question: What was the purpose of building the COMPASS receiver ?
answer: report tracking and multipath characteristics of the `` I '' signals on E2 and E5B
turker_answer: The purpose of building the COMPASS receiver was to report tracking and multipath characteristics of the `` I '' signals on E2 and E5B .
rule-based: The purpose of building the COMPASS receiver was report tracking and multipath characteristics of the `` I '' signals on E2 and E5B .