GPS is an accurate navigation system that has been utilized in surveying practices. This technology uses signals from satellites to determine geospatial location. Thanks to the introduction of GPS technology, it’s easier to calculate latitude and longitude positions in an accurate manner.
As experts in land surveying, we’re here to explain the GPS surveying basics. This blog is about the three main methods of GPS measurement utilized by professional surveyors.
Static GPS Baseline
This surveying technique is used to determine coordinates for survey points. Although this static GPS baseline is considered basic, it produces highly accurate data for land surveying.
In this method, two stationary GPS receivers are simultaneously tracking the same satellites. These receivers collect GPS observations for at least 20 minutes.
Once done, the GPS data is transferred to software for processing. This special type of GPS software is utilized to calculate the difference in position between the two receivers. After processing, land surveyors can get coordinates within 5mm accuracy. Static GPS baseline measurements are great for long distances. Using this technique, a 30-kilometer distance can be measured with about 30 mm of uncertainty.
Real-Time Kinematic (RTK) Observations
Similar to the GPS baseline method, RTK observations use two receivers. It has a static base station and a second receiver to measure coordinates. In this method, two receivers are placed at each end of the property. The first receiver (base station) stays stationary, while the other one (rover station) moves between multiple points in quick succession.
The position of the rover station is calculated and stored within a few seconds. The data will be transferred to GPS software and used as survey data. Like baseline measurements, RTK ensures high accuracy within 10km of the base station.
The RTK positioning is typically used in land surveys and navigation of unmanned aerial vehicles (UAV). This method gathers real-time survey data for smaller areas.
Continuously Operating Reference Stations (CORS)
A CORS-based system is a network of GNSS receivers and antennas that are permanently installed. These components can be distributed anywhere in your local area. With CORS, professional surveyors can collect data without setting up base stations. They simply need to obtain data from the receivers, which are sent to GPS software.
All the geospatial data from CORS are used by surveyors to calculate positions and fix errors. When your surveyor uses multiple CORS, more accurate results can be achieved. Aside from land surveys, CORS is used for mining sites, major engineering projects, and local government projects. CORS systems are used in some countries to deliver data over the internet and collect field data.
GPS Surveying Instruments
Professional land surveyors use a variety of instruments to make precise measurements. With GPS survey equipment, it’s a lot easier to obtain location and distance accurately. Here are some of the commonly used surveying tools and equipment:
Theodolite – measures horizontal and vertical angles between points
Total Station – records the coordinates of the survey points by measuring angles and distances
GPS Receiver – receives and converts data from satellites into geographical position
GPS Rover Rods – serves as an accessory for GPS applications that help extend the rover’s range
GPS Poles – helps surveyors produce precise and accurate results
GPS Bipods or Tripods – allows you to easily clamp or set up your GPS poles into place
GPS Antennae – helps you obtain more signal strength for your survey data gathering—even in bad weather and environment
Differential GPS – provides improved location accuracy by eliminating errors and sending corrections/discrepancies
Electronic Distance Meter – determines the length between two points using electromagnetic waves (distances of up to 100 kilometers)
Key Takeaway
The surveying industry has changed over the years—thanks to technology. With the help of GPS technology, measurements and calculations are now done quickly and accurately. Land surveying is a highly technical process that should be done by certified professionals.
At Pittsburgh Land Surveyors, we work on residential and commercial surveying projects. Our team offers ALTA surveys, flood elevation certification surveys, mortgage surveys, and so much more. No matter what service you need, we ensure that our survey reports are highly accurate, detailed, and affordable. Let’s prove to you that we survey the extra mile.
Contact us today to schedule an appointment with us. We look forward to working on your next land survey project!
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