Category: Space & Earth

Suborbital flight demonstrates interoperability of GNSS receivers
At sunrise on Oct. 1, 2024, SL-15 launched into a perfectly clear blue sky over the desert from Spaceport America, in Las Cruces, New Mexico. The flight — conducted by UP Aerospace with support from NASA’s Flight Opportunities program — carried aloft the payloads and hopes of researchers from three countries — Italy, Germany and the United States — and ten organizations.

Spaceport America, the first commercial spaceport in the world, is an FAA-licensed launch complex. Situated on 18,000 acres adjacent to the U.S. Army White Sands Missile Range in southern New Mexico, it has a rocket-friendly environment of 6,000 square miles of restricted airspace, low population density, a 12,000 ft by 200 ft runway, vertical launch complexes and about 340 days of sunshine and low humidity.

UP Aerospace, a Denver-based company created in 1998, conducted its first suborbital flight from Spaceport America in 2006, which was also the inaugural flight from the spaceport. UP Aerospace maintains a launch complex, a payload processing center and a space propulsion center at the spaceport. Its launch operations and SpaceLoft suborbital launch vehicle were designed and built as a reliable, low-cost Reusable Launch Vehicle (RLV) system.

NASA’s Flight Opportunities program rapidly demonstrates technologies developed by industry, academia, as well as NASA and other government scientists through testing with various commercial flight providers. The program matures capabilities needed for NASA missions and commercial applications while strategically investing in the growth of the U.S. commercial space industry. Available flight platforms include suborbital rockets, rocket-powered landers, aircraft flying parabolic profiles to achieve reduced gravity, high-altitude balloons, and hosted orbital vehicles.

Interoperability test

One of the payloads carried to suborbital heights by the SL-15 rocket was a suite of multi-GNSS receivers from NASA’s Space Communications and Navigation (SCaN) program, the European Space Agency (ESA) / European Space Operations Centre (ESOC), the Italian Space Agency (Agenzia Spaziale Italiana or ASI), and their contractors Fraunhofer (a German, publicly owned research and development organization) and Qascom (a private Italian engineering company offering security solutions in satellite navigation and space cybersecurity). A key goal of the flight test was to determine the scope of the interoperability of these receivers. The full results of the test will be presented at the intercessional meeting of the International Committee on GNSS (ICG), a part of the United Nations Committee for the Peaceful Uses of Outer Space (COPUOS) in Vienna in June 2025.

QN400-SPACE (GARHEO) SL-15 altitude profile. (Photo: ASI/Qascom)

QN400-SPACE (GARHEO) SL-15 velocity profile. (Photo: ASI/Qascom)

One of the other payloads on the flight was an experiment by the New Mexico Institute of Mining and Technology — aka New Mexico Tech — on spacecraft health monitoring and real-time systems built by the company Immortal Data, which also tested out and collected environmental data on some of its own equipment as it relates to product development. Another payload was an advanced prototype Automatic Dependent Surveillance-Broadcast (ADS-B) transmitter that could potentially be used for independent, low-cost tracking of space launch vehicles.

Lisa Valencia, an electrical engineer for Overlook Systems Technologies, Inc. and NASA’s SCaN Program at NASA Headquarters, was the program manager for the SCaN payload mission. In November 2019, SL-14 tested NASA’s Autonomous Flight Termination Unit as well as Qascom’s GNSS signal recorder. Oscar Pozzobon, co-founder, president, and CEO of Qascom, was able to post-process the data collected by the recorder. SL-15 was originally planned to launch in November 2022; however, it was scrubbed due to interference between the launch vehicle’s S-band transmitter and the L-band GNSS receiver on board. In May 2023, the original SL-15 booster was used for SL-17, a mission carrying student payloads, which experienced an anomaly, ending the flight test three seconds after launch. Therefore, Valencia, her team, and the other teams involved were elated when the October 2024 launch was successful.

QN400-SPACE (GARHEO) SL-15 C/N0 profile. (Photo: ASI/Qascom)

QN400-SPACE (GARHEO) SL-15 Doppler frequency profile. (Photo: ASI/Qascom)

The objective and the teams

Building on the success of the previous SL-14 launch, the SL-15 mission to fly two GPS-Galileo receivers on a sounding rocket is the result of an agreement between NASA, ASI and ESA. The primary objective was to assess GPS-Galileo performance in a highly dynamic environment. The secondary objective was to have the GNSS receivers integrated with the avionics on board the vehicle, with the aim to test the real time use of PVT available during the flight, in contrast to post processing on SL-14. This allowed the evaluation for operational use of multi-constellation / multi-frequencies GNSS for Autonomous Flight Termination Systems (AFTS). AFTS is an independent launch vehicle subsystem designed for range safety operations. From 2014 to 2019, Valencia was the project manager for AFTS in the Engineering Directorate at NASA’s Kennedy Space Center.

The interoperability experiment on the SL-15 mission included two Autonomous Flight Termination Units (AFTU) and two GPS-Galileo receivers utilizing the L1/E1/L5/E5a signals: a GNSS Dual Frequency / Dual Constellation QN400-SPACE receiver for GPS-GALILEO Receiver for Human Exploration & Operations (GARHEO) program of ASI and Qascom, and a GNSS Receiver with Open Software Interface (GOOSE) receiver from ESA/ESOC and Fraunhofer; as well as a JAVAD GPS L1 receiver. During the flight, a 12-second launch and boost phase was followed by ascent coasting until the rocket reached apogee at an altitude of 115 km, followed by descent, re-entry, and landing, for a total flight duration of 13 minutes. The rocket reached a maximum speed of 1400 m/s, a maximum acceleration of 13.5 G, and a maximum spin rate of 7 Hz.

The NASA sponsor for the GNSS Payload mission is James J. Miller, Executive Director of the National Space-based Positioning, Navigation, and Timing (PNT) Advisory Board with the SCaN Program. The team members are:
- NASA: James J. Miller, Lisa Valencia, Hubert Chang, Paul De León, Anh N. Nguyen
- ASI: Giancarlo Varacalli, Claudia Facchinetti, Mario Musmeci
- Qascom:Oscar Pozzobon, Riccardo Longo, Salvatore Guzzi, Samuele Fantinato
- ESA:Werner Enderle, Mark Van Kints, Erik Schoenemann, Volker Mayer
- Fraunhofer:Matthias Overbeck, Santiago Urquijo, Inigo Cortes, Fabio Garzia
- UP Aerospace: Jerry Larson, Trevor Morgan, Eric Larson, Craig McEwen, and Jay Holcombe
Results and next steps

Integrated QN400-SPACE (GARHEO) GNSS receiver. (Photo: ASI/Qascom)

During this highly dynamic flight, all GNSS receivers successfully tracked, with high accuracy, based on position, velocity and time (PVT) solutions, meeting the interoperability payload objectives of dual constellation (GPS and Galileo) and dual frequency (L1/E1 and L5/E5a) compatibility.

One plot of the rocket’s altitude changes over time produced from the data collected is striking: a blue line representing the data from the GARHEO and a red one representing data from a monitoring radar on the ground overlap perfectly, resulting in a single purple line on the graph.

During a launch, space vehicles rely on GNSS signals for tracking, monitoring, and safety. Their ability to receive signals from multiple GNSS constellations would offer launch vehicles more precise and reliable real-time PVT information. The SL-15 GNSS experiment demonstrated the benefits of interoperability between Galileo and GPS in highly dynamic environments.

The next step will be a detailed analysis of the data collected during the flight. ESA/ESOC’s next steps will be to process the data from the GOOSE receiver taken on-board and to apply different concepts and algorithms in order to achieve the highest possible accuracy for the SL-15 flight trajectory. Among them will also be a Precise Point Positioning (PPP) GNSS technique that utilizes the GOOSE receiver data in combination with precise orbits and clocks for Galileo and GPS, which will be calculated by ESOC’s Precise Navigation System (EPNS) software. Results are expected in early 2025. ASI/Qascom’s next steps include utilizing the data collected by the SL15 experiment to support the development and validation of the new generation of high dynamics GNSS receivers providing enhanced robustness against GNSS threats. This is the main objective of Qascom’s receiver. At least one launch vehicle is planning to incorporate a multi-GNSS (GPS + Galileo) receiver into their AFTS.

Quotes

“The success of SL-15 is the result of a multi-year collaborative effort with the Italian Space Agency (ASI) and the European Space Agency (ESA) to develop multi-GNSS capabilities to improve resilience for space users. The multi-national SL-15 team worked extremely well together to overcome many challenges, leading to a successful mission. The successful launch of SL-15 was particularly rewarding to our international team in light of the numerous delays we had due to export control restrictions, high winds at the launch site, and key personnel catching COVID-19 during pre-launch checkout. These delays, however, gave us time to resolve payload interference issues identified during one of the launch preparations as well as have our payload reassigned from a rocket with a faulty engine that ended up failing on another mission (SL-17).”

— Lisa Valencia

“The key benefit of this mission was validating our ability to track both GPS & Galileo signals under the highly dynamic conditions of a sounding rocket launch. These included an initial acceleration to 14G (or 14 times the gravitational acceleration on Earth’s surface), a 7 Hz spin rate (seven spins every second), and a maximum speed more than 1400 m/s (3,132 mph).”

— A.J. Ora, Ph.D.

“The integration of GPS+Galileo for high-dynamic space applications will most certainly continue opening up more operational scenarios as GNSS signals become more available and resilient in the sparse and challenging space domain. The use of additional GNSS signals to augment GPS is developing rapidly and is a cornerstone of strengthening international collaboration as called for in Space Policy Directive-7 (SPD-7). NASA is therefore a proud contributor in helping to develop navigation tools that will benefit all space sector users as more knowledge is gained and adopted.”

— James Miller

“UP Aerospace appreciates the opportunity to work with NASA and the vast array of customers they serve. We have partnered in many successful launch campaigns. It can be challenging to integrate so many different payloads into one vehicle, but we are excited at the success of SL-15. Launching rockets is a risky business and sometimes anomalies can occur. The key is to learn from each launch and incorporate the lessons-learned into subsequent flights, ensuring their success.”

— Trevor Morgan, President/CEO of UP Aerospace
January 17, 2025
NASA and Italian Space Agency demonstrate lunar GNSS payload

NASA and the Italian Space Agency (ASI) are collaborating on the Lunar GNSS Receiver Experiment (LuGRE), which seeks to demonstrate the viability of providing positioning, navigation and timing capabilities on the moon using GPS and Galileo signals.

LuGRE’s payload consists of a weak-signal GNSS receiver, a high-gain L-band patch antenna, a low-noise amplifier and an RF filter. The receiver is designed to track GPS L1 C/A and L5 signals, as well as Galileo E1 and E5a signals. It will collect pseudorange, carrier phase and Doppler measurements, calculate onboard navigation solutions, and have the capability to record raw I/Q baseband samples for ground processing.

NASA‘s Space Communications and Navigation (SCaN) Program office funded and oversaw the experiment. It was selected as one of ten research and technology demonstrations for lunar surface delivery by Firefly Aerospace, under NASA’s Commercial Lunar Payload Services (CLPS) initiative.

LuGRE builds upon previous missions in the Space Service Volume, including experiments by AMSAT-OSCAR 40, GOES-R series satellites and the NASA Magnetospheric Multiscale mission. It aims to be one of the first demonstrations of GNSS signal reception and navigation in the lunar environment, potentially paving the way for operational use in future lunar missions.

The target launch date for the Blue Ghost 1 mission carrying LuGRE is Jan. 15, 2025. Upon completion, all LuGRE science data will be made available to the public for the benefit of the GNSS and space communities.

January 16, 2025
US Space Force selects L3Harris to design GPS satellites

L3Harris Technologies has received a contract from the U.S. Space Force’s Space Systems Command to develop design concepts for Phase 0 of the Resilient Global Positioning System (R-GPS) program.

This initiative aims to enhance the existing GPS constellation by integrating cost-effective small satellites, providing increased resilience for both military and civilian users. The R-GPS program seeks to augment the current 31-satellite GPS constellation with up to eight additional satellites. The new satellites are designed to counter various threats, including jamming, spoofing and more, ensuring uninterrupted positioning, navigation and timing (PNT) services.

L3Harris has provided navigation technology for all U.S. GPS satellites launched to date. The company has also contributed to the development of control systems and monitoring receivers and user equipment for GPS. This experience serves as the basis for their proposed R-GPS solution.

L3Harris is leveraging its investments in transformational PNT technology to meet the Space Force’s evolving requirements by using commercial form factors and interfaces to create a modular, scalable solution, the company said. Additionally, L3Harris is collaborating with the Space Force as the prime contractor for the experimental Navigation Technology Satellite-3 program, which focuses on developing innovative technologies and accelerating development timelines.

January 10, 2025
ESA releases plans for FutureNAV Industry Day 2025

The European Space Agency (ESA) will host the first FutureNAV Industry Day on Feb. 18, 2025 — at ESTEC, the Netherlands — to address the growing demand for advanced positioning, navigation and timing (PNT) technologies. This event aims to bring together European stakeholders in satellite navigation to discuss future developments and foster collaboration within PNT and GNSS sectors.

As the leading system developer and design authority for Galileo and EGNOS, ESA plays a crucial role in Europe’s satellite navigation landscape. The agency launched the FutureNAV program in 2022 to unify efforts in advancing navigation technologies. Two key missions under this initiative are low-Earth orbit (LEO) PNT, which will demonstrate the potential of navigation satellites in LEO and Genesis, which will combine four geodetic techniques in one satellite to improve Earth’s reference frame.

FutureNAV Industry Day seeks to provide attendees with insights into ESA navigation plans and potential opportunities for European industry. It will follow a Request for Information on LEO-PNT industrialization, gathering information on European production capabilities for payload building blocks and satellite platforms.

To complement these upstream initiatives, the Navigation Innovation and Support Programme (NAVISP) Industry Days will be held at the University of London on March 4-5, 2025, focusing on downstream applications and bringing together industry leaders and innovators.

Click here to register and learn more about the event.

January 1, 2025
New services and capabilities for Galileo

Galileo is Europe’s civil global navigation satellite constellation and a major success of the European Union (EU). It provides the world’s most precise satellite navigation performance. Galileo services began in December 2016 and are currently supplied to more than 3 billion users. They offer several high-performance services worldwide, featuring various levels of accuracy, robustness, authentication and security.

Galileo is a key component of mass-market applications for such areas as transport, agriculture and timing but also for security-critical applications, such as health services, emergency and rescue services and law enforcement. Galileo services continue to expand with many new capabilities that are unique with respect to other GNSS.

The European Union Agency for the Space Programme (EUSPA) and the European Space Agency (ESA) continue to collaborate effectively on the many developments, deployments and evolution activities of the Galileo Programme, each according to their respective responsibilities for exploitation and system development, with the European Commission acting as the program manager.

Stable Service Performance

Galileo services continue to deliver excellent performance every month in a safe, secured and seamless manner, managed by EUSPA. The performance parameters of the Galileo services are independently monitored by the Galileo Reference Centre (GRC) and are regularly published on the web portal of the GNSS Service Centre (GSC): gsc-europa.eu.

The performance of the Open Service (OS) remains “Best in Class” among the GNSS providers. Timing users also continue to receive accurate (in the order of 5 ns) access to Galileo System Time, which they can trace to Universal Coordinated Time (UTC) through the corresponding offset parameters transmitted by the satellites.

The Search and Rescue (SAR) service was delivered well beyond the commitment to the users, for both forward and return link services, while the High Accuracy Service (HAS) and the Public Regulated Service (PRS) continue being provided as planned in the corresponding Service Definition Document (SDD).

Benchmark with respect to other GNSS.

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December 20, 2024
SpaceX launches GPS III satellite for US Space Force

Following weather delays, the U.S. Space Force’s Space Systems Command (SSC) and Space Operations Command expedited the Rapid Response Trailblazer launch schedule to fulfill a specific warfighter requirement. On Dec. 16, 2024, SpaceX’s Falcon 9 rocket launched the GPS III SV-07 satellite from Space Launch Complex 40 at Cape Canaveral Space Force Station, Florida.

For the mission, multiple Space Force organizations collaborated to retrieve an existing GPS III satellite from storage, expedite integration and launch vehicle preparation, which was quickly processed for launch. The success of the launch proved a two-fold concept of operations. SSC’s Assured Access to Space showcased its agility in partnering with industry to meet evolving national needs, completing a National Security Space class launch in less than five months.

This marks the first Space Operations Command mission led by Mission Delta 31 for a Space Vehicle launch, and it demonstrated exceptional flexibility by reducing the typical six-month pre-launch processing timeline to approximately three months, Space Operations Command said. This effort involved close coordination with Lockheed Martin in Colorado to rapidly prepare SV-07 for launch.

The GPS III SV-07 satellite joins a robust constellation comprising 31 active vehicles, seven in reserve status and three completed GPS III vehicles awaiting launch. Equipped with M-Code technology, these satellites offer improved anti-jamming and anti-spoofing capabilities, enhancing secure access to military GPS signals for U.S. and allied forces.

December 19, 2024
Research roundup: Advancing space and lunar navigation

SpacePNT and European Engineering and Consultancy (EECL) delivered the final presentation of the European Space Agency (ESA)-funded project, “Earth Moon GNSS Spaceborne Receiver for In-Orbit Demonstration.” This project aims to develop the NaviMoon GNSS receiver for lunar applications. (Photo: SpacePNT)

GNSS researchers presented hundreds of papers at the 2024 Institute of Navigation (ION) GNSS+ conference, which took place Sept. 16-20 in Baltimore. The following papers focused on lunar and space applications. The papers are available here.

Clock and Orbit Determination for LEO Satellites

More than 50 years after the Apollo program, there is a growing interest in establishing a sustainable human presence on the moon, with various missions being planned in different lunar orbit regimes to support lunar exploration. To address the challenges of navigation in the lunar environment, researchers have proposed a technique leveraging time-differenced carrier-phase (TDCP) measurements from GPS satellites, which offer millimeter-level accuracy when integer ambiguities are correctly fixed.

The proposed framework utilizes an extended Kalman filter that combines intermittently available terrestrial GPS TDCP values with gravitational accelerations predicted by an orbital filter. To handle the unique challenges of the lunar environment, such as weak gravity and strong third-body perturbations, the researchers implement an adaptive state noise compensation algorithm and introduce an augmented state vector to address time correlations across TDCP measurements. Through Monte Carlo simulations of lunar satellites in various orbits, the technique demonstrates improved positioning and onboard timing accuracy compared to pseudorange-only navigation solutions.

Keidai Iiyama, Sriramya Bhamidipati and Grace Gao, “Precise Positioning and Timekeeping in a Lunar Orbit via Terrestrial GPS Time-Differenced Carrier-Phase Measurements.”

Satellite Ephemeris Parameterization for Lunar Navigation

This paper explores the development of satellite ephemeris parameterization methods for lunar navigation systems. As space agencies plan to establish satellite networks around the moon for communication and positioning, navigation and timing (PNT) services, the authors investigate optimal techniques for efficiently and accurately broadcasting satellite ephemeris data to lunar users. They propose a framework that directly approximates satellite position and velocity in the inertial frame, using signal-in-space-error requirements as constraints to guide the search for the best ephemeris parameter set.

The study evaluates different methods based on ephemeris prediction precision, fit interval and message size. It demonstrates the framework’s ability to approximate satellite ephemeris for both low lunar orbits and elliptical lunar frozen orbits while meeting signal-in-space-error requirements. The research considers polynomial and Chebyshev basis types for surrogate models and evaluates performance based on precision and orbital coverage. By quantifying the broadcast message’s fit interval and size, the authors aim to guide the selection of optimal parameterization methodologies for lunar navigation systems.

Marta Cortinovis, Keidai Iiyama and Grace Gao, “Open Access Satellite Ephemeris Parameterization Methods to Support Lunar Positioning, Navigation, and Timing Services.”

Improving Navigation Accuracy in GEO

The authors introduce a new approach to improving the accuracy of satellite position determination in geostationary equatorial orbit (GEO). They propose integrating a regional navigation satellite system (RNSS) with GNSS. Specifically, they suggest using RNSS signals, such as those from the Quasi-Zenith Satellite System (QZSS), to complement the signals provided by GNSS for GEO satellites.

The research addresses the challenges faced by GEO satellites in using GNSS signals, including poor dilution of precision (DOP) and significant radial errors due to limited observability. By incorporating RNSS signals, the researchers aim to improve the diversity of signal directions and enhance navigation precision. The paper demonstrates the feasibility of receiving QZSS signals across a substantial range in GEO through link budget analyses. Two comprehensive simulations were conducted: a point solution and an extended Kalman filter-based orbit determination. The results confirm the anticipated improvement in navigation precision indicated by the DOP analysis.

While RNSS signals can be received from any longitude in GEO, enhanced navigation precision depends on the distance between the satellite and the RNSS. The authors suggest that this concept can be adapted to various longitudes within GEO by selecting appropriate RNSS options and promoting stable, high-precision navigation.

Yu Nakajima and Toru Yamamoto, “Enhancing Navigation Accuracy in a Geostationary Orbit by Utilizing a Regional Navigation Satellite System.”

Integrating Orbit and Attitude Precision for CubeSat Positioning

This research paper addresses ways to enhance CubeSat capabilities for demanding missions, particularly in low Earth orbiting positioning, navigation and timing (LEO-PNT) systems. The authors propose an array-aided combined precise orbit and attitude determination model that offers an optimal solution to improve orbital accuracy and provide reliable attitude information. By utilizing multi- and affine-constrained models for precise attitude determination and reconstructing highly precise observations for an antenna array, the method addresses the challenges of higher orbital accuracy and reliable attitude information required for advanced applications.

The authors recorded significant improvements in orbital accuracy and attitude determination. Validation results show that reconstructed observations outperform original ones, leading to improved orbital components with a three-dimensional root mean square (RMS) of 4.1 cm. Additionally, observation residuals are smoother, with an RMS of 6 mm, half of that obtained via a single antenna. The results show a promising solution for enhancing CubeSat capabilities, particularly for applications requiring high-precision orbit and attitude information.

Amir Allahvirdi-Zadeh and Ahmed El-Mowafy, “Array-Aided Precise Orbit and Attitude Determination of CubeSats using GNSS.”

December 19, 2024
EUSPA awards GMV for Galileo Emergency Alert System upgrade

The European Union Agency for the Space Programme (EUSPA) has awarded GMV a framework contract to deliver new Galileo functionalities under the EmeRgency Alerting System (ERAS). This four-year contract, valued at approximately $6 million, will enable significant advancements in Europe’s disaster response capabilities. The GMV-led consortium includes Ineco, ALTEN Spain and Kineton as subcontractors.

ERAS will primarily allow Member States’ National Civil Protection Authorities to broadcast emergency warning messages directly to populations in at-risk or affected areas. These alerts will be transmitted via Galileo satellites to smartphones and other Galileo-enabled devices. According to EUSPA, the messages will contain crucial information about the hazard, including its type, severity, affected area, expected onset and duration, as well as guidance for appropriate responses.

The Galileo Emergency Warning Satellite Service (EWSS) and ERAS seek to enhance Galileo by offering resilience and complementarity to existing public warning systems, independence from terrestrial and mobile networks, rapid communication with global reach and particular benefits for remote areas with limited mobile coverage.

The system is designed to provide a robust and versatile solution for emergency communications, ensuring that critical alerts reach populations even in challenging scenarios. ERAS is expected to be fully operational in the first half of 2026.

The implementation of ERAS comes at a critical time, as highlighted by the State of the Climate in Europe (ESOTC) report for 2024. Europe has experienced numerous extreme weather events in recent years, including heat waves, forest fires, floods and droughts. The continent is warming at approximately twice the global average rate, emphasizing the urgent need for effective warning systems and robust climate policies, GMV shared.

The joint use of Galileo ERAS and the Copernicus Emergency Management Service seeks to enhance the European Union’s and its Member States’ disaster management capabilities. This integration will provide a comprehensive approach to alerting populations about risks such as the recent disasters in Valencia, Spain and other parts of Europe.

December 16, 2024
The status of QZSS

Space Policy and QZSS Plan

Japan’s Cabinet Office (CAO) is currently developing the Quasi-Zenith Satellite System (QZSS) seven-satellite constellation (7SV-const.)

Japan’s cabinet revised our new basic space policy plan on June 13, 2023. It states that the number of QZSS satellites should be increased from seven to 11 to improve stability and reliability as one of the social infrastructures by securing backup function for coming full-scale use and to reduce the dilution of precision (DOP).

On June 12, 2024, the National Space Policy Secretariat revised the action plan for the satellite positioning system for the first time in three years. According to this plan, the completion of the QZSS 11-satellite vehicle constellation is anticipated by the late 2030s.

Figure 1 System expansion of QZSS.

Brief History of QZSS

Since 2006, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Aerospace Exploration Agency (JAXA), the Ministry of Internal Affairs and Communications (MIC), the Ministry of Economy, Trade and Industry (METI) and the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) have collaborated to develop the world’s first centimeter-level positioning satellite.

The first QZS satellite was launched in September 2010, for what was then envisioned as a four-satellite regional satellite navigation system, also known as MICHIBIKI. In September 2011, the Cabinet approved a plan to build the four-satellite constellation (4SV-const.) in the late 2010s, with the goal of building a 7SV-const. in the future. The budget was approved in JFY2012 to promote this as a national project.

In 2017, QZS-2, 3 and 4 were successfully launched and a 4SV-const. was established. On Nov. 1, 2018, QZSS officially began service. On Oct. 26, 2021, the successor to the first MICHIBIKI was launched.

Development is underway to launch three additional satellites for the 7SV-const. sequentially from JFY2023 to JFY2024, depending on the development status of the H3 launch vehicle.

To improve resilience for more stable positioning and improved DOP, CAO has started a study to transition from a 7SV-const. to an 11SV-const. (See Figures 1 and 2)

Figure 2 QZSS Constellation Expansion Plan.

Service Overview

The 4SV-const. provides GPS Complementary Service (PNT service); GNSS Augmentation Service, i.e. Sub-meter Level Augmentation Service (SLAS), Centimeter Level Augmentation Service (CLAS), MADOCA-PPP and satellite-based augmentation service (SBAS), as well as a messaging service.

The QZSS constellation consists of a geostationary orbit (GEO) satellite, QZS-3 and three QZO satellites.

QZSS’s performance of the positioning, navigation and timing (PNT) service and signal-in-space user range error (SIS-URE) was much better than specified. Evaluation results are shown in Table 1.

The evaluation period was “08/01/2023＃07/31/2024.” The specification is less than 2.6 m (95%).

Toward Seven-Satellite Constellation

Three additional satellites will be positioned in an inclined geostationary synchronous orbit (IGSO) at 90.5° east longitude and in a quasi-geostationary orbit at 175° west Longitude. This constellation is designed to ensure that multiple satellites are visible at high elevation angles, with the goal of having more than four satellites visible for extended periods of time, ultimately improving the DOP.

The positioning signals of 7SV-const. are shown in Table 2. QZS 5 to 7 transmit L1C/B.

Table 1 Performance of the QZSS PNT service.

After the QZS-5 service starts, QZS1R’s signal will switch from L1C/A to L1C/B. The QZSS Navigation Message Authentication (QZNMA) service for other GNSS is included in L6E signals.

QZS5-7 development is ongoing. A system-level test is in progress. The plan is to launch QZS 5-7 around 2025. QZS-5 and 6 have almost finished the system-level test. QZS-7 finished the electrical test, and now it is in the environmental test phase.

QZSS antenna patterns for SSV users, published since Aug 2023, correspond to the ICG WG-B recommendation “Release of GNSS Transmit Antenna Patterns Including Side Lobes,” submitted on Dec. 11, 2019.

QZSS satellite information for precise orbit determination (POD) users was also updated online.

The QZSS ground system, capable of operating with seven satellites, was completed in August 2023. The only remaining task is to conduct compatibility tests between the satellites and the ground radio frequency. The QZSS ground system consists of two master control stations located in Hitachi-Ota and Kobe, as well as 10 satellite tracking and control stations (telemetry, tracking and command stations), primarily situated in the southwestern islands. Additionally, there are more than 30 monitoring stations worldwide, established in cooperation with various countries.

The following additional services began this year or will begin next year:

Users obtain position, velocity, and time (PVT) solutions using ranging signals provided by the 7-SV const. The Navigation Message Authentication (NMA) began in April 2024.

Multi-GNSS Advanced Orbit and Clock Augmentation — Precise Point Positioning (MADOCA-PPP) covers a major part of the Eastern Hemisphere and provides PPP error corrections on the L6 signal. It enables highly precise positioning by providing augmentation data to correct some GNSS errors and provides two service levels, i.e., (a) global-PPP and (b) fast-PPP with ionospheric correction.

Operational service started on April 1, 2024 and Internet distribution of MADOCA-PPP in July 2024.

Expanded Satellite Report for Disaster and Crisis Management (DC report), Early/Emergency Warning Satellite Service (EWSS).

Figure 3 MADOCA-PPP service evaluation results.

In addition to the current DC report service generated by the Japan Meteorological Agency, other disaster-related reports, called L-alert and J-alert, such as an evacuation order, began on April 1, 2024.

The Global PPP service provides highly precise positioning where QZSS L6E signals can be received.

It provides satellite-dependent error corrections (orbit, clock, code/phase bias) by QZSS L6E signals.

Faster PPP using observation data from regional/nationwide Continuously Operating Reference Stations (CORS). In addition to global PPP, QZSS L6D (QZS-6 and 7) signals will provide regional error corrections (ionospheric correction).

MADOCA-PPP began operational service on April 1, 2024. For MADOCA’s stable operation, the GNSS Integrated Data Sharing System (MIRAI) was released in April 2022. The ionospheric correction data will be broadcast to reduce the initial convergence time starting in 2025.

MADOCA-PPP service was defined and described on PS-QZSS 003, published on March 17, 2022. Internet distribution of MADOCA-PPP, including ionospheric correction data, began in July 2024 to promote MADOCA-PPP utilization. MADOCALIB, test library of MADOCA-PPP, has been open-sourced and made available on GitHub this April, and updated to process ionospheric correction data in July 2024. MADOCA-PPP performance results from May to August 2024 using IGS monitoring station are shown in Figure 3.

Better initial convergence time than the defined specification and approximately 10 cm of accuracy are confirmed.

Thanks to the cooperating countries, ionospheric correction data can be generated, and the initial convergence time reduction was confirmed in all areas.

CAO started the Internet distribution, including the ionospheric correction data for these areas.

Figure 4 QZSS applications.

QZNMA

QZNMA began on April 1, 2024, to enhance the constellation’s resilience against spoofing attacks.

Navigation messages in the following signals are authenticated using the Elliptic Curve Digital Signature Algorithm (ECDSA P256).

■ QZSS signals (L1C/A(C/B), L1C, L5) are directly protected by self-authentication.

■ GNSS signals (GPS: L1C/A, L1C, L5, Galileo:E1b, E5a) are protected by cross-authentication (L6E).

The interface specification (IS-QZSS-SAS-001) is now available on our website. All the verifications were successful.

QZSS Applications

As of September 2024, approximately 434 products are compatible with QZSS (See Figure 4). New applications such as autonomous driving, drone operations and buoys for real-time ocean tide monitoring are emerging. We expect that many applications and devices using QZSS will emerge. We appreciate your cooperation and support of QZSS.

December 13, 2024
Raytheon receives Space Force GPS OCX contract extension

The U.S. Space Force’s Space Systems Command (SSC) has awarded Raytheon a $196.7 million contract extension for the GPS Next Generation Operational Control System (OCX) program — despite being years behind schedule. This latest award brings the total OCX contract value to nearly $4.5 billion since its inception in 2010. However, according to the U.S. Government Accountability Office (GAO), the total amount is approaching $8 billion.

The OCX program, designed to enhance GPS infrastructure, has faced significant setbacks. It is currently about seven years behind the original schedule, with the GAO reporting that the system of 17 ground stations was not ready by its October 2024 deadline. Further testing is required for the system to be operational by December 2025.

Despite these challenges, OCX remains critical for modernizing GPS capabilities. The system will enable full M-Code capabilities, providing jamming-resistant GPS signals for military operations in contested environments. OCX is also designed to improve cybersecurity for both military and civilian applications significantly. Once operational, OCX will command all modernized and legacy GPS satellites, managing all civil and military navigation signals.

The program has faced scrutiny due to its delays and cost overruns. The GAO has flagged the program’s delays as a risk to the GPS enterprise, while lawmakers have expressed frustration over the delays and budget increases. Despite this, the Space Force continues investing in the program to enhance GPS capabilities for military and civilian users. OCX is expected to provide improved accuracy, availability and resistance to jamming compared to the previous ground control segment. The system will also support the launch and operation of GPS III satellites.

December 10, 2024
Ligado moves forward with lawsuit against DOD

The U.S. Court of Federal Claims has allowed Ligado Networks to proceed with its $39 billion lawsuit against the federal government, marking a significant development in a long-standing dispute over 5G spectrum usage and property rights.

Judge Edward Damich partially favored Ligado by acknowledging the company’s case for property interest in the spectrum allegedly used by the Department of Defense (DOD) while rejecting its claim that the FCC license constituted a property right subject to federal taking.

The controversy stems from the FCC’s 2020 decision granting Ligado exclusive authority over spectrum near GPS frequencies, raising concerns about potential interference with GPS systems. Ligado’s October 2023 lawsuit accuses the U.S. government of conducting a “multiyear misinformation and disparagement campaign” to conceal its activities and misappropriate Ligado’s licensed spectrum for DOD systems without permission or compensation.

The government attempted to dismiss the lawsuit in January 2024, arguing lack of jurisdiction and that Ligado couldn’t establish a cognizable property interest in its FCC license. However, Judge Damich’s ruling allows the case to proceed.

At the core of this dispute is the proximity of Ligado’s L-band spectrum to GPS frequencies, raising concerns about potential interference with critical GPS signals used for navigation, timing and various applications essential for national security and economic stability. The DOD, GPS companies and industry officials have strongly opposed Ligado’s plans for a terrestrial 5G network, arguing it could cause harmful interference to GPS receivers.

December 10, 2024
Australia and India advance resilient PNT

Skykraft, an Australian space technology company, has signed a participating project partner agreement to advance positioning, navigation and timing (PNT) systems in low-Earth orbit (LEO). This agreement, backed by an International Space Investment (ISI) India Projects grant from the Australian Government, marks a significant milestone in fostering space cooperation between Australia and India.

The project’s primary objective is to develop and demonstrate collaborative PNT systems. This includes establishing the viability of large-scale LEO constellations, addressing vulnerabilities in existing GNSS in denied environments, and exploring novel applications for PNT signals from LEO. Additionally, the project aims to create a comprehensive roadmap for collaborative LEO-PNT by implementing resilient, easily updatable constellations.

The project also seeks to enhance environmental monitoring capabilities through GNSS-reflectometry (GNSS-R) and radio occultation (GNSS-RO) technologies. This will improve understanding of Earth’s oceans, droughts, and floods while enhancing real-time space and terrestrial weather forecasting. It will explore emerging applications, such as tsunami monitoring and warning systems.

December 9, 2024