GPS and GNSS technologies have gained popularity in recent years in the fields of aviation, autonomous vehicles, maritime operations, and defense. But what happens when signals are blocked, jammed, or inaccessible? Urban canyons, underwater, tunnel-like structures, and interference zones do not have any conventional systems;7 this is the domain of INS.
INS operates entirely autonomously. Their monitoring of the position of the system is done through an internal accelerometer and gyroscope sensor suite. This article covers the above and highlights the significance of inertial navigation systems in the absence of GNSS signals and the importance of seamless operations during outages of satellite systems.
What Is a GNSS-Denied Environment, and Why Does It Matter?
The use of satellite-based navigation systems for tracking shipments and traveling internationally has made life easy. No doubt, it all has its advantages, but the restrictions in GNSS-covered areas must also have their relevance. The term GNSS denied Environment refers to the conditions in which satellite signals are at risk of being blocked, degraded, or disrupted. In these situations, operations dependent on the satellite systems become more and more unreliable. The risk of unavailability poses dependency on technologies such as Inertial Navigation Systems (INS), which in turn makes a balanced reliance harder to maintain.
Understanding GNSS (Global Navigation Satellite Systems)
Global Navigation Satellite Systems (GNSS) are a constellation of satellite systems that provide geo-spatial positioning for users on Earth. Some common systems are:
- GPS (Global Positioning System) – Operated by the United States
- GLONASS – Developed by Russia
- Galileo – Maintained by the European Union
- BeiDou – China’s satellite navigation system
Apart from geo-spatial information, these systems provide advanced functionalities like smartphone navigation, routing for commercial flights, precision farming, and prompt actions during emergencies. They also serve as critical infrastructure that supports the execution of daily activities.
What Makes an Environment “GNSS-Denied”?
An environment where one cannot access the satellite navigation signals is called a GNSS denied environment. These scenarios may occur in nature or even be created deliberately. For example:
- Facilities Located Underground, such as tunnels and mines.
- Underwater Operations that are deeply submerged.
- Indoor Spaces where the structure of the building obstructs satellite signals.
- Spoofing and jamming urban canyon areas where military aggressors disable access to GNSS systems.
Concerns regarding the denial of signals being spoofed and jammed have become more prevalent with rising cases of cyber warfare. The ability to intercept and manipulate signals poses risks not only to drones but to aircraft and ground troops as well.
Enter Inertial Navigation Systems (INS): The Reliable Backup
Unlike other navigation systems, Inertial Navigation Systems (INS) do not require external assistance. Their importance is clearly seen in scenarios when external systems cease to function, where critical navigation tasks need to be performed. Dependence on GNSS proves to be a major drawback in situations where precision is vital.
What Are Inertial Navigation Systems and How Do They Work?
For inertial navigation systems (INS), external information is of no use since they operate through onboard sensors. However, a vehicle’s operation will be considerably smoother if important information like position, velocity, orientation, among other things, and a set of multiple sensors are placed on the vehicle. Such self-contained systems contain the following components:
- Direction sensors are known as accelerometers.
- Rotational responses are measured by devices known as gyroscopes.
With no need for satellites or other reference beacons, an Inertial Navigation System (INS) is capable of determining an object’s current position, speed, and trajectory relative to a fixed starting point. The complete autonomy of the system makes it ideal for use in situations where GNSS is not accessible, blocked, or has been manipulated.
The Advantages of INS in GNSS-Denied Zones
An INS provides critical value in the absence of GNSS due to:
- Flexibility of Operation: The INS is functional in underwater, indoor, over-the-horizon contexts, and during GNSS outages or hostile jamming activities.
- Spoofing and Cyber Attack Protection: INS is immune to spoofing and cyber attacks, which makes it dependable for sensitive missions that require defense-grade security.
- When used with GNSS, an INS can smoothly sustain operation through short signal loss as one module works while the other corrects long-term drift. With unmatchable accuracy, this configuration provides dependability that is impossible to lose.
Rather than viewing the INS as a backup to GNSS, the industry now considers it a fundamental part of navigation systems, especially during dynamic, time-critical, or high-stakes events.
Why Inertial Navigation Systems Are a Must-Have in High-Stakes Applications ?
In critical areas like the military, movement precision and reliable access to highly controlled or restricted areas are key to mission success. Whether flying and traveling deep into the sea or on the ground, navigation is unimpeded. GPS technologies do not operate in these areas, and so INS systems are imperative.
➤ Aerospace and Aviation
The aerospace and aviation sectors also grapple with the absence, or total unavailability, of GPS systems. During flights, GNSS signals are subject to jamming, interference, or geographic obstacles. This situational reliance creates untrustworthy circumstantial navigation dependencies. Alternative methods for navigating are equally vital under such conditions.
INS systems offer consistent satellite navigation during both short and long outages by tracking the position of the aircraft. This type of EMT redundancy is critical to commercial and military aircraft flight safety, regulatory requirements, and mission-critical objectives during all phases of flight.
➤ Submarines and Underwater Operations
Submersibles like submarines, ROVs, and AUVs rely on inertial navigation systems internally due to the lack of GNSS signals above the surface of the water.
Without an INS, vessels would have great difficulties operating below the surface during military missions, deep-sea research, or underwater construction work. Designing a safe and accurate pathway for navigation would be impractical.
➤ Military and Defense Technology
Modern warfare incorporates methods such as e-attacks on nav systems. Spoofing and jamming of satellite signals are a growing concern in modern warfare, introducing even more dangers to satellite signals.
Space signals are of vital importance for modern military operations. For stealth, high-priority tactical combat, and maneuvering into heavily defended areas, these capabilities need to be protected. During electronic warfare maneuvers, advanced INS technologies are required. These systems allow personnel and equipment to operate unhindered in contested environments.
Trusted Inertial Navigation Solutions Built for Challenging Conditions
Safran Navigation & Timing is the world leader in Inertial Navigation Systems, and its systems stand out by ensuring accurate navigation even deep underground, underwater, or in hostile terrain. Safran develops advanced systems designed to operate in GNSS-denied environments.
Why Industry Leaders Rely on Advanced INS Solutions?
Like any other system, an inertial navigation system (INS) will vary in quality. The best hyperspectral imaging solutions can be differentiated by:
- High-grade sensors that capture drift-free, accurate, and consistently reliable data.
- Ability to endure rugged and harsh operating environments.
- Ease of system integration due to modular and scalable designs.
These attributes, paired with agility, solidify hyperspectral imaging systems as a fundamental tool in numerous industries.
Safran’s Inertial Navigation Systems: Engineered for Mission-Critical Accuracy
Safran specializes in these types of technologies, focusing on the terrain, air, and maritime domains. Known for their innovative dependability, the inertial navigation systems are critical for supporting defense operations, civil aviation and geo-information, geospatial intelligence, GNSS denied operations, and other sophisticated services.
Examples of some of the offered products include:
- Sigma 95 – An aviation high-performance system using inertia aiding for flight continuity during restriction or jammed airspace.
- Geonyx™ – These INS are perfectly suited for combat situations where GPS signals are blocked, due to their use in military vehicles and artillery.
- Navsight – A modular INS aids tailored for surveying and mapping professionals where GNSS signals are lacking.
Where precision is required, Safran stands unmatched in providing navigation solutions, solidifying its reputation in the entire industry.
Final Thoughts: When Signals Disappear, INS Steps In
For systems that require reference signals to sustain navigation, such as in tunnels, deep underwater, or in contested electronic warfare environments, INS is vital. Unlike satellite systems, INS does not need outside signals, as systems based on internal signal generation ensure a constant stream of position and directional data. It is preferred in aviation and maritime operations because of its critical accuracy.
Navigating Tomorrow’s Challenges with Confidence
Operations complexity continues to grow for armed forces while satellite navigation faces increasing threats. Whether cruising at thirty thousand feet, diving to ocean depths, or moving through contested battle spaces, robust military-grade INS are critically needed. These scenarios enhance situational awareness while tailored real-time navigation enables seamless trusted systems.
