Onboard GRB trigger algorithms of SVOM-GRM

The Gamma-Ray Monitor (GRM) is a high energy detector onboard the future Chinese-French satellite named the Space-based multi-band astronomical Variable Object Monitor which is dedicated to studies of gamma-ray bursts (GRBs). This paper presents an investigation of the algorithms that look for GRBs by searching for a significant increase in the photon count rate for the computer onboard GRM. The trigger threshold and trigger efficiency, which are based on a given sample of GRBs, are calculated with the algorithms. The trigger characteristics of onboard instruments GRM and ECLAIRs are also analyzed. In addition, the impact of solar flares on GRM is estimated, and a method to distinguish solar flares from GRBs is investigated.