A Future Framework for Positioning, Navigation, and Timing Applications

The Global Positioning System (GPS) is integral to our day-to-day lives. The ubiquity and worldwide reliance upon GPS, however, has raised concerns for its security. Sextant aims to facilitate new approaches and technologies for precision positioning, navigation, and timing (PNT) that can enhance the resiliency of PNT while still leveraging the global GPS signal. Sextant is not intended to replace GPS, but to create an alternative to our current PNT framework that ensures long-term GPS integrity. In short, it is the future of GPS.

Figure 1 – Vertical integration model

Figure 1 – Vertical integration model

The Open-Source Framework

In the production and development of technology, the “open-source” architecture typically involves universal access to a product’s design or blueprint, universal redistribution of that design or blueprint, and subsequent improvements to the model by anyone. This not only democratizes the development process, but fosters innovation, collaboration, and transparency, and also lowers costs. The Android mobile device platform is a recent example of a highly successful open-source model. Android developers were able to take the open-source Android platform to create a wide variety of applications without the usual barriers to entry imposed by licensed mobile operating systems. The Android platform now represents more than 80% of the mobile device market.

Sextant, much like Android’s open-source model, is a proposed open-source PNT framework in which a flexible data processing platform provides the foundation for a horizontal architecture that can dynamically accept multiple inputs in a common PNT data format. Processors can then use this common standard to analyze the inputs, assess data integrity, and integrate the data to provide position and time. This approach allows various devices and technologies that provide singular elements of PNT to contribute to an overall PNT “ecosystem.” The business model for PNT under Sextant includes an open-source marketplace for end users, allowing developers the flexibility to create devices and applications based on a common PNT standard. Disaggregating the PNT user base could potentially reduce the overall reliance on GPS, significantly improving security and resilience in national security space.

A Vertical-to-Horizontal Integration

The GPS satellite structure is currently vertically integrated, in that all the components (processor, receiver, transmitter, PNT data, reference, and phenomenon) are structured hierarchically, so that each function is wholly dependent on the previous function to operate. A loss of a single functional component, like the transmitter, can compromise the integrity of the entire structure. Additionally, vertical integration makes it difficult, if not impossible, to formulate a new follow-on that does not heavily impact a vast array of existing users.

Sextant proposes to flip the architecture to a horizontal framework for accomplishing the PNT mission, including architectures in which GPS is not necessarily the primary source of PNT information. In the same manner that the human brain can interpolate sensory information such as light and sound through neural impulses to make decisions, an open-source PNT framework enables multiple sources of data to communicate with processing mechanisms to determine PNT information.

Figure 3 – Horizontal integration model

Figure 2 – Horizontal integration model

SEXTANT Benefits All Users

Many industries, including telecom, media, and the information technology sector, have gained tremendous value transitioning from licensed to common standards, and Sextant aims to mimic these examples, envisioning a future “PNT ecosystem” in which multiple service providers can address more esoteric user-specific needs.

To existing customers, Sextant is an enhancement to GPS because it fulfills our customers’/stakeholders’ elusive goal of a more resilient system that provides flexibility in addition to anticipatory options for the future. The Sextant concept shows that broad architectural changes to the PNT collective structure can be accomplished while simultaneously addressing emerging threats, affordability, and technology insertion challenges. Sextant is a prime example of Aerospace’s forward thinking, and our willingness to leverage innovative ideas from multiple sectors in pursuit of enhanced resiliency of our PNT infrastructure.

“Moving forward, the Air Force is looking at the next generation of satellites and ensuring they will be more resilient and have more defensive capabilities built into them.” — General John E. Hyten, Commander, Air Force Space Command