Overview of the RADARSAT Constellation Mission

The RADARSAT Constellation Mission (RCM) is a Canadian synthetic aperture radar (SAR) mission consisting of the design, construction, launch, and operation of three C-band SAR satellites as well as the design and build of an associated ground segment. RCM is currently being implemented by a Canadian industrial team led by MacDonald Dettwiler and Associates (MDA) under contract to the Canadian Space Agency (CSA). This article provides an overview of the RCM. A description of how mission requirements drove the selection of key mission parameters is given, including number of satellites, orbit selection, and major radar parameters. Emphasis is placed on providing a description of those capabilities of RCM that are unique or innovative. These capabilities include a constellation optimized for coherent change detection (CCD), a compact polarimetry mode, special imaging modes optimized for ship detection, and a combined SAR and automatic identification system (AIS) capability. To support CCD, the system design includes maintaining the satellites in a narrow orbital tube, a tight requirement on azimuth antenna pointing control, and ScanSAR burst timing calculated from on-orbit spacecraft location data in order to accurately synchronize ScanSAR bursts with along-track position. For compact polarimetry, a capability to transmit circular polarization and receive horizontal (H) and vertical (V) polarizations simultaneously is part of the design. For ship detection, innovative ScanSAR modes are used with a large number of beams and variable resolution and number of looks designed to optimize ship detection across a wide swath. The combined SAR and AIS capability is achieved with an AIS instrument using both on-board AIS processing and on-ground AIS processing.