Understanding GPS Technology
The Global Positioning System, or GPS as it is commonly known, is a satellite-based navigation system comprised of a network of satellites placed into orbit by the U.S. Department of Defense. GPS works in any weather conditions, anywhere in the world, 24 hours a day, without the need for any subscription fees or setup charges. The U.S. government maintains the system, and it’s available to anyone with a GPS receiver.
Functioning of GPS
GPS operates by sending signals from satellites to receivers on the ground. When a GPS receiver gets a call from a satellite, it calculates the distance to that satellite based on the time it took for the signal to reach the receiver. The GPS receiver can pinpoint its location on Earth by combining data from several satellites.
The Application of GPS in Surveying
Surveying is the science of determining points’ terrestrial or three-dimensional position and the distances and angles between them. Traditionally, surveying involved a lot of manual labour, long hours of fieldwork, and cumbersome calculations. However, with the advent of GPS, the surveying industry has seen a revolution in precision and efficiency.
Precise Location Determination
GPS in surveying is the precise determination of locations. Each point on a landmass can be defined by three values: latitude, longitude, and elevation. In the past, these measurements required complex calculations and specialised equipment. Thanks to GPS, these measurements can now be obtained with unparalleled precision.
Time-Efficiency
Another significant benefit of GPS in surveying is its time efficiency. Unlike traditional surveying methods that require laborious measurements and calculations, GPS can quickly provide the necessary information. This can significantly reduce the time taken for large surveying projects, thus enhancing productivity and reducing costs.
Accessibility and Reach
GPS has also made reaching previously tricky or impossible areas to survey GPS equipment easier due to their location. Whether it’s the top of a mountain or the middle of a desert, as long as the GPS receiver can connect to the satellites, it can determine its location. This ability has expanded the scope and accessibility of surveying projects.
The Evolution of GPS in Surveying
As with any technology, GPS in surveying has evolved over the years. Today’s systems offer enhanced precision, flexibility, and user-friendliness that were unimaginable when GPS was first introduced.
Real-Time Kinematic (RTK) GPS
RTK GPS is a technique used in land surveying based on measurements of the phase of the signal’s carrier wave. This method enables real-time corrections, improving the precision of position data derived from satellite-based positioning systems, making it a preferred choice for precision surveying.
Static and Fast Static GPS Surveying
Static GPS surveying is an absolute positioning method requiring two receivers placed simultaneously at two points. The data collected from the receivers is then processed to get the precise coordinates. Fast static is a similar method but requires less observation time and can work in areas with shorter satellite visibility.
Challenges and Limitations of GPS in Surveying
Despite the numerous benefits and continuous evolution, GPS in surveying has challenges and limitations.
Signal Interference and Multipath Errors
One of the main issues is signal interference. Tall buildings, dense forests, or even atmospheric conditions can obstruct the signals from the satellites, causing a delay in the transmission and leading to errors in positioning. Multipath errors, where the GPS signals are reflected off a surface before reaching the receiver, can also lead to inaccuracies.
Dependence on Satellite Availability
The accuracy of a GPS survey largely depends on the availability of satellites. If only a few satellites are visible to the receiver, it may need more data to determine the precise location.
The Future of GPS in Surveying
Despite its challenges, the role of GPS in surveying is poised to grow in the future, thanks to advancements in technology and an increased understanding of its potential.
Integration with Other Technologies
One promising trend is the integration of GPS with other technologies, such as Geographic Information Systems (GIS) and drone technology. This combination allows surveyors to gather and analyse real-time geographic data and produce high-quality, detailed maps and models.
Improvement in Accuracy
Improvements in technology will continue to enhance the accuracy of GPS in surveying. Techniques such as Differential GPS (DGPS), which uses a network of fixed ground-based reference stations to broadcast the difference between the positions indicated by the GPS satellites and the known fixed positions, are already making GPS more accurate.
Conclusion
The introduction of GPS revolutionised the field of surveying. It has enhanced precision, increased efficiency, and expanded the scope of surveying. Despite challenges and limitations, GPS is promising.
