Land surveying involves gathering information about the
positions of certain points as well as the angles and distance between them.
Through the use of certain instruments, surveyors can create maps, establish
property lines, and gather important information for architects, engineers, and
The accuracy of land surveying measurements is dependent on
the quality of the instruments used to gather the data. With the invention of
GPS technology, land surveyors are now able to make complex calculations more
quickly and accurately than ever before.
What Is GPS
and How Is It Used in Land Surveying?
GPS stands for global positioning system, and it uses signals from satellites to pinpoint
a location on the Earth’s surface. In addition to transmitting information
about location, GPS can provide data about velocity and time synchronization
for various forms of travel. GPS uses at least 24 separate satellites in a
system that consists of six Earth-centered orbital planes, each having four
Generally speaking, GPS has five key uses:
- Determining a position (location)
- Moving from one place to another (navigation)
- Monitoring the movement of a person or object
- Creating a map of an area (mapping)
- Making precise time measurements (timing)
The Global Positioning System was originally developed for
military use but has been readily available for civilian use since the 1990s.
In addition to its use in mobile devices and car navigation systems, GPS is used
for land surveying.
Surveying was one of the first commercial adaptations of GPS
technology. It can provide accurate latitudinal and longitudinal location
information regardless of weather conditions and without the need for measuring
angles and distances between points. Though GPS makes surveying possible in
nearly any location, it does have its limits.
the Best GPS Instruments for Land Surveying?
GPS survey equipment makes it possible to obtain location,
distance, and height measurements almost instantaneously – the only requirement
is that the instrument has a clear view of the sky to receive signals from GPS
satellites clearly. When used properly, GPS for land surveying offers the
highest level of accuracy and is much
faster than conventional surveying techniques.
Different types of GPS land survey equipment are used for
different purposes, though there are three methods of GPS measurement used most
often by surveyors:
– This method is used to determine the coordinates for survey
points by simultaneously recording GPS observations over both a known and
unknown survey point for at least 20 minutes. The data is then processed to
determine coordinates within 5mm accuracy.
- Real-Time Kinematic (RTK) Observations – In
this method, one receiver remains open over a known point (the Base Station)
while another receiver moves between different positions (the Rover Station).
Using a radio link, the position of the Rover Station can be calculated within
a few seconds, ensuring a similar level of accuracy to baseline measurements as
long as they are within 10km of the Base Station.
Operating Reference Stations (CORS)
– In this system, a survey grade GPS
receiver is permanently installed in a particular location as a starting point
for any GPS measurements in the area. GPS survey equipment can collect field
data and combine it with CORS data to accurately calculate positions.
Certain instruments are required for proper implementation
of GPS land surveying methods. Here is a quick summary of the most common GPS
land survey instruments:
- GPS Receiver – This instrument is required to receive signals from GPS satellites in
order to make calculations. These instruments come with a variety of optional
features such as multiple band channels, built-in Bluetooth and Wi-Fi
technology, and OLED displays.
- GPS Rover Rods – These instruments can be used to extend the rover’s reach. They can be made from a variety of durable materials and come in different
- GPS Poles – Used to mount GPS surveying equipment, these poles are typically lightweight but durable and come in different lengths.
- GPS Bipods/Tripods – For greater stability in mounting GPS
equipment, bipods and tripods come in adjustable lengths and numerous sizes.
- GPS Antennae – This piece of equipment makes it possible for GPS systems to receive signals from satellites. Many systems come with an internal antenna, but you can purchase external antennas to boost the signal.
- Total Station – A combination of an electronic theodolite, electronic distance
measuring (EDM) device, and software running on an external computer, a total
station is used to calculate the coordinates of survey points using angles and
distances. It may also incorporate GPS technology to produce more accurate
The cost of a GPS land surveying system varies depending on
the type and number of receivers you choose. A GPS receiver ranges from $4,000
to over $10,000, and the software itself
costs upwards of $400. Additional equipment such as rover rods, poles, and
tripods may increase the overall cost.
and Cons of GPS for Land Surveying
The Global Positioning System changed the world of land
surveying in many ways, most of them good. There are, however, some downsides
to this type of equipment. Here is a quick summary of the pros and cons for GPS
- It offers a higher level of accuracy than
conventional surveying methods
- Calculations are made very quickly and with a
high degree of accuracy
- GPS technology is not bound by constraints such
as visibility between stations
- Land surveyors can carry GPS components easily
for fast, accurate data collection
- Some GPS systems can communicate wireless for
real-time data delivery
- GPS land surveying equipment requires a clear
view of the sky to receive satellite signal
- Interference from dense foliage and other
structures can limit function and communication
- All GPS survey equipment is subject to failure
from dead batteries and system malfunction
- Special equipment may be required and can be costly
The world of land surveying is constantly
changing as new technology replaces old. Commercial survey equipment has made
leaps and bounds over the past few decades and, with the help of GPS
technology, will only become faster and more accurate over time.
Used properly, GPS for land surveying offers the highest level of accuracy and is much faster than conventional surveying techniques. We break down the details.