In a contested battlefield, access to assured positioning, navigation, and timing (APNT) is critical for boosting situational awareness, ensuring secure communications, and making real-time decisions. To gather that necessary information, military services across the Department of Defense are leveraging the latest advancements in APNT solutions for foot troops, and all vehicles whether on the ground, sea, or air.
Providing APNT solutions across the battlefield is critical. Soldier-worn, ruggedized solutions with anti-jamming capabilities can still pinpoint the exact time and location of the signal even when GPS signals are jammed and under attack. In a recent interview with Matthew Bousselot, Technical Fellow, PNT Systems Engineering at Collins Aerospace, we spoke about the next generation of capabilities for PNT and the distribution of the data in the contested battlefield.
“PNT distribution is simply the ability for your system to send that PNT data to the systems and users within the platform,” Bousselot said. “This could be sending position and timing information to a comm radio, a targeting system, or a display with mapping capability in the vehicle.”
Many systems use GPS as their position and timing source, but as satellites become more vulnerable to attack, there is a need to harden GPS receivers and augment them with other sensors for a layered navigation approach to mission-critical systems, Bousselot explained.
Now, with many of the systems incorporating GPS receivers within vehicles and mobile comms devices, eventually, the challenge is to ensure proper functionality in a threat environment and do so without having to remove and replace all existing systems that are currently using GPS information. At this point, the DoD must consider how they will integrate PNT data into the receivers. They may retrofit platforms or forward-fit them, Bousselot said, but that is where APNT distribution plays a significant role.
Bousselot outlines a few ways to address this problem that many military customers are facing:
Embracing Open Systems Architecture: When looking at the forward fit platform approach, the DoD is leaning heavily on an Open Systems Architecture (OSA). As they redesign the vehicle’s platform, they are integrating individual sensors and systems that use a common digital interface for standardization, Bousselot explained. For example, leveraging VICTORY, which is a common standard Ethernet interface, allows systems in the vehicle to talk to each other.
Retrofitting the DAGR: When forward fitting a platform is not a reality, the DoD is looking to retrofit GPS receivers, such as the Defense Advanced GPS Receiver (DAGR), to receive alternative PNT data. Modern APNT systems can seamlessly integrate with existing vehicle systems by providing new information over the IS-GPS-153 interface, which is the legacy GPS standard. In addition, this PNT distribution method supports additional interfaces such as HAVEQUICK, SINCGARS, 1PPS time synchronization, and multiple serial ports in a single DAGR emulator. Instead of purchasing multiple DAGR emulators to distribute various PNT data, Bousselot explained that the current Collins Aerospace solution incorporates four DAGR emulators into one sole APNT system.
Radio Frequency (RF) Distribution: In the other two APNT distribution examples that Bousselot shared, the data distribution relies on access to a data port in the vehicle system that receives PNT data. Yet, in legacy vehicle systems, there may not be a data port to receive the new PNT data, especially in systems with embedded GPS receivers, such as a comms radio. That is where RF distribution comes in handy. By integrating an RF signal into an APNT distribution solution, it can emulate a signal to look like it’s coming from a GPS satellite, Bousselot explained. While some vehicles may have upwards of 10 receivers, both military and commercial, they are all typically connected to a common GPS antenna, making PNT RF distribution a simple integration solution. Once the PNT RF distribution is implemented, all GPS receivers in the vehicle are provided a multi-sensor APNT solution. This enables continued position and timing when the GPS signal in space is degraded or denied.