Overview of new RADARSAT Constellation Mission
RCM is a combination of three identical and equally spaced satellites, flying in the same orbit plane 32 minutes apart at an altitude of 600 km. Each of the spacecraft carries Synthetic Aperture Radar (SAR) aboard, plus a secondary sensor for Automatic Identification System (AIS) for ships. When RADARSAT-2 has left- and right-looking operation, then RCM is only right-looking, because multiple satellites increase revisit times and eliminate the need to look both ways. The SAR device aboard RCM satellites is quite similar to RADARSAT-2 – C-Band antenna, 100 MHz bandwidth, 4 regular polarization modes (HH, VV, HV, VH) plus compact polarimetry. Polarization isolation is slightly better: >30 dB. See detailed comparison of RADARSAT satellites here.
The constellation system provides better coverage with smaller and less expensive satellites. This configuration allows for daily revisits of Canada’s territory, as well as daily access to 90% of the world’s surface. RCM can provide a four-day exact revisit (3 satellites equally phased in a 12 day repeat cycle orbit), allowing coherent change detection with InSAR. For specific applications (ship detection, maritime surveillance) data latency from acquisition to delivery can be only 10-30 minutes, but in general it will be from hours to 1 day.RCM has several observation modes, but the mission is primarily designed for medium-resolution monitoring:
- Low resolution (100 m), swath 500 km, NESZ -22 dB
- Medium resolution (16, 30, 50 m), swath 30-350 km, NESZ -25…-22 dB
- High and very high resolution (3-5 m), swath 20-30 km, NESZ -17..-19 dB
- Spotlight (1x3 m), swath 20 km, NESZ -17 dB