At about the same time, Motorola proposed a new system using pseudo-random pulse-chains. This mechanism ensures that no two chains within a given period (on the order of many seconds) will have the same pattern, making it easy to determine if the signal is a groundwave from a recent transmission or a multi-hop signal from a previous one. The system, Multi-User Tactical Navigation Systems (MUTNS) was used briefly but it was found that Loran-D met the same requirements but had the added advantage of being a standard Loran-C signal as well. Although MUTNS was unrelated to the Loran systems, it was sometimes referred to as Loran-F."Proceedings of the Eleventh Annual Technical Symposium", pg. 7.
