Gain tactical advantage with 3D NAVWAR simulation in the lab

Increased use of spoofing and jamming by nation states is driving up demand for robust and resilient positioning, navigation and timing (PNT) solutions. But replicating realistic NAVWAR scenarios in the lab can be challenging, particularly since multiple interference sources may be present in a conflict zone.

In a recent webinar with Inside GNSS and Inside Unmanned Systems, three Spirent specialists discussed the complex nature of today’s NAVWAR tactics and considered the challenges of testing offensive and defensive solutions in the lab. The NAVWAR testing and 3D modeling capabilities of Spirent PNT X were presented, along with the results of a series of tests run using PNT X.

You can register to watch the recorded webinar, or find the summary below.

The rise of global NAVWAR

Tactics like RF jamming and GNSS signal spoofing have been around for years, but their use by nation states is growing rapidly. A new study from OPSGROUP records a 500% increase in spoofing incidents in Q3 2024 compared to the first two quarters, rising from c.300 per day to 1,500 per day worldwide. The website gpsjam.org, meanwhile, shows that daily patterns of GNSS interference encountered by aircraft have intensified significantly in the past two years.

The increased use of NAVWAR is spurring development of ever more sophisticated defensive capabilities, including controlled radiation pattern antennas (CRPAs), encrypted signals, signal authentication, and alternative PNT solutions. All these capabilities must go through a rigorous testing process, often starting in software and progressing to RF simulation in the lab before finally being tested in a live sky environment—typically on an outdoor test range.

The more testing that can be completed in the lab, the more comprehensive the testing can be, and the faster and more cost-effective the development. Until now, however, developers have lacked the ability to re-create the complexity of real world GNSS-contested environments with simulation equipment. In particular, the impact of the physical terrain on PNT signals and interference sources has been challenging to model realistically, with simulations often falling back on statistical modeling for effects like signal obscuration, diffraction and multipath.

Creating realistic 3D NAVWAR scenarios in PNT X

There are a number of key concepts to understand in order to test and develop robust solutions. This webinar focuses on two in particular; firstly, how the distance between the receiver and the interference source affects the performance of the receiver and the effectiveness of the jammer or spoofer; and secondly, how the impact of the interference on the receiver is also affected by the physical environment.

A real-world scenario can be extremely complex, featuring multiple interference sources of differing types and potentially situated at different altitudes, along with physical terrain that blocks, reflects or diffracts RF signals.

This is complex enough to simulate with static receivers and interference sources, but real-world NAVWAR scenarios are often dynamic, with transmitters and receivers moving relative to each other. In some cases—such as a fighter jet flying through an area of interference—the movement is extremely fast.

For the example explored here, we can consider three key capabilities delivered by the simulation equipment. The first is continuous dynamic range, where the power of the interference source(s) can be continually represented dynamically in relation to the position of the receiver. For example, if the receiver is moving closer to the interference source, the simulator should emulate the increasing strength of the received interference waveform coherently with the changing relative position.

The second is realistic 3D terrain modelling, ideally using 3D maps to render physical features such as mountains, gullies, tree cover, tunnels, etc. Combined with this, the third is ray-tracing capabilities to accurately model the effects of the terrain on both the navigation signals and interference waveforms. As is explained in this webinar, the impacts can be significant and even counterintuitive.

Demonstrating the results of NAVWAR testing in PNT X

In the final part of the webinar, Spirent’s Senior Staff Systems Engineer Esther Anyaegbu demonstrates the kinds of fine-grained insights that can be achieved using the continuous dynamic range and 3D terrain modelling capabilities of Spirent PNT X, the ultimate test platform for mission-critical PNT and NAVWAR capabilities.

The experiment highlights the impact of intermittent signal obscuration of the jamming beacons from the vehicle under test. It also demonstrates the impact of diffracted jamming signals when the beacon is not in view. The results demonstrate how exposing a receiver to constant line-of-sight interference is not sufficient to evaluate its impact.

Being able to achieve these insights in the lab means that more design work can be done on the receiver at an earlier stage, accelerating the development of novel offensive and defensive NAVWAR techniques, reducing the cost of development, and thus conferring significant tactical advantage.

Learn more about NAVWAR testing with PNT X

If you’d like to know more about NAVWAR testing with PNT X, you can register to watch the recorded webinar, visit the website, or get in touch.