ArcEdge Space Completes JAXA Commissioned Study on Dedicated LEO PNT Element Technologies

ArcEdge Space, Inc. (HQ: Koto-ku, Tokyo; CEO: Takayoshi Fukuyo), which provides comprehensive solutions for small-satellite constellations from planning and design to mass production and operation, announced the completion of the 2025 JAXA-commissioned project: 'Study on Element Technologies and Related Systems for Dedicated Low Earth Orbit Positioning, Navigation, and Timing (LEO PNT)'.

LEO PNT is a new system expected to provide global information required for determining the location of objects on Earth and precise timing, utilizing a constellation of ultra-small satellites orbiting at low altitudes of 500–1,200 km—about one-twentieth the altitude of existing GNSS systems (approx. 20,000 km).

In recent years, existing GNSS has become a vital source for location data and a critical infrastructure for precise time synchronization in sectors like finance, telecommunications, and power. However, with the deteriorating global security environment, jamming and spoofing have become urgent threats that must be addressed.

In this project, we explored and organized the necessary element technologies, signal designs, receiver technologies, and overall system frameworks to realize a robust LEO PNT system that can provide location and timing information without relying on GNSS, even in scenarios where it is unavailable.

Achieving precise orbit-time determination for LEO satellites without GNSS was a critical challenge. To resolve this without installing large atomic clocks—which increase satellite size and costs—we investigated a new architecture. This involves sharing information from ground-based precision time sources (e.g., Pseudolites) via inter-satellite optical communication to achieve on-orbit synchronization.

Additionally, we studied measures to strengthen anti-jamming capabilities, including frequency diversification, new signal design and receiver specifications, and encryption/authentication tailored for LEO satellites. These efforts yielded results that will facilitate further study and development of a more robust, GNSS-independent positioning and timing service.

Project Overview: Name: Study on Element Technologies and Related Systems for Dedicated LEO PNT Objective: Summarize the prerequisites and work requirements for a LEO PNT system capable of providing robust positioning and timing services that mitigate GNSS vulnerabilities. Scope: - Study and organization of GNSS-independent LEO PNT element technologies - LEO PNT signal design - Study of LEO PNT signal reception technology - System study, etc. Duration: September 2025 – March 2026

Key Achievements: 1. Organization of GNSS-Independent Orbit-Time Determination Methods We explored methods to maintain satellite positioning functions without relying on GNSS under scenarios where GNSS signals are completely unavailable due to jamming. We compared methods such as transmitting time information from ground Pseudolites and using inter-satellite optical communication for on-orbit precision tracking, deepening our analysis for system-wide optimization. 2. Study of Satellite Constellation Configuration To realize a LEO PNT system, we analyzed configurations considering service specifications and economic efficiency, including orbit altitude, satellite numbers, and ground station (Pseudolites) deployment, leading to a realistic roadmap for future LEO positioning services.