White Paper

w w w. m r c y. c o m WHITE PAPER 4 ACE uses hardware to offload the Ethernet stack, uses strict time and space partitioning and runs ARINC 653 RTOS-based software. The user datagram protocol/internet protocol (UDP/IP) stack through fine- tuning of the supported features associated with a fixed, pre-defined address plan configuration removes the primary sources of Ethernet's non-determinism. The ACE software interface is based on simple communication channels associated to defined sets of Ethernet addresses and ports (MAC, IP, and UDP). It supports broadcast and multicast addressing. ACE manages random traffic internet control message protocol (ICMP) and aerospace recommended practice (ARP) with low priority to guarantee that this traffic never affects the real-time data flow through communication channels. ACE provides hardware mechanisms to filter poorly formatted Ethernet frames and frames addressed to inactive destination ports. An additional end-to-end integrity checking mechanism guaranties the correctness of all data received, from CPU memory to CPU memory (not always via Ethernet connectivity). Embedded commanded built-in test (CBIT) mechanisms monitors all types of detected errors for real-time safety and security analysis by software application. Time Synchronization EGNOS algorithms rely on precise and accurate time synchronization over the entire network. Each station locally distributes a precise time clock, using GPS and local atomic clocks. Each ECCP subsystem internally generates a highly precise clock to synchronize the software partition scheduling. This internal clock smoothly tracks the station reference signal with precise monitoring of its synchronization state. This internal clock generator acts as a safety barrier. Secure Boot and Secure Linux The EGNOS GPS processing solution feature robust system-wide, built- in security. This security is native to Mercury's pre-engineered compute building blocks. Augmenting this security is additional encryption and authentication mechanisms are embedded into the hardware to protect EGNOS computers from unauthorized, malicious and cyber-attack vectors. Secure Linux runs on ECCP-1 single SBC version to provide front-end communication between European stations. The secure-boot guarantees the authentication of the secure Linux kernel and its root file-system at startup. Security features authenticate communication through a dedicated network between EGNOS stations and provides continuous safety and security reports. Each front-end station continuously monitors the heartbeats of all other ECCPs inside the station to detect any dysfunction and raise alarms in case of anomaly. Board Support Packages Mercury provides complete and full board support packages (BSPs) and drivers for COTS RTOS including the boot loader, BIT, health monitoring, security features and others. System integration and software installation is completed using the comprehensive software that is supplied. System Safety Requirements EGNOS was able to leverage Mercury's pre-engineered, open system compute building blocks, which are designed for quick, low risk integration into mission-critical and high-reliability processing subsystems requiring the highest level of flight-safety certification. This includes requirement-based development, extended life cycle support, safety analysis and global time and space partitioning constraints that affect both hardware and software designs. Mercury's ARINC 653 RTOS domain expertise orientates the I/O design, which integrates hardware buffers, time-controlled DMAs and safety barriers to enable full partition embedded driver models. This driver model simplifies robust partitioning analysis. Summary Mercury developed high-performance, modular ground station compute solutions that leveraged our pre-engineered BuiltSAFE OpenVPX ecosystem, which includes the multi-safety zone ROCK2 chassis. BuiltSAFE ROCK2 chassis are a modular, programmable and scalable architecture built on advanced embedded GPU, high-performance and safety certifiable processors with dedicated hardware assistance. Proven ROCK2 computers have been deployed in space and remotely piloted aircraft system (RPAS) ground stations to meet the security, performance and safety requirements of today and tomorrow.

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