The Army tested the EGI units with enabled M-code on the MQ-1C Gray Eagle unmanned aerial system and validated it to be deployed on military aircraft. This year, the Army will begin migrating its fleet to the Honeywell EAGLE-M EGI with M-code, as this navigation solution enhances the resiliency of GPS navigation to enemy actions.
Image: Honeywell
The defense technology company has delivered more than 300 EGIs with M-code to customers and will deliver qualified units, featuring M-code GPS, to the Army. Honeywell is a leader in EGI for military applications and has provided more than 45,000 EGI units for several different types of aircraft in more than 30 countries.
On Jan. 6, ROCK Robotic, a geospatial company specializing in lidar-based data processing and high-definition mapping, announced the availability of ROCK Base, a triple frequency RTK base station. Additionally, ROCK Robotic has partnered with the Web3 GEODNET initiative to support critical applications in civil surveying, high-definition mapping, digital twin creation and more.
ROCK Base is a resilient, secure, full-constellation GNSS receiver, capable of tracking signals transmitted from GPS, GLONASS, Galileo, BeiDou, QZSS, and the IRNSS navigation satellite constellations. It includes 1,400 channels, survey-grade antennae, cables and antennae-mounting equipment required to set up a permanent continuously operating reference station location.
To make high-definition mapping more accessible and affordable, ROCK Robotic joined the Web3 GEODNET initiative, the largest decentralized GNSS reference network globally. Under the new partnership, ROCK Robotic customers will have access to the GEODNET base-station network to geo-reference ROCK Robotic’s 3D data products to millimeter-level absolute position accuracy, without setting up ground control points. Additionally, ROCK Base is pre-certified on the GEODNET network.
In October 2022, Raytheon Missiles & Defense, a Raytheon Technologies company, received a $207 million contract from the United States Army for Ku-band radio frequency sensors (KuRFS) and Coyote effectors. The Army plans to equip two of its divisions with KuRFS and Coyote effectors to defend against threats from unmanned aerial systems (UAS).
The KuRFS precision targeting radar and scaled Ku-720 mobile sensing radar provides 360-degree detection, identification and tracking of airborne threats. Coyote Block 2 kinetic and Block 3 non-kinetic effectors can defeat single UAS and swarms at high altitudes and long ranges.
The Army’s Mobile-Low, Slow, Small, Unmanned Aircraft Integrated Defeat System, integrates KuRFS and Coyote effectors with Northrop Grumman’s Forward Area Air Defense Command-and-Control system and Syracuse Research Corporation’s electronic warfare system. This creates a mobile deployed system that provides a complete extended-range defense solution.
In October 2022, Curtiss-Wright Corporation’s Defense Solutions division, a supplier of modular open system approach-based solutions, released the VPX3-673A module. This module is the first to deliver assured position, navigation and timing (A-PNT) along with alternative RF navigation and pntOS architecture.
The VPX3-673A is a rugged, 3U OpenVPX, form factor module, which integrates with existing navigation sensors in vehicles operating in environments with limited or denied access to GPS, to increase assurance in the platform’s PNT solutions. It is designed to ingest positioning and timing data from multiple sensors and output accurate timing and navigation information on the battlefield using VICTORY data messages.
It is compatible with the United States Army’s C5ISR/EW Modular Open Suite of Standards and aligned with the Sensor Open Systems Architecture Technical Standard 1.0.
VPX3-673A includes a low noise chip-scale atomic clock with intelligence provided by Xilinx MPSoc, an alternative RF navigation receiver and a 10-degree of freedom IMU. It supports an internal or external GPS module via a front panel connector. Additionally, the VPX3-673A provides processing resources and sensor interface capabilities needed for operability with a variety of external processing and sensor units.
On Jan. 3, Synaptics released the SYN4778, a small, low power, accurate GNSS integrated circuit for Internet of Things (IoT) devices. SYN4778 is designed to extend battery life, reduce product size, and enhance performance of advanced location-based services for IoT devices, including wearables, mobile accessories, asset tagging and tracking systems, UAVS and transportation navigation.
SYN4778 includes advanced multi-path interference mitigation using L5 band signals from GPS, Galileo, BeiDou, NAVIC, SBAS, and Quasi Zenith Satellite System (QZSS). The chip also uses L1 satellite bands to reduce the time to first fix, as well as the power consumed, improving end-user experience, and enabling product developers to add additional functionality and features to their IoT devices.
This GNSS chip includes LTE jamming and signal filtering, and continuous — highly parallel — search and track of all GNSS channels for greater positioning accuracy for LBS applications, specifically in urban environments. Additionally, it offers support for multiple operating systems and third-party software to enable a broader range of application-optimized IoT devices.
SYN4778 is currently only available to select customers.
Cepton, a Silicon Valley-based lidar solutions company, and ALP.Lab GmbH, an Austrian-based provider of autonomous vehicle testing solutions and TE Connectivity, which produces sensors and connectors, have completed a proof-of-concept project called Periscope. Periscope is a vehicle-to-everything (V2X) solution, which extends a driver’s field of view using lidar sensors installed at intersections to warn of road hazards ahead before they are in view.
The companies created Periscope in response to the global issue of traffic accidents involving pedestrians and cyclists. The V2X solution communicates information about road conditions in real time, providing more time to react, preventing accidents and enhancing overall safety.
For the proof-of-concept project, Cepton provided its Helius Smart Lidar System, which combines lidar sensors with edge computing and perception software to provide real-time, 3D object detection and tracking. TE Connectivity contributed its V2X hardware components in the vehicle used for testing and for the surrounding infrastructure, as well as provided technology for an on-board display of the vehicle’s location and road hazards. ALP.Lab supervised the system integration and testing, while also providing the testing area and infrastructure.
Cepton, ALP.Lab and TE Connectivity are planning to collaborate on further testing this year to confirm Periscope’s initial findings.
On Jan. 5, FocalPoint announced an investment from GM Ventures, and collaboration with General Motors (GM), on the integration of next-generation GPS technology in the automotive industry. This collaboration will explore the deployment of electric and autonomous vehicles and aims to apply FocalPoint’s technologies into future vehicles produced by GM to make navigation more precise, especially in urban environments.
Image: FocalPoint
FocalPoint’s Supercorrelation is designed to increase positioning accuracy in urban environments and is highly resilient to spoofing attacks. It will be integrated into GM vehicles to provide more accurate navigation. The goal of the integration is to enhance and expand GM’s Super Cruise, and upcoming Ultra Cruise, hands-free, driving assistance technology.
Supercorrelation is already licensed to u-blox and is in advanced trials with other major manufacturers including Molten Ventures, Greshham House, Passion Capital, IQ Capital, Cambridge Angels and more.
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:
On Nov. 29, 2022, Russia launched the 51st Glonass-M satellite, completing a 20-year history that began on Dec. 10, 2003, with the launch of the first one. These satellites have been providing navigation signals in two frequency bands, L1OF and L2OF, to civil users since 2011.The average orbit lifetime for this type of satellite is more than 10 years, and 13 Glonass-M satellites operate beyond their guaranteed lifetime. The last set of seven satellites has been broadcasting the first CDMA civil signal, L3OC, by means of an additional antenna and onboard transmitter.
Starting this year, the constellation will be renewed by Glonass-K and Glonass-K2 satellites, which provide CDMA signals to users. Furthermore, four Glonass-K satellites will be supplemented with additional Glonass-K satellites and the first Glonass-K2 satellite. The K2 satellite has passed all ground tests and is ready to be transported to the launch site (Figure 1). Table 1 lists the technical characteristics of GLONASS satellites.
Figure 1. Artist’s rendition of the Glonass-K2 satellite in orbit.Table 1. The evolutions of GLONASS satellites.
The distinguishing feature of this satellite’s design is its two antenna arrays — one for CDMA signals with phase centers on the geometrical axis of the satellite, and the second for FDMA signals with phase centers shifted by 0.9 m relative to that axis.
The optical reflector panel center is also located on the satellite’s geometrical axis and passed through its mass center. It seems to be a very interesting scientific task to estimate the satellite flight model parameters by International Laser Ranging Service stations with the objective to improve the accuracy of the navigation signals for both antenna arrays.
Future GLONASS satellites will have a single antenna array for CDMA and FDMA signals (see Figure 2).
Figure 2. The evaluations of GLONASS satellites.
For analogous updates on the other three GNSS constellations, please see:
First, happy New Year to everyone. As a follow up to my November 2022 column on the geodesy crisis, I’d like to highlight that the National Geospatial Advisory Committee (NGAC) of the Federal Geographic Data Committee (FGDC) just adopted a resolution on the need for the federal government to understand and aggressively address the US geodesy crisis. See below. This is great news and, hopefully, the FGDC and others will follow up with discussions with other organizations such as the Office of Science and Technology Policy (OSTP) in the White House.
Now for this month’s column. Last year the National Geodetic Survey (NGS) started suppressing height information in Southeast Texas (see my April 2021 and June 2021 columns). See below for more information. Last year’s columns highlighted the potential effects of subsidence on published heights in the Houston, Texas, region which implied that most of the published heights, which are based on older surveys in the region, are not current or accurate. At the time of NGS’s announcement, only 28 marks with orthometric heights were published on NGS datasheets in southeast Texas. Click here for more information and see below.
This column will provide an update on the following: the current set of published orthometric heights in the southeast Texas region based on recent GNSS surveys performed during 2021 and 2022, NGS’s rules for estimating and publishing GNSS-derived orthometric heights using OPUS Projects, and the status of NGS’s GPS on Benchmarks program.
I always retrieve the latest published coordinates using NGS’s datasheet website routine. See the graphic below of the published NAVD 88 orthometric heights as of Nov. 20, 2022 (I used NGS’s monthly archive by State retrieval option). There are currently 147 marks with published orthometric heights within NGS’s definition of the southeast Texas zone of subsidence. From mid-October to early December of 2022, another GNSS project sponsored by the Harris-Galveston Subsidence District (HGSD) was performed in the region. In this project, 154 marks in the southeast Texas region were observed. The results of this project should be published and disseminated by NGS in the spring of this year.
Latest Published Heights in Southeast Texas. Image: Dave Zilkoski
The current version of OPUS projects allows the user to estimate NAVD 88 orthometric heights, providing they adhere to NGS’s recommendations and procedures. A presentation titled “Heights Suppression in Southeast Texas” by Boris Kanazir, NGS, provides guidance on estimating NAVD 88 orthometric heights using OPUS projects.
See below for the requirements for number of occupations, duration of each session, and the spacing of marks with valid NAVD 88 published orthometric heights.
The requirements include:
a minimum of two NAVD 88 control marks per new mark observed
a mark must be observed twice on different days and at different times of the day
the maximum distance between new marks and NAVD 88 control is between 30-50 km, based on session duration
I like to think of this concept as drawing Venn diagrams around marks. See below for an example of the concept.
Venn Diagram. Image: Dave Zilkoski
So, what does this mean in the real world? The map below demonstrates the concept in the Houston-Galveston, Texas, region. As shown, many of the 30 km circles overlap, indicating that in these overlapping areas there are two CORS with published NAVD 88 orthometric height. This means that a user can occupy a mark for two hours and use the data from two CORS as NAVD 88 control. Of course, the mark must be occupied twice for redundancy.
30 km Radius Circles around SE TX CORS with NAVD 88 Heights. Image: Dave Zilkoski
Increasing the radius to 40 km includes more overlapping areas. This means that the user would have more overlapping areas with two CORS that have published NAVD 88 orthometric heights, but the marks would have to be occupied twice for at least four hours each time.
Image: Dave Zilkoski
Now, when you apply a 30 km radius around the current 147 marks that have published NAVD 88 heights, most of the region has overlapping areas (see below). This means that the user could occupy two of the NAVD 88 marks along with any new marks for at least two hours.
30 km Radius Circle Around all 147 NAVD 88 Marks in SE TX. Image: Dave Zilkoski
The previous figure may seem confusing because of all the circles. In the example below, based on only two marks, 11 marks fall inside the overlapping sections of the two circles. They could be established using the two NAVD 88 control marks that were used to make the 30 km circles.
Example of Two 30 km Radius Circles. Image: Dave Zilkoski
As depicted in my June 2021 column, the Houston-Galveston, Texas, region is subsiding. The map below provides the latest estimates of subsidence in Houston-Galveston, Texas, region based on a Harris-Galveston Subsidence District (HGSD) report “Determination of Groundwater Withdrawal and Subsidence in Harris and Galveston Counties – 2021“ published in 2022. Most of the rates are small, less than 0.5 cm/year, but some are greater than 1 cm/year. This means that some marks may have subsided around 5 cm in five years.
Estimate of subsidence in SE TX. Image: Dave Zilkoski
The surveying and mapping community has done a tremendous job of increasing the number of published heights in the Houston-Galveston, Texas, region (from 28 to 147). That said, the amount of movement in the Katy region is more than -2 cm/year (see box titled “Estimate of Subsidence in the Katy Area”). That means, the marks in this area may subside 10 cm in five years.
Estimate of subsidence in the Katy Area. Image: Dave Zilkoski
Heights that change 10 cm cannot be considered NAVD 88 control marks. NGS’s OPUS Projects User Guide states the following about superseding a mark’s coordinates:
“Users should review the newly adjusted coordinates on user marks to decide whether they recommend that the user mark be re-determined (re-published). Typically, this would happen if the coordinates have shifted by more than 2 centimeters horizontally or 4 cm vertically from the published coordinates marks.”
Therefore, these marks in the Katy region may not be valid NAVD 88 control marks in about two years. Even marks that are subsiding at 1 cm/year may not be valid NAVD 88 control marks in about four years.
The community needs to maintain these marks to account for movement in the region. As previously stated, the Harris-Galveston Subsidence District (HGSD) has marks, denoted as PAMS, that are occupied continuously for a week several times throughout the year. These PAMS and the CORS in the area could be used to estimate crustal movement rates and maintain a set of valid, published heights in the region. See the boxes titled “ArcGIS Online HGSD Subsidence Rates” and “PAM 98 Subsidence Rate.” Additionally, the Texas Spatial Reference Center (TSRC) could provide the appropriate services to help maintain the published coordinates. The TSRC website states, “The technical mission of TSRC is to conduct basic and applied research contributing to NGS’s national Height Modernization program. TSRC is a repository for information used by researchers to develop improved understanding of elevation, geodetic and vertical datums in the state of Texas. The TSRC goal is to re-establish accurate evaluations throughout Texas in cooperation with qualified geospatial scientists, professional engineers, and professional land surveyors.”
In 2025, NGS will replace all three North American Datum of 1983 (NAD 83) frames and all vertical datums, including the North American Vertical Datum of 1988 (NAVD 88), with four new terrestrial reference frames and a geo-potential datum. As stated in my previous columns – April 2022, April 2021, June 2020 – the new reference frames will rely primarily on Global Navigation Satellite Systems (GNSS) as well as on a gravimetric geoid model. These new reference frames will be easier to access and to maintain than the current NSRS. NGS will provide tools similar to the OPUS suite of routines that will facilitate users’ ability to submit data to NGS to maintain and publish survey marks. See the graphic below.
I would like to highlight that NGS has extended the cut-off date for submitting data for use in the 2022 Transformation Tool. The new cut-off date is Sept. 30 (see below).
This column provided an update on the current set of published orthometric heights in the southeast Texas region based on recent GNSS surveys performed during 2021 and 2022, NGS’s rules for estimating and publishing GNSS-derived orthometric heights using OPUS Projects, and the status of NGS’s GPS on Benchmarks program. Additionally, it highlighted that the NGAC of the FGDC adopted a resolution on the need for the federal government to understand and aggressively address the United States geodesy crisis. This is a good step forward, and I hope that others will follow up with discussions with other organizations such as the OSTP in the White House. Finally, “The Geodesy Crisis” white paper can be downloaded from the American Association for Geodetic Surveying (AAGS) website.
I hope everyone has a happy new year filled with optimism, happiness and a generous amount of enthusiasm and fun.
The European Union Agency for the Space Programme (EUSPA) along with the European Commission, have published guidelines that specify the baseline applicable to the Galileo Open Service Navigation Message Authentication (OSNMA) receiver service provision phase. The new documents include the OSNMA Signal-in-Space (SIS) Interface Control Document (ICD), and OSNMA Receiver Guidelines.
The OSNMA SIS ICD specifies, among other things, the interface between the Galileo Space Segment and the Galileo User Segment. This document is an addition to the Galileo Open Service (OS) SIS ICD.
The OSNMA Receiver Guidelines provide generic instructions for the user segment implementation of the OSNMA functionality and complement the OSNMA SIS ICD. Additionally, the guidelines explain user capabilities and steps to implement to verify the authenticity of the Galileo navigation message.
Both documents will be used for the upcoming OSNMA Service Provision Phase that will begin after the OSNMA Service Declaration. They have been developed as an evolution of the Galileo OSNMA User ICD for test phase (v1.0) and the Galileo OSNMA Receiver Guidelines for test phase (v1.1). Copies of the documents can be found here.
The European Union Agency for the Space Programme