SAR data is collected using radar systems mounted on airborne platforms such as aircraft or satellites. These systems transmit radar pulses to the Earth’s surface and receive reflected echoes from objects and terrain features. As the platform moves along a predetermined path, the radar antenna continuously emits pulses and records the reflected signals. Platform movement or antenna movement during data collection allows SAR to synthesize a large antenna aperture electronically, improving spatial resolution and image quality compared to traditional radar systems with antennas fixed.
Availability of SAR data varies depending on provider and purpose. Although some SAR data may be freely available through government agencies or research institutions for scientific and environmental studies, other data sets may require purchasing or licensing agreements from commercial providers. Governments often provide SAR data for disaster monitoring, environmental management and defense applications, promoting access to researchers and organizations involved in public interest projects. Open data initiatives and collaborations between international space agencies also contribute to the availability of SAR data for global research and operational applications.
SAR imaging works by transmitting radar pulses to the Earth’s surface and recording reflected echoes from objects and terrain features. As the radar platform moves, either on an aircraft or satellite, SAR collects radar returns from different positions along its path. Signal processing techniques, such as range compression, Doppler processing and azimuth focusing, are applied to these echoes to create high-resolution radar images. By synthesizing a large antenna aperture electronically by movement, SAR achieves fine spatial resolution and image quality suitable for applications in agriculture, forestry, urban planning, disaster monitoring and defense.