TOTAL STATION SURVEY TERMS

 

📍 What is Zenith?  शीर्षबिंदु

In surveying, Zenith refers to the point in the sky directly above your instrument or head — a 90-degree vertical angle from the horizontal plane.

     Zenith (0°)  शीर्षबिंदु

         |

         |

         |  (45°)

         | 

---------+---------  (90° Horizontal line)

         |

         |  (135°)

         |

  Nadir (180°) पतन

Zenith = The point directly above your position.
Zenith Angle = The vertical angle between the zenith and your target.

📏 T-P Corr. = Temperature & Pressure Correction

In Nikon Total Station, T-P Corr. stands for Temperature-Pressure Correction.
It’s a setting that helps correct the distance measurement based on the real environmental conditions — specifically:

• 🌡️ Temperature (°C)

• 🌬️ Air Pressure (hPa or mmHg)

💡 Why is this important?

When you use a Total Station, the instrument uses light waves (EDM — Electronic Distance Measurement) to measure distances.
But light travels differently depending on the air temperature and pressure — the higher or lower these values, the more the light can bend or slow, which changes the distance result.

So, if you input the correct T-P values, the Total Station can apply an automatic correction for the true distance.

🌊 What is Sea Level Correction?

In surveying, the Sea Level Correction is used to adjust the measured slope or horizontal distances to account for the curvature of the Earth — meaning your measured distances are corrected as if they were measured at mean sea level (MSL), rather than at the elevation where you are standing.

⚙️ Why is this important?

When you measure distances with a Total Station, you measure on the surface of the Earth — which is curved.
But for large-scale or precise surveying (like geodetic, highway, or railway projects), the distances need to be calculated as if they were measured at sea level, because that's the standard reference.

🧮 How does Nikon Total Station handle this?

In the Sea Level Correction (SLC) setting:

• You enter the Elevation (height) of your survey station above sea level.

• The instrument uses this to automatically correct the distances you measure.

• The higher your elevation, the more significant the correction.

💡 Simple Formula:

Corrected Distance = Measured Distance - (Measured Distance × Elevation / Earth's Radius)

🌍 Earth’s average radius ≈ 6,371,000 meters
So the correction is very small — but important in precise work!

📌 When to use Sea Level Correction?

• For long-distance surveys.

• For high-precision projects like roads, pipelines, railways.

• When you need to report distances on official survey records.

🔍 C&R Corr. = Collimation & Refraction Correction

This setting combines two important corrections that affect angle and distance accuracy in Total Station measurements:

1️⃣ C = Collimation Correction

• Collimation error happens when the telescope's sight line (crosshair) is slightly misaligned with the true optical axis.

• If uncorrected, this causes small errors in vertical angle (VA) and horizontal angle (HA) readings, especially noticeable when you sight targets at different elevations.

• The Total Station can apply a correction if you input or calibrate the collimation error, improving the angle measurement accuracy.

2️⃣ R = Refraction Correction

• Atmospheric refraction bends the light beam slightly as it travels through the air, especially over long distances.

• Without correction, this bending can cause height and distance errors.

• The refraction correction uses air data (often linked to Temperature & Pressure) to adjust measurements for this bending effect.

Correction	Purpose

Collimation

Fixes angular errors caused by misalignment of the telescope.

Refraction

Adjusts for bending of light in the atmosphere to improve height/distance accuracy.

🧭 What does ENZ stand for?

E = Easting
N = Northing
Z = Elevation (or Height)

📌 Meaning in Surveying:

ENZ is a coordinate system used to describe the position of a point in space:

Symbol	Meaning	Description

E

Easting

Distance eastward from a reference line (usually the X-axis)

N

Northing

Distance northward from a reference line (usually the Y-axis)

Z

Elevation (Height)

Vertical distance above a fixed datum (usually sea level or project base level)

💡 Example:

Point	Easting (E)	Northing (N)	Elevation (Z)
P1	500.250 m	300.150 m	105.750 m

This means:

• The point is 500.250 meters East and 300.150 meters North from the reference origin.

• And the height is 105.750 meters above the reference datum.

        ↑ Northing (N) / Y-axis

        |

        |

        |__________→ Easting (E) / X-axis

       Origin (0,0)

🧭 What is AZ Zero?

AZ Zero means Azimuth Zero — it refers to setting the zero direction for your horizontal angle measurement (HA).

In simple terms, it defines which direction your instrument considers as 0° on the horizontal circle.

🔹 Why is AZ Zero important?

When you start a survey, you must decide where 0° is — this is called setting the azimuth zero.
Once you set AZ Zero, all horizontal angle readings are measured from that reference direction.

For example:

• If you set AZ Zero while pointing at a known station or a north reference,
  the Total Station will measure angles from that point.

• If you skip setting AZ Zero, the Total Station might use the last random direction as 0°, and your measurements will be inaccurate.

EDM (Electronic Distance Measurement) Unit

The EDM (Electronic Distance Measurement) Unit in a Nikon Total Station is a crucial component responsible for measuring distances between the total station and a reflector (prism) or target. It uses advanced technology to provide highly accurate distance measurements, typically via laser or infrared signals. Here's an overview of how the EDM unit works and its key components:

Ext. Comm (External Communication)

in a Nikon Total Station refers to the system or interface that allows the device to communicate with external devices, such as computers, data collectors, GPS systems, printers, or other surveying equipment. External communication is essential for transferring survey data, receiving configuration updates, and integrating the total station with other equipment used in a surveying project. Here’s a breakdown of how Ext. Comm works and its various components:

Baud

refers to the baud rate, which is the unit of measurement used to describe the speed at which data is transmitted over a communication channel, such as in serial communication between devices like a Nikon Total Station and external equipment.

Definition of Baud Rate:

• Baud rate is the number of signal changes (symbols) transmitted per second in a communication channel. In simpler terms, it indicates how quickly data is sent or received.

• The baud rate is typically used in serial communications (like RS-232 or other serial interfaces) to determine the speed at which data is transferred between devices, such as a total station and a computer or data logger.

Parity 

in the context of communication, especially in serial data transmission (like with a Nikon Total Station), refers to a method used for error checking during data transmission. Parity is a simple form of error detection that ensures data integrity by checking whether the number of set bits (1's) in a data unit (usually a byte) is even or odd.

Stop bit

is a part of the data transmission protocol in serial communication systems, including those used by devices like the Nikon Total Station. It indicates the end of a data packet or frame and provides a clear delimiter between individual data units (such as bytes) to ensure proper timing and synchronization during data transmission.

In the Stakeout section of a Nikon Total Station, the term Add PT and LG Dist are used as part of the process of setting out or staking points on the ground. The information you provided, like Add PT 1000 1000 1000 and LG Dist 1.00 feet (0.30m) 1.00 feet (0.30m) 1.00 feet (0.30m), likely refers to the coordinates and the measurement tolerance for stakeout operations.

🏗️ Basic Nikon Total Station Terminology

Term	Full Form / Meaning	Explanation
HA	Horizontal Angle	Measures the angle from the reference line (usually North or a backsight) on the horizontal plane.
VA	Vertical Angle	Measures the angle from the horizontal line (0°) to the target, up or down.
SD	Slope Distance	The direct line distance measured from the instrument to the target (along the slope).
HD	Horizontal Distance	The horizontal (flat) distance from the instrument to the target, calculated from SD and VA.
HT	Height of Target	The height of the prism or the target point above the ground (entered manually).
HI	Height of Instrument	The vertical distance from the ground to the instrument's telescope center (entered manually).
EDM	Electronic Distance Measurement	The system inside the total station that sends and receives signals to measure distance.
LG Dist	Long Distance Measurement	Indicates long-range measurement mode or the acceptable error margin when staking out points.
MSR1	Measure Mode 1	Single-shot distance and angle measurement.
MSR2	Measure Mode 2	Continuous measurement mode for fine targeting or adjustments.
TRK	Tracking Mode	Continuously tracks and measures a moving prism or target.
RST	Reset	Resets the angle reading to zero for new reference orientation.
Stakeout	Point Marking Process	Guides you to place physical markers at specific coordinates based on design data.
Ext. Comm	External Communication	Refers to connection with external devices (data collectors, PC, controllers) via cable or wireless.
Baud	Data Transmission Rate	The speed at which data is transferred between the total station and another device (bps).
Length	Data Bits Length	Sets the number of data bits per communication packet (usually 7 or 8).
Parity	Error Checking Mode	A setting for ensuring data transmission accuracy — None, Odd, or Even.
Stop Bit	Stop Signal in Data Transfer	Indicates the end of one data packet — typically set to 1 or 2.
XYZ	Coordinates	X = Easting, Y = Northing, Z = Elevation.
BS	Backsight	The known point used to orient the total station at the start of a survey.
FS	Foresight	The point forward from the total station, usually the point being measured or set.
OC	Occupied Station	The exact position where the total station is set up.
REF HT	Reference Height	Used during stakeout for adjusting point heights.
REM	Resection Method	Technique to determine the instrument's position by measuring to known points.
COGO	Coordinate Geometry	Tools in the total station for calculating distances, angles, intersections, etc. on-site.

🔑 DSP Key — Display Key

In Nikon Total Station terminology, DSP stands for Display.

The DSP Key is the button used to: ➡️ Switch between different display screens
or
➡️ Toggle information shown on the screen.

💡 Purpose of the DSP Key:

When you are working in Measurement Mode or Survey Mode, pressing the DSP key allows you to:

• Change the data view on the screen.

• Cycle between different types of displayed information (such as HA, VA, SD, HD, coordinates, elevation).

• Show or hide extended measurement data.

• Simplify or expand the on-screen readout depending on your need.