The SENTINEL-1 constellation offers an improvement in revisit time over ERS-1/2 and ENVISAT ASAR, and a continuity of wide area coverage with ENVISAT ASAR, but achieving higher resolution and potentially global dual polarisation coverage over landmasses.
Each SENTINEL-1 satellite will be in a near-polar, sun-synchronous orbit, with a 12-day repeat cycle and 175 orbits per cycle. Both SENTINEL-1A and SENTINEL-1B share the same orbit plane with a 180° orbital phasing difference.
A single SENTINEL-1 satellite is potentially able to map the global landmasses in the Interferometric Wide swath mode once every 12 days, in a single pass (ascending or descending). The two-satellite constellation offers a 6 day exact repeat cycle at the equator. Since the orbit track spacing varies with latitude, the revisit rate is significantly greater at higher latitudes than at the equator.
Figure 1: Revisit time for S-1A and S-1B in Days per Revisit
Conflict-free operations, enabled by a main operational mode over land, allow exploitation of every data-take and creation of a consistent long term data archive for applications requiring long time series.
Figure 2: SENTINEL-1 Swath Coverage
EW mode will be used primarily over selected European seas, Arctic and Southern Ocean areas, mainly for sea-ice monitoring services and maritime surveillance, with the capability to cover 400 km wide area at each data-take. SM mode will be used on request mainly for emergency management. Over open ocean, WV mode will be the main operational acquisition mode acquiring vignettes at regular intervals.
Read more about the SENTINEL-1 observation scenario.