We have been talking a lot about how drones are used across industries, serving as the key to various automated processes such as mapping, spraying and so on. Precision mapping particularly has seen massive drone integration into its processes. That may be credited to the fact that the mapping accuracy is on par with the conventional land survey and reliable.

In this article, we will be looking at the mechanism behind surveying drone that has rendered it to be extremely useful in land surveying and construction industry.

Real-Time Kinematic (RTK)

RTK stands for Real-Time Kinematics which is a GPS/GNSS technique used to enhance the precision of position data received from satellite-based positioning systems. RTK is centred on the usage of fixed base points which wirelessly sends out corrections to a moving receiver to increase the accuracy of GPS signals.

The satellite and base station corrections will enable more accurate and the GPS engine can fix the position of the antenna to within 1 – 2cm. Traditional GPS receivers, like the ones you can find in your smartphone, or on most robotic platforms could only determine their position with 2-4 meters accuracy. 

Base point is actually a single GCP that constantly provides correction and calibration of the drone’s locational data. Successive GPS measurements at the base stations are paired with the GPS measurements made by the drone. This provides a mechanism for the reduction and elimination of the errors common between the two measurements. These corrections are applied real-time, requiring the drone and the base stations to communicate with each other constantly throughout the survey.

Image credit via Pix4D

Post-Processed Kinematic (PPK)

Post-Processed Kinematics or PPK is actually similar to RTK except for the fact all the corrections are done after the data collection. This means the need for base points as used in RTK processes is eliminated.

Drones that process data using RTK or PPK do not have different sets of hardware. Instead, a PPK drone merely uses a different processing workflow. Data collected by an RTK drone can be corrected using a PPK process, but it will involve a lot of customization.

Image credit via Pix4D

You should be able to understand the basic mechanism of RTK and PPK before we move on to the comparative advantages that PPK haas over RTK which we will be discussing next week!

Discover how drones are aiding the construction works tremendously by optimising time and material management.


Last week, we have discussed in-depth about the application of drones inside the agricultural field. But as I have stressed this all this time, there’s a whole lot more about drone application that can be realised through the technology advancement.

Today, we will be discussing one of the popular industrial application of drone; construction sector.

Construction sector is one of the biggest industries that is incorporating drone as one of the effective tools to aid the construction process.

Now, let’s see how exactly drone helped out through the various stages of a construction process.

Pre-Construction

A pre-construction survey is a thorough process that documents the condition of the properties adjacent to or neighbouring your construction activity through visual observations, photographs, notes, and other diagnostic devices as warranted by the complexity of the project.

The pre-construction phase is very crucial for the engineers as there are a few things that needed to be surveyed. A construction survey typically consists of determining current site conditions for future above-ground and in-ground infrastructure.

Land surveyors stake elevations for footings, collect topographic data for mapping existing drainage courses, invert elevations and diameters of pipe and manholes perform a number of other services. Land surveying services are used to establish the accurate location of proposed structures, accesses, pipelines, buildings, and other improvements.

The conventional land surveillance practice.
Image via Harbor Compliance

Land surveying method usually involves using human resources, heavy machinery & expensive surveying tools, that produce complex data. In actuality, you can get the job done in half the time & money, with greater accuracy by using drones.

Drones equipped with advanced payloads that can produce high-quality digitised map such as Digital Elevation Models (DEM), Digital Surface Models (DSM), and Digital Terrain Models (DTM).

Related: DEM, DSM & DTM Differences

These maps serve the purpose of the survey process, and in addition to site analysis, boundary & topographic surveys, maps, and plats, they also:

  • Help mitigate the risk of potential future regulatory enforcement actions
  • Minimize or eliminate costly delays in project schedules
  • Maximize project startup efficiencies through comprehensive regulatory planning
  • Provide data which helps define project scope and aids strategic pre-construction planning
A land survey using UAV
Image via Site Design Concept

During Construction

Minimising the risk and avoiding any accident is mainly the priority during the building phase, alongside materials management and quality inspection.

Drones are a lot safer to send in for inspections instead of manual inspection by the workers. Engineers and managers can identify the problems or any issues on the site via complete footage, live or recorded from the comfort of office desks.

Moreover, drones are suitable to be used for construction that is near any waterbody.  Plus, through orthomosaic map produced by the camera payload mounted on drones, can help with detecting deviations and taking early corrective action, thus reducing thousands of dollars in change orders.

Bridge inspection using UAV
Image from statescoop

Progress tracking and reporting to your client can be easier with the high reachability of drones. For example, you can track the level of the building completed simply just by deploying your drone and then comparing orthomosaics across various dates enable precise progress tracking and reporting.

A quite innovative way to use drone in construction is to examine the placement of post-tension cable. You can read more about this here: Using Drones to Reduce Risk in Concrete Construction

Post Construction

With drone, the BIM (Building Information Model) can be produced directly as it provides 360 degrees of views and insight of the building from bird-eye view.

Plus, aerial photography and videography can be a great marketing material of the property as aerial captured photos and videos are quite popular these days. Drones can reach places humans can’t, meaning you can capture a wide range of images of your building. These can be utilized in marketing collateral, on a company’s website, on social media platforms and beyond.

Drone-based method also can help in conducting after completion quality assurance process by identifying defects in the outer side of high-rise building.

On Going Asset Maintenance

Not only limited to the building construction, but also is beneficial in the long run; ie. the building maintenance and damage assessment. The data captured by a drone can be used to plan and improve long-term maintenance of the structure as well. After a project is completed, you can produce the as-built drawings and models created with the help of our drones. This detailed information makes it easier for the owner to renovate, manipulate and upgrade aspects of the facility in the future.

Drones equipped with thermal imaging can also fly over a building and detect if there are leaks in the building envelope. They can also identify areas of leak potential so owners can proactively maintain their facility before a small problem turns worse.

Drones can also help assess damage after a hurricane or any natural disaster. For example, if the roof is torn away by strong thunderstorm ; it is advisable to use a drone to safely identify the extent of the damage and plan for the proper repairs.

Bottom Line

Drone are consciously changing how we are constructing buildings and structures. Information and data that once took days to be collected can now be captured with incredible accuracy in a matter of hours — this translates into huge time and cost savings for anyone.

Like any cutting-edge technology, the research and applications of drones change continually, and we should always be exploring how we can continue to leverage their benefits moving forward.