GNSS

US and Australia collaborate to Eehance GPS resilience

Members of the Australian Department of Defence recently joined forces with the Joint Navigation Warfare Center to put GPS devices to the test. The goal was to assess their performance under simulated jamming conditions and enhance their resilience in contested environments.

The DAGR, a widely used GPS device by both U.S. and allied forces, plays a critical role in land, sea and air navigation. By subjecting it to an anechoic chamber that mimics contested and limited GPS conditions, the team aimed to uncover insights that could enhance its resilience. www.315aw.afrc.af.mil

FCC takes important step towards new band plan

NextNav announced that the Federal Communications Commission (FCC) released a public notice seeking comment on its innovative spectrum solution in the Lower 900 MHz band (902-928 MHz band).

On April 16, NextNav filed a rulemaking petition asking the FCC to open this proceeding to reconfigure the Lower 900 MHz band and adopt new rules to enable a terrestrial 3D PNT network to complement and back up the Global Positioning System (“GPS”). This rearrangement of the band would also free up 15 MHz of valuable low-band spectrum for 5G broadband while appropriately protecting incumbent operations.

The FCC has requested comments from the public on this proceeding that are due September 5, 2024, followed by reply comments due September 20, 2024. The Commission then considers the comments and reply comments in developing proposed rules.

NextNav is the primary geographic licensee in the Lower 900 MHz Band and has used its existing licenses to develop industry-leading PNT expertise and products. However, much of this band is underutilized due to a legacy band plan and rules. Reconfiguring the band would pave the way for terrestrial PNT services as a complement and backup to GPS. It also would open 15 MHz of low-band spectrum for 5G broadband. https://nextnav.com

New IGS Analysis Center Coordinator Announced

The International GNSS Service (IGS) Governing Board and Central Bureau have announced that the next IGS Analysis Center Coordinator (ACC) will be a collaborative effort led by the NASA Goddard Space Flight Center and Geoscience Australia, with support from GFZ German Research Centre for Geosciences Potsdam and the Massachusetts Institute of Technology.

The ACC is responsible for establishing the detailed specifications for IGS products, while working closely with ACs and the IGS Reference Frame Coordinator. The new NASA/GA+ ACC will undertake a phased approach to ensure a smooth and thorough transition towards a fully multi-GNSS IGS, enhancing the accuracy and reliability of future GNSS products, while working towards achieving the IGS strategic goal of “multi-GNSS Technical Excellence.”

Lockheed Martin receives Laser Retroflector Arrays for GPS III SV9, SV10

In partnership with NASA and the National Geospatial-Intelligence Agency, the U.S. Space Force GPS III Program Office has delivered two laser retroflector arrays to Lockheed Martin. On May 6, the LRAs were delivered under a directed program to rapidly integrate hosted payloads on GPS satellites ahead of launch call up. The LRAs will be installed onto two GPS III satellites, SV9 and SV10, in preparation for a 2025 launch.

The addition of the LRA hosted payload onto GPS satellites marks an expansion of NASA’s Space Geodesy Program space instrument network. The GPS III LRAs will allow NASA to make precise range measurements to the sub-centimeter level using the Satellite Laser Ranging technique, enabling accurate determination of the Earth’s center. The NASA Space Geodesy Program and NGA will use collected SLR data from the GPS III LRAs to maintain a globally available, high quality terrestrial reference frame.

The LRA instrument is an array of passive “Corner Cubes” that reflects laser light back to a transmitting SLR ground station. By measuring the round-trip time of the laser pulse, the ground stations are able to accurately measure the orbit of the GPS satellite. SLR can achieve millimeter-level precise orbits, which enables the scientific community to also conduct fundamental physics experiments in general relativity, as well as Earth monitoring missions, to include sea level changes, and mass redistribution in the Earth-ocean-atmosphere system.

Galileo Performance Reports for Q1 2024 are now available!

The Galileo Open Service (OS), the Galileo High Accuracy Service (HAS) and the Enhanced Search and Rescue (SAR) service performance reports for Q1 2024 are available at the European GNSS Service Centre electronic library, providing the status of the Galileo constellation and the achieved performance.

The quarterly reports provide information to users on parameters such as:
• Galileo OS: Ranging Performance, Galileo UTC and Galileo-GPS Time Offset (GGTO) Dissemination and Determination Performance, Galileo Positioning Performance, the Timely Publication of NAGUs (Notice Advisory to Galileo Users).
• Galileo HAS: Accuracy and Availability of the HAS corrections, and Service Coverage.
• SAR/Galileo Enhanced Services: Forward Link Service, Detection and Location Performance, Return Link Service, Return Link Message (RLM) Delivery Latency and Reception Probability Performance, European MEOLUT and Space Segment Availability Performance.

www.gsc-europa.eu/news/galileoperformance-reports-for-q1- 2024-are-now-available