Electronic distance measurement (EDM) instruments have revolutionized the way measurements are taken in various fields such as construction, civil engineering, surveying, and mapping. These instruments use advanced technology to accurately measure distances between remote points, eliminating the need for physical measurements. With their ease of use, quick results, and high precision, EDM instruments have become a preferred choice for professionals. This article will delve into the various types of electronic distance measurement instruments, their functions, and how they operate, offering a comprehensive understanding of these powerful tools. Whether you are new to EDM instruments or looking to upgrade, this article will provide valuable insights into their capabilities and help you make an informed decision.
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Origin of Electronic Distance Measurement
Electronic distance measurement (EDM) is a modern technique used in the field of surveying and civil engineering to measure distances with extreme precision. It is a vital part of most construction and engineering projects and has greatly revolutionized the surveying industry.
The first attempts at electronic distance measurement can be traced back to the early 19th century, where basic principles of electromagnetic radiation were explored. But it was not until the 1940s that the idea of using electromagnetic waves for distance measurement was developed. This led to the creation of various prototype devices by different researchers, including a tachometer developed by Swiss engineer Jürg Pletscher in 1948.
In the 1950s, a major breakthrough in EDM technology occurred when the first commercially successful instrument was developed by Rudolf Hilkemann, a German engineer working for the Swiss company Wild Heerbrugg. This instrument, called the Wild DI-10, used infrared light to measure distances and quickly became the industry standard.
The 1960s saw a significant advancement in EDM technology with the development of the electronic distance measuring system (EDMS). This system utilized the principles of electromagnetic waves and the Doppler effect to transmit and receive signals, allowing for more accurate distance measurements. The first EDMS device was developed by Sharp and Woller in the UK and was called the Harpedon, which was later upgraded to the Distomat in the 1970s.
Further development in the 1980s led to the creation of the Global Positioning System (GPS), which incorporated satellite technology with EDM. This allowed for more accurate and efficient distance measurements, especially over long distances.
In the 1990s, the introduction of powerful computers and advanced technology led to the development of the Global Navigation Satellite System (GNSS). This system uses a constellation of satellites to provide real-time positioning and data regarding distances, locations, and elevations.
Today, EDM technology has greatly advanced and is widely used in the construction industry for various purposes such as highway design, building construction, and land development. Advancements in laser technology have also led to the development of laser rangefinders, which are more compact and portable compared to traditional EDM instruments.
In conclusion, the origin of electronic distance measurement can be traced back to centuries ago, but it was not until recent decades that significant advancements took place, making it an essential tool in modern surveying and construction practices. The continuous development of EDM technology has greatly improved the accuracy, efficiency, and safety of distance measurements, making it a crucial component in the field of civil engineering.
Types of Electronic Distance Measurement Instrument
Electronic distance measurement (EDM) instruments are electronic devices used to accurately measure distances between two points. These instruments have revolutionized the field of surveying and civil engineering, making it quicker, more precise, and less labor-intensive. There are several types of electronic distance measurement instruments available, each with its own unique features and advantages. In this article, we will discuss the most commonly used types of EDM instruments.
1. Total Station:
Total stations are the most versatile and widely used electronic distance measurement instruments. They combine the capabilities of an electronic theodolite, EDM, and data collector in one device. They use an infrared beam to measure distances and an electronic theodolite to measure angles. They also have a built-in data collector, which allows the user to record and store survey data. Total stations are highly accurate and can measure distances up to several kilometers.
2. Laser Distance Meters:
Laser distance meters (LDM) use laser technology to measure distances. They emit a laser beam, which bounces off the target and returns to the instrument. The time taken for the laser beam to return is used to calculate the distance. LDMs are compact, lightweight, and easy to use. They are ideal for measuring distances up to 100 meters and are widely used for interior and small-scale measurements.
3. Global Positioning System:
The Global Positioning System (GPS) is a satellite-based navigation system that uses a network of satellites to determine the position, velocity, and time of a receiver on Earth. GPS receivers have the ability to measure distances between points by calculating the distance between the receiver and multiple satellites. They are commonly used in large-scale projects such as road construction, where they provide accurate and real-time positioning data.
4. Electronic Tapes:
Electronic tapes, also known as electronic measuring tapes, are a simple and cost-effective distance measuring instrument. They use ultrasonic or laser technology to measure distances by emitting an ultrasonic pulse or laser beam and measuring the time it takes to return. Electronic tapes are portable and can measure distances up to 30 meters. They are commonly used for small-scale indoor and outdoor measurements.
5. Robotic Total Stations:
Robotic total stations are an advanced type of total station that eliminates the need for an operator to manually aim the instrument at the target. They have a built-in motorized tracking system that automatically follows the reflector. This makes them ideal for large-scale projects where there are multiple targets, and the operator needs to move frequently. Robotic total stations simplify the surveying process, increase efficiency, and reduce errors.
In conclusion, electronic distance measurement instruments have revolutionized surveying and civil engineering by providing accurate and efficient distance measurement capabilities. Each type of EDM instrument has its own unique features, advantages, and limitations, and the selection of the appropriate instrument depends on the requirements of the project. It is essential to have a thorough understanding of the various types of instruments and their capabilities to choose the most suitable one for a particular project.
Operations of Electronic Distance Measurement Instruments
Electronic Distance Measurement (EDM) instruments are used in the field of civil engineering for precise and accurate measurement of distances between two points. They have revolutionized the traditional methods of measuring distances using chains, tapes, and rods.
The basic principle of operation for EDM instruments is triangulation. It involves measuring angles and distances to determine the position of a point in space. The following are the main components and their operations in EDM instruments:
1. Theodolite – A theodolite is a precision instrument used to measure angles both vertically and horizontally. In EDM instruments, it is used to measure the vertical and horizontal angles to a point and also to align the instrument towards a target.
2. EDM Unit – The electronic distance measuring unit is the primary component of an EDM instrument. It emits an infrared beam towards a target and measures the time it takes for the beam to reflect back to the instrument. By using the speed of light and the time taken, the distance to the target can be calculated.
3. Reflective Target – A reflective target is used to reflect back the infrared beam emitted by the EDM unit. The target is placed at the point to be measured and is aligned with the crosshairs of the theodolite.
4. Electronic Display Unit – The electronic display unit is used to display the angles and the distance measured by the instrument. It can also store the measurements for further calculations.
The operations of an EDM instrument involve the following steps:
1. Set Up – The EDM instrument is set up on a tripod and leveled using the built-in bubble level. The theodolite is then aligned towards a known point.
2. Targeting – Using the theodolite, the instrument is aligned towards the target point by measuring the horizontal and vertical angles.
3. Measurement – The EDM unit emits an infrared beam towards the target point and measures the time taken for the reflection. The distance is then calculated and displayed on the electronic display unit.
4. Data Collection – The instrument can store the measured distances and angles, which can be downloaded onto a computer for further calculations and analysis.
5. Error Checking – To ensure accuracy, the instrument has built-in error checking capabilities. The electronic display unit displays any errors or inconsistencies in the measurements, which can be corrected by re-measuring or adjusting the instrument.
EDM instruments have made distance measurements in civil engineering projects more efficient and accurate. They have reduced the time and effort required for traditional methods of measurement and have allowed for faster and more precise data collection. With continuous advancements in technology, EDM instruments are constantly improving and becoming an essential tool for civil engineers.
Error in Electronic Distance Measurement Instruments
Electronic distance measurement (EDM) instruments are vital tools used in civil engineering for accurate and efficient measurement of distances in surveying and construction works. However, like any other electronic device, they are prone to errors. These errors can lead to significant discrepancies in distance measurements and result in flawed design and construction works. Here are some of the common errors that can occur in EDM instruments.
1. Instrumental errors:
These errors occur due to the imperfections in the design and manufacturing of the EDM instrument. They can be caused by misalignment of the instrument, imperfections in the electronic components, or distortion due to changes in temperature and humidity. These errors can be reduced by using high-quality instruments and calibrating them regularly.
2. Atmospheric errors:
Atmospheric conditions such as temperature, humidity, and air pressure can affect the accuracy of EDM measurements. Changes in temperature can cause thermal expansion or contraction of the instrument, leading to distance measurement errors. Humidity can cause refraction of the laser beam, resulting in incorrect distance measurements. Air pressure variations can also affect the speed of the laser beam, leading to errors in distance measurement.
3. Human errors:
The accuracy of EDM instruments also depends on the expertise and experience of the operator. Human errors such as misalignment of the instrument, incorrect handling of the controls and settings, and misreading of the results can significantly affect the accuracy of distance measurements.
4. Target errors:
EDM instruments require a reflector target to bounce back the laser beam for distance measurement. If the target is not properly placed or maintained, it can cause measurement errors. Uneven surface or dirty targets can also lead to inaccurate distance readings.
5. Electrical interference:
EDM instruments work on electronic signals, and any external electrical interference can cause measurement errors. Sources of interference can include nearby power lines, radio and TV towers, or other electronic devices. Shielding the instrument and using it away from such sources can help reduce these errors.
To minimize the errors in EDM instruments, regular calibration and maintenance are essential. It is also crucial to use the right instrument for the specific task and to train the operators properly. Additionally, double-checking the measurements with alternative methods can help identify errors and ensure accurate results. Furthermore, keeping a record of the measurement data and cross-checking it can also help detect any discrepancies. By identifying and addressing these errors, civil engineers can ensure precise and reliable distance measurements, resulting in successful project outcomes.
In conclusion, Electronic Distance Measurement (EDM) instruments have revolutionized the field of surveying and measurement. With their advanced technology and precise measurements, they have become an essential tool for various industries such as construction, road engineering, and land surveying. The different types of EDM instruments, including Total Stations, Laser Distance Meters, and Global Navigation Satellite Systems, offer a wide range of functions and operations to cater to different needs and requirements. It is crucial to understand the principles and proper handling of these instruments to ensure accurate and efficient results. As technology continues to advance, we can expect further developments in EDM instruments, making them even more versatile and reliable for various applications.