New Broadcast Standard Can Provide PNT Capability Needed for Public Safety
By John Contestabile
Friday, September 18, 2020 | Comments
The FCC has recognized the potential of television broadcasting to evolve and has allowed licensed operators to transition to an all IP-based broadcast technology called Advanced Television Systems Committee (ATSC 3.0) or NextGen TV. This wireless standard, the result of work that was aligned with Third Generation Partnership Project (3GPPP) and other IP-based communications platforms, is just now being deployed. By the nature of its underlying awareness of Coordinated Universal Time (UTC), and ability to transport time synchronous data packet payloads, there now exists a new tool that has an ability to impact the world of Position/Navigation/Timing (PNT).

In this article, readers will develop an understanding of PNT and related issues/concerns of today, and present foundational ideas that should bring broadcast television into focus as an important auxiliary source of national importance. There is also great commercial value associated with the PNT capabilities discussed. When one applies next-generation broadcast PNT to the broad scope of existing GPS derived capabilities, new efficiencies and economies of scale become available.

Also, the ‘one to many’ nature of broadcast to large audiences of devices is important to public safety. For example, the successful broadcast transport of a 1 gigabyte (GB) file to a million vehicles — there are 200+ million vehicles on the road in the US today — is the equivalent traffic of a Petabyte (1,000,000GB) in the traditional unicast wireless infrastructure. Broadcast sends a single 1 GB file simultaneously to everyone, whereas unicast must make one million separate connections to deliver that same 1GB file. Implementing an IP-based broadcast datacasting capability to the realm of first responders and emergency services brings efficiencies to ‘congested’ wireless networks by the purposeful offloading of data appropriate to the broadcast infrastructure.

In an earlier article, it was pointed out that real time situational awareness (RTSA) is the holy grail for public safety and others. Our desire to know what is going on in near real time is important to responding with the appropriate resources as soon as possible in order to hopefully prevent an evolving situation from escalating. That is true for public-safety agencies as well as businesses.

Further, in order to obtain RTSA, it requires that data from a variety of data sources be brought together — spatially, temporally and visually — in order to have actionable information. We need the right information to the right people at the right time. In a large building fire for example, this data could be floor plans, a list of occupants, record of any hazardous materials stored there, the roof configuration and the attack plans of mutual aid responding units to name a few. This requires that several barriers must be overcome in order to provide that common operating picture (COP), namely that one must be able to discover the necessary data, access the data, reformat/exchange the data, analyze the data and transport the data to where it is needed. In short, one must perform at least five functions — discover/access/exchange/analyze/transport — to make the data interoperable so that it can be combined with other data to provide the necessary information for RTSA.

While much can be written about the various IT techniques that can be employed to perform the five functions noted above, we should pay some attention to the transport or communications function. Transport implies moving the data from where it is normally housed to where it needs to be processed and ultimately provided to the end user as actionable information. Between operations centers, this often occurs over wired transport mechanisms such as ethernet and fiber optic cables. Increasingly, wireless transport is important, given the gains in capacity and coverage. Transport of public-safety data could take place within a personal area network that may involve near field communications or Bluetooth technology, an incident area network over Wi-Fi or a wide area network which may involve broadband, LTE or satellite.

It should be noted that the television broadcast infrastructure has for decades provided a consistency in robustness and is ‘hazard hardened’, providing transmission services in the worst of emergency conditions, including hurricane Sandy; California wildfires; and the July 2020 hurricane Isaias, which left 4 million stranded without power and services, and the recent hurricane Laura. Legislatively, broadcasters have received formal designation and status as a federal first informer ‘essential service provider’ through the Securing Access to Networks in Disasters Act SANDy Act 3 and other action on the part of Congress and the president. The ability to leverage this robust ATSC 3.0-enabled wireless infrastructure and bring superior broadcast related transport of services to mobile and portable devices brings alignment of interests to all stakeholders: first responders, government and the American public.

Of late, considerable focus has been upon FirstNet, a public-safety broadband network (PSBN) provided by AT&T. This utilizes LTE, and increasingly 5G, technology for wireless transport of public-safety data. It is certainly an important communications tool for public safety as this network provides priority and pre-emption service for voice, data and multimedia content. FirstNet provides a robust communications path exclusively for public safety, and allied agencies, that will have nationwide coverage and can dramatically improve the communications interoperability that is needed across agencies and jurisdictions for larger scale events. Improved hardening of many of facilities is required to ensure the same level of ‘continuity of service’ as provided through the television broadcast infrastructure, particularly given the long-term disruptions that plague large service areas in the aftermath of hurricanes and other natural disasters.

Rediscovery of Television Broadcast
The purpose of this article is to focus some attention on another wireless transport mechanism that warrants consideration. A few years ago, I was able to work with the Department of Homeland Security (DHS) Science & Technology Directorate (S&T) on a new transport path for public safety called datacasting. The technology was not particularly new, but its application to the public-safety field was new.

Datacasting leverages television broadcast spectrum by allowing insertion of an encrypted IP stream of data into the over-the-air broadcast television. A public-safety entity with the proper decryption key and credentials could then wirelessly receive the streamed data, which could be video or any other IP formatted data] within the TV broadcast signal. The primary advantage of this form of transport is its wide geographic coverage, reliability, in building penetration and the one-to-many advantage of broadcast. While this transport mechanism is one way, from the TV station to the receiver, it was envisioned to be a compliment to wireless broadband. The uplink from the end user could leverage broadband, while the downlink distribution of the data could be via television broadcast spectrum/datacasting.

This experience led me to consider how television spectrum and the commercial and public stations themselves could add value to the public-safety communications ecosystem. The TV broadcast infrastructure is already established, it is robust and reliable, and its coverage is considerable. And while there has been much fanfare associated with the introduction of “5G” technology in the commercial wireless space, there is a similar digital transition occurring in broadcast over the air television with the introduction of the new ATSC 3.0 broadcast standard. This standard was established by the ATSC and is the newest version of over-the-air broadcasting that brings to TV services a much richer viewing experience with ultra-high definition 4K video and improved audio. But as an all-IP data-agnostic wireless broadcast standard, its capabilities reach beyond television.

This standard is being rolled out nationally now with some 60 markets planned in 2020. From a public-safety standpoint, there are certain features of ATSC3.0 that must be leveraged to best advantage. They include the ability to transmit multiple broadcast signals within the spectrum, which is datacasting; geotargeted warnings to those in the path of danger; a way to “wake up” Next Gen capable phones, tablets, TV sets, vehicles and other ATSC 3.0 enabled devices to display emergency information; the ability to convey rich multimedia to supplement warnings with added information such as evacuation maps; and the ability to take advantage of the robustness and resiliency of the broadcast infrastructure.

In addition, this new standard provides the ability to use the terrestrial TV tower system as a position and timing system. This timing capability is usually provided via satellite, such as GPS, and allows for position/navigation/timing applications. It is this ATSC 3.0 timing feature that deserves some consideration. We have come to rely on GPS for location tracking of many things. Personally, we use it nearly every day to navigate our way to unfamiliar locations. It is essential in construction and surveying. You can tag locations, so you can easily return to that spot. The stock market and the utility industry use its precise timing for trading and operations.

Indeed, this capability has found its way into numerous useful everyday applications. And these applications are important to public safety as well. Uses include showing the location of a caller to 9-1-1 dispatch and the location of the closest resources to that caller. Analyzing calls and locations allows an agency to optimize patrol coverage. Tracking public-safety assets during emergencies to provide situational awareness and reduce response times. These are all important applications of GPS to public safety and we have grown accustomed to this functionality.

GPS Challenges
However, GPS faces some challenges. Its PNT functionality is valued and utilized by an estimated two billion GPS devices in numerous industries. At the consumer level, GPS is a “free” service as the satellites upon which it is reliant are operated by the United States military. However, since it relies on satellites thousands of miles above the earth, the signal is not particularly strong and can be overridden. Airlines have reported increasing number of cases of losing GPS signals on their approach to landing. In incidents involving at least four major airports in recent years, approaching pilots have suddenly lost GPS guidance.

Likewise, navigation can be affected by a disruption of the satellite signal. This may in part be due to jamming, whereby a stronger signal from a software defined radio can override the GPS signal. Jamming devices are available on the internet for less than $158. Or the system can be spoofed in which a stronger signal can deliver similar but false information, altering the receiver’s perceived location or time.

Even a slight alteration in time can have cascading effects on related systems and their functionality. For instance, in January 2016, as the U.S. Air Force was taking one satellite in the country’s constellation of GPS satellites offline, an incorrect time was accidentally uploaded to several others, making them out of sync by thirteen millionths of a second. The tiny error disrupted GPS-dependent timing equipment around the world for more than 12 hours. While the problem went unnoticed by many people thanks to short-term backup systems, panicked engineers in Europe called equipment makers to help resolve things before global telecommunications networks began to fail. In parts of the U.S and Canada, police, fire and EMS radio equipment stopped functioning. BBC digital radio was out for two days in many areas, and the anomaly was even detected in electrical power grids.

Experts have determined that nation states have developed capabilities to disrupt GPS as part of an offensive cyber strategy. Surprisingly, the United States rivals, notably Russia and China, do not have this same vulnerability as they both have built terrestrial based backup systems in case of such failures of GPS.

It is expected that as the internet of things (IoT0 continues to rollout devices and sensors that are connected to the internet, this vulnerability will only grow. These 5G-enabled devices will rely on GPS in order to locate themselves and sync with other devices and systems. As intelligent transportation systems [ITS] and smart cities evolve, this reliance on GPS will likely increase and become even more embedded in our various critical infrastructure systems. Given this concern, the DHS has been working with the National Institute of Standards and Technology (NIST) to develop standards to make receivers less vulnerable to jamming and spoofing. In fact, the DHS Cyber Infrastructure and Security Agency [CISA] released a report to congress on April 8, 2020 on PNT backup capabilities.

Its findings were:
•Mitigating temporary GPS outages can and should be the responsibility of the individual user and not the responsibility of the federal government.
•GPS is not the only source of PNT data. Other sources are currently available for purchase, and include alternate space-based systems and constellations, terrestrial beaconing systems, time-over-fiber, cellular and wireless signals, and local terrestrial systems.
•Critical infrastructures are heavily reliant on GPS although their uses vary. Some depend more on timing, while others depend more on position/navigation.
•Business decisions, the lack of a federal mandate and potentially an underappreciation of the risk associated with GPS dependence are factors in the lack of resilience to GPS disruption.

The report recommended that:
•End users take more responsibility for mitigating temporary disruptions to GPS,
•The federal government should encourage more diversity and adoption of multiple PNT sources in the open market,
•PNT systems must be designed with security and resilient features in order to continue to operate through interference and anomalous inputs, and
•There should be research and development to support innovation and incorporating signal diversity in the PNT ecosystem.

An Opportunity to Resolve
Thus, the current dependence upon GPS in critical infrastructure and public safety is well known, the vulnerabilities of the current system to jamming/spoofing are understood, and viable alternatives exist. These include hardening the existing system to the extent possible or ATSC3.0 PNT as we are discussing. Based upon the experience of other countries, it would seem that a terrestrial-based alternative for PNT would be a reasonable course of action. Enter the television industry and the ATSC 3.0 evolution. As ATSC3.0 is rolled out, it presents the opportunity to leverage that system as an alternative PNT solution. Using fixed tower triangulation and timing, the broadcasting system could provide the alternative to GPS.

An advantage of using broadcast for this terrestrial network is that it is a very high-powered system. Typically, broadcast stations transmit at powers up to1 megawatt. GPS received signals arrive at a level of ~ 0.1 femtowatt. As an illustration, if the present GPS receive signal is equivalent to 1 candle, the broadcast station would be equivalent to 10,000,000,000,000,000,000,000 candles. One can understand how such a strong signal would be much more resistant to jamming and spoofing because of the higher power differential.

Another aspect to consider is how ATSC 3.0 and PNT applications could be leveraged from a public-safety standpoint. If, for example, a broadcast receive chip were installed in a cellular smartphone, then all the locational aspects discussed above, as well as geo targeted alerting and warning, could be achieved.

A longstanding issue for public safety has been in-building location tracking or the so called Z axis dimension. Given the strength of the broadcast signal and the extent of building penetration, determining a person’s in-building location may be easier than some of the approaches presently being considered.

Public safety is very much interested in establishing RTSA. In order to create RTSA, the location of assets/persons is of paramount importance. To achieve this, satellite-based GPS is presently utilized. However as we know and have seen, that system is vulnerable to jamming and spoofing. An alternative terrestrial-based system should be constructed, and given the robust attributes the evolution of ATSC 3.0 brings to the television broadcast industry, it is a worthy candidate for consideration to fill that need.

As the broadcast industry is in the early stages of deploying NextGen services to the US market, now is the opportune time for public safety and governments to join them to execute such a proof-of-concept of a terrestrial based system. By early stage we mean that broadcasters, understanding the important nature of PNT and related infrastructure dependencies, can offer priority attention to developing and deploying a robust alternative to GPS providing diversity and segmentation to diffuse risk. It also allows for testing of these capabilities in a greenfield environment unencumbered by present systems or providers.

As part of that test, a smartphone with required ATSC 3.0 capability installed will bring the locational and public-safety benefits to the primary stakeholders and individual end users – either members of the public or the first responder community.

While the public-safety community is eager to utilize newly developed communications systems, such as FirstNet, the time to ensure those systems we have worked hard to bring about don’t fail due to a GPS loss is before the catastrophe happens, not in the aftermath of one.

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John Contestabile is the director of Public Safety Solutions for Skyline Technology Solutions. He joined Skyline in July of 2019 and provides strategic direction for their public-safety and transportation solutions. He joined Skyline after a 10-year career as a program manager for emergency preparedness and response systems in the homeland security practice for the Johns Hopkins University/Applied Physics Lab. In that capacity, he provided program oversight and project management of a variety of projects for government sponsors such as the Department of Homeland Security (DHS), as well as various state/local governments. He joined the lab in July 2009, after retiring from the Maryland Department of Transportation (MDOT) where he held a variety of senior positions related to engineering, procurement, transit safety/security, homeland security and emergency management.

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On 9/30/20, John Contestabile said:
Yes Jack Public Safety ought to leverage all the tools available and find was to integrate disparate data for improved situational awareness....including the various transport pathways and new ways of PNT.

On 9/24/20, Jack Markey said:
Thinking in integrative ways is what allows us to move public safety forward. No matter how virtuous and well guarded history shows that monocultures FirstNet are susceptible to risk. Risk that can be mitigated by tools like ATSC 3.0 as discussed. Its not an either or decision.

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