Customers and trainees often ask us about the differences between using a GNSS Rover and a Total Station. Each has particular pros and cons which can be utilized in various situations. So how do you know which instrument is the best choice for you?
Choosing between a Robotic Total Station and a GNSS Rover
The main difference in total station and the GNSS rover is that the total station depends on your input for its location and orientation while the GNSS rover has a location and orientation from a series of satellite constellations. Both are highly advantageous if used in their correct environment.
For example, if you are carrying out a topographic survey a GNSS rover has more advantages. The speed of carrying around the GNSS Rover and recording points as well as the speed of setup far outweighs that of the Total station. No need to worry about line of sight or station set up. Its accuracy is going to be close to between 10mm and 20 mm in horizontal and vertical and more than enough for this task.
Using a 1-man total station is possible but you will need clear line of sight to every point on the site and you will also need control stations to survey in its correct location and orientation.
With a total station you can survey or stake out from your own local coordinates, but they will not be georeferenced unless you use ITM or Irish Grid coordinates (Ireland).
Setting out with high accuracy required
If holding down bolts are being installed for a structural steel building, the 1-man robotic total station is the only surveying tool that should be used. Brickwork, formwork, and façade elements should only be set out with a Total station.
Setting out where accuracy is less than 25mm
For housing estates, the GNSS rover can be used to set out foundations and roadways, manholes and kerb lines and boundary walls.
Static survey for house set out
This method can be used over a longer time to reduce errors and get a higher accuracy. Houses can also be set out but must be checked with the 6-point check with measuring tapes for square and accuracy.
The 6-point check consists of the 2 side dimensions the front and back dimensions and the 2 diagonal dimensions. These dimensions can be found on X-PAD surveying software through the Info tab with your choice of 2 points.
5 Advantages a Robotic Total station has over GNSS Rover
- Higher accuracy +/-1-2mm
- Can work better under trees, close to buildings & indoors*
- Does not require subscriptions to any network (annual subscriptions)
- Works better in urban areas.
- You are not depending on connection to network or GSM Signal for corrections
5 Advantages a GNSS Rover has over a Robotic Total Station
- Works straight away in the field without stationing the instrument- has position from network and satellite constellations.
- For land surveying, there is not limit on area that can be surveyed, and the survey can be completed faster than with a total station.
- Does not require line of sight from the instrument to record a point just no obstructions overhead.
- Units are cheaper to buy and can adapt better to harsh conditions.
- Don’t have to worry about setting up an instrument and being knocked over, the flexibility of carrying around the GNSS rover leaves surveying and staking out a lot handier and time friendly.
In general, it will depend on the time, money, man power, and expertise you have available when deciding on the right tool for your job. You need to consider all of these before you make your final decision.
*Today’s GPS receivers typically track all the major satellite constellations—GPS, GLONASS, Galileo and Beidou—and are referred to as “GNSS receivers”. Because they are tracking more satellite constellations, GNSS receivers can provide better coverage and performance even in tough environments—near buildings, under tree canopy or in deep cuttings or mines.
If you need help picking the right tools for your next project, feel free to get in touch with us. Call 01 257 2323 or email email@example.com today to arrange a free consultation or schedule a demo.