In recent years, surveying drones have completely transformed how professionals collect, process, and visualize land data. From construction to mining, and agriculture to infrastructure, the ability to generate high-accuracy 3D models using drones and photogrammetry software has made traditional methods faster, safer, and more cost-effective.

From Drone Imagery to 3D Models: How It Works

Applications of 3D Models in Surveying?

3D models generated from drone data are highly valuable across industries.

    Construction Planning: Monitor site progress and generate as-built documentation.

    Topographic Mapping: Quickly survey large areas with high resolution and accuracy.

    Mining & Quarrying: Measure stockpile volumes and site changes.

    Urban Planning: Create detailed models of buildings, roads, and terrain.

    Agriculture: Analyze terrain and water flow for better land management.

When it comes to land surveying, accuracy and efficiency aren’t just nice to have — they’re everything. Whether you’re building roads, planning a mining site, or laying railway tracks, precision in your data collection is what lays the foundation for success. Enter DGNSS (Differential Global Navigation Satellite System) and drone-based surveying — two technologies that are transforming how surveyors and civil engineers work on the ground.

In this blog, we’ll break down what DGNSS and drone surveying are, how they work together, and why industries like mining, construction, road and railway departments are shifting to these modern tools.

What is Drone Surveying?

Drone surveying uses UAVs (Unmanned Aerial Vehicles) equipped with high-resolution cameras or LiDAR sensors to capture aerial data over large areas. Instead of spending days walking the terrain with a total station, drones can cover 60 hectares in one flight — in just minutes.

Why Drones Make Sense:

• Speed: Quick data capture means faster project planning.
• Safety: No need to send people into dangerous or inaccessible areas.
• Coverage: Large areas can be surveyed in a single flight.
• Accuracy: With GNSS correction, drone data is incredibly precise.

    Fun Fact: Our Surveyaan V1 drone is a compact, sub-2kg UAV perfect for this.

How DGNSS and Drone Surveying Work Together

Who’s Using This Technology?

Surveying is built on precision. A few centimeters can make or break a boundary line, construction layout, or mining volume calculation. Traditionally, Differential GNSS (DGNS) receivers required the pole to be held perfectly vertical to ensure accuracy. But in real-world environments — uneven terrain, obstructed areas, or busy sites — that’s not always feasible.

How Does DGNSS Tilt Compensation Work?

Why Tilt Compensation Matters

Why Tilt Compensation Matters

Whether you’re a beginner or a seasoned surveyor, tilt-enabled DGNSS can improve your workflow in many environments:

• Mining: Safely survey benches and edges without going right to the edge
• Construction: Quickly map out features like corners, manholes, or rebar points
• Urban Surveying: Reach tight spots near fences, walls, or parked vehicles
• Agriculture: Handle sloped fields without worrying about pole leveling

Is Tilt Compensation Accurate?

Yes — and then some. High-quality DGNS receivers with calibrated IMUs can provide centimeter-level accuracy even when tilted up to 60°. Of course, performance depends on sensor quality, GNSS signal strength, and environmental factors — but for most professional tasks, tilt compensation is not only sufficient — it’s essential.

Tilt Is the Future of Efficient Surveying

Tilt compensation isn’t a luxury feature anymore — it’s becoming a standard expectation in professional GNSS systems. By reducing physical strain, increasing safety, and speeding up workflows, it empowers surveyors to work smarter and safer.

Tilt compensation has revolutionized field surveying by improving safety, speed, and flexibility — without sacrificing accuracy. With devices like the SurveyPod DGNSS, surveyors can now handle complex environments more confidently and efficiently.

If you’re still leveling your pole manually at every point, it might be time to experience the benefits of tilt for yourself.

This brings us to the end of the blog. I hope this article gained some knowledge for you!

Thank you for reading.

Global Navigation Satellite Systems (GNSS) like GPS, GLONASS, Galileo, and BeiDou provide essential positioning data for navigation, surveying, and autonomous systems. However, GNSS signals can be disrupted by obstacles like buildings, tunnels, or dense foliage. This is where an Inertial Measurement Unit (IMU) becomes crucial.

In this blog, we’ll explore the importance of IMU in GNSS, how it enhances accuracy, and why it’s a game-changer for high-precision applications.

Drones have become increasingly popular for recreational, commercial, and industrial purposes. However, with the rise in drone usage, regulatory bodies like the Directorate General of Civil Aviation (DGCA) in India have introduced strict guidelines to ensure safety and security. One such requirement is the Unique Identification Number (UIN) for drones.

In this blog, we’ll explore what a UIN is, why it’s necessary, and how drone operators can obtain one.

Is UIN Mandatory for All Drones?

This brings us to the end of the blog. I hope this article gained some knowledge for you!

Systematic field procedures are part of any successful DGNSS survey that guarantees that data obtained is both accurate and reliable. Whether in terms of setting up base and rover stations or the field procedures and collection of data, the same case applies — best practices ensure results are both accurate and reliable. This blog will, therefore, be focusing on some of the most fundamental practices of successful DGNSS surveying.

Rapid Static (Fast Static)

Rapid static positioning, also known as fast static positioning, is a technique in DGNSS (Differential Global Navigation Satellite System) surveys that balances the accuracy of static positioning with the efficiency of kinematic methods. It involves shorter observation times than traditional static surveys, making it suitable for projects requiring quick and precise measurements at multiple points.

Real-Time Kinematic (RTK) Surveying
Real-Time Kinematic (RTK) is a high-precision positioning technique used in DGNSS (Differential Global Navigation Satellite System) surveys. RTK provides real-time corrections to the rover receiver, enabling centimeter-level accuracy. This technique is widely used in applications requiring immediate and precise positioning, such as construction, agriculture, and topographic surveys.

Post-Processed Kinematic (PPK)
Post-Processed Kinematic (PPK) is a technique in DGNSS (Differential Global Navigation Satellite System) that provides high-precision positioning by applying differential corrections after data collection. Unlike Real-Time Kinematic (RTK), PPK does not require real-time communication between the base and rover, making it suitable for areas with poor communication infrastructure.

This brings us to the end of the blog. I hope this article gained some knowledge for you!

Thank you for reading.

In the realm of precision navigation and positioning, Differential GNSS (DGNSS) often emerges as a critical yet misunderstood technology. Despite its pivotal role in enhancing GPS accuracy, several myths persist, clouding its true value. Today, let’s discuss some common misconception in the survey world related to DGNSS (or DGPS).

There are a total of 120 operational satellites: GPS (31), Galileo (24), GLONASS (24), BeiDou (30), NavIC (7), and QZSS (4). These satellites are distributed across the orbital plane and are not all visible from a particular point on Earth.

What is an Elevation Mask?

An elevation mask is a threshold angle that defines the minimum elevation above the horizon that a satellite must have to be considered in the positioning calculations of a DGNSS receiver. The purpose of this mask is to filter out low-angle satellite signals that are more likely to be degraded by atmospheric interference, multipath effects, and obstructions.

What value to keep for Elevation Mask?

It is recommended to set the Elevation Mask to 15 degrees to use only high-quality satellites for positioning. However, even with an Elevation Mask set to 5 degrees, you wouldn’t be able to see even half of the satellites simultaneously.

How many satellites with Elevation Mask as 5 degrees?

With an Elevation Mask of 5 degrees, you would only be able to track a maximum of 14 GPS, 6 Galileo, 6 GLONASS, 11 BeiDou, and 4 QZSS satellites. Out of the 7 NavIC satellites, only 5 are operational, and many companies do not support NavIC.

So how many Channels?

Now, let’s talk about channels. The L1 and L2 bands require only one channel each, whereas the L5 band requires two channels. Interestingly, out of the 120 satellites, only 40–45 have L5 bands.

Here’s the mathematical calculation with a 5-degree Elevation Mask (in general, if you set it to 15 degrees, which is the industry standard, the number would be lower):

Total satellites being used: 14 (GPS) + 6 (Galileo) + 6 (GLONASS) + 11 (BeiDou) + 4 (QZSS) + 5 (NavIC) = 46 satellites. Not all of these would have L5 bands; let’s assume 20 do.

So, the total number of channels required would be: 46*1 (L1) + 46*1 (L2) + 20*2 (L5) = 132 channels. In reality, this is still an exaggerated number. In the real world, no more than 100 channels are typically required. Claims of needing 400, 800, or even 1200 channels are overly futuristic and marketing/selling strategy. It will take more than 10–15 years to even approach the utilization of 300 channels.

Does All Satellites Used in DGNSS Provide the Same Level of Accuracy?

The accuracy of signals from GNSS satellites can vary due to several factors, including the satellite’s position, health, and atmospheric conditions affecting the signal’s travel to Earth. Differential GNSS (DGNSS) enhances overall accuracy by correcting these variable errors. However, the effectiveness of DGNSS corrections is influenced by the quality of the correction data, which depends on the proximity and condition of the reference station, as well as the quality of the communication link between the reference station and the DGNSS receiver. Therefore, it is crucial to closely examine the quality of the satellites being used for positioning.

Thank you for reading.

From the reconstruction of ancient artifacts and archaeological sites to enhancing urban planning and disaster response, photogrammetry offers a novel approach to understanding our world.

In this blog series, we will embark on a captivating journey through the realm of photogrammetry and its outputs.

Photogrammetry is a technique used to measure and map physical objects or environments using photographs. It combines the principles of photography and geometry to create accurate 3D models or measurements from 2D images. Photogrammetry is used in the military, construction, land surveying, real estate, etc.

Through the process of photogrammetry, multiple images of an object or scene are captured from different angles or viewpoints. These images are then analyzed and matched to extract precise measurements, shapes, textures, and even colors. The software algorithms used in photogrammetry can reconstruct the 3D structure of the object based on the visual information provided by the images.

With the help of a Worldfile we can also import an orthomosaic into AUTOCAD and georeference it with the help of the GEOREFIMG AutoCAD command.

• Worldfile: It is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images.
  

• JPEG: JPEG is a common image format and orthomosaic maps can be saved as high-quality JPEG files. While they are more accessible for visualization, they may lack the georeferencing information that GeoTIFF provides.

• PDF (Portable Document Format): Orthomosaic maps can be exported as PDFs for easy sharing and printing. However, like JPEG, they may not contain geospatial data.

I have used Surveyaan Geoworkspace photogrammetry software to create the orthomosaic and its formats.

The possibilities of orthomosaic mapping are limitless, and as technology continues to advance, we can expect even greater achievements and innovations.

The Projected Coordinate System helps you to project a specific round-earth model onto a flat surface or map. PCS are created by projecting the 3D GCS onto a 2D surface. The projected coordinate system tells the data on how to draw on a flat surface. There are many different map projections, and each displays the earth differently. Some are good for preserving areas on your map, others for keeping angles or distances.

The Projected coordinate system place points on 2-dimensional projections rather than using degrees to represent points on a spheroid. These coordinate systems frequently express the x and y coordinates for particular points using measurements in feet or meters. The benefits of these systems include easy-to-express and understand coordinates and more short distance and area calculations due to constant lengths and angles across the projection. Examples of projected coordinate systems include Universal Transverse Mercator (UTM), State Plane Coordinate System (SPCS), and Lambert Conformal Conic.

Converting from 3d to flat surfaces may cause distortions.

Depending on the projection used, different spatial properties will appear distorted. Projections are designed to minimize the distortion of one or two of the data’s characteristics, yet the distance, area, shape, direction, or a combination of these properties might not be accurate representations of the data that is being modeled. There are several types of projections available.

As you can see from the figure, India is covered by six UTM zones to minimize distortion. The zones are UTM 42N, UTM 43N, UTM 44N, UTM 45, UTM 46N, and UTM 47N. The N after the zone means that the UTM zones are north of the equator.

For example, the location of the Taj Mahal is 27°10' 30.36"N and 78 2' 31.56"E in Geographic Coordinate System. After converting it to the Projected Coordinate System, we get UTM zone no 44 and zone letter R, and the grid position is 206910.89 m Easting, 3009286.62 m Northing.