... , and arouse the problem part by its intelligent voice messenger in case of some problem.Data ... Crest, a Trimble Company, multi-satellite, multi-system kernel.2. Built-in transmit-receive UHF, exchangeable ... accuracy<1mm with 1Hz wide band, Low elevation-angle tracking technology Initialization Time: <10 seconds Initialization reliability: > ... lasted advanced multi-channel, multi-frequency RTK GPS system