Embedded Avionics, Military

Northrop Grumman’s E-2D, F-22 Embedded GPS System Upgrade to Run on INTEGRITY-178 RTOS

Northrop Grumman selected a real time operating system to be provided by Green Hills Software to develop an upgraded embedded GPS system for E-2D Hawkeye and F-22 Raptor aircraft. Photo: U.S. Air Force.

Northrop Grumman’s $59 million contract to develop an upgraded embedded GPS system for E-2D Hawkeye and F-22 Raptor aircraft will run on a real time operating system (RTOS) supplied by Green Hills Software.

The embedded GPS/INS-modernization (EGI-M) program was first awarded by the U.S. Air Force in November 2018, with the goal of providing E-2Ds and F-22s a new open-system architecture capable of rapidly integrating new capabilities. Green Hills Software announced the selection of its INTEGRITY-178 Time-Variant Unified Multi Processing (tuMP) RTOS running on a quad-core ARM Cortex A53 central processing unit for EGI-M program development on Feb. 28.

Northrop Grumman is currently in the midst of a detailed hardware and software design phase for the EGI-M system and expects to complete a critical design review for it by the third quarter of 2020. Naveen Joshi, director of strategy and business development for Northrop Grumman’s navigation and positioning systems business unit told Avionics International that under the EGI-M contract, the F-22’s inertial navigation system, LN-100, will be upgraded to the LN-300. The E-2D’s LN-251 will also be upgraded to the LN-351.

“EGI-M will provide three main capabilities at the end of engineering, manufacturing and development. First, EGI-M integrates a new M-Code capable GPS receiver which provides improved performance in various operating environments. Second, EGI-M includes a new resilient (non-GPS based) timing capability to aide with aircraft network and subsystem timing requirements. Finally, EGI-M is being developed to stringent DO-178 and DO-254 design processes which support safety certification and interoperability in civil controlled airspace,” Joshi said.

Using the INTEGRITY system, EGI-M’s embedded architecture will feature model-based partitioned software that is capable of meeting DO-178C certification while utilizing a multi-core processor. As with other avionics upgrade programs, a major goal for the U.S. Air Force on the EGI-M program is to enable to a much more flexible open systems architecture that is also secure.

Joshi said this was one of the leading factors behind their decision to select the INTEGRITY-178 RTOS. It will also support Northrop’s goal of achieving MSO-C145 certification, which the U.S. military uses to assess the performance of airborne navigation sensors.

“EGI-M negates the risk of vendor lock by providing the U.S. Government ownership of all key interfaces and unlimited rights to most hardware subassemblies in the common EGI-M product line. The technology is designed to be a future Assured Positioning, Navigation and Timing (A-PNT) Hub with spare processing, additional I/O, and a modular software architecture that comes with a software development kit (SDK). The SDK enables third parties to develop PNT applications in EGI-M, operating in a separate ‘partition’ from flight safety and cyber-secure software areas running critical navigation functions,” Joshi said.

Green Hills describes the INTEGRITY-178 system as using asymmetric multi-processing (AMP) and bound multi-processing (BMP) in a time-partitioned manner on a multicore processor.

Dan O’Dowd, founder and chief executive officer of Green Hills Software, said in a statement that the system was “designed from the beginning to be a multicore RTOS,” and is the “only FACE-conformant RTOS that has ability to run a DAL-A partition across multiple cores and mitigate multicore interference per CAST-32A.”

A representative for Green Hills Software told Avionics that the INTEGRITY system enables a major advancement in assigning applications to processor cores and achieves the embedded computing industry’s highest rate of processor utilization.

“Because INTEGRITY-178 tuMP goes beyond just providing a Multiple Independent Levels of Security (MILS) operating environment by supporting Multi-Level Security (MLS) applications, the integrator can devote more of their development and runtime resources to end-user functionality instead of security infrastructure,” the representative said.

Another major factor in Northrop’s selection of INTEGRITY was its ability to safely address the interference issues that are outlined in the CAST-32A position paper that currently serves as the official global regulatory guidance for ensuring safe implementation of multicore processing within avionics systems. Both EASA and FAA plan to release new regulatory policy updates concerning multicore processors in avionics systems later this year.

“Without a general solution to multicore interference mitigation, the integrator must hand tune the placement and timing of applications running simultaneously on different processor cores. That hand tuning breaks when a new application is added or an existing one is modified, which requires retesting and revalidating the entire system.  INTEGRITY-178 tuMP enables the integrator to regulate the bandwidth to shared resources on a core-by-core basis so that changing an application on one core will not affect applications running simultaneously on other cores,” the representative for Green Hills said.

Green Hills has completed delivery of the specific version of the Integrity-178 RTOS that Northrop is using for their quad-A53 processor system as part of EGI-M development.

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