  The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is an
approved satellite mission for Gamma-Ray Burst (GRB) studies, developed in
cooperation between the Chinese National Space Agency (CNSA), the Chinese
Academy of Sciences (CAS), the French Space Agency (CNES) and French
laboratories. SVOM entered Phase B in 2014 and is scheduled for launch in 2021.
SVOM will provide fast and accurate GRB localizations, and determine the
temporal and spectral properties of the GRB emission, thanks to a set of 4
on-board instruments. The trigger system of the coded-mask telescope ECLAIRs
images the sky in the 4-120 keV energy range, in order to detect and localize
GRBs in its 2 sr-wide field of view. The low-energy threshold of ECLAIRs is
well suited for the detection of highly redshifted GRB. The high-energy
coverage is extended up to 5 MeV thanks to the non-imaging gamma-ray
spectrometer GRM. GRB alerts are sent in real-time to the ground observers
community, and a spacecraft slew is performed in order to place the GRB within
the field of view of the soft X-ray telescope MXT and the visible-band
telescope VT, to refine the GRB position and study its early afterglow. The
ground-based robotic telescopes GFTs and the wide angle cameras GWAC complement
the on-board instruments. In this paper we present the ECLAIRs soft gamma-ray
imager which will provide the GRB triggers on-board SVOM.
