Finessing in-vehicle communications

More and more communications equipment is being fitted into public safety vehicles, which means that the job of the installer is becoming increasingly complex and important, as James Atkinson reports

The communications equipment in public safety vehicles is perhaps the most important tool available to emergency services personnel in the field. It is essential that it is installed correctly.

When it comes to best practice for the installation of RF equipment and ancillary kit in vehicles, it is difficult to find better guidance than the Federation of Communication Services’ ‘FCS1362: 2016 UK Code of Practice’. “FCS1362 governs the position of how the kit is installed and where, the type of equipment, how the cables are routed, and what provides a good power supply,” says Jason McComb, scheme manager for the FCS Installer Training and Accreditation Scheme (FITAS).

It might sound obvious, but the primary consideration is to use a reputable installer. “Public safety vehicles are complex, so you need to ensure that whoever does the installation is qualified and experienced,” says John Thomson, technical sales & support manager at Panorama Antennas and head of the FCS Installers Group. “If you select an installer on a cheapest price basis, that could be expensive down the line.”

Usually the comms fit-out design for public safety vehicles is determined by the individual police, fire or ambulance service. Most police vans and ambulance vehicles are bought as chassis and then specialist converters will build the vehicles to the desired specifications. Ambulances are usually built in batches and to a specific design, according to Rob Compton, consultant engineer with vehicle installation specialist Comptons. “Usually the paramedic crews, unions and so on all agree on the design and the ambulances are ordered to that specification. But in general the communications layer will stay the same.”

McComb says: “With police vehicles it depends on each force what equipment goes where – there is no commonality necessarily. The ambulance service is the same. There are 10 to 15 different ambulance converters in the UK all providing different architectures within the vehicle, so in turn that has an effect on where things are installed.”

That said, Compton notes that police cars tend to have similar installations as they need to be pretty generic, at least within individual forces: “It is important that anyone can get into the vehicle and know where everything is.”

The easiest way to install the equipment is during the conversion stage. Implementing the wiring looms, cable runs, power connections and antennas during vehicle assembly makes fitting the radio and peripheral equipment later much simpler. Retrofitting fully converted vehicles, on the other hand, is hard work. “In ambulances all of the surfaces in the rear area are sealed to avoid contamination, so removing the panelling and so on is quite tricky,” notes Thomson. Some vehicles do require one-off bespoke designs, so as Thomson observes, it is down to the skill of the installer to provide a safe, well-thought-out installation.

First steps
Thomson advises the installer adheres to safety and legislative guidance. “The equipment must be suitable for vehicle installation with the correct CE approvals and E markings.”

Generally, the principles of installation are common for most radio systems, as the main job involves installing a device, a transceiver and usually a separate radio control head, but the power levels of P25, TETRA and DMR may differ. The next step is to decide where to site the radio equipment so that it is both ergonomically positioned and safe to use. “You have to make sure the comms equipment does not interfere with the vehicle safety equipment or the driver’s vision,” points out McComb.

A display screen must not get in the way of the controls or impede the driver’s view of the road. Radio control heads, satnavs and other dashboard equipment must not be installed within the airbag’s deployment zone. “Airbags can be a nightmare for installers,” says Compton. “That includes curtain airbags behind pillars in ambulances. You must not run any cables across the pillar, as the airbag might remove it and disconnect something important.”

The positioning of other peripheral equipment such as speakers and cameras must also be carefully considered. “You need to make sure the radio transmitters and other equipment do not interfere with the vehicle electronics. So, you need to ensure the electromagnetic compatibility protection is quite a high level of RF,,” advises Thomson.

Tablets and dashboard equipment must be installed in a way that does not impede the driver, while avoiding the airbag deployment zone

One of the most complex areas to deal with is power supply. “Most public safety vehicles have a managed power supply with a total power distribution system,” says Thomson. “The distribution systems in these vehicles are quite complex, as they may incorporate an auxiliary battery. The power must come from a clean source, usually a battery, and normally you connect the comms system to the main battery.”

McComb highlights a more recent challenge when it comes to power, namely electric and hybrid vehicles. “The key thing to consider when fitting equipment in hybrid electric vehicles is: will it drain the battery too quickly? There is not a lot of knowledge out there about this area even within the public safety community, and installers do not have the knowledge about how to work on them safely.”

Installers need to be properly trained as the voltages present in such vehicles are significantly higher (currently up to 650 volts) than those in other vehicles (12/24 volts). The UK Health & Safety Executive also advises that components may retain a dangerous voltage even when a vehicle is switched off.

Compton adds that another issue is dealing with modern vehicle smart charging systems. These employ an engine control unit (ECU)-controlled alternator on vehicles to lower fuel consumption and reduce emissions. “But when you have a parasitic load like the radio comms system, it is continually loading the batteries, so that means you might need auxiliary batteries to run the comms off its own power supply.”

But this adds another complication as smart charging alternators have a charging threshold. The vehicle may have long periods below this threshold when the auxiliary battery is not being charged, which might affect the occupant’s ability to communicate. Shoreline charging to the mains is one way to avoid being caught out, which is fine for fire engines as they spend a lot of time at the station, but ambulances do not.

Compton says there are ways around the smart charging issue, but that can create yet another problem. “Does the solution then affect the Euro 5 and 6 emission standards for that vehicle? You also have to watch whether the charging system will cause interference to the radio.”

Antenna installation is another aspect to consider. The higher the power, the higher the electromagnetic radiation, so the antenna needs to be sited at a distance from the occupants that ensures radiation levels are not exceeded. Compton adds that installers must also be careful about how many aerials they add to the roof. Too many holes in the roof and you can affect the structural integrity of the vehicle. Multiple antennas combined in one housing can overcome this problem.

Communications equipment installed in Boise City Police Department’s police cars including a Cradlepoint 4G router (located between the large boxes in the centre)

Migration to 4G
Public safety communications are beginning a migration to 4G LTE cellular solutions and various models are emerging for mission-critical LTE, partly determined by individual national requirements, geography and budget.

For example, Finland’s blue-light vehicles have TETRA mobile radios and 3G/4G routers installed with two SIM cards and two modems connecting to two MNOs for added resilience. But as Antti Kauppinen, head of department, Mobile Technology Development and Strategy at Suomen Virveverkko Oy (State Security Networks), points out: “We are looking at a broadband solution to replace TETRA, but that’s when it gets complicated. TETRA radios and routers mounted inside the car have more powerful transmitters than normal cellular 4G LTE smartphones.

“4G LTE coverage is good in the cities, but what about rural areas? You need to build more coverage or you need tactical networks – in other words you bring your network with you, and that is much more complicated with 4G.

“We are used to TETRA where a police officer in the field can talk to the command and control room or back to colleagues in the cities. But how do we provide that same service in rural areas with commercial LTE? Satellite backhaul is one possibility, but most satellites do not really have a presence in the far north of Finland! It is a bit of a worry. Either the government or the MNOs could build out new coverage to expand the reach of the commercial networks. So, what we might see is the build-out of some additional MNO coverage and some tactical 4G networks.”

He points out that Finland’s TETRA network covers about 97 per cent of the country’s geographic land mass. “We are more or less the same size as the UK, but our population is only five million and they live mostly in the south of the country. In the northern areas there is a ratio of two people per square kilometre, so no commercial MNO is going to put coverage there without financial support from the government.”

For Kauppinen the biggest issue is how to find a replacement for TETRA direct mode operation (DMO). “If you have no DMO available, you have no fallback, and that is critical. 4G tactical networks are one way of replacing DMO. If public safety personnel are relying on a commercial LTE service in the future, then maybe firemen could connect to a tactical 4G bubble in the vehicle outside and so replace DMO that way,” he says.

Meanwhile, the supply side has 4G routers ready and waiting to go. Both Sierra Wireless and Cradlepoint provide 4G routers/gateways that provide connectivity within the vehicle and the kind of tactical Wi-Fi/4G bubble of coverage around the vehicle that Kauppinen refers to.

These routers receive and transmit multiple types of connectivity including Wi-Fi, private and public cellular, satellite and traditional land mobile radio (LMR). The routers automatically detect networks and connect to the best available one based on predefined priority management policies.

Benoît Tournier, marketing director, IoT solutions at Sierra Wireless, explains: “The Vehicle Area Network gateways can use an onboard diagnostics (OBD) interface to retrieve in-vehicle telemetry to help identify performance issues and prevent breakdowns. Wi-Fi connects tablets, laptops, printers, DVR, body-worn cameras, as well as drones taking video footage. The control centre can remotely monitor the vehicle, the driver’s behaviour and the environment around the vehicle.

“The gateways also allow public safety personnel out in the field to access computer-aided dispatch, AVL, criminal records databases and video management systems. They can also be used to hook up with IoT devices such as biometric harnesses on policemen and firemen or to cameras and sensors on helmets and belts.”

Todd Krautkremer, chief marketing officer at Cradlepoint, observes: “The thing is that there are a lot more bits of equipment that first-responders want to connect to nowadays, such as sensors, firearm holders, lights and sirens.

“So, when the blue lights and siren are turned on, when the shotgun is removed from the clip or the evidence box is opened, an alert is sent to the command and control room to make them aware that something is escalating. But you no longer need to alert them over the radio. It is about registering real-time connectivity to provide better outcomes for the communities they serve.”

Tournier thinks the most important evolution in public safety connectivity will come from the Internet of Things (IoT). “For police forces, IoT devices can provide a higher level of transparency of their acts. IoT sensors can record different types of contact, which can help police officers defend themselves.”

He adds that there is also likely to be more connection between public safety organisations and smart cities. “In San Francisco, the public authority can change the luminosity of the street light if there is police action going on or dim it when nothing is happening and save energy. It is about providing wider situational awareness to public safety personnel by connecting them to the smart city public networks.”

5G is looming on the horizon and Krautkremer reports that the Los Angeles Police Department (LAPD) is looking forward to harnessing it. “They have a lot of mobile command centres, which are very mobile and they would like to be able to leverage high-speed 5G connectivity. A lot of video is being captured, but it is not always possible to transfer it over existing LTE networks. So, they have to come back to the station to offload it.

“The LAPD want 5G pockets or hotspots around communities, so that as they drive through, the router automatically offloads the video. 5G won’t be everywhere. It will be distributed on a local neighbourhood-by-neighbourhood basis rather than blanket coverage across the city. 5G will also help with other applications such as augmented and virtual reality.”

Public safety vehicles with 4G and later 5G routers will certainly transform what the emergency services can do and the way they work. But to return to the opening theme, skilled and well-trained installation engineers are needed to fit all this new communications equipment in a reliable and safe manner, so that it does not fail when it is most urgently needed.

It is important that enough installation engineers are trained and available. The FCS’s McComb is concerned that this is not the case. “The training of the engineer is lacking at the moment or not adequately checked. It is still a daily challenge to get people properly trained and accredited. The problem is a lot of people think they are properly trained already.” Something to watch out for, then.