3.3 - Total Stations
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Introduction to Total Stations
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Today we will learn about Total Stations, which are essential tools in modern surveying. Can anyone tell me what they think a Total Station does?
Is it used to measure distances and angles?
That's right! Total Stations measure both distances and angles. They integrate an electronic theodolite and an EDM. This means they simplify the surveying process significantly.
How do they actually measure these things?
Great question! The Total Station sends out infrared waves that reflect off prisms. By calculating the time it takes for the waves to travel to the prism and back, it figures out how far away the target is.
What components do they have?
Essentially, a Total Station includes a tripod, a mainframe for data collection, a prism, and a battery. Remember the acronym 'TPMB' for Tripod, Mainframe, Prism, and Battery!
To summarize, a Total Station is an advanced instrument that leverages technology for precise measurements in surveying.
Steps in Total Station Surveying
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Now, let’s discuss the steps you’d take in a Total Station survey. Can anyone outline how you would start?
You need to set up the instrument on a tripod.
Exactly! The first step is to securely place the Total Station on the tripod. What comes next?
You have to level it using a bull's eye level.
Right! Leveling ensures accuracy. After leveling, we focus on the diaphragm, and place the prism at the correct height target. Why do we focus on the prism?
To ensure that we're measuring accurately to the right point!
Correct! Remember that focusing on the prism is crucial for precise measurements. All together, it’s important to take several readings for higher accuracy.
In summary, setting up a Total Station involves careful placement, leveling, focusing, and recording data.
Functions and Applications of Total Stations
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Let’s dive into what functions a Total Station serves after all the setup. What do you think it can do?
It can measure angles and distances.
Yes, exactly! Total Stations measure both horizontal and vertical angles with incredible precision. Can anyone give me an example of how this might be applied in real life?
Maybe in construction site surveys?
Absolutely! They're used in construction to ensure that buildings are set up correctly according to plans. They also track progress and measure deformation, like ensuring buildings remain stable over time.
Can we use them in places like forests or disaster areas?
That's a critical point! With reflectorless functionalities, Total Stations can measure distances without a prism, which is helpful in hazardous areas.
In summary, Total Stations play a crucial role in various surveying applications, providing precise measurements and efficiency.
Robotic and Reflectorless Total Stations
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Now, we have more advanced options like Robotic Total Stations. Does anyone know how they work?
Do they follow the prism automatically?
Correct! They use servomotors to track prisms without a second person. This makes them very efficient. What about reflectorless Total Stations?
They can measure distances without needing a prism?
Exactly! They use a laser beam for measurement, which is great for hard-to-reach areas. Remember this: 'Reflectorless = Accessibility!'
Why does that matter?
It allows surveying in dangerous or inaccessible environments, enhancing safety and efficiency. In conclusion, both Robotic and Reflectorless Total Stations represent significant advancements in surveying technology.
Introduction & Overview
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Quick Overview
Standard
Total Stations combine the functionalities of an electronic theodolite and an electronic distance measurement (EDM) device, enabling efficient measurement of angles, slopes, distances, and data computations. They include essential components such as tripods, prisms, and microprocessors to process and store the data collected during a survey.
Detailed
Total Stations
Total Stations are sophisticated surveying instruments that integrate an electronic theodolite for angle measurements and an electronic distance measuring (EDM) device for distance calculations. These instruments enable surveyors to take accurate measurements of horizontal and vertical angles, slope distances, and compute important data like coordinates and elevations.
Key components of a Total Station include:
- Tripod: Supports the Total Station at the survey point.
- Mainframe Device: Processes and records data.
- Prism and Prism Pole: Aids in precise distance measurement, with the ability to measure distances up to several kilometers using triple prisms.
- Battery: Provides power to the device.
The steps involved in Total Station surveying include setting up the device on firm ground, leveling it accurately, focusing on the target prism, and taking measurements. The instrument gathers data which can later be transferred to computers for further analysis.
Modern Total Stations have various features, such as reflectorless capabilities, allowing measurement of inaccessible points, and robotic functionalities to track prisms automatically, which significantly increases efficiency in surveying tasks.
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Introduction to Total Stations
Chapter 1 of 7
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Chapter Content
This instrument is an integrated version of an electronic Theodolite and an EDM, as shown in Figure 3.6. It also has a small micro-processor, electronic data collector and storage system. A Total Station is an electronic/optical instrument used to measure sloping distance of object to the instrument, horizontal angles and vertical angles (Garg, 2021). Micro-processor in Total Station processes the collected data to compute the average of multiple angles measured, average of multiple distance measured, horizontal distance, elevation of ground, and 3-D coordinates of the observed points. These data can be stored in the system itself but each Total Station has a limited storage space. The data can be transferred to a laptop and desktop later for its processing.
Detailed Explanation
A Total Station combines the functions of an electronic theodolite and an electronic distance measuring (EDM) device. It measures the angles and distances from the instrument to a target point, allowing surveyors to calculate the coordinates and elevation of that point. The integrated micro-processor helps in processing this data, averaging multiple measurements, and storing them for later use. Because the Total Station has limited internal storage, data is often transferred to larger systems for further analysis.
Examples & Analogies
Think of a Total Station like a smartphone equipped with a camera and GPS. Just as your phone can take pictures of locations and record their coordinates, a Total Station measures the angles and distances to points in a survey. Like saving photos and maps on your phone for later use, the Total Station saves survey data to be used for creating maps and planning projects.
Working Principle of Total Stations
Chapter 2 of 7
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Chapter Content
The Total Station sends out infrared waves that are reflected by the prism kept at the object. By taking measurements of the prism, the Total Station computes the prism’s coordinates as well as reduced level of the ground point. Some of the major advantages of using Total Station over the conventional surveying instruments are; saving in time, ease in working, increase in accuracy, and facility to use computer for storing, processing the data and derive the final result in a desired format (Gopi et.al., 2017).
Detailed Explanation
Total Stations work by sending infrared waves toward a prism placed at the target point. When these waves hit the prism, they reflect back to the Total Station. By measuring the time it takes for the waves to travel to the prism and back, the Total Station calculates the distance to the prism. This distance, combined with angle measurements, allows the instrument to determine the target's exact coordinates on the ground. The efficiency of this system makes it faster and more accurate than traditional methods.
Examples & Analogies
You can think of the Total Station's operation like a game of catch with a friend in a park. When you throw the ball (the infrared wave) at your friend (the prism), timing how long it takes for the ball to come back gives you an idea of the distance. Just as you can adjust where you throw the ball to reach your friend accurately, the Total Station adjusts its settings to accurately measure distances and angles.
Components of a Total Station
Chapter 3 of 7
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Chapter Content
Total Station consists of a distance measuring instrument (EDM), an angle measuring instrument (Theodolite) and a simple micro-processor (Figure 3.7). It is a compact instrument, and one person can easily carry it to the field from one point to another. Total Stations with different accuracy, in angle measurement and different range of measurements, are available in the market. The components of a Total Station are as follows: 1. A tripod which is used to hold the Total Station 2. A mainframe device which is used to record, calculate and even manipulate the field data. 3. Prism and prism pole/tripod which can be used to measure distances up to 6-7 km with triple prism 4. Battery is required to provide power source to the instrument.
Detailed Explanation
A Total Station combines several key components: the EDM for measuring distance, a theodolite for measuring angles, and a micro-processor for data processing. This compact device is lightweight and portable, allowing surveyors to carry it easily to different field sites. It typically includes a tripod for stabilization, a mainframe to record data, and a prism, which reflects the infrared waves back to the Total Station for distance measurement. Battery power is essential for the operation of the device in field conditions.
Examples & Analogies
Imagine a Total Station as a high-tech camera tripod. Just as the tripod holds your camera steady to capture perfect photos, a Total Station rests on its tripod to ensure precise measurements. The camera (EDM) snaps distance measurements, the lens (theodolite) captures angles, and the 'computer' inside (micro-processor) helps organize all that data so you can create beautiful maps and models later, just like photo editing software helps you process your photos at home.
Steps Involved in Total Station Surveying
Chapter 4 of 7
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Chapter Content
Fix the instrument on the tripod that has been firmly kept on the ground. Fix the instrument on the tripod with the help of a given screw in tripod. Set up the instrument on the ground point. Some instruments have optical plummet which consists of a sharp laser beam and may be used for centering purpose. Levelling of the instrument approximately with the help of “bull’s eye bubble” using eye judgement. Use the standard procedure for levelling, and then correct the levelling precisely electronically. Focus the diaphragm. Fix the prism on the prism rod at a known height. Since, the prism rod is graduated so height of the prism is known. Measure the height of instrument with the help of a tape. Set up the working unit in the instrument. Enter the height of prism pole, height of instrument, coordinates of point where instrument is kept (if known), temperature and atmospheric pressure at the site (if known). Focus the prism kept at the other point. Bisect the centre of reflecting prism and with the help of appropriate functional buttons in the instrument. The measurement will be displayed on the display panel. Store all the measurements in the instrument itself. Compute the other data from measured observations. To speed up the work, more than one prism set is used the field. Various persons can set up the prisms at respective locations and observer from the same location of instrument can take observations all around. It saves lot of time in data collection.
Detailed Explanation
Surveying with a Total Station involves several key steps. First, the instrument is secured onto a stable tripod. Then, it is leveled using a 'bull's eye bubble' for initial adjustments and electronic corrections. After focusing on the prism, the surveyor enters necessary parameters, including the height of the instrument and prism. Measurements are taken to determine the coordinates and elevations of points. To improve efficiency, multiple prisms can be set up at various locations, allowing the surveyor to gather data more rapidly.
Examples & Analogies
Think of setting up a Total Station like preparing to play a game of darts. You need a firm and stable board (tripod) to hold the dart (Total Station) steady. You check to make sure the board is level (leveling the instrument) before trying to aim at your target (prism). Once everything is set up, you can throw darts at multiple targets quickly, similar to using several prisms around your Total Station to take measurements all at once.
Functions of Total Station
Chapter 5 of 7
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Chapter Content
Most Total Stations have a distance measuring accuracy of 2-3 mm at short ranges, which will decrease to about 4-5 mm at 1 km (Mishra, 2014). Although angles and distances can be measured and used separately, the most common applications for Total Stations occur when these are combined to define the position in control surveys. 1. Angle measurement: To measure horizontal and vertical angles, the Total Station is used with an accuracy of better than one seconds. For horizontal measurement of angles, any direction can be taken as reference. In case of vertical measurement of angles, horizontal direction is taken as reference. 2. Distance measurement: The EDM is a major part of Total Station. To measure the distance, EDM instrument of Total Station is used with an accuracy of 5-10 mm per km or better. The accuracy varies with each Total Station equipment. They are also available to be used in Robotic mode, with automatic target recognizer.
Detailed Explanation
Total Stations are notably accurate in both angle and distance measurements. Angle calculations are precise to less than one second, and distance readings typically range from 5 to 10 mm of accuracy per kilometer. These two measurements, when combined, allow for precise positioning on the surveyed land. Additionally, modern Total Stations also come in robotic versions that can automatically recognize and track targets, further enhancing productivity in the field.
Examples & Analogies
You can visualize the accuracy of Total Stations like a GPS in your car while navigating. Just as a GPS gives you clear turn-by-turn directions (distances) and the exact angles to turn at intersections (angles), Total Stations give surveyors precise measurements to ensure they accurately map or lay out land for new projects. In a robotic Total Station, it's like your GPS learning to predict when to reroute based on traffic, offering even smoother navigation.
Types of Total Stations
Chapter 6 of 7
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Chapter Content
There are two methods of measuring the distance; (i) With reflector and (ii) Reflectorless or prismless modes. The prism method uses a reflective prism at the measurement point, and the non-prism or reflectorless method does not require a reflective prism. Both the methods have been widely used in engineering and industrial surveying systems to measure the distances and angles automatically (Xia et al, 2006).
Detailed Explanation
Total Stations can operate in two main modes: with a reflector and without a reflector (reflectorless). The reflector method requires a reflective prism placed at the target point to measure distance and angles accurately. In contrast, the reflectorless mode utilizes a laser beam to measure distances without a prism, making it ideal for challenging terrain or hazardous locations. Each method has its own applications, and it is essential to choose the right mode based on the surveying conditions.
Examples & Analogies
Think of these two methods like using binoculars versus a camera zoom to see a bird in a tree. The binoculars (reflector method) give you a clear view, but you need to be close enough to the bird (the prism) to get a good shot. Using a zoom camera (reflectorless method) allows you to capture the same bird from far away without frightening it off, making it easier to get a good picture without needing to approach the subject directly.
Robotic Total Stations
Chapter 7 of 7
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Chapter Content
Another advancement in Total Station is the emergence of Robotic Total Station (RTS) which is able to follow a prism horizontally and vertically through servomotor in the instrument. These RTSs are expensive as they have more sensors in the device as well as prism. These sensors make the instrument to work in robotic mode. The servomotor automatically rotates the instrument, as it communicates with an Advanced Tracking Sensor (ATS) fitted in the prism for tracking the movement of the prism (Garg, 2021).
Detailed Explanation
Robotic Total Stations represent a significant technology advancement, allowing for automated tracking of prisms without the need for the surveyor to constantly adjust the instrument's position. Using servomotors and advanced sensors, these devices can automatically rotate to follow the prism's movement, making them very efficient for surveying tasks, especially in dynamic environments. Although they are more expensive due to their sophisticated technology, they significantly reduce labor costs and time in the field.
Examples & Analogies
Imagine a studio camera that automatically follows an actor during a performance without the need for a camera operator. Just as the camera adjusts its angle and focus to keep the actor in the frame, a Robotic Total Station follows the moving prism, allowing one person to conduct a detailed survey as effortlessly as the camera captures the action on stage.
Key Concepts
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Total Station: A modern surveying instrument that integrates electronic theodolite and EDM.
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Prism: Essential for accurate distance measurement in Total Stations.
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Robotic Total Station: Automates tracking of prisms for efficient surveying.
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Reflectorless Measurement: Uses laser beams to measure distances without a prism.
Examples & Applications
A Total Station is used in constructing a new bridge to ensure it is built at the correct angles and elevation.
Using a reflectorless Total Station, surveyors measure a hillside's elevation without placing a prism in potentially dangerous areas.
Memory Aids
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Rhymes
Total Station's a tool oh so fine, measures distance and angles inline.
Stories
Imagine a surveyor named Sam who uses his Total Station to ensure that every building he constructs stands perfect and tall. With the EDM helping him measure distances and the prisms guiding his way, Sam works efficiently and correctly every day.
Memory Tools
'TAME' for Total Station components: Tripod, EDM, Microprocessor, Prism, and Energy source.
Acronyms
'RATS'
Robotic Total Station = Automation
Tracking
Sensor.
Flash Cards
Glossary
- Total Station
An integrated surveying instrument that combines an electronic theodolite and an EDM for measuring distances and angles.
- Electronic Distance Measurement (EDM)
A method that uses electromagnetic waves to measure the distance between the instrument and a target.
- Robotic Total Station
A Total Station equipped with a servomotor that allows it to automatically track the reflection of a prism.
- Reflectorless Total Station
A type of Total Station that uses a laser beam to measure distances without requiring a prism.
- Prism
A reflective device used with Total Stations to measure distances and angles accurately.
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