GPS repeaters (also known as GPS reradiators, GPS retransmission, GNSS repeaters) enable the reception of satellite signals inside a building or indoor location where they cannot ordinarily be received. This allows any testing, calibration or research involving GPS satellite signals to be undertaken inside, improving efficiencies and reducing costs. GNSS receivers whether GPS, GLONASS, Galileo or Beidou can be kept ‘live’ around the clock even when indoors or undercover for long periods of time, removing any satellite re-acquisition delays and ensuring equipment is always completely up to date even when it has no sky view.