RADARSAT-1 components (Click to enlarge)

RADARSAT covers the Arctic daily, and most of Canada every 72 hours depending on where the instruments are pointing, and what they are monitoring. It covers the entire Earth every 24 days.

Synthetic Aperture Radar on RADARSAT-1 

RADARSAT-1 is equipped with an advanced radar sensor, the synthetic aperture radar (SAR). It is a powerful microwave instrument. It transmits and receives signals for capturing high quality images of the Earth night and day and in all weather conditions. As an active sensor, RADARSAT-1's SAR transmits a microwave energy pulse (C-band at 5.3 GHz frequency) to the Earth, and the SAR measures the amount of energy that is reflected back to the satellite from the Earth's surface.

Imaging modes and beam calibration information

RADARSAT's SAR instrument can shape and steer its radar beam using C-band. A wide variety of beam widths are available to capture swaths of 45 to 500 kilometres, with a range of 8 to 100 metres in resolution and incidence angles of 10 to 60 degrees. These images can be downlinked in real-time to the receiving stations or recorded on the on-board recorder for later downlink to Canada.

For technical information of interest to data users, please consult the pages on beam calibration.

Imaging modes

Beam mode ground coverage

Coverage

RADARSAT can provide nearly complete global landmass coverage, and can support specific requirements. The satellite's orbit path repeats every 24 days. But RADARSAT can also

• provide daily coverage of the Arctic, 

• view any part of Canada within three days

• achieve complete coverage at equatorial latitudes every six days using the 500-kilometre wide swath

Orbit

RADARSAT is in orbit 798 kilometres above the Earth, circling from pole to pole in a sun-synchronous orbit. The dawn-to-dusk orbit places its solar panels in sunlight almost constantly ensuring reliable solar power and provides the optimum number of viewing opportunities. 

RADARSAT's dawn- to-dusk path (red line) ensures that the solar arrays are constantly exposed to the Sun, although in June-July, it is in the dark for a few minutes of each orbit over Antarctica

Because of its sun-synchonous orbit, it passes over a given place at the same local time. This minimizes the effects of diurnal variations and is key in obtaining data over time as is, for example, data used in predicting harvests. The satellite is rarely in eclipse and can acquire data at any time. The descending equatorial crossing for a dawn-to-dusk orbit is 06:00.

RADARSAT can acquire up to 28 minutes of data for each 100.7-minute orbit. Data is downlinked in real time to ground receiving stations or stored on the onboard tape recorder until RADARSAT is within range of a receiving station. In critical situations, data can be processed and delivered within four hours of acquisition.