The intent of this research opportunity is to incorporate resilient and flexible forward error correction (FEC) techniques into next generation Global Navigation Satellite Systems (GNSS) for ultra-reliable low-latency GNSS-enabled PNT information, which enhances real-time situational awareness for command and control, synchronizes communications, and enables the accuracy and efficiency of DoD capabilities at every point in a time-critical kill chain, all of which work together to field a lethal, resilient, and highly adaptable Joint Force. GNSS-enabled PNT service will be determined to be ultra-reliable and low latency compliant if it continues to provide reliable PNT information over the time period required by a specific mission at certain levels of timeliness and accuracy required by the time-critical mission in the contested physical, electromagnetic, and cyber environment.
While Low-Density Parity-Check (LDPC), convolutional codes and the likes will remain the cornerstone FEC capability for GNSS-enabled PNT services, theoretical performance limits of such finite-length coded schemes have not been explored at all. Therefore, it is not clear how effective and efficient the existing FEC designs are in terms of near-capacity performance, time to first fix, bit-level error correction, packet-level erasure protection, and urban multi-path fading environments. Of the various components within this tech need, the development is needed in: i) Diverse navigation data structures, including evolving short and very short block lengths; ii) Low latency FEC codes having flexible code rates and lengths, pre/post bit error rates, operations per bit; iii) Information-theoretical limits for overlaying short and very-short FEC codes onto existing families of satellite spreading codes and navigation modulations; and iv) Fast and scalable signal processing techniques subject to size, weight, and power requirements.
References
1. T.-K. Le, U. Salim, and F. Kaltenberger, “An Overview of Physical Layer Design for Ultra- Reliable Low-Latency Communications in 3GPP Releases 15, 16, and 17,” IEEE Access, vol. 9, pp. 433–444, 2021.
2. Congress, “Spectrum Interference Issues: Ligado, the L-Band, and GPS,” Congressional Research Service. Available online at https://crsreports.congress.gov/product/pdf/IF/IF11558, 2020.
Forward error correction; ultra-reliable low-latency GNSS; flexible code rates; scalable signal processing; information-theoretic limits