The Importance of IMU in GNSS: Enhancing Accuracy Reliability

30.04.25 11:17 AM - By SurveyGyaan by Surveyaan

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)


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