Introducing Microchip’s 3U OpenVPX Source Card: SV-3200-C00
The PNT source card, developed in alignment with the Sensor Open Systems Architecture (SOSA™) Technical Standard, is a payload slot-compatible plug-in card used to measure and publish PNT data using the All-Source Positioning and Navigation (ASPN) message format.
These concerns can be addressed by integrating robust and resilient PNT components such atomic clocks; GNSS receivers, both civilian and M-Code versions, and an Inertial Measurement Unit (IMU) into a system. However, if this integration is not based on an open standard, the extensibility of the system ends up being limited.
3U OpenVPX Source Card
The PNT source card can be equipped with components such as an M-Code or civilian GNSS receiver, a Miniature Atomic Clock (MAC) or a tactical-grade Inertial Measurement Unit (IMU), and a magnetometer. These components provide precise PNT data that is measured and time stamped by the PNT source card with pico-second level accuracy. The PNT source card works in tandem with the SV-3100 timing card to provide PNT data within a chassis or to other chassis as part of our decentralized timing architecture. The decentralized approach for timing between chassis enables new levels of system federation and simplifies the deployment and configuration of new PNT resources.
We leverage our 30+ years of heritage in delivering timing systems to military and defense applications across the globe. As a market leader, we continually challenge conventional wisdom and are reinventing timing architectures to facilitate autonomous, adaptable and resilient operations using software-defined PNT systems.
Key Features and Options
- Quad-core Arm® Cortex® processor with embedded Linux® Operating System
- PolarFire® FPGA
- Software-defined PNT system configuration at runtime, rather than design time
- PNT sources can be decentralized across PNT systems vs. consolidated in single system
- GNSS or M-Code receiver
- Miniature Atomic Clock (MAC) frequency reference
- Inertial Measurement Unit (IMU)
- Magnetometer
- External PNT reference inputs
Decentralized Architecture
Microchip’s PNT system design is based on the MOSA approach and CMOSS/SOSA standards that enable PNT technologies to be interconnected without limitations. The complete stack of hardware and software designed into our portfolio is in alignment with the SOSA Technical Standard for C5ISR systems, All-Source Positioning and Navigation (ASPN) data model and the PNT Operating System (pntOS) plug-in architecture to collectively create a framework that enables PNT technologies to be mixed and matched to achieve new levels of system performance and flexibility.
Traditional timing cards developed in alignment with the SOSA Technical Standard have taken a stovepipe approach by integrating multiple-core PNT sources into a single card. This is a highly centralized approach that limits the flow of PNT information across a system.
Using a decentralized approach largely eliminates the historical constraints on device placement imposed by hierarchical timing architectures, as there is no predefined flow of PNT information. This eliminates a single point of failure associated with hierarchical models and enhances sensor interoperability across vendors/suppliers.
In other words, the traditional construct of defining an authoritative timing source and then distributing that reference to other substations is neither required nor enforced. Our decentralized PNT architecture allows a PNT source deployed in a local node to be utilized by any other peer node. This enables software-defined run-time configuration so that PNT sources no longer need to be designed onto a card in order to work together, or even installed on multiple cards in the same chassis. The decentralized PNT architecture supports a new generation of resilient PNT for critical air-, land- and sea-based missions.
Traditional Approach to PNT
- Hierarchical architecture creates vulnerable points within the system
- If chassis A becomes compromised, PNT data is unavailable in downstream chassis
Decentralized Approach to PNT
- PNT sources can be deployed independently and within any peer chassis
- Remote PNT sources can be mapped for use by a local PNT system, enabling inter-chassis peer-to-peer PNT resource sharing
Distributed PNT Sources
The key to building resiliency into a PNT system is the distribution of PNT resources in a decentralized manner. Vendors often pack the radial clock card slot with PNT sources, then align payload cards to follow that card. This centralized and hierarchical architecture is fragile and not designed for resilient operation.
Microchip’s approach is to not require all PNT resources to be designed into the radial clock card, rather we put the PNT sources on a payload card to give you greater flexibility in your choice of PNT sources and the number of PNT sources that an application can fuse together. Resilience is built by avoiding a single point of failure within a system or network of systems. Our distributed and decentralized approach promotes upgradability of resources when new technology is available without needing to replace the clock card.
Distributed Operation
In the example below, the PNT source card in chassis A sends the local time reference measurements to the timing card in chassis A. Using software PNT data routing, the MAC is virtualized and sent to chassis B over the asynchronous two-way time transfer fiber link.
Chassis B receives the virtualized MAC and translates it into the local time frame. In parallel, the PNT source card in chassis B time stamps the data from the local IMU and sends it to the timing card. The timing card in chassis B now contains PNT data from the IMU and the MAC in the local time frame.
In the second step of the example, given below, the timing card in chassis B containing PNT data in the local time frame routes the data as an ASPN message to chassis C, over the asynchronous two-way time transfer fiber link.
The timing card in chassis C receives PNT data and translates it to the local time frame. In parallel, the local PNT source card time stamps GNSS observables to the same local time frame. With all PNT sources translated into the local time frame of chassis C, the application developer can construct pntOS software applications using ASPN-formatted measurement data as if all physical PNT sources are local.
Card Functional Block Diagram
PNT Controller and Publisher
Management
PNT Configuration: The specific settings and parameters of the PNT sources, such as the MAC, IMU or GNSS/M-Code receiver, can be configured through the management function of the software. An example of this would be
configuring the elevation mask on the GNSS receiver.
PNT Data Collector: The PNT source card measures and time stamps PNT data from the different sources on the card. Possible data includes GNSS/M-Code logs, MAC stability and phase deviation logs, IMU logs and other data.
PNT Status: Status from on-card PNT sources—for example, MAC temperature or GNSS input CN/o signal level—are reported through this function. Status alarm thresholds can be set by the user to receive notification of faults.
Publishing
PNT Data Format: The PNT source card takes the time stamped PNT data from on-board sources and encodes it in the ASPN message format to be sent to the timing card for processing.
Network/Port Configuration: This setting configures the PNT source card’s network interface so that it can send data to the timing card over the correct channel.
Trigger Rate: This is a user-configurable setting that is related to the frequency of PNT measurements made by the PNT source card, as well as the data transfer rate to the timing card.
PNT Data Transfer: PNT data is continuously time stamped from the on-board PNT sources. This data is published to the timing card within the same chassis for intra-chassis use or routed to a remote chassis using the timing card’s asynchronous two-way time transfer.
PNT Source Options
The PNT source card offers several different configurations of PNT sources on the card to support a decentralized PNT architecture.
- MAC or IMU
- GNSS or M-Code receiver
GNSS/M-Code Receiver
The PNT source card has several configurations that include an M-Code receiver or a GNSS receiver.
The GNSS receiver offers high position availability with multi-constellation, multi-frequency tracking, spoofing detection, interference detection and mitigation. The receiver also features configurable channels to optimize satellite availability in any condition, no matter how challenging.
The M-Code receiver can receive both existing operational GPS signals and M-Code signals. Features include aggressive acquisition and reacquisition strategies to improve performance and reduce power consumption. The receiver can monitor up to 24 satellites and choose the best position.
Inertial Measurement Unit
The IMU is a tactical-grade, low weight and high-performance unit. It contains three very accurate MEMS gyros, three highstability accelerometers and three inclinometers to provide nine degrees of freedom measurements. The IMU also has a customer-configurable output format, sampling rate and filter settings.
Miniature Atomic Clock
The miniature atomic clock rubidium frequency reference enables the PNT source card to be a system reference with excellent holdover during periods of GNSS denial. The internal MAC uses a unique physics package based on the Coherent Population Trapping (CPT) atomic clock. It consumes less power and has broad temperature operation and longer life than legacy lamp-based rubidium clocks.
Stability
Ordering Options
Microchip offers the PNT source card in five configurations to meet the specific needs of our customers. The table below outlines the different options.
About Microchip
Microchip is a world leader in timing and network synchronization systems for highly accurate distribution using today’s precise timing standards like GPS-based timing. Achieving highly accurate precision timing is no easy feat from a technological perspective, so it is important to find a resource you can trust to reduce design risk and speed your time to market.
Microchip’s end-to-end timing solutions generate, distribute and apply precise time for multiple industries, including communications, aerospace and defense, IT infrastructure, financial services and power utilities. Providing a broad portfolio of clock and timing systems, Microchip has applied expertise in PNT and products that support the SOSA standard to provide world-class solutions for customers.
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