NaviMoon project validates GNSS technology for future Moon missions

NaviMoon advanced autonomous GNSS receiver. (Photo: SpacePNT)

SpacePNT and European Engineering and Consultancy (EECL) have completed the final presentation of the European Space Agency (ESA)-funded Earth Moon GNSS Spaceborne Receiver for In-Orbit Demonstration project. This project aimed to develop and qualify the NaviMoon GNSS spaceborne receiver for lunar applications.

Currently, geostationary orbit (GEO) and geostationary transfer orbit (GTO) missions utilize GNSS signals for in-orbit positioning, navigation and timing (PNT). NASA’s Magnetospheric Multiscale (MMS) mission has shown that GPS signal tracking is possible up to 150,000 km from Earth’s surface, which is half the distance to the Moon. ESA has assessed the feasibility of extending GNSS use for lunar missions through studies under its General Studies Program (GSP). These studies indicate that lunar navigation using GNSS might be feasible if specific high-sensitivity techniques are implemented in GNSS spaceborne receivers.

NaviMoon is an advanced version of SpacePNT’s spaceborne GNSS receiver NaviLEO. It supports dual constellation (GPS and Galileo) and dual frequency (E1/L1 and E5a/L5) operation. The receiver is based on commercial off-the-shelf (COTS) components with radiation mitigation measures. It features fast digital signal processing in hardware and handles acquisition, tracking control and navigation in software. NaviMoon also includes a dedicated microcontroller for interface management and can be reprogrammed in flight.

EECL contributed to the project by providing the GNSS reflectometry front end for remote sensing. The company developed the lunar low-noise amplifier (LNA), which is crucial for detecting ultra-weak signals at lunar distances.

The NaviMoon project involved comprehensive testing, including mechanical tests, thermal vacuum tests, electromagnetic compatibility testing and a full GNSS test campaign. The presentation shared that it is a robust platform with high radiation tolerance and environmental performance. It aims to deliver less than 100 m accuracy at Moon distance while reducing dependence on costly Earth infrastructure for orbit determination.

This project was funded under ESA’s NAVISP program, which is dedicated to European industrial technology innovation in the PNT sector. It also received support from ESA’s GNSS Science Advisory Committee (GSAC).