Surveyaan: Drone Survey & Mapping Solutions - Blog , UncategorizedSurveyaan: Drone Survey & Mapping Solutions - Blog , Uncategorizedhttps://www.surveyaan.com/blogs/UncategorizedFri, 13 Mar 2026 05:07:12 +0530http://zoho.com/sites/<![CDATA[Mastering Tilt Compensation in DGNSS: Why It’s a Must-Know for Today’s Surveyors]]>https://www.surveyaan.com/blogs/post/mastering-tilt-compensation-in-dgnss-why-it-s-a-must-know-for-today-s-surveyors

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.

The Traditional Challenge
​Traditionally, achieving high accuracy with GNSS required meticulous leveling of the receiver pole. Any deviation from vertical introduced errors in the measured horizontal position. Surveyors had to constantly adjust the pole using levels and tripods, which could be slow and frustrating, particularly when:
    1. Working on uneven ground.
    2. Measuring points in hard-to-reach locations like building corners or under obstructions.
    3. Conducting large-scale surveys requiring numerous measurements.
This need for constant leveling not only reduced productivity but also increased the physical strain on surveyors.

What Is DGNSS Tilt Compensation?

Tilt compensation allows a GNSS receiver to accurately record positions even when the pole is not held vertically. This is made possible by integrating sensors like IMUs (Inertial Measurement Units) into the receiver, which calculate the tilt angle and correct the final coordinate accordingly.


Instead of worrying about bubble levels or perfect posture, the system does the math for you — making your workflow faster, easier, and safer.

How Does DGNSS Tilt Compensation Work?

When tilt compensation is enabled, the DGNSS receiver continuously monitors its tilt angle and direction. Combined with the GNSS positioning data and the known height of the pole, the system uses trigonometric calculations to determine the true horizontal position of the point being measured. This eliminates the need for the user to meticulously level the pole for each measurement, significantly increasing efficiency and ease of use.

Why Tilt Compensation Matters

  1. Faster Surveys: No need to spend time leveling the pole before every measurement. Tilt-compensated receivers allow for faster point collection, especially in high-volume or rugged environments. Measurements can be taken much faster as there is no need to level the pole precisely. Some manufacturers claim up to a 20% increase in point measurement efficiency and a 30% improvement in stakeout productivity.
  2. Safer Data Collection: In areas like open-pit mines or construction sites, it’s not always safe or practical to reach the exact location of a point. Tilt compensation enables surveyors to collect data from a safe distance while maintaining accuracy.
  3. Improved Accuracy on Slopes and Obstacles: Surveying in sloped or obstructed areas is much easier with tilt compensation, reducing both human error and the time spent re-collecting points.
  4. Reduced Fatigue: The physical strain of trying to keep the pole perfectly vertical for extended periods is reduced.
  5. Calibration-Free Options: Some advanced systems with IMUs offer calibration-free tilt compensation, making them ready to use immediately.

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.


About SurveyGyaan

SurveyGyaan is an educational initiative under the Surveyaan brand, which is a subsidiary of Nibrus Technologies Private Limited. Surveypod specializes in DGNSS/DGPS manufacturing in INDIA.

Surveypod: www.surveypod.in


Surveyaan: www.surveyaan.com

]]>Wed, 02 Jul 2025 10:44:52 +0000<![CDATA[How DGNSS and Drone Surveying are Revolutionizing Land Surveying and Mining Industry]]>https://www.surveyaan.com/blogs/post/How-DGNSS-and-Drone-Surveying-are-Revolutionizing-Land-Surveying-and-Mining-Industry

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:

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.

]]>Wed, 02 Jul 2025 10:44:52 +0000<![CDATA[The Importance of IMU in GNSS: Enhancing Accuracy Reliability]]>https://www.surveyaan.com/blogs/post/the-importance-of-imu-in-gnss-enhancing-accuracy-and-reliabilityIn 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.]]>

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.

What is an IMU?

An Inertial Measurement Unit (IMU) is an electronic device that measures acceleration, angular rate, and sometimes magnetic field using a combination of accelerometers, gyroscopes, and magnetometers.


Key Components of an IMU:

  1. Accelerometers — Measure linear acceleration.
  2. Gyroscopes — Measure angular velocity (rotation).
  3. Magnetometers (optional) — Detect Earth’s magnetic field for heading reference.

IMU + GNSS: A Powerful Combination

GNSS provides accurate absolute positioning by triangulating signals from satellites. However, it has limitations, such as:

        Signal loss in urban canyons, forests, or tunnels

        Latency and lags in fast-moving environments

        Susceptibility to multipath errors

By integrating an IMU, GNSS receivers gain inertial data, which helps:

  1. Bridge signal gaps when satellites are temporarily lost
  2. Maintain positioning accuracy during high dynamic motion
  3. Provide smooth and continuous data streams even in GNSS-denied environments

Key Benefits of IMU in GNSS Systems


1. Improved Accuracy and Reliability : When GNSS signals degrade or drop, the IMU keeps tracking the position through dead reckoning, minimizing errors in output data. This is vital in drone surveying and autonomous systems. 

2.Real-Time Orientation and Attitude : IMU provides pitch, roll, and yaw data — crucial for accurate georeferencing of aerial imagery, especially in photogrammetry and LiDAR missions.

3. Integrated RTK : Real Time Kinematic (RTK) is a technique that uses a reference station (base) to provide corrections to the GNSS receiver, resulting in sub-centimeter level accuracy. Many GNSS IMU systems have integrated RTK capabilities, allowing for even higher accuracy navigation solutions.

4. Enhanced Mapping Precision : In applications like corridor mapping, road surveys, or construction monitoring, IMU ensures accurate heading and tilt correction, resulting in cleaner, more precise data.

Disadvantages of IMUs


The following are some of the disadvantages of IMUs:


1. It can drift over time : The accuracy of IMU measurements can degrade over time due to drift, which means that the IMU may slowly lose its ability to accurately measure the object’s orientation, velocity, and acceleration.

2.They are susceptible to noise : IMU measurements can also be affected by noise. This noise can come from various sources, such as vibrations, electromagnetic interference, and temperature changes.

3. Require calibration : IMUs typically require calibration to ensure that they are providing accurate measurements. This calibration process can be time-consuming and complex.

Applications Benefiting from GNSS + IMU Integration


1. Drone Mapping & Aerial Surveying : Ensures accurate image geotagging and stable flight control.

2.Mobile Mapping Systems : For land-based vehicles mapping roads or railways.

3. Autonomous Vehicles : Essential for navigation without full GNSS visibility.

4. Agriculture & Mining: Enables reliable operation in harsh and obstructed environments.

5. Marine Navigation : Stabilizes heading and pitch in wave-affected areas.


The integration of IMU with GNSS is critical for high-precision, reliable, and continuous positioning in dynamic and signal-challenged environments. Whether for autonomous systems, drones, or surveying, an IMU ensures that navigation remains accurate even when satellite signals are unavailable.


For industries requiring uninterrupted and precise positioning, a GNSS + IMU solution is indispensable.


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


Thank you for reading.


About SurveyGyaan


SurveyGyaan is an educational initiative under the Surveyaan brand, which is a subsidiary of Nibrus Technologies Private Limited. Surveyaan specializes in drone manufacturing and the development of photogrammetry software.


Surveypod: www.surveypod.in (DGNSS Manufacturer Website)


Surveyaan: www.surveyaan.com (Drone Manufacturer Website)


Surveyaan Geoworkspace: app.surveyaan.com (Cloud Photogrammetry Software Website)


]]>Wed, 30 Apr 2025 11:17:09 +0000<![CDATA[How to apply UIN for Drones? A Complete Guide for Indian Drone Operators and Manufacturers]]>https://www.surveyaan.com/blogs/post/how-to-apply-uin-for-drones-a-complete-guide-for-indian-drone-operators-and-manufacturersLearn everything you need to know about obtaining a Unique Identification Number (UIN) for drones in India. This step-by-step guide covers drone categories, DGCA regulations, eligibility, application process via Digital Sky, and the importance of drone registration for safe and legal operations.]]>

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.

Drone Categories

  1. Nano Drones (≤ 250 grams) — Lightweight drones and need no license or registration.
  2. Micro Drones (251g — 2 kg) — Registration is required for commercial use.
  3. Small Drones (2 kg — 25 kg) — Registration is mandatory.
  4. Medium Drones (25 kg — 150 kg) — Because of the increased safety and privacy hazards associated with their size and prospective uses, operating medium is subject to tougher laws.
  5. Large Drones (>150 kg) — Because of the increased safety and privacy hazards associated with their size and prospective uses, operating large uavs is subject to tougher laws.

Figure 1: Drone Categories in India

What is UIN?

The Unique Identification Number (UIN) is a registration requirement for anyone looking to operate drones in India. The UIN number is a distinctive identifier for each drone. It functions like a license plate for vehicles linking it to the owner in official records. It is essential for ensuring accountability and facilitating easier regulation of drone activities.

Figure 2: Drone with UIN Number

Is UIN Mandatory for All Drones?


Not for all. Here’s the eligibility:


  • Nano Drones (≤250 grams): UIN is not required for non-commercial use.

    • Micro, Small, and Medium Drones (>250g to ≤150kg): UIN is mandatory.
    • Imported Drones or those without Type Certification cannot get a UIN and are not allowed to operate.

    Why is UIN Important?

    • Legal Compliance: Flying a drone without UIN (if required) is illegal and can lead to penalties.
    • Tracking & Safety: Helps authorities track drones in case of incidents or airspace violations.
    • Required for Permissions: To apply for any flight permissions via Digital Sky, a UIN is mandatory.
    • Proof of Ownership: Establishes rightful ownership and acts as drone identity.

    Step-by-Step Process to Register Your Drone

    Figure 3: Registering drone through DGCA website

      1. 1. Obtain a Digital Sky Account

              2. Apply for a Unique Identification Number (UIN)

      There are 2 ways to generate UIN Number.

      Apply UIN for cases exempted from Type Certificate (Model or a Nano UAS)

      • Organisations can create manufacturer account and profile on DigitalSky platform, if not already created.
      • Login to DigitalSky platform and Select ‘Add Exempted Model’ menu option from the dashboard
      • Fill all mandatory details of your Exempted UAS model and add your model on Digital Sky Platform
      • Once model is added, Individual/Organisation user can Add UAS Serial Number from dashboard, for the added UAS Model.
      • User can Click Apply for UIN for the added UAS serial number
      • Preview the Application for Registration of UIN, Pay ₹100 fee and Submit Form D-2 (Application for Unique Identification Number) Upon successful receipt of requisite fee, the UIN will be generated.

    1. Apply for UAS which is Type Certified model
      • Create your account and profile on Digital Sky platform, if not already created.
      • Login to Digital Sky platform and add your UAS Serial Number from dashboard.
      • Navigate to the list of UAS and Apply for UIN for the added UAS serial number
      • Preview the Application for Registration of UIN (Unique Identification Number)
      • Pay ₹100 fee and complete the submission of Form D-2 (Application for Unique Identification Number)
      • Upon successful receipt of requisite fee, the UIN will be generated.

    Flying Without UIN? Think Again.


    Using a drone without UIN (when it’s legally required) may lead to:

    • Heavy fines
    • Drone confiscation
    • Ban from flying operations

    Figure 4: Using a drone without UIN (when it’s legally required)

    Registering your drone in India is a simple but mandatory process to avoid legal issues. By following DGCA guidelines, you ensure safe and lawful drone operations.

    How to check if your done has UIN number?


    To check if your drone has a UIN (Unique Identification Number) in India, follow these steps:


    1. Check the Drone Surface

    Most drones with UINs issued by the DGCA have the UIN printed or affixed visibly on the base frame.

    It usually looks like: UXXXXXX.


    2. Log into the Digital Sky Platform
    Visit: https://digitalsky.dgca.gov.in

    Under Issued UINs tab you can search by either class/owner/model


    For Eg Surveyaan — a brand of Nibrus Technologies is a drone manufacturing company in India which has type certified models. Surveyaan have a drone model named Surveyaan V1. To check if any drones have UIN number you can search company name/model name in the search tab.

    Figure 5: UIN under DGCA

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


    Thank you for reading.


    Thank you for reading.


    About SurveyGyaan


    SurveyGyaan is an educational initiative under the Surveyaan brand, which is a subsidiary of Nibrus Technologies Private Limited. Surveyaan specializes in drone manufacturing and the development of photogrammetry software.


    Surveypod: www.surveypod.in (DGNSS Manufacturer Website)


    Surveyaan: www.surveyaan.com (Drone Manufacturer Website)


    Surveyaan Geoworkspace: app.surveyaan.com (Cloud Photogrammetry Software Website)


    ]]>    Thu, 10 Apr 2025 11:32:23 +0000    <![CDATA[Best Practices for DGNSS (Differential Global Navigation Satellite System)]]>https://www.surveyaan.com/blogs/post/best-practices-for-dgnss-differential-global-navigation-satellite-systemIn this blog, we outline essential best practices for DGNSS surveying, including how to set up your base and rover stations, prepare for field conditions, and choose the right positioning techniques (Static, RTK, PPK, or Rapid Static).]]>

    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.

    Pre-survey Preparations

              Ensure all your equipment is properly calibrated, batteries are charged, and software and firmware updates          are done before commencing the survey.

    • Check the weather forecast and satellite availability and any other factors that might cause interference or obstruction to the measurement, including buildings, trees, power lines, or radio signals. Also, prepare for any contingencies related to the malfunction of equipment, loss of data, and denial of access to the site of interest.
    • Locate memory devices (typically SD cards) and verify sufficient storage is available.
    • If not familiar with the gear, perform a full setup test, check that the communications are working correctly between devices before heading to the field, or be prepared to troubleshoot later.
    • If possible, investigate your field area. Topographic maps, Google Earth Imagery, or pre-trip to the area can dramatically increase your chances of success on your field day. Using this knowledge, plan the base sites, data points and paths to navigate the field site. A good plan will reduce time spent in the field later. Anticipate the number of points to be collected and time associated with the plan.
    • Pack all equipment using a checklist.


    In-Field Techniques

    • Stable and High Ground: Place the base station on stable, solid ground to ensure that it will stay in one place during the entire survey. Put the base station as high as practical. This minimizes multipath from the surrounding area and enables the radio broadcast to the maximum distance. Also, the higher the gain on the antenna, the longer the range.
    • Clear Sky View: Mount the base GPS antenna where there will be clear view of the sky in all directions. Not near vertical obstructions like buildings, deep cuttings, site vehicles, towers, tree canopy, etc. This is to ensure that the receiver do not have to deal with messy multi-path signals.
    • Check Base Station Regularly: Periodically check the base station to make sure it is functioning correctly and is transmitting data. Ensure that the base is monitored at all time as it can be stolen or knocked down by wind/animals.
    • Field Notes: Keeping detailed field notes of the survey, including possible problems or oddities observed in the course of surveying.
    • Data Quality Checks: Checking the quality of correction data received from time to time and verifying the positional accuracy obtained from the Rover that should be within the acceptable limits.
    • Safety Precautions: Observe precautions for personal safety, especially when working in the vicinity of live traffic, in remote areas, or in bad weather.
    • Known Coordinates: Use a location with known and accurate coordinates or establish the position of the base station by precise static observations.
    • Power Source: The GNSS receiver should never run out of power. The GNSS receiver has an internal battery that must be charged. Provide external power in order to use continuously for more than a day without losing power at the base station.
    • Electromagnetic Interference: Ensure that the base is away from heavy machinery, radio/mobile towers and overhead power lines as the electromagnetic fields associated with these utilities can interfere with the DGNSS signals.


    Data Collection Techniques

    Effective Effective data collection in a DGNSS survey involves various techniques to ensure precision and reliability. Here are key techniques for data collection during a DGNSS survey:data collection in a DGNSS survey involves various techniques to ensure precision and reliability. Here are key techniques for data collection during a DGNSS survey:


    Static Positioning
    Static positioning is a method in DGNSS (Differential Global Navigation Satellite System) surveys that involves collecting data at a fixed point over an extended period to achieve high-precision coordinates. This technique is particularly useful for establishing control points, base station locations, and other critical survey markers that require high accuracy.

    Picture 1: DGNSS set to Static Mode

    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.

    Figure 2: The rover is getting real time corrected data from base

    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.

    Figure 3: The rover is getting real time corrected data from base

    Adhering to best practices in DGNSS surveying is essential for achieving high-precision and reliable results. By meticulously setting up your base and rover stations, continuously monitoring signal quality, and carefully documenting field conditions, you can mitigate potential sources of error. Utilizing techniques like RTK, PPK, static, and rapid static positioning, each suited for specific scenarios, allows for flexibility and precision in various surveying contexts.

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

    Thank you for reading.


    About SurveyGyaan


    SurveyGyaan is an educational initiative under the Surveyaan brand, which is a subsidiary of Nibrus Technologies Private Limited. Surveyaan specializes in drone manufacturing and the development of photogrammetry software.


    Surveypod: www.surveypod.in (DGNSS Manufacturer Website)


    Surveyaan: www.surveyaan.com (Drone Manufacturer Website)


    Surveyaan Geoworkspace: app.surveyaan.com (Cloud Photogrammetry Software Website)



    ]]>    Thu, 10 Apr 2025 09:17:32 +0000    <![CDATA[How many Satellites and Channels require in your DGNSS?]]>https://www.surveyaan.com/blogs/post/how-many-satellites-and-channels-require-in-your-dgnssIn this blog, we break down one of the most persistent myths in the surveying industry: the belief that more channels in a DGNSS receiver automatically mean better performance.]]>

    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).

    You may have heard people emphasize the importance of having 400, 800, or even 1200 channels in a DGNSS receiver. Have you ever thought deeper to understand what this actually means? Let’s clarify this with some simple mathematical calculations.

    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.


    About SurveyGyaan


    SurveyGyaan is an educational initiative under the Surveyaan brand, which is a subsidiary of Nibrus Technologies Private Limited. Surveyaan specializes in drone manufacturing and the development of photogrammetry software.


    Surveypod: www.surveypod.in (DGNSS Manufacturer Website)


    Surveyaan: www.surveyaan.com (Drone Manufacturer Website)


    Surveyaan Geoworkspace: app.surveyaan.com (Cloud Photogrammetry Software Website)

    ]]>    Thu, 10 Apr 2025 06:28:45 +0000    <![CDATA[Photogrammetry Output - Orthomosaic]]>https://www.surveyaan.com/blogs/post/photogrammetry-outputs-orthomosaicIn this blog, we’ll take a closer look at orthomosaics, how they are created, and their wide-ranging applications across diverse range of fields.]]>

    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

    1. Mining: Orthomosaic maps are used in the mining industry for monitoring mine sites, managing stockpiles and prevent enroachment.
    2. Agriculture: Precision agriculture relies on orthomosaics for crop monitoring, disease detection, and yield estimation.
    3. Urban Planning: Orthomosaics are used for urban development and infrastructure planning, including land use zoning, road design, and utility mapping.
    4. Construction: Monitoring construction progress, evaluating structural integrity, and analyzing terrain.
    5. Corridor Mapping: Inspecting tracks and roads, planning and monitoring, plotting elevation changes.
    6. 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.

    ]]>    Tue, 09 Jan 2024 06:50:54 +0000    <![CDATA[Benefits of Cloud-based Photogrammetry Software]]>https://www.surveyaan.com/blogs/post/benefits-of-cloud-based-photogrammetry-softwarePhotogrammetry is the technology of creating 3D models, orthomosaics, point clouds, or other geospatial data from a series of overlapping photographs or images.]]>

    Photogrammetry is the technology of creating 3D models, orthomosaics, point clouds, or other geospatial data from a series of overlapping photographs or images. With photogrammetry, you can measure and model the real world with a camera. Photogrammetry is used in the military, construction, land surveying, real estate, etc.

    Photogrammetry extracts geometric information from a two-dimensional image. You can create a three-dimensional image by combining several images. Photogrammetry is the process of creating a 3D scan of an object by combining multiple images. It is possible to create a 3D model of an object by taking several pictures of the object from various angles to obtain a complete representation of the object. With the help of a simple smartphone, tablet, or camera, you can capture photos.

    What is a photogrammetry software?

    Photogrammetry software is a computer program that provides the tools for performing photogrammetric measurements, such as loading photos from your camera and producing accurate measurements, maps, and models from those photos. In drone technology, photogrammetry sensors are typically high-resolution cameras that take pictures from various angles while flying over the area of interest. A 3D point cloud of the terrain or object is then produced by stitching together these images using specialized software. This point cloud can then be further processed to create a full 3D model, allowing anyone to view it from any angle as if they were physically holding it in their hands. The software to process these images can be desktop or cloud-based.

    Cloud-Based Photogrammetry Software

    Cloud-based photogrammetry software refers to applications that leverage cloud computing resources for processing and storing data related to photogrammetry. Cloud-based survey software makes it easier for companies to create surveys and receive responses quickly, making the entire process cost-effective. Compared to locally based solutions, cloud-based survey software doesn’t require a particular computer as it can be used online using a web browser.

    Salient Features of cloud-based photogrammetry Software

    • Data Upload: Users can upload their images or datasets to the cloud platform for processing. The software may support various image formats and offer tools for organizing and managing the data.
    • Data Processing: The cloud-based software uses powerful computational resources in the cloud to perform photogrammetric processing tasks. These tasks include feature extraction, image matching, triangulation, dense point cloud generation, and mesh reconstruction.
    • Automation and Optimization: Cloud-based photogrammetry software often includes automated processes and optimization algorithms to streamline the photogrammetric workflow. These features help improve the accuracy and efficiency of data processing.
    • Visualization and Analysis: The software lets users visualize and analyze the photogrammetric results once the processing is complete. This may include viewing 3D models, orthomosaics, digital surface models, and point clouds, measuring distances, area, and volumes, and extracting specific information from the data.
    • Collaboration and Sharing: Cloud-based platforms often provide collaboration features, allowing multiple users to access and work on the same datasets simultaneously. They also enable sharing and distribution of processed data through online galleries, sharing links, or embeddable viewers.

    Pros

    • Cost-effective: Cloud-based photogrammetry software follows a subscription-based pricing model, allowing users to pay for what they need when needed. This eliminates the need for significant upfront investments and provides more predictable costs.
    • Time-saving: Cloud platform reduces risk and automates manual tasks.
    • Accessibility: Cloud-based software allows users to access their photogrammetry tools and projects from anywhere with an internet connection. This flexibility benefits remote collaboration, fieldwork, or accessing projects on different devices.
    • High accuracy and detail: Cloud Photogrammetry software can produce highly accurate and detailed 3D models and point clouds with high-resolution images and appropriate processing techniques.
    • Flexibility and scalability: Photogrammetry software offers flexibility regarding the type of imagery it can process, such as aerial or ground-based photos, and can handle large datasets. Cloud-based solutions often offer scalable processing power and storage. You can easily handle large datasets and complex projects without investing in expensive hardware upgrades.
    • Storage and Data Security: The data can be accessed anytime, anywhere since the data is stored in the cloud. There is no risk of losing the data.
    • Collaboration: Cloud-based platforms enable real-time collaboration and data sharing among team members or stakeholders. Multiple users can simultaneously work on the same project, facilitating efficient teamwork and feedback exchange.
    • Automatic Updates: Cloud-based software providers can release updates and improvements seamlessly without requiring users to install them manually. This ensures users can access the latest features and enhancements without additional effort.
    • Integration: All outputs can be downloaded and exported to third-party CAD and GIS software for further analysis.

    Cons

    • Internet Dependency: Cloud-based software heavily relies on internet connectivity. If you have a slow or unreliable internet connection, it can hinder your ability to upload and process large image datasets efficiently.
    • Data Security: Storing data in the cloud may raise concerns about data security and privacy. It’s essential to ensure that the chosen cloud provider has robust security measures and complies with industry standards and regulations.
    • Data Transfer and Upload Times: Uploading large image datasets to the cloud can be time-consuming, particularly if you have limited bandwidth. This process may introduce delays before you can start processing your photogrammetry projects.
    • Limited Offline Functionality: Cloud-based software generally requires an internet connection to access and use the tools. If you work in an area with limited connectivity, you may be unable to work on your projects or access your data.
    • Dependency on Service Provider: When using cloud-based software, you depend on the service provider’s availability and performance. Any downtime or technical issues on their end can impact your ability to work on your projects.

    ]]>    Mon, 08 Jan 2024 11:12:55 +0000    <![CDATA[Projected Coordinate Systems]]>https://www.surveyaan.com/blogs/post/projected-coordinate-systemsThe Projected Coordinate System helps you to project a specific round-earth model onto a flat surface or map.]]>

    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.

    • Area — These projections preserve the area of specific features. The Albers Equal Area Conic projection is an example of an equal area projection.
    • Shape — These projections preserve local shape for small areas. The Lambert Conformal Conic projections is an example of equal shape projections.
    • Distance — These projections preserve the distances between certain points by maintaining the scale of a given data set. The Equidistant Conic projection is an example of equidistant projection.
    • Direction — These projections preserve the direction from one point to all other points by maintaining some of the great circle arcs. The Lambert Equal Area Azimuthal projection is an example of a projection that preserve direction.

    No projection can preserve all of these spatial properties


    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.

    Universal Transverse Mercator

    The UTM system comprises 60 zones, every six degrees of longitude in width. The zones are numbered 1–60, beginning at 180 degrees longitude and increasing to the east. The UTM CRS is a global map projection.

    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.

    The UTM projection minimizes distortion within that zone. Distortion is small near the central meridian, and as you move away it worsens. It is difficult to use UTM if your area of interest covers more than one UTM zone. Therefore, using the UTM coordinate system is not the best choice for mapping extremely large areas.

    The UTM zone number, zone letter, and the easting and northing planar coordinate pair in that zone give a position on the Earth.

    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.

    Please find the video on our YouTube channel from here.

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

    Thank you for reading.

    ]]>    Thu, 04 Jan 2024 13:28:54 +0000