In this article, we will teach you Why is SAR called synthetic?, What is synthetic aperture imaging?, What is the synthetic length of SAR?
Why is SAR called synthetic?
SAR, or synthetic aperture radar, is called “synthetic” because it creates a virtual or synthetic antenna aperture much longer than its physical size through the movement of the radar platform (such as a satellite or aircraft). Normally, the size of the physical aperture (antenna) determines the resolution of radar images.
However, SAR overcomes this limitation by synthesizing a much larger aperture through the movement of the radar platform along its flight path. This synthetic aperture allows SAR to obtain high-resolution images comparable to those obtained with a physically larger antenna, resulting in detailed radar images suitable for various applications such as remote sensing, environmental monitoring and military reconnaissance.
What is synthetic aperture imaging?
Synthetic aperture imaging refers to the technique used by SAR to create high-resolution radar images of the Earth’s surface.
As the radar platform moves along its flight path, SAR continuously transmits radar pulses to the ground and records reflections (echoes) that bounce back from the surface. By combining these reflections collected across the entire flight path, SAR constructs a synthetic aperture that is much longer than the size of the physical antenna. This synthesized aperture improves the resolution of radar images, allowing SAR to distinguish fine details on the ground, such as buildings, roads, vegetation and geological features.
Synthetic aperture imaging is essential for producing detailed and accurate radar maps used in applications ranging from agriculture and urban planning to disaster response and defense.
What is the synthetic length of SAR?
Synthetic SAR length refers to the effective length of the virtual aperture synthesized during radar data processing. This synthetic aperture is created by combining radar echoes received from multiple positions along the path of the radar platform.
The length of this synthetic aperture is significantly longer than the size of the physical antenna, which improves the resolution of SAR images. Synthetic length is a critical factor in determining the spatial resolution and level of detail of SAR images. Longer synthetic apertures result in high-resolution images with finer details, making SAR an effective tool for precise mapping and monitoring of the Earth’s surface over large areas.
Synthetic aperture radar (SAR) technology has been developed independently by several researchers and organizations over the years.
One of the pioneers of SAR development was Goodyear Aircraft Corporation engineer Carl Wiley, who conducted early experiments in the 1950s. However, the modern concept and practical implementation of SAR have been significantly advanced by researchers from the Stanford Research Institute (SRI) in the 1960s. They demonstrated the feasibility of synthetic aperture radar imaging using aircraft platforms and contributed significantly to the development of SAR technology.
Since then, SAR has been refined and deployed on various platforms, including satellites and aircraft, by many organizations and countries around the world for applications in Earth observation, environmental monitoring, agriculture, defense, etc.
We trust this overview of Why is SAR called synthetic? has been clear
