Optical Repeaters

GPS Multiplexer MUX / DEMUX

To Extend GPS Indoor Coverage

SEE GPS MUX and DEMUX are devices to maintain GPS Service continuity in tunnels and confined areas effortless.
Multiplexing is a method by which multiple analog or digital signals are combined into one signal over a shared medium, so to to share a scarce resource.

The multiplexed signal is transmitted over a communication channel such as a cable.

Consequently, a device that sends multiple signals on a carrier channel at the same time in the form of a single, complex signal to another device that recovers the separate signals at the receiving end, is called a Mux.

The receiver is called a Demux, as the reverse process of Mux.

Now discover SEE’s GPS MUX and DEMUX Devices.

The Usage

SEE’s GPS Mux system allows for dividing the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred.

SEE’s GPS Demux device is the reverse process, known as demultiplexing that extracts the original channels on the receiver end.

  • GPS Service Continuity in tunnels, subterranean and confined areas
  • Locate maintenance workers in confined area…
  • …without changing the current infrastructure
  • Effortless Insertion into the current infrastructure
  • From DC up to 980 MHz


Why is our MUX / DEMUX Device so unique and different?

Radio Data

  • Increase the response time of the position feedback
  • Transparent system for standard GPS equipments
  • Enhance Geolocation accuracy


  • Easy installation
  • Compact device: MUX 1U, DMUX direct cable assembly


Detailed Features

Number of ChannelsUp to 4
Frequency BandsTETRA, TETRAPOL, DMR, P25, UHF, VHF, 3G, 4G/LTE, 5G, FM, DAB
Impedance50 Ohms
Output Power+30 dBm / 4 carriers
Gain55 to 85 dB
Filter options100 KHz to 5 MHz
Noise figure4,5 Db
Group delay channel / band<12μs / <2μs
ALC channel / bandTime slot / RMS based with frame pick hold
Power supply230VAC / 110VAC / 48VDC
Rack Size19'' 3U
Plug inPlug in modules included to make integration easy
Support ServicePhone and Email: 24/24 7/7

They use our GPS MUX / DEMUX

Use Case

It’s not that hard to get radio signal in a tunnel, though you, the commuter, can’t really do much to improve your chances. Instead, the tunnel has to have its own radio transmitters installed for it to work, and some of them do.

A tunnel radio transmitter works the same way a big FM radio station transmitter works, by amplifying a signal through an antenna to produce the FM radio waves that are picked up by your car, just on a smaller scale and underground.

Radio equipment in the tunnel’s ventilation buildings pick up the outside FM signal, and then broadcasts the signal into the tunnel through wall-mounted antennas.

The tunnel radio systems aren’t just to prevent drivers from losing their favorite Oldies classics in rush hour gridlock returning to their idyllic suburbs, though. The system can be overridden by the Port Authority to transmit traffic, safety and security information directly to each car’s radio in the event of an emergency.

More importantly these days, tunnel transmitters could also be used to transmit cell phone signal inside the tunnel, to keep your Waze navigation accurate and the Spotify chugging along, though you lose the excuse of dropping the call you don’t want to be on in the tunnel.

All SEE GPS MUX / DEMUX Features

Download the brochure

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