The In-Flight Realtime Trigger and Localization Software of GECAM

TL;DR

This paper details the development and validation of a real-time onboard trigger and localization software for GECAM, enabling efficient detection and positioning of gamma-ray bursts with low latency and high accuracy.

Contribution

It introduces a multifunctional onboard software system with optimized algorithms for real-time burst detection and localization on GECAM, including verification through ground tests and in-flight data.

Findings

High trigger efficiency for celestial bursts

Low false trigger rate due to background suppression

Successful real-time localization with minimal latency

Abstract

Realtime trigger and localization of bursts are the key functions of GECAM, which is an all-sky gamma-ray monitor launched in Dec 10, 2020. We developed a multifunctional trigger and localization software operating on the CPU of the GECAM electronic box (EBOX). This onboard software has the following features: high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation, dedicated localization algorithm optimized for short and long bursts respetively, short time latency of the trigger information which is downlinked throught the BeiDou satellite navigation System (BDS). This paper presents the detailed design and deveopment of this trigger and localization software system of GECAM, including the main functions, general design, workflow and algorithms, as well as the verification and demonstration of this software, including the on-ground trigger tests with simulated gamma-ray bursts made by a dedicated X-ray tube and the in-flight performance to real gamma-ray bursts and magnetar bursts.