Real-time locating system using GPS time difference of arrival with digital off-air access units and remote units

A system for localization using satellite navigation signals in a Distributed Antenna System (DAS), the system comprising:

• one or more Off-Air Access Units (OAAUs) operable to:
• receive a first satellite navigation signal from a first satellite,
• receive a second satellite navigation signal from a second satellite, and
• route the first satellite navigation signal to a Digital Remote Unit (DRU);
• and
• route the second satellite navigation signal to the DRU;
• and
• the DRU, the DRU being located at a location remote from the OAAU and comprising a switch, wherein the DRU is operable to:
• receive the routed first signal from the one or more OAAUs,
• receive the routed second signal from the one or more OAAUs,
• transmit a first portion of the first signal to an antenna while the switch is in a first position, and
• transmit a second portion of the second signal to the antenna while the switch is in a second position.