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How does the lack of GPS signal in an underground bus station affect real time information displays?

GPS repeater system in bus terminals ensure that timetable systems are up-to-date at all times


A GPS repeater in underground transport stations ensure real time data is up to dateIn these fast-moving, highly-connected times, bus customers expect accurate real time information at their fingertips.  For example, the Citymapper App helps to get you around London with ease ……….

Modern passenger busses carry GPS satellite navigation systems to give their exact location at all times.

The on-board system transmits its location data to a central computer. In turn, the computer communicates the information to passengers via an array of interfaces.

The RTI is displayed in several ways, including:

  • Visual displays at bus stops show arrival times, service updates and delays.
  • Bus company websites provide similar information for website users.
  • Most bus companies and some independent service providers present the information via iOS and Android apps.


When inside underground bus stations / terminals, busses cannot receive a live GPS signal. As a result, Real Time Information (RTI) systems are not updated and passengers receive inaccurate timetable information.

A GPS repeater in underground bus station helps ensure you don't miss the bus! It continues to transmit location data to the central computer via its mobile communications system. However, this is no longer real-time.

The location information now comprises the coordinates of the place where it last had sky-view, just before it entered the underground bus station.

In effect, the system transmits stale information when the bus leaves the terminal until it receives live GPS signals again.

There are two additional issues that may affect the time it takes for a bus to be fully online and sending real time information again.

If it has been underground for say an hour, the satellites that the bus was receiving signal from have moved on to another section of their orbit. The GPS receiver would have to download location information of the satellites that are now visible which can take up to 15 minutes, especially in urban canyons. The bus is out of sync with the satellites.


A GPS repeater system installed in an underground bus station ensures that:

  • Satellite navigation equipment in busses is ‘locked-on’ to the GPS signal at all times when underground.
  • When busses are underground they continue to receive live GPS signals and will send real-time information to central computer systems.
  • When busses leave the station, there is zero satellite acquisition delay, hence no gap in service.

What does this mean to bus customers? They have a better experience of the bus company as travellers always say that they want to be kept up to date on arrival times etc. Increasingly, bus information is being fed into apps which revolve around timely information. A modest investment in this area delivers improved service quality based on reliability, punctuality, real-time availability of timetable information including incidents affecting the service, and shorter waiting times at bus stops.

FalTech GPS has extensive experience of providing indoor GPS coverage; since 2012 we have supplied and installed over 1,000 systems across a wide range of industries and applications.

If we can help you to overcome the issues caused by being inside a signal-denied space, please do get in touch.

You can email us through the contact page or if you would prefer a good old-fashioned chat we still have a telephone in the office – please call 01326 336 444 in the UK or +44 1326 336 444 from outside the UK.


Six years and one thousand GPS repeater systems later …

In early 2012, a friend suggested that I investigate the possibility of bringing GPS repeater systems to market in the UK.

Well, the truth is that my investigations were somewhat half-hearted since I just didn’t “get it”.

I could see how the technology worked but I couldn’t fathom what anyone would want a GPS repeater for.

So maybe I’m not the sharpest implement in the toolbox after all …..

Automotive research facility benefits from GPS, DAB radio and FM radio signal repeater system

To enable development and testing of infotainment systems, FalTech has designed and installed a multi-function repeater system inside a research facility which previously was an RF-denied zone.


Vehicle infotainment consoleIn-Vehicle Infotainment (IVE) and In-Car Entertainment (ICE) systems are integral to most vehicles these days. In this connected world, the minimum expected level of equipment in a new car includes FM/DAB radio and GPS satellite navigation systems.

Not to mention video players, in-car internet and WiFi, USB and Bluetooth connectivity and eCall technology.

One automotive company that FalTech GPS worked with was having a problem with a lack of GPS, FM and DAB signals inside their research building due to the blocking effect of the largely steel structure. The situation caused frustration and delays as the only way to test any of these systems was to take the prototype vehicles outside in order to receive a usable signal.

FalTech GPS attends British APCO annual conference 20 & 21 March 2018

Link to the BAPCO 2018 Exhibition & Conference page

For the fifth year running, FalTech GPS will be exhibiting at the BAPCO annual exhibition and conference in Coventry on 20 & 21 March 2018.

As BAPCO members, we will be there at Stand C20 with our equipment supplier, Roger-GPS, the market-leading manufacturer of GPS repeater systems based in Helsinki, Finland.

So what is our link with BAPCO?

Well, since 2012, FalTech has supplied and installed over 300 GPS repeater systems in fire and police stations across the UK.

Our fire and police services, like most others across the globe, are affected by some specific challenges caused by the lack of GPS signal inside their buildings.

GPS repeaters in fire stations

When inside a fire station, the mobile data terminal (MDT) installed on most appliances will not receive a GPS signal due to the blocking effect of the building structure.

This means that when the MDT transmits its location to the command and control centre, the data is stale and indicates the location when the appliance last had sky-view – just before it entered the fire station.

However, the real problems begin when the appliance leaves the station because it can take several minutes
for the MDT (and satnav devices if present) to re-acquire a GPS fix.

The appliance could be quite some distance away from the fire station before the GPS fix occurs.

This has two main effects:

  1. Fire crews have to find their way to the incident without the aid of the MDT or the satnav device
  2. The command and control centre continues to see the appliance’s location as the fire station long after it left the building

Local knowledge can sometimes aid fire crews to get where they need to be.  However the command centre staff won’t necessarily have the confidence of knowing exactly where their resources are at all times, which means that they are not always able to marshal resources to where they are most needed.

The solution

A GPS repeater system installed in a fire station ensures that MDTs and satnav devices receive live satellite signals at all times.

GPS repeater in a fire station providing continuous signal to MDT and satnav devices

Which means that:

  • The MDT reports accurate, up-to-date location information at all times.
  • Satnav devices maintain a GPS fix while indoors.
  • There is no satellite acquisition delay on exiting the station.
  • Response times minimised and public safety enhanced.

There is a full description of how a GPS repeater works in a fire station here.

GPS repeaters in police stations

The issues faced by police officers are similar in nature to those seen by firefighters; when they go indoors and their personal radios stop receiving a live GPS signal they continue to transmit stale location data.

When exiting the police station the officer may get into a vehicle and head off to an incident before the radio has a chance to acquire GPS lock.

As far as the command and control centre is concerned, the officer’s location appears on the status screens as back at the station, when in fact he or she could be several miles away.

It doesn’t help that the officer and the radio is in a steel box (police car) and the GPS acquisition delay is prolonged.

A GPS repeater system installed in a police station ensures that personal radios receive live satellite signals at all times.

Which means that:

  • The personal radio device reports accurate, up-to-date location information at all times.
  • There is no satellite acquisition delay on exiting the station.
  • All officers visible at the command centre whether indoors or outdoors.
  • Response times minimised and public safety enhanced.


There is a full description of how a GPS repeater system works in a police station here.

If you are at the BAPCO centre at the Ricoh Arena on 20th & 21st March please do come along and speak with us, we’d be happy to tell you about how we have solved this problem for fire and police services across the UK and further afield.

In fact, you may be interested to see a case study of the largest known repeater system installed in an underground police garage.

If you are attending and would like to meet up, by all means call Phil Whitting on +44 (0) 1326 336 444 or email him and he would be happy to see you.  He may even buy you a coffee!


Do GPS tracking devices work indoors?

And if they don’t, does it matter?

Every day, vast amounts of cargo are transported around the world by land, sea and air.

Keeping track of shipments as they make their way around the globe is often achieved by use of GPS-enabled tracking devices.

Knowing the exact location of a highly valuable consignment of prescription drugs, for example, would surely make any logistics professional sleep better at night.

A tracking device can be fitted to almost anything, in an open or a covert way.

While there are many, many available options and variations on a theme, there are essentially two types of trackers – passive and active.

Passive trackers use GPS location information to record their position (and possibly environmental data such as temperature and humidity) as it makes its journey.

The data is logged within the tracking unit itself and is stored in internal memory or on a memory card and can be downloaded at a later date for analysis on a computer.

Active trackers provide real-time location and environmental information to a central tracking portal. This data can be viewed by the owner of the cargo and/or the tracking company employed to carry out the monitoring on behalf of its clients.

When the shipment is delayed, for example by stormy weather at sea or by leaves on the railway line, the tracking data can be used to update clients with an accurate timeline.

So this isn’t exactly breaking news to those who have been in the asset tracking industry for some time.  I suspect most of us have received a parcel from a delivery courier firm that provides a link to a portal so that you can see the delivery vehicle making its way to your location.

So here’s the question I have in mind: how does a GPS tracking device determine its position when it is under cover?

For example when it’s inside

  • A warehouse
  • The hold of a ship
  • A transport depot
  • A train station
  • An aircraft hangar

The issue is the same for all indoor locations where a container may spend a period of time during its journey.

If there is no sky view the GPS signal can’t penetrate to the interior of the building.





That’s OK, the last time it had a live signal was just before it went into the building, so it must still be in there, right?

Not necessarily …..

When the GPS tracking device loses sight of the sky due to the blocking effect of the building structure, it will continue to report its location periodically as it was just before it entered the building.

Not only would the tracking device be reporting stale, out-of-date location data, there may be a long acquisition delay (possibly several minutes) upon exit as the GPS receiver regains a positional fix.

Using a GPS repeater to maintain sky view while indoors

A GPS repeater relays live GPS signal from the outside of the building to the inside.

This ensures that sky view is available at all times, and the GPS tracker will always be reporting accurate location information to the tracking portal.

An antenna is placed on the roof and a coaxial feeder cable transports the signal to an indoor GPS repeater unit.

The repeater re-radiates the signal inside the facility, providing live sky view to all GPS receivers in the vicinity.

Yes, a GPS tracking system can work indoors, providing end-to-end visibility of cargo

It’s reasonably easy to solve a potentially serious issue.

A GPS repeater kit comes with all you need to provide signal in any indoor space.

We can also create a custom-designed system if the requirement is larger or more complex than a kit can handle; just let us know what you need and we’ll happily work with you to ensure you get the right solution.

If you would like to discuss this or any other aspect of providing GPS signal indoors, please do get in touch.

Within the UK call 01326 336444

From outside the UK call +44 1326 336444

Or send an email to phil@gps-repeaters.com

Phil Whitting
FalTech GPS