The Technical Challenges of Developing Effective and Reliable A-PNT Solutions

Position, Navigation and Timing

Designing and developing an Assured Position, Navigation and Timing (A-PNT) solution that relies on information from multiple complementary sources and provides the same level of performance as GPS is not an easy task. From a design and engineering perspective, there are, quite literally, a lot of moving parts to consider and combine to arrive at a PNT truth.

In addition, solutions must be easy to integrate into the existing available space on the ground-, air-, and water-based platforms. And they must provide reliable positioning information in GPS-degraded environments where tall buildings, heavy foliage, and underground positions can affect signal quality, as well as in GPS-denied environments where adversaries have intervened to jam or compromise GPS signals.

The following summaries provide a brief overview of just a few of the technical challenges involved in developing effective and reliable A-PNT solutions.

Position, Navigation, Timing

Figure 1: Assured Positioning, Navigation, and Timing (A-PNT)

Data Processing

Data from all of the available PNT sources must be processed in a way that allows accurate positioning information to be provided to warfighters and systems when needed.

This is extremely challenging. The solution must be able to process data that is received from a wide variety of sources, at different times, and in different formats. Complex data processing algorithms are required to amalgamate and process all of this information in a way that accounts for varying and disparate temporal and spatial data. And all of this processing must be completed extremely quickly so that people and systems always have access to accurate PNT information.

Data Distribution

Once the data is processed, it must be made available to a variety of other systems and clients on the platform. The data may also need to be made available to systems on associated platforms in the field and at command centers.

The main challenge here is that deployed platforms combine a variety of legacy and modern systems and clients with differing levels of sophistication, communications interfaces, and data processing requirements. Each system to which PNT information — and more importantly, Assured PNT information — will be distributed must be considered.

The considerations for distributing data to some types of legacy equipment can be quite involved. For example, existing GPS receivers and systems using GPS receivers must be made capable of providing A-PNT truth rather than the GPS data they were designed to provide.


A-PNT solutions must also be able to interoperate with existing legacy and modern systems on the deployed platform. And they must anticipate future interoperability requirements.

Hardware interoperability is challenging because it means A-PNT solutions must support the right combination of physical interfaces and pinouts to connect to legacy, modern, and future systems. Software interoperability is challenging because it means software must be easily updatable to support new capabilities and technologies as they emerge.

In short, the entire A-PNT solution must be designed to interoperate with past, present, and future hardware and software.


Designing and implementing security that provides the right level of protection for the application is a major challenge in any solution. In an A-PNT solution, getting security right is even more difficult due to the factors outlined above — the need to protect information that arrives at different times and in different formats, then securely distribute that information to a variety of legacy and modern hardware and software systems and clients.

The breadth of these requirements means that A-PNT solutions must straddle all of the different security enclaves on a platform. This includes the need to securely receive and distribute changing combinations of classified and unclassified information. Only A-PNT solutions that are fully cyber hardened can provide the resiliency needed to adequately protect all of the hardware and software involved in delivering A-PNT truth.

Ease-Of-Use and Flexibility

A-PNT solutions must provide PNT information to warfighters in a way that is fast and easy for them to access and understand, even while they are on the move or in dangerous situations.

This is challenging because warfighters are already very familiar with GPS systems and how GPS information is provided. The transition to A-PNT information must be “invisible” so warfighters can continue to focus on mission tasks rather than struggle with unfamiliar controls and information formats. Developing A-PNT solutions that deliver an imperceptible level of change across all of the different systems involved is extremely difficult from every perspective —physical design, installation, integration, and usability.

Solutions must also give warfighters the ability to be part of the solution. Warfighters must be able to manually incorporate information from additional PNT sources into the final location calculation. And they must be able to override the PNT assessment provided to them with information they know to be more accurate for any number of reasons.

To learn how to overcome these A-PNT challenges, read our new white paper: “Assured Positioning, Navigation, and Timing (A-PNT)”.