Surveyaan: Drone Survey & Mapping Solutions - Blog #Indian Bureau of Mines

How DGNSS and Drone Surveying are Revolutionizing Land Surveying and Mining Industry

Wed, 02 Jul 2025 10:44:52 +0000

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 DGNSS & Why Does It Matter for Drone Surveys?

DGNSS = Differential GNSS (Global Navigation Satellite System)

Unlike standard GPS (which can have 5–10m errors), DGNSS corrects satellite signals using:
A base station (on a known coordinate)
A rover (drone/RTK receiver)
This brings accuracy down to 1–2 cm — critical for engineering-grade surveys.

Two Flavors of DGNSS:

RTK (Real-Time Kinematic) — Corrections sent live to the drone (best for real-time mapping).

PPK (Post-Processed Kinematic) — Data corrected later using software (more reliable in areas with poor connectivity).

Fun Fact: Our SurveyPod DGNSS supports both RTK & PPK, so you’re covered in any terrain.

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

Here’s where it gets interesting. Drone surveying becomes exponentially more powerful when paired with DGNSS. With a GNSS base station providing corrections, you can geo-tag aerial images with high-accuracy coordinates, enabling:

Accurate orthomosaic/orthophotos, dsm/dtm, point clouds
Precise 3D and 2D models
Reliable contour and elevation data

For instance, in a road widening project, you could:

Use Surveyaan V1/Surveyaan V1+ to capture the entire stretch of land.
Use Surveypod DGNSS to place accurate Ground Control Points (GCPs).
Process everything in a cloud photogrammetry tool like Surveyaan Geoworkspace for instant outputs.

Who’s Using This Technology?

Industries already adopting UAVs + DGNSS surveys include:

Civil engineers & Surveyors: For land survey, topographic surveys, aerial maps and more.
Mining departments: For volume calculations, pit mapping, and safety monitoring.
Highway & Road departments: For route alignment, site inspection, and project monitoring.
Railway departments: For corridor mapping and encroachment analysis.
Infrastructure companies: For project planning, reporting, and audit documentation.

In a world where projects are bigger, timelines are tighter, and accuracy is non-negotiable, DGNSS and Drone surveying are not just buzzwords — they’re becoming the new standard. Whether you’re surveying a quarry, planning a bridge, or laying down a new railway line, combining these two technologies can save time, cut costs, and boost reliability

If you’re curious to explore how modern tools can help your team, check out our Surveypod DGNSS receiver and Surveyaan V1 drone — designed and built for real-world survey professionals like you.

Photogrammetry Output - Orthomosaic

Tue, 09 Jan 2024 06:50:54 +0000

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.

In this blog, we’ll take a closer look at orthomosaics, how they are created, and their wide-ranging applications across diverse range of fields.

Orthomosaic map is revolutionizing the field of aerial imagery and mapping applications. They are often referred to simply as orthomosaics and are created by combining remote sensing techniques with advanced photogrammetry algorithms. Orthomosaic images can be generated from overlapping aerial photographs(orthophotos). It allows us to take a bird’s-eye view of the world, capturing vast landscapes with an unprecedented level of detail and accuracy.

Applications

Mining: Orthomosaic maps are used in the mining industry for monitoring mine sites, managing stockpiles and prevent enroachment.
Agriculture: Precision agriculture relies on orthomosaics for crop monitoring, disease detection, and yield estimation.
Urban Planning: Orthomosaics are used for urban development and infrastructure planning, including land use zoning, road design, and utility mapping.
Construction: Monitoring construction progress, evaluating structural integrity, and analyzing terrain.
Corridor Mapping: Inspecting tracks and roads, planning and monitoring, plotting elevation changes.
Archaeology: Discovering and documenting ancient sites, burial mounds, and historical landscapes.

Different Formats of Orthomosaic Map

Orthomosaic maps can be generated in various formats to cater to specific needs and applications. These formats offer different levels of detail, precision, and accessibility. Here are some common formats in which orthomosaic maps are available:

GeoTIFF (Georeferenced Tagged Image File Format): GeoTIFF is one of the most widely used formats for orthomosaic maps. It combines image data with geospatial information, allowing it to be precisely located on the Earth’s surface. This format is compatible with various Geographic Information System (GIS) software and is suitable for many geospatial applications.

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.

IBM Drone Survey SOP March 2023 Updated

Mon, 08 Jan 2024 07:01:45 +0000

The Government has updated the Standard Operating Procedures (SOP) for drone surveys and submission of Digital Aerial Images of Mining areas to the Indian Bureau of Mines. Let’s see what has been updated under the new SOP.

IBM has updated the Ground Control Points. With a certified DGPS instrument, the mine should establish at least 5 GCP per sq km of the lease area. An example is also provided to aid comprehension. If the leased area is 478 ha, a minimum of 24 GCPs, including three permanent GCPs, should be placed within the leased area.

The updated SOP has also given more comprehension of the leased area covered with thick canopies. It is not possible to place GCPs in areas filled with dense canopies within the leased area. In such leased areas with dense canopy parts, GCPs can be reduced proportionally and distributed well in the remaining parts of the leased area. E.g., If 200 ha of the 478 ha lease area is covered with a thick canopy, then 14 GCPs, including three permanent GCPs, must be established in the remaining 278 ha.

The figure above shows a leased boundary containing part of a canopy. It is not possible to place GCPs in areas filled with dense canopies. So here, the GCPs are distributed well in the remaining parts of the leased boundary.

The data outputs needed to be provided to IBM by the lessee have also been updated. The updated data outputs are discussed one below the other.

The Orthomosaic image should include a buffer zone of 100m, and it should be a single image.The spatia resolution of the image has also been defined, which should be less than or equal to 5 cm in UTM Projected Coordinate System and in Geotiff format.

The previous SOP only mentioned submitting the Digital Elevation Model (3D), i.e., Digital Surface Model and Digital Terrain Model. In the new updated SOP, it has been made clear that the Digital Elevation Model (3D), i.e., Digital Surface Model and Digital Terrain Model, should include the 100m buffer zone. The spatial resolution of the image has also been defined, which should be less than or equal to 15cm in UTM Projected Coordinate System and in Geotiff format.

Compared with the Previous SOP, the new updated SOP clearly defines the GCPs that must be submitted to IBM. The new updated SOP has divided the GCPs that must be submitted to IBM into three files.

The total GCPs DGPS Survey data, including permanent GCPs, must be submitted to IBM in GCS WGS-84 datum and UTM Projected Coordinate System in Excel Format.
The Permanent GCP data needs to be submitted to IBM both in GCS WGS-84 datum, and UTM Projected Coordinate System in Excel Format.
The plan of GCPs needs to be submitted to IBM in UTM Projected Coordinate System in shapefile format.

In the new SOP, submitting the RMSE report in .txt, .doc, and .pdf format has been mandatory. Earlier, the RMSE report needed to be submitted only in .txt and .doc format.
There are also major updates in the map of the mining lease area. More features have been added to the map that needs to be marked in the map before submitting it to IBM. The updated features are listed below.

1. ML Boundary
2. Topsoil stack
3. Infrastructure
4. Roads
5. Railways
6. Tailing Pond
7. Effluent Treatment Plant
8. Mineral Separation Plant
9. Township Area
10. Others to specify (Green Belt area)

The data should be submitted in the UTM Projected Coordinate System in the shapefile format in polygon geometry along with the associated files. The above-mentioned applicable land use data needs to be provided in a single shape file with proper nomenclature of features in the attribute data of the shape file.

In the previous SOP, the Boundary Pillar coordinates must be submitted in the shapefile and Excel format in Geographic Coordinate System and Projected Coordinate System. In the new updated SOP, the boundary pillar coordinates must be submitted in Excel format in GCS and UTM. Also, a plan of the leased boundary pillar coordinates also needs to be submitted in UTM and GCS in WGS 84 datum. Although here, two separate shapefiles for GCS and UTM must be submitted.

Finally, As per the previous SOP, the Drone Survey Log Sheet needed to be submitted only in the .doc format, while in the new updated SOP, it has been made clear that the drone survey log sheet needs to be submitted both in .doc and pdf format.

As per the updated SOP, the processed output data must also be submitted to the State Governments. It had to be submitted to the Chief Mining Geologist and the Respective Regional Offices of IBM earlier.

IBM Drone Survey SOP — Output Data Submission

Mon, 08 Jan 2024 06:29:59 +0000

Standard Operating Procedure (SOP) addresses guidelines for the drone pilot to follow during flight, pre-flight and post-flight procedures to ensure the highest degree of safety. Each lessee must provide IBM with the data output for the previous financial year.

10. Data Output and Formats

The outputs that need to be submitted are discussed below:

Orthomosaic

Orthomosaic is a large, high-resolution map-quality image that combines many smaller images called orthophotos. Submitting the orthomosaic image of the leased boundary to IBM is mandatory. As a reminder, the orthomosaic of the leased boundary should also incorporate a 100m buffer zone. The buffer zone is included to monitor the environmental impact and ascertain any excavation therein. The data should be submitted in a GEOTIFF format.

The figure above shows the Orthomosaic map in Geotiff format.

Make sure the Ground Sample Distance (GSD) is less than 5 cm per pixel or 5cm per pixel.

GSD is the distance between the centers of two successive pixels on your map, measured in inches, centimeters, or millimeters. A drone can measure with a GSD of 5 cm/px, meaning that each pixel on your digital map represents 5 centimeters of actual space in the real world.

Digital Elevation Model (3D) — DSM & DTM

The Digital Elevation Model is a 3D representation of the terrain elevations on the earth’s surface.

The Digital Terrain Model is a subset of DEM and consists of the earth’s surface and excludes buildings, trees, etc.

The Digital Surface Model is a subset of DEM and consists of the earth’s surface, including all objects like buildings, trees, etc.

While submitting to IBM, ensure the DSM and DTM are in GeoTif format.

The Figure above shows the Digital Surface Model and Digital Terrain Model in GeoTif format.

The resolution of the Digital Elevation Model (DEM) should be 15 cm per pixel or better.

Ground Control Points

Ground Control Points (GCPs) are the points on the earth’s surface that help georeference raster data such as satellite, aerial, or drone imagery. The GCP data should be submitted to IBM in shapefile and Excel format.

The figure above is an Orthomosaic image in GeoTif format. The red points are the Ground Control Points overlaid on the orthomosaic file in shapefile (SHP) format.

The figure above shows the GCP data in Comma Separated Value (CSV) format.

RMSE Report

RMSE is used to measure the difference between 2 values or datasets. Here, the first dataset is the error value obtained from the GCP points in the ground, and the second dataset is the error value obtained after processing in the Photogrammetry Software. With the help of any Photogrammetry Software, we can get a detailed GCP report. I have generated the report using Surveyaan Geoworkspace. The RMSE report should be submitted to IBM either in .txt or in .doc format.

From the figure above, we can view the GCP report in .doc format.

Map

The lessee should submit the map of the mining lease to IBM showing area of;

a) actual excavation (mineral and waste)

b) Mineral storage

c) Subgrade dump

d) Waste dump

e) Afforestation

f) Backfilled, reclaimed, and rehabilitated area

within the lease for the preceding financial year. The data should be submitted in the UTM Projected Coordinate system in shp format.

In the figure above, the black shape shows the waste dump, and the blue shape shows the reclaimed area. Both are in Shapefile (shp) format and in UTM Projected Coordinate System.

In the figure above, the area is calculated from the Surveyaan Geoworkspace using the Area tool in the Measurement Tools. The measurements are then saved with a suitable name. The shapefiles are then generated then using the DXF SHP export button.

Boundary Pillar

It helps in identifying the mining boundary and also helps to prevent encroachment. Unique identification numbers also mark the pillars. With the help of the DGPS, the coordinates of the pillars are noted. The Boundary pillar data should be submitted to IBM in shapefile (shp) and Excel.

In the figure above, the red points show the boundary pillars’ position. Here the points are in shapefile (shp) format and are in UTM Projected Coordinate System.

In the figure above, the red points show the boundary pillars’ position. Here the points are in shapefile (shp) format and are in Geographic Coordinate System.

Drone Survey Log Sheet

The drone survey log sheet consists of general checking fields like the airspace map, wind speed, cloudiness etc. It also contains the flight log where information on each flight including the date, place and time of operation are recorded. The drone survey log sheet should be submitted to IBM in .doc format.

The figure above, is kind of a General Log Sheet and IBM has not defined any standard format for it.

11. Submission of Data to IBM

The processed output data of the drone survey shall be submitted in soft copy only in storage media (i.e., external hard disk) on or before 1st July every year along with the Output data submission form at the following addresses.
The Chief Mining Geologist, Indian Bureau of Mines, GM&MM Cell, 1st Floor, A- Block Indira Bhavan, Civil Lines, Nagpur- 440001, Maharashtra
Respective Regional Offices Indian Bureau of Mines

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