Positioning, Navigation, and Timing (PNT) refers to a wide range of technologies, services, methods and data that collectively underpin a wide range of products and services that modern society relies on every day. The modern world is as dependent on PNT as it is on power, clean water, and access to the internet. Whether you are using a smartphone map application, coordinating transportation logistics in a supply chain, synchronising financial transactions, running a telecommunications network, or ensuring the safety of aircraft and maritime operations, PNT services are fundamental to making all of these functions possible today.
Positioning is the ability to determine a specific location in three dimensions relative to some reference, such as the Earth’s surface. Recording a location’s Latitude, Longitude and Altitude is the most common form of determining a position. Accurate positioning is typically required in order to provide safe and reliable navigation.
Navigation is the act of moving between a sequence of positions. In general the desire is not just to navigate efficiently but also safety, avoiding collisions. Navigation therefore typically involves a variety of sensors, not just those capable of calculating positions, but also those capable of predicting where the platform will move next, and capable of detecting and avoiding objects or threats in the local environment. Since navigation involves motion, position intervals and time intervals both need to be measured and combined in calculating navigation progress and in planning out journeys. A navigation computer typically maintains an understanding of 3D position, 3D velocity, roll, pitch and yaw, time, and a variety of sensor settings, parameters and errors.
Timing has two major core capabilities in the PNT space. Firstly, timing is vital for navigation purposes for accurately calculating speeds and in accurately providing control inputs (the lengths of time that accelerations, and decelerations and turning forces are required for successfully executing a series of navigation manoeuvres). Secondly, timing has an entirely separate but critical purpose for synchronising events in multiple separate places, and for providing stable local frequency references (clocks). For some applications such as high frequency trading, telecommunications, secure communications and for sensitive scientific work, highly-accurate and stable clocks are needed. Humanity has harnessed physics at the atomic level to allow us to build clocks that are so accurate they will only lose or gain 1 second after 40 billion years of running, which is three times longer than the current age of the universe.
In the current era we have become overly dependent on GNSS (Global Navigation Satellite Systems) for providing the vast majority of our PNT needs. The GNSS receiver chips in our smartphones is the size of a grain of sand, costs less than $1USD, and is capable of calculating positions anywhere on Earth with fundamental accuracy better than 1 metre and fundamental timing accuracy around 1 nanosecond. The huge challenge we face therefore is becoming dependent on such an amazing capability, and then losing access to it with no equivalent backups in place. The core principles of resilient PNT aim to reduce the vulnerabilities to single points of failure in our PNT systems that can often occur when all PNT data is being sourced by a GNSS receiver with no fallback plans or backup systems. When PNT services are disrupted, the impacts can be far-reaching, affecting safety, security, and economic performance across multiple sectors.
Positioning and timing services are a critical component of the UK's infrastructure, enabling a diverse range of essential safety, security and economic functions across increasingly interconnected systems.
However, satellite-derived positioning and timing has inherent vulnerabilities, with a risk of disruption and service loss, either due to technological failures, naturally occurring events or malicious activity.
The links below are to resources which will give accessible explanations on the nature of the over-reliance on positioning, navigation and timing, the impacts, and what actions are being taken.
Link 1: RIN-authored report for the National Preparedness Commission on Preparing for a Loss of Positioning and Timing.
Link 2: UK Government Positioning, Navigation and Timing Framework. This framework includes a response plan in the event that current PNT services become unavailable, as well as the creation of a dedicated National PNT Office.
Link 3: RIN-authored White Paper on Recommendations to Promote Resilient PNT.