E - How Does GPS Surveying Work

1. How Does GPS Surveying Work? If you've ever used a navigation app on your phone, you've experienced the utility of GPS. But in the world of property and infrastructure development, the technology achieves a level of precision far beyond consumer-grade location services. A professional GPS survey is now a fundamental component of modern site measurements, transforming everything from boundary mapping to large-scale construction layout. This technology allows surveyors to capture highly accurate data rapidly and efficiently, defining our physical world with centimeter-level precision. Pinpointing Your Position with Satellites At its core, a satellite positioning relies on a global network of orbiting satellites. Surveyors use specialized receivers that do two critical things: 1. Receive Signals: The receiver detects radio signals transmitted by multiple satellites (typically four or more) simultaneously. 2. Calculate Distance (Trilateration): Each satellite’s distance is measured by how long its signal takes to reach the receiver. By calculating these three-dimensional distances from several known points (the satellites), the receiver can accurately determine its precise location on Earth. This entire process is instantaneous and continuous, providing surveyors with reliable coordinate data that is tied to global reference systems. Techniques for Achieving Professional-Grade Accuracy While your phone's GPS might be accurate to a few meters, professional land surveying requires accuracy down to the millimeter. This increased precision is achieved through specialized techniques and equipment unique to the surveying industry: Real-Time Kinematic (RTK) and Differential Correction in a GPS Survey Standard GPS accuracy is subject to atmospheric interference and minor clock errors. To correct these errors in real-time, surveyors use differential correction. This often involves: Establishing a Base Station: A fixed GPS receiver is placed over a known point (a control monument) to act as a reference. Calculating Corrections: The base station measures the satellite signals and calculates the errors (the difference between the known position and the measured position). ● ●

2. Transmitting Data: These highly precise error corrections are transmitted instantly to the roving receivers (rovers) being carried by the field crew. Result: The rovers adjust their positioning data in real-time, yielding true survey-grade accuracy. ● ● Network RTK and Virtual Reference Stations (VRS) In many areas, surveyors utilize large networks of permanent base stations maintained by public or private entities. These networks eliminate the need for a surveyor to set up their own base station, relying instead on the network's processing capabilities to generate a "Virtual Reference Station" near the rover. This significantly boosts efficiency, allowing the Oklahoma surveyor to work faster and more flexibly. The Role of GPS in Modern Land Surveying Projects GPS technology is now integral to almost every type of site mapping project, providing significant benefits over older, optical methods like total stations, especially for large sites: Boundary Definition: GPS is used to locate historical boundary markers and set new property corners based on precise coordinates. Topographic Mapping: Surveyors efficiently map the contours, elevations, and features of the land, providing essential data for design and drainage analysis. Construction Layout: GPS is used for construction staking, ensuring roads, buildings, and utilities are placed precisely according to the engineered design. ALTA/NSPS Surveys: GPS provides the foundation for the rigorous coordinate data required for these complex commercial surveys. ● ● ● ● Why Expertise from a Professional is Essential While the equipment is advanced, the success of these complex measurements hinges on the skill of the professional operating it. A licensed Oklahoma Surveyor brings essential expertise that technology cannot replace. This includes: Legal Knowledge: Interpreting deeds, property law, and historical evidence to determine where boundaries should be, as GPS only measures where the receiver is. Local Regulations: Ensuring the survey is compliant with specific municipal and county codes, which vary widely across Oklahoma. Site Context: Knowing how local terrain and geological characteristics affect signal reception and overall accuracy. ● ● ●

3. Leveraging Technology for Precision At Sisemore & Associates, we understand that precision is the foundation of every successful project. We specialize in providing comprehensive surveying services, utilizing cutting-edge GPS survey equipment and advanced differential correction techniques to ensure every measurement is accurate and legally defensible. Our experienced local professionals are dedicated to delivering the clear, reliable data needed to move your project forward. Contact us today to discuss your surveying needs.