point

Once accuracy is ensured data collection can be done. The TS is now oriented and positioned correctly.

Note : The position (E,N and Z) of unknown points can be measured using GPS-Global Positioning System or GNSS-Global Navigation Satellite Syste (RTK GNSS), then the position of other points can be measured using TS.