Measuring Coastal Change at the Centimeter Level with Autonomous Drone Operations
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How the University of Zadar Uses DJI Dock and Drone Harmony for Environmental Monitoring in Croatia
Coastal environments are constantly changing. Waves reshape beaches, storms move sediment, and changing water conditions affect ecosystems over time. Understanding these processes requires frequent, accurate, and consistent data collection—a challenge that has traditionally demanded significant fieldwork and manual effort.
At the Martinska research site near Šibenik, Croatia, researchers from the Center for Geospatial Technologies (GAL) at the University of Zadar and the Ruđer Bošković Institute are taking a different approach.
Using a DJI Dock operated through the Drone Harmony platform, the team has developed an innovative multi-sensor monitoring framework that combines autonomous drone operations, environmental sensors, meteorological measurements, and advanced geospatial analysis. Their goal is ambitious: to detect and analyze coastal change with centimeter-level accuracy while creating a scalable system for long-term environmental monitoring.
Understanding a Dynamic Coastal Environment
The research focuses on the Krka River Estuary, one of the most distinctive coastal ecosystems on the eastern Adriatic coast.
Here, freshwater flowing from the Krka River meets seawater from the Adriatic, creating a complex environment with varying salinity, temperature, and nutrient levels. These conditions influence water quality, sediment transport, shoreline dynamics, and the overall health of the ecosystem.
Monitoring such a dynamic environment requires more than occasional field surveys. Researchers need precise, repeatable measurements collected consistently over time to understand how the ecosystem evolves and responds to natural processes.
Why Traditional Monitoring Was Not Enough
Before implementing autonomous drone operations, monitoring shoreline change relied primarily on GNSS field surveys. Researchers had to walk along the beach to collect measurements at regular intervals.
While this method provided accurate positioning, it also had limitations. The surveys were time-consuming, required repeated field visits, and, importantly, walking across the beach could itself disturb the sediment surface being measured.
In addition, collecting consistent data over time was challenging. Traditional methods made it difficult to capture frequent observations while maintaining the level of repeatability needed to accurately analyze subtle changes in coastal morphology.
To overcome these limitations, the research team developed an automated monitoring framework using a DJI Dock and the DroneHarmony platform, enabling repeatable drone surveys without disturbing the study area.
Building a Multi-Sensor Monitoring Framework
To overcome these limitations, the team established a comprehensive monitoring system at Martinska.
The framework combines:
Autonomous drone operations
Environmental monitoring sensors
Hydrological measurements
Meteorological observations
High-precision geospatial reference networks
At the heart of the system is a DJI Dock integrated with Drone Harmony, enabling automated and repeatable data acquisition without requiring a pilot on site.
What is a DJI Dock? A DJI Dock is an automated drone base station that allows a drone to launch, perform a mission, land, recharge, and prepare for its next flight automatically. When combined with Drone Harmony's advanced mission-planning capabilities, it enables highly repeatable and autonomous drone operations.
How Drone Harmony Supports the Research Workflow
Drone Harmony plays a central role in the project's operational workflow.
Researchers use the platform to:
Design and schedule automated missions
Generate repeatable flight plans
Ensure consistent survey parameters
Execute autonomous flights from the DJI Dock
This repeatability is critical for scientific monitoring.
Every survey follows the same predefined flight path, allowing researchers to compare datasets collected over time with a high degree of confidence. The result is a reliable foundation for detecting environmental change and producing scientifically robust analyses.
"Predefined flight plans ensure a high level of geometric consistency across repeated surveys, which is critical for reliable environmental change detection." — Prof. Ante Šiljeg, University of Zadar
From Drone Images to Scientific Insights
During automated missions, the drone captures high-resolution RGB and thermal imagery of the research area.
The collected imagery is processed into:
Orthomosaics
Digital Surface Models (DSM)
Digital Terrain Models (DTM)
These datasets are then integrated with water-quality measurements, hydrological observations, and meteorological data collected at the site.
What is an Orthomosaic?
An orthomosaic is a highly detailed aerial map created by stitching together many individual drone images. It provides an accurate, measurable representation of the landscape and is commonly used for environmental monitoring and change detection.
This integrated approach allows researchers to analyze interactions between:
Coastal morphology
Water quality
Weather conditions
Hydrodynamic processes
Sediment transport
By bringing all these data sources together, the team can develop a much deeper understanding of how the estuary functions and changes over time.
Detecting Coastal Change at the Centimeter Scale
One of the project's primary objectives is to develop a methodology to measure coastal change with exceptional precision.
Using autonomous drone surveys, advanced photogrammetry, and high-accuracy geospatial reference networks, the team has built a framework capable of detecting centimeter-level changes.
The results from Martinska demonstrate the value of this approach.
Between May 30 and June 8, measurable geomorphological changes were detected across 76.6% of the monitored area.
During this short observation period:
Erosion affected approximately 146.5 m²
Sediment accumulation affected approximately 79.0 m²
Average vertical changes ranged between 7 and 12 cm
A net sediment loss of approximately 1.32 m³ was observed
These findings reveal how dynamic coastal environments can be, even over a period of only a few days.
Achieving Survey-Grade Accuracy
For environmental monitoring, accuracy matters as much as frequency.
The project evaluated different positioning approaches and demonstrated substantial improvements when combining RTK positioning with a ground control network.
The resulting workflow achieved centimeter-level horizontal and vertical accuracy, providing a reliable foundation for detecting subtle environmental changes and generating high-quality geospatial datasets.
This level of precision is essential when monitoring gradual processes such as shoreline movement, erosion, and sediment redistribution.
Beyond Data Collection: Real-Time Environmental Understanding
While autonomous drone operations enable efficient data acquisition, the true innovation lies in integrating all data sources into a single analytical framework.
The multi-sensor system developed at Martinska enables automated data integration, processing, and analysis, providing a reliable foundation for quantifying coastal change and understanding its drivers. Researchers can evaluate how meteorological conditions, hydrological processes, and coastal morphology interact and influence one another.
This transforms environmental monitoring from periodic field campaigns into a continuous, data-driven process.
Looking Ahead
The research team plans to further expand the system by integrating multispectral sensors that measure additional water-quality indicators, such as chlorophyll concentration, suspended solids, and dissolved organic matter.
When combined with machine learning and advanced geospatial analytics, these datasets could enable spatially continuous mapping of water quality and provide deeper insights into the dynamics of the Krka River estuary.
Future applications may include:
Coastal erosion monitoring
Water-quality assessment
Flood mapping
Habitat monitoring
Climate adaptation studies
Natural hazard assessment
Enabling the Future of Environmental Monitoring
The Martinska project demonstrates how autonomous drone operations can be integrated into a comprehensive environmental monitoring infrastructure.
By combining DJI Dock automation with Drone Harmony's mission planning and repeatable flight execution capabilities, researchers can collect consistent, high-quality geospatial data at a scale that would be difficult to achieve through manual operations alone.
For organizations responsible for monitoring coastlines, rivers, ecosystems, or critical infrastructure, autonomous drone systems offer a powerful new way to understand change, improve decision-making, and support long-term environmental protection.
As projects like Martinska continue to evolve, they show how autonomous drone technology can help bridge the gap between data collection and environmental understanding.
Interested in learning how autonomous drone operations could support your project? Contact our team—we'd be happy to discuss your use case.