SAR Optical satellite images for asset risk monitoring

SAR and Optical Satellite Images for Advanced Asset Monitoring 

In today’s data-driven world, the ability to monitor and analyze assets with precision and accuracy is crucial for various industries. 

Traditional methods of on-ground inspections and surveys are time-consuming, expensive across large areas, and sometimes not even possible for remote locations or under disastrous conditions. Satellite imagery has emerged as a game-changing technology that provides a comprehensive view of our planet’s surface, making asset monitoring more accessible, cost-effective, and efficient. 

Among the vast array of satellite imagery options, Synthetic Aperture Radar (SAR) and Optical satellite images have gained significant attention due to their unique capabilities in asset monitoring and analytics. In this article, we will explore the immense potential of SAR and Optical satellite images and delve into the derived analytics that is revolutionizing asset monitoring across diverse sectors.

Understanding Optical Satellite Images

Optical satellite imagery relies on capturing and recording the reflected sunlight from the Earth’s surface using sensors that detect specific spectral bands in the visible, near-infrared, and sometimes shortwave infrared regions. It is typically acquired during daylight hours when the sun is illuminating the Earth’s surface. Optical images represent the visible and colourful appearance of objects, similar to what our eyes perceive. With the advancement of multispectral and hyperspectral imaging technologies, optical satellite images have become even more powerful in identifying specific objects or materials on the Earth’s surface.  

Optical satellite image for remote sensing

Understanding SAR Satellite Images

Synthetic Aperture Radar (SAR) technology operates by transmitting microwave pulses towards the Earth’s surface and measuring the reflected signals to create images. Unlike Optical satellite images, SAR is not dependent on natural light conditions, enabling it to acquire data regardless of weather conditions. SAR can penetrate through clouds, smoke, and haze, and can acquire data both day and night. SAR imagery generally has lower spatial resolution compared to optical imagery and is typically represented in grayscale, with the intensity of the radar return indicating the properties of the surface.

SAR satellite image for remote sensing

Deriving Analytics for Advanced Asset Monitoring

Both SAR and Optical satellite images serve as rich sources of data, but the true value lies in the derived analytics that enables advanced asset monitoring. Through sophisticated image processing techniques and machine learning algorithms, satellite images can be transformed into actionable insights for decision-makers. 

Let’s discuss key analytics derived from SAR and Optical satellite images, including:

  • Vegetation Monitoring: Both SAR and optical imagery can be used to monitor vegetation growth and health around power lines, pipelines, and other infrastructure. Evolution in vegetation density can be detected, allowing for proactive maintenance and the prevention of vegetation-related outages or disruptions.
  • Change Detection: By comparing images captured at different times, both images are valuable for detecting changes in infrastructure and the surrounding environment. These changes can include new construction, land subsidence, encroachments, or illegal activities. Timely detection of changes helps with ensuring regulatory compliance as well as assets safety and operations continuation.
  • Climate Conditions Monitoring: This data helps in analysing changes in temperature, precipitation, wind and other weather patterns, which can have a significant negative impact on infrastructure and energy systems. This allows infrastructure owners to improve their assets’ resiliency towards changing climate conditions.  
  • Land and Asset Motion Assessment: Both optical and SAR imagery offer valuable insights into changing land and asset structures, with SAR excelling in detecting and monitoring ground displacements with millimeter-level accuracy. This capability is achieved through a technique called interferometry (InSAR), which involves comparing phase differences between multiple SAR images taken at different times. The received analysis allows for early identification of potential risks to transmission towers, pipelines, and transportation networks, enabling infrastructure stability and timely maintenance or remediation measures.
  • Flood Monitoring and Management: SAR imagery is particularly useful for flood monitoring, as it can penetrate through clouds and provide information on flood extent, water levels, and inundated areas. This data assists in emergency response planning, flood mapping, and the assessment of flood impacts on critical infrastructure.


Compared to traditional on-ground inspections or aerial surveys, both optical and SAR satellite imagery offer a cost-effective solution for asset monitoring at scale. It eliminates the need for expensive equipment, reduces labor costs, and minimizes logistical challenges. Also, it is important to highlight that there is a vast availability of free and open-source satellite imagery accessible to all users. By leveraging existing satellite data archives, historical imagery can be utilized for comparative analysis, further enhancing cost-effectiveness.


Both optical and SAR satellite images can be obtained at regular intervals. Some satellites may have a revisit time of one day allowing near real-time monitoring, while others may have longer revisit times ranging from a few days to several weeks or even longer. The frequency of satellite image capture depends on various factors, including the data provider’s satellite fleet size, data storage limitations, and recharging requirements.

Limitations and Considerations

Open-source optical images offer a resolution of approximately one meter, whereas commercially tasked images can achieve even higher resolutions, reaching as low as 30-50 cm. 

SAR images typically have lower spatial resolution compared to optical satellite imagery. For instance, open-source SAR images range from 5 to 15m in resolution. Also, SAR images may not have the same level of visual interpretation as optical images, as they represent radar reflections rather than direct visual information. This makes their interpretation and analysis more complex compared to optical imagery.

Integration with other data sources, such as ground-based sensors or aerial surveys, can help overcome these limitations and provide a more comprehensive understanding of asset conditions.


SAR and Optical satellite images, along with the derived analytics, have transformed asset monitoring across industries. The ability to capture data from space, regardless of weather conditions or time of day, has provided unparalleled insights for decision-makers. From assessing vegetation health and handling natural disasters to optimizing infrastructure maintenance and monitoring environmental changes, the potential applications are vast.

Looking ahead, satellite technologies for asset monitoring will continue to evolve rapidly, providing even more advanced tools and insights. This involves the improvement of resolution capabilities, advanced 3D modeling and mapping, further integration of satellite data with other technologies, enhanced data analytics and processing, and, ultimately, increased technology accessibility and affordability for massive adoption.

The work done is part of the project co-financed by NCBR.

Niccolo Teodori
Niccolo Teodori

Spottitt Chief Growth Officer

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