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.