TrustPoint has transmitted its first Low-Earth Orbit Navigation System (LEONS) time-transfer and tracking signals from a ground node to spacecraft in orbit. The milestone advances the development of commercial navigation infrastructure independent of GPS.
GNSS satellites require knowledge of their own time and orbital position to provide accurate data to Earth-based users. Most LEO spacecraft currently rely on GPS or medium-Earth orbit (MEO) signals for that information. Interference and jamming are increasingly affecting these LEO connections, degrading or blocking signals.
LEONS provides GPS-independent time transfer and orbit tracking. Initially developed for TrustPoint’s planned constellation, the system can be adapted for other LEO operators requiring timing and navigation for their spacecraft. The ground-to-space infrastructure is designed to support a GPS-independent PNT layer in orbit.
“With the pace of modern threats accelerating, the difference between concepts and capabilities matters,” said Nicole Hilliard, director of government programs at TrustPoint. “This milestone demonstrates that commercial partners can field resilient, GPS-independent PNT capabilities that strengthen national security architectures and justify continued investment in companies that deliver.”
The demonstration supports TrustPoint’s participation in the SpaceWERX AltPNT Challenge, which awarded the company two contracts to develop alternative PNT capabilities. The program seeks to deploy new options for precise, dual-use PNT systems.
GLONASS remains a core of Russia’s positioning, navigation and timing (PNT) system and is utilized by people around the world. Annual shipments of new GLONASS/GNSS receivers for the communications, transport, agriculture and power industries exceed 25 million units in Russia alone. These users are interested in continuously increasing the quality of PNT primarily based on the improvement of the basic service radio navigation field generated by the GLONASS space complex.
This space complex consists of the constellation comprising medium-Earth orbit (MEO) satellites, the modernized ground control complex and the ensemble of user equipment. The current constellation consists of 26 satellites comprising three generations and five modifications. For the past 15 years, GLONASS-M has been the core satellite and now the constellation includes 21 of them. The fact that 14 of them successfully function beyond their guaranteed active lifetime verifies their high reliability. They are steadily being replaced with GLONASS-K satellites, of which there are already four in the constellation. Along with GLONASS-K launches, the in-orbit testing of the first GLONASS-K2 satellite was initiated on August 7, 2023.
Since the launch of the first GLONASS satellite, the navigation signals have changed significantly. Initially, each of 24 GLONASS satellites transmitted the signals with its own separate carrier frequencies in the L1 and L2 bands (Figure 1). The total bandwidth of the registered GLONASS satellite network was 23.72 MHz in L1 band and 20.72 MHz in L2 band, respectively.
Figure 2. First phase GLONASS FDMA signals spectrum transformation in L1 band. Image: Sergey Karutin
Figure 3. Second phase GLONASS FDMA signals spectrum transformation in L1 band. Image: Sergey Karutin
Figure 4. Final GLONASS FDMA signals spectrum in L1 band. Image: Sergey Karutin
In 1995, the Russian Federation assumed obligations to protect the band used in radio astronomy in the search for extraterrestrial life. At the first stage (until 1998), the broadcast of the navigation signals in the carrier frequency channels 16-20 was terminated and the frequency channels 13, 14, 20 and 21 were used under exceptional circumstances (Figure 2). Then, all newly launched satellites transmitted the signals only in the frequency channels 0-12. By 2005, the total bandwidth of GLONASS satellites was reduced to 16.97 MHz in L1 band and 15.47 MHz in L2 band respectively (Figure 3).
Starting in 2005, GLONASS satellites have been using the frequency channels from -7 to +6 (Figure 4) to broadcast frequency division multiple access (FDMA) navigation signals. As a result, the upper limit of the GLONASS signal bandwidth in the L1 band dropped from 1620.61 to 1610.485 MHz and the lower limit went down from 1596.89 to 1592.953 MHz. The signal bandwidth in L2 band changed similarly.
The GLONASS-K2 satellite was developed to improve GLONASS user performance. The satellite broadcasts new code division multiple access (CDMA) signals in the above mentioned bands as well as in the L3 band. The first satellite of this batch was successfully deployed in orbit on August 7, and already started to broadcast the new CDMA signals. The radio telescope of Bauman Moscow State Technical University is used to monitor the broadcast signals to analyze the frequency and power characteristics of the satellite.
The radio telescope has a large-aperture fully rotatable antenna with a dish diameter of 7.75 m. It ensures that the width of the main lobe of the antenna’s pattern in 1.6 GHz band is 1.8° and the power amplification of the received navigation signals is 40 dB.
Primarily, users are interested in the new CDMA navigation signal on L1OC transmitted along with the conventional signal on L1OF. The joint group bandwidth of the FDMA signals with the carrier frequency 1598.625 MHz, which refers to the frequency channel -6, and the CDMA signals with the carrier frequency 1600.995 MHz is shown in Figure 5.
The exploitation experience of recently manufactured satellites in practice demonstrates that their operational capacity exceeds their planned lifetime by one and a half times. The final GLONASS-M satellite (No. 761) launched in the last year was manufactured in 2015. These circumstances make it possible to predict that the renewal of the whole constellation with new GLONASS-K2 satellites broadcasting the full ensemble of CDMA signals is likely to be finished by 2035.
In 2024, the renewal of the constellation will continue due to the launches of GLONASS-K satellites and another GLONASS-K2 satellite.
Figure 5. FDMA and CDMA signals spectrum in L1 band, broadcasted by first Glonass-K2 satellite. Chart: Bauman Moscow State Technical University
With the launch of the first GLONASS-K2 satellite accomplished, the Passive Quantum-Optical System (PQOS) is implemented on the base of Russian quantum-optical systems with a wavelength of approximately 0.5 nm. The PQOS ensures pseudorange measurements in the optical band. The elements of the system include specialized ground equipment to register moments of laser pulse emission by a ground laser station (ground PQOS) and specialized satellite payload equipment to register moments of the laser pulse reception onboard (onboard PQOS). Therefore, all GLONASS new generation satellites are capable of performing both conventional active (two-way) measurements and passive (one-way) measurements with the accuracy of timescale difference definition better than a nanosecond and based on the data of laser optical systems.
The processing of active and passive measurements gives an opportunity to get their difference combinations to compare timescales kept by onboard and ground frequency standards at a previously unachievable picosecond level of precision. The accuracy of PQOS results is sufficient to provide in-orbit tests of prospective new generation onboard frequency standards with a daily stability σ around 5×10-15.
The achieved accuracy level of PQOS results is also sufficient to calibrate measurement links for prospective GLONASS satellites, including links of active measurement systems, inter-satellite links and ionosphere-free linear measurement combinations conducted by passive measurement equipment based on FDMA and CDMA signals. The obtained results correspond to the world accuracy level in metrology and ensure the uniformity of measurements. The developed PQOS and technologies based on its measurements fully contribute to the effective metrological support for the tests and operation of the GLONASS space complex, including prospective GLONASS-K2 satellites and the ground complex.
What are your thoughts on the “geodesy crisis” and what do you propose to address it?
Bernard Gruber
“Evidence seems to be very clear that we, as a country, need geodesists and that there has been a decline in investments, training, and research in geodesy. While our decline relative to China may be shocking, it should not be surprising. U.S. industry and government relentlessly pursues STEM graduates, or those with relevant experience, but that does not meet current needs. Besides maybe surveying, it is unclear to the public what the geodesy profession is all about, why it is needed, and quite frankly, why it is an exciting career choice.”
— Bernard Gruber Northrop Grumman
Does crowding of low-Earth-orbit (LEO) space — with new satellites and space debris — pose any problems for the launch or operations of GNSS satellites in medium Earth orbit (MEO)?
Ellen Hall
“This was a focused topic at SATELLITE 2022, where the discussion centered on the 6,000 tons of space debris circulating in LEO. Even the smallest piece of debris can be lethal to a satellite, so the key is to track and maneuver where possible. Add to that about 5,000 active satellites and plans to launch tens of thousands of additional ones into LEO over the next few years, and you have a serious problem to overcome. While there are treaties and plans for tracking and maneuvering these satellites, the debris is the real challenge.”
In 2022, the Galileo GNSS continued to provide the world’s most precise satellite navigation information, to a user base that stands at more than 3.5 billion worldwide. Furthermore, provided services continue to improve and expand, with plans for high-accuracy positioning and signal authentication now reaching fruition.
The European Union Agency for the Space Programme (EUSPA) and the European Space Agency (ESA) continue to enjoy an effective collaboration on the many development, deployment, and evolution activities of the Galileo Programme — each according to their respective responsibilities for service provision and system development with the European Commission (EC) acting as the program manager.
Ranging accuracy performance from January to September 2022.
Positioning-related MPLS from January to October 2022.
New Services Launched in 2022
Excellent Performance
Service delivery operations and maintenance of operational systems are managed by EUSPA, which supervises many contracts that carry out the day-to-day activities from dedicated control and monitoring centers throughout Europe. In 2022, Galileo timing, navigation, and SAR/Galileo services were delivered with excellent performances that continue to exceed the formal declarations for minimum performance levels (MPL), which were increased in January, both in terms of absolute accuracy and overall service availability. The entry into service of two additional satellites in May and August, have further consolidated the overall service availability to end users.
Galileo FOC Batch 3 satellite under testing.
Expansion of Service Portfolio
The service provision teams have been able to focus on improvements to, and expansion of, the service portfolio.
The I/NAV improvement will positively impact end users by enabling a faster time to first fix, and updates to the data validity status flags will lead to better protection of users against expired navigation data. These changes are implemented in updates of the onboard software of the satellites being rolled out across the constellation. At present, seven operational satellites have been successfully updated; the complete software upgrade campaign is planned to be completed this summer.
Galileo’s new High Accuracy Service will provide free precise point positioning (PPP) corrections, in the Galileo E6-B data component and by terrestrial means, for Galileo and GPS (single and multi-frequency) to achieve real-time user position improved by up to 10 times. The infrastructure to support an initial service (Phase 1) is nearing completion, and the formal declaration of the service capabilities is planned for early this year.
To provide users with a method of authenticating the received Galileo signals, especially the satellites ephemerides and the Galileo timing parameters, the new Open ServiceNavigation Message Authentication (OSNMA) service enables a receiver to confirm that a navigation message originated from the EU Galileo infrastructure. Many application areas are expected to benefit from this capability, including smart tachographs, telematics and logistics, UAVs, location-based services, and timing services. Having successfully demonstrated the technology behind the service in 2022, including a public observation phase, the roll-out of the Initial Service is planned to take place by the end of the year.
A fourth Medium Earth Orbit Local User Terminal (MEOLUT) in La Réunion will extend the SAR/Galileo Forward Link Service Coverage Area over the Indian Ocean as part of the SAR/Galileo full operational capability (FOC) declaration expected in the first quarter of 2023. The Cospas-Sarsat commissioning of this new station was completed in September 2022, and operational data is already being distributed to Cospas-Sarsat.
Reference documents for the above services can be found at the EUSPA European GNSS Service Centre website, including technical notes, interface control documents and service declaration documents.
SAR/Galileo-related metrics from January to October 2022.
Extension of the SAR/Galileo Forward Link Service Coverage Area over the Indian Ocean.
FOC Infrastructure Development Nears Completion
Satellite Production
The production of the third batch of Galileo FOC satellites advanced further in 2022 with the completion of the environmental tests and the system compatibility test campaigns at the European Space Agency Test Centre in Noordwijk, The Netherlands. After 10 years of successful testing, on Oct.18, 2022, the last Galileo FOC satellite (flight model number 34) left the test center to return to the premises of the satellite manufacturer, OHB Systems, in Germany. Testing of the remaining 10 satellites has confirmed that they have been correctly built and will perform well in orbit. The acceptance review of the last couple of satellites will take place this summer.
At the beginning of 2023, the plan is to start in-orbit testing of a quasi-pilot signal on the E5 frequency using the Galileo GSAT201/202 satellites in elliptical orbit. The provision of a signal offering coarse acquisition in Galileo E5-A/GPS L5 can be a distinguishing feature for Galileo with respect to all other constellations to further improve the capability to acquire the E5 signal at low complexity. Following in-orbit testing, the strategy for roll-out of this capability will be assessed with the involvement of receiver manufacturers.
New SAR Galileo MEOLUT facility in Réunion island.
Access to Space
The discontinuation of Soyuz launch services from the Kourou Space Centre in French Guiana, because of the Russia-Ukraine conflict, has caused delays in the two Galileo launches that had been planned for 2022. The Launch 12 campaign had to be interrupted and in March 2022 the FM25 and 26 satellites were put in storage at the Kourou launch base, then returned to Europe in November.
Ariane 6 is the baseline launcher for Galileo satellites to ensure European independent access to space. The remaining Batch 3 satellites will be launched with the Ariane 62 launcher vehicle, the two strap-on solid booster variants of Ariane 6, now undergoing the final stages of development led by prime contractor Ariane Group. Ariane 6’s maiden flight is scheduled to take place in the fourth quarter of 2023.
Ground Segment
An upgrade of the ground control segment, in charge of command and control of the satellite constellation, is being developed by the industrial consortium led by GMV. The upgrades will address resolution of hardware and software obsolescence including cyber security, operability improvements, and a security monitoring overlay.
With the planned increase in the number of satellites in orbit, an additional telemetry tracking and control facility (TTCF) is being deployed in Kourou leading to seven operational TTCF stations in early 2023.
The ground mission segment, in charge of navigation control, is undergoing a complete technological refresh, including hardware/software virtualization performed by an industrial consortium led by Thales France. This upgrade will provide additional robustness, including a system extended contingency mode resilient to outages lasting up to seven days and a new state-of-the-art cyber security monitoring system. It will also provide ranging authentication through encrypted codes on the E6-C signal component for the implementation of the Commercial Authentication Service. Global coverage will be further increased with the introduction of two Galileo sensor stations in Wallis (Pacific Ocean) and Bonaire (Caribbean Sea), for a total of 15 sites around the globe.
OSNMA-related metrics from January to October 2022.
G2G Development Started
Galileo’s second generation (G2G) will introduce many innovative technologies to offer unprecedented precision, robustness, and flexibility.
2022 was a key year for the evolution of G2G activities with the fast development cycles of the first batch of G2 satellites, beginning development of the associated G2G in orbit validation (IOV) ground segment and system test beds, and the consolidation of the G2G final system capabilities — including the coordination of the mission/service roadmaps with the EC, EUSPA, and the EU Member States delegates.
Ariane 62 launcher.
G2G Satellite Manufacturing
From the satellite development point of view, the two parallel contracts to develop and manufacture each of the six G2G batch one (G2SB1) satellites are progressing in a fast development environment, with the first hardware units ready for integration and testing.
Following the completion of preliminary design review, these two contracts (for six satellites each) are preparing for unit-level validation/testing, which will lead to the critical design review.
These satellites will provide the following key innovations:
Reconfigurable fully digital navigation payload
Point-to-point connection between satellites by inter-satellite-link for command and control, and ranging functionalities
Electric propulsion for orbit-raising capabilities
Advanced jamming and spoofing protection mechanisms to safeguard.
The Galileo signals will improve with:
On-board authentication capabilities
Increased ground-to-space data rate
Improved time reference (number of clocks and advanced clock monitoring functions).
G2G IOV Procurements
2022 was also the year in which two key events took place with respect to G2G in-orbit validation (IOV) ground segment and system test bed procurements:
Finalization of the procurement cycle, now in the final evaluation/award phase, to be kicked off in the first quarter of this year
Confirmation of the IOV design through different coordinated actions with the EC and EUSPA, including the G2 system preliminary design review.
The contracts will provide Europe with the following capabilities:
G2SB1 satellite launch and early orbit phase, in-orbit testing and enhanced legacy services provision
G2 new capabilities in-orbit validation, including prototyping and validation of all the novel technologies that can exploit the full capabilities of the G2SB1 satellites.
Eleven contracts will be issued to manage in synchrony all the G1 and G2 assets for the coming years:
G2 IOV ground control segment (G2 GCS) for satellites monitoring and control
G2 IOV ground mission segment/secured facility (G2 GMS-GSF) for the production, dissemination and monitoring of all enhanced legacy services and the dissemination of new G2 advanced capabilities for validation
G2 IOV security monitoring (G2 SECMON), for the cyber/security monitoring of the system
G2 filling device (G2 FD), to ensure proper initialization of system assets
G2 system test bed (G2STB), to generate and monitor new G2 capabilities for validation of the G2G mission/services
G2 PRS test bed (G2PRSTB), similar to G2 system test bed but focused on advanced PRS capabilities for validation purposes
G2 security chain (G2SC), a test bed to ensure proper satellite-ground segment qualification before launch
Four system engineering support contracts (G2 SETA), where the main GNSS technical experts from different industries in Europe provide their support to ESA and EUSPA in their different fields of expertise.
These contracts are complemented by a significant set of system research and development and test tools, such as test user receivers and radio frequency constellation simulators.
G2G batch number one (G2SB1) satellites.
Galileo Second Generation System PDR
The Galileo Programme is not only focusing on short-term G2G development activities, but also looking forward to the future in terms of the consolidation and definition of G2G final operation capabilities. During the second half of 2022, more than 200 public representatives from the EC, EUSPA, ESA and Member States held countless meetings in the frame of the G2G system preliminary design review, which concluded in early December 2022.
As part of this review, the long-term implementation (G2G in orbit capability, or IOC, and final operational capability, or FOC) was reviewed and an agreement was reached on future steps. The evolution of Galileo capabilities will not only provide better services through advanced technical solutions, but will also ensure continuity of service and enhanced backward compatibility for first-generation legacy users.
Conclusions
The efforts of ESA and EUSPA continue with the aim of providing users continuous and stable services and evolving space and ground infrastructure to maintain Galileo competitiveness with the other global navigation satellite systems.
For analogous updates on the other three GNSS constellations, please see:
In 2022, the BeiDou Navigation Satellite System (BDS) continued to improve its service performance, expand global applications, and deepen and promote international cooperation.
On Nov. 4, 2022, a white paper titled “China’s BeiDou Navigation Satellite System in the New Era” was published. The paper shows the continuous, stable and reliable operational capability of BDS, its applications achievements across the industries, international development with openness and integration, and unremitting pursuit of helping to build a community with a shared future for humanity and a better world.
System Services Performances
In orbit are 45 BDS operational satellites, including 15 BDS-2 satellites and 30 BDS-3 satellites. Figure 1 shows the number of visible BDS satellites worldwide as of BDT 06:00 on Dec. 6, 2022.
Figure 1. Number of visible BDS satellites. (Image: www.csno-tarc.cn)
BDS has reached a continuity of 99.996% and an availability of 99%. The innovative constellation involves inter-satellite links, signal system optimization, intelligent operation and maintenance, software reconstruction and upgrading of in-orbit satellites, and global test and assessment.
As measured by the International GNSS Monitoring and Assessment System (iGMAS), the BDS global positioning accuracy is less than 1.5 m horizontally and 2.5 m vertically (95% confidence) — better than the nominal service performance parameters.
So far, the measured signal power spectrum envelope of the BDS satellites remains consistent with the superior signal quality; the signal-in-space accuracy of any BDS satellite is better than 4.6 m. The time offset between BDT and UTC (NTSC) remains within 26 ns.
The BDS Coordination Framework has maintained consistency with the International Terrestrial Reference Frame 2014, and the accuracy is better than 3 cm. The orbital accuracy of the broadcast ephemeris of the BDS-3 medium Earth orbit (MEO) satellite is better than 0.5 m, and the clock offset of the broadcast ephemeris of the BDS-3 satellites is better than 5 ns.
BDS concentrates on construction of the application infrastructure and has established four major characteristic service platforms:
Short Message Communication Service
Satellite-based Augmentation System Service
Search-and-Rescue Service
Ground Based Augmentation System Service.
These platforms will expand and upgrade the applications and provide more efficient and convenient services for users.
The BDS Short Message Communication Service platform realizes the interconnection with ground mobile communication systems and networks, and integrates the BDS short message communication functionality into smartphones without the need to change the SIM card or contact number.
For the BDS Satellite-based Augmentation System Service platform, the system’s ground segment includes 30 monitoring stations and two data processing centers. The system will provide single frequency (SF) and dual-frequency multi-constellation (DFMC) services through GEO satellites. The Civil Aviation Administration of China has initiated and organized the technical testing and certification of SF service before applications.
The BDS Search-and-Rescue Service provides users with distress alert information access and distribution, as well as return link services. It is currently at the initial operational stage with sound performances. The operational status of the BDS SAR payload has been submitted to Cospas-Sarsat.
The BDS Ground-Based Augmentation System Service platform’s real-time positioning accuracy can reach 2 cm horizontally and 5 cm vertically. The post-processing accuracy can reach 2 mm horizontally and 5 mm vertically. At present, the BDS ground-based augmentation network has provided the A-BDS positioning and the BDS high-precision services for more than 1.5 billion users in more than 230 countries and regions, with services delivered 2 trillion times in total, equivalent to nearly 3 billion on average per day. BDS has provided high-precision positioning services for more than 20 million mobile phones in the country.
The BDS Applications Industry
The BDS applications industry has achieved sustainable development. In 2021, the total output of China’s satellite navigation and location-based service industry reached about 469 billion yuan (about 67.4 billion U.S. dollars), with a compound annual growth rate of more than 20%. A complete industrial chain covering chips, modules, antennas, boards, terminals and services has been established.
Industrial applications. BDS has been fully applied in various industries — including transportation, agriculture, forestry and fishery, public security, disaster mitigation and relief — and has been integrated into infrastructure such as electric power, water conservation, finance and communications.
As BDS applications fields expand, its in-depth applications have been growing as well. As of June 2022, more than 8 million BDS terminals had been installed in the transportation sector. More than 1.3 million terminals were used in the farming, forestry, livestock and fishing industries, and more than 1.8 million terminals were adopted by public security agencies. Large-scale BDS applications have been advanced in communication and timing services, meteorological monitoring, emergency response and disaster mitigation, and urban management. In emerging applications sectors, BDS has served epidemic prevention and control, telemedicine, caring for seniors, promoting the realization of intelligent health services that serve everyone, and accelerating intelligence and modernization in related fields.
Mass market applications. BDS has been widely used in mass market applications, such as mobile phones and wearable devices. In the first half of 2022, among all types of smartphones that applied for network access in China, 128 supported the BDS-based positioning function. More than 130 million smartphones supporting BDS services were shipped, accounting for more than 98% of the country’s total volume. The BDS positioning service is used more than 100 billion times daily on average for a platform that supports mobile map navigation. In particular, mobile phones have been fitted with high-precision positioning services. Lane-level navigation has been implemented in eight cities in China, including Shenzhen, Chongqing and Tianjin. The first mobile phone in the world that supports BDS-3 regional short message communication services has been officially released, enabling users to send short messages through BDS.
BDS international applications. BDS has been applied in more than half the countries and regions in the world, with more diversified application modes and application fields.
BDS products, technologies and services have been recognized by more international users:
In Mozambique, BDS-based UAVs have greatly improved the efficiency of plant protection operations
In Lebanon, BDS-based high-precision technology has been successfully applied to the construction and measurement of the port of Beirut
In Burkina Faso, BDS supported surveying and mapping during the construction of hospitals to prevent and control local infectious diseases, such as COVID-19
In Saudi Arabia, BDS is widely used in fields such as surveying and the collection of geographic information, the construction of urban and municipal infrastructure, and the positioning of personnel or vehicles in deserts
In Asia, BDS-based high-precision positioning services are contributing to the monitoring of Sarez Lake Dam in Tajikistan, the completion of the China-Kyrgyzstan-Uzbekistan Highway, the China-Kazakhstan crude oil pipeline, and the routine operation of China-Europe Railway Express.
International Cooperation
Following the principles of openness, cooperation and resource sharing, BDS has been actively carrying out practical international cooperation and exchanges as well as facilitating the development of global satellite navigation.
Multilateral cooperation. BDS representatives continue to participate in international activities under the framework of the United Nations International Committee on GNSS and other multilateral forums, to advocate joint development of global satellite navigation by contributing Chinese wisdom and proposals. BDS has also participated in international academic conferences in the field of satellite navigation, such as the Institute of Navigation meetings, the Munich Satellite Navigation Summit, and the Multi-GNSS Asia Conference.
Bilateral cooperation. The Ninth Meeting of the China-Russia Project Committee on Major Strategic Cooperation in Satellite Navigation was successfully held in September 2022. Under the framework of the Committee, BDS and GLONASS have carried out continuous cooperation in such areas as compatibility and interoperability, system performance testing and assessment, and joint applications. China’s Satellite Navigation Office signed cooperation documents in the field of satellite navigation with partners from the United Arab Emirates and the Arab Civil Aviation Organization, to carry out extensive cooperation and continue to deepen cooperation with Pakistan, Iraq, Thailand, Argentina, South Africa and other countries.
International Standards. BDS is increasingly recognized by international organizations such as the International Maritime Organization (IMO), the International Civil Aviation Organization (ICAO), Cospas-Sarsat, IEC, 3GPP and RTCM. In November 2022, the BDS Message Service System (BDMSS) was ratified by the Global Maritime Distress and Safety System (GMDSS), making BDMSS the third GMDSS satellite communication system recognized by the IMO. The Declaration of Intent for Cospas-Sarsat MEOSAR Cooperation was signed between the cooperating agencies (from Canada, France, Russia, and the United States) of the International Cospas-Sarsat Program and the Maritime Safety Administration of China, meaning China formally becomes the provider of the Cospas-Sarsat space segment.
The Future
In the future, BDS will launch back-up satellites to ensure better performance by upgrading the constellation’s availability. While maintaining stable operation, BDS will speed up in combination with new technologies such as 5G, artificial intelligence and Big Data to build a more ubiquitous, more integrated, and more intelligent national comprehensive PNT system by 2035. BDS will continuously adhere to the development concept that “BDS is developed by China, dedicated to the world and aiming to be world class,” promote system development and make contributions to social development and construction of the community with a shared future for mankind.
For analogous updates on the other three GNSS constellations, please see:
19% of tracked space objects threaten GPS and other GNSS satellites. While there are many fewer objects in MEO than in LEO, the risk in the former is arguably greater because GPS is so critical to almost all of our technology.
The Risk
GNSS satellites, especially GPS satellites, are critical to the well-being and smooth functioning of economies and national security. This is especially true in Europe and the United States, which do not have complementary terrestrial systems able to provide vital positioning, navigation and timing (PNT) services when signals from space are not available.
While the probability of debris damage to GNSS in medium Earth orbit (MEO) is much less than for satellites in low Earth orbit (LEO), the consequences of such an event would be much, much higher. The loss of one satellite would be a concern; that of multiple satellites, a major problem. The unthinkable chaos, national security damage, and severe economic impacts to the $21 trillion U.S. GDP make the risk unacceptable.
For those who think we need not worry about the low probability of collisions at MEO, the Galileo collision avoidance maneuver in March 2021 should be a wakeup call. The problem is here. We need to act now.
Background
Much like a nuclear fission reaction, the problem of space debris starts small then grows exponentially, as each collision creates more pieces that, in turn, can collide with other objects.
The MEO debris environment is 100 times less dense than the LEO. The spatial density of orbital debris in LEO (up to 2,000 km), shown in Figure 1, suggests that LEO is the likely location where a runaway chain reaction will initiate. This could easily result in a region of space so dangerous that it would effectively deny access to MEO, where the GPS constellation resides.
While the debris situation at MEO is much better, there are still 4,021 tracked debris objects that could impact GPS and other GNSS satellites. Because future orbital debris collisions in LEO will be responsible for more debris in MEO, the situation is guaranteed to get worse. The dead and debris objects in highly elliptical, or Molniya, orbits, shown in Figure 2, could be responsible for such collisions pushing LEO debris into MEO.
Contributions to the general MEO debris population come from launch systems and other factors. Early GPS satellites (Block II/IIA/IIR) used internal orbital-insertion motors to avoid leaving uncontrolled stages in the operational orbit range when moving from transfer orbit to MEO. For survivability reasons, they were also deployed with sufficient fuel to make several major orbital moves. Unfortunately, later versions used separate orbital-insertion stages, which were left drifting in the orbital neighborhood and carried less fuel, resulting in fewer possible maneuvers to avoid collisions.
Using the CelesTrak visualization interface to extract space situational awareness data captured by the Combined Force Space Component Command’s 18th Space Control Squadron (18 SPCS) reveals a much more dire image of MEO. Of the 21,266 total tracked objects in Earth’s orbit, 157 are active GNSS satellites, as shown in Figure 3.
Figure 3. Active GNSS satellites. (Image: Celestrak)
However, a total of 4,021 objects reside or pass through MEO, which are either active (331), dead (668), debris (1,761), rocket bodies (1,100) or unknown (161) objects, as shown in this video.
These 4,021 objects represent 19% of the total number of tracked objects from the 18 SPCS space catalog. While the total 21,266 tracked objects is a far cry from the 100 million objects NASA’s Orbital Debris Program Office represents, one can imagine that a significant portion of untracked debris objects, under 10 cm in size, reside or pass through MEO as well. This is significant, according to NASA, which says that objects with a diameter of 1 cm to 10 cm are the most dangerous due to the lack of tracking data, which essentially makes them invisible.
False Sense of Security
The growing orbital-debris concern is a threat too big to ignore. Unfortunately, to date attempts to manage space traffic have amounted to passive measures, such as establishing policy, characterizing the environment, and creating orbital protection guidelines. Even the highly touted, $6 billion U.S. “Space Fence” is a passive measure that contributes nothing active to solve the problem. Not at all a “fence,” it is merely a way to detect the larger and more dangerous debris.
These efforts may, in all actuality, be counterproductive if they instill a false sense of security in the public and government leaders that the problem is being adequately addressed.
A Proactive Solution
Since 1978, the orbital debris population has been touted as our biggest space problem. It is important to do as much as we can with policies and procedures to keep the problem from getting worse faster. However, even if we humans were to completely resist our seemingly natural impulse to pollute everywhere we go, collisions with existing debris would continue to increase the number of dangerous objects in orbit.
Active debris removal (ADR) is the only solution. The sooner it begins, the safer we will all be. Like the oceans and cyberspace, orbital space suffers from the tragedy of the commons. Everyone wants to use it, but no one owns it. No one is responsible for ensuring it is cared for and maintained. As a result, user behavior is difficult to control, and the environment often suffers. Government action, presumably supporting the best interests of all users, is the default answer.
The proposed Space Debris Act of 2021 is a great start. It paves the way for persistent funding and creates an industry responsible for safeguarding humanity’s orbital infrastructure. It would introduce tax credits to incentivize non-government funding contributions and reduce the price of debris removal, so that satellite operators and the emerging space tourism industry can afford to clean up space where they plan to operate.
The bill is currently being presented by OrbitGuardians to members of Congress for sponsorship. Organizations wishing to support these efforts should contact Ken Eppens at OrbitGuardians at [email protected].
GPS/GNSS and other critical space assets are at an unacceptable level of risk from debris. It is time to safeguard orbital infrastructure to protect the interests of the United States and humanity’s future in space.
China successfully launched a pair of BeiDou-3 navigation satellites into medium Earth orbits on Oct. 15, according to GB Times.
Four hours after the launch, the two satellites were inserted into their intended orbits, according to the China Aerospace Science and Technology Corporation (CASC). The satellites, numbered M15 and M16, are the 39th and 40th launched as part of China’s Beidou system, following the launch of the first in 2000.
Another pair of BeiDou satellites is expected to be launched in November, according to Richard Langley’s Upcoming Satellite Launches.
Liftoff of the Long March 3B rocket sending the Beidou-3 M15 and M16 satellites into orbit. (Photo: CALT)
For the Oct. 15 launch, a Long March 3B rocket with a Yuanzheng-1 upper stage lifted off from the Xichang Satellite Launch Centre in southwest China at 04:23 universal time (12:23 local, 00:23 Eastern).
The China Academy of Launch Vehicle Technology (CALT), which developed the Long March 3B rocket, reported that data logging and active tracking equipment was placed aboard for tests to determine to altitude and timing for future parachute landings for boosters.
Expended rocket boosters frequently land in or near populated areas downrange of Xichang. The trial phase of parachute booster landings is expected in 2019.
