By Denis Lyskov, Deputy Head of the Russian Space Agency, Roscosmos
The fundamentals of Russian government policy in satellite navigation are defined in Presidential Decree #638 of May 17, 2007, and specify that:
- GLONASS services are provided globally and free of any user fees;
- GLONASS is used as a basis of the National Positioning, Navigation and Timing System.
To efficiently implement the government policy in satellite navigation, in March 2012 the Government approved the dedicated Federal Program focused on GLONASS sustainment, development, and expansion of applications. This program covers activities aimed at:
- improving the accuracy and integrity of navigation;
- ensuring conditions for guaranteed positioning, navigation, and timing solutions in restricted visibility, interference, and jamming environments;
- enhancing current application efficiency and broadening application domains.
This year, the extensive efforts aimed at development of new generation GLONASS satellites, augmentations, and performance monitoring facilities were taken. The results obtained help to define the main directions of GLONASS development for the upcoming years.
The new navigation satellite will ensure navigation services for all categories of users using current frequency-division multiple access (FDMA) signals in L1 and L2 as well as new code-division multiple-access (CDMA) signals in L1, L2, and L3 bands. The full set of GLONASS signals will be transmitted using two separate phased antenna arrays — one for FDMA signals, and the other for CDMA signals. Introduction of new signals broadens the possibilities of improving the GLONASS orbital constellation configuration, structure and composition of navigation message data, as well as accuracy, reliability, and integrity of navigation solutions in various conditions. The constellation sustainment plan includes the launch of GLONASS-M-55 satellite in 2014. This satellite, similar to GLONASS-K-11 launched in February 2011, will carry an L3 navigation payload and transmit a CDMA signal in L3.
The L3 CDMA signal will also be transmitted from seven more GLONASS-M satellites planned for launch in 2014–2015.
The implementation of a GLONASS modernization program will produce a more than four-fold improvement of accuracy. This will be made by means of:
- ground control segment upgrade;
- introduction of a new on-board atomic frequency standard, based on different technologies;
- introduction of advanced technologies of satellite control, based on intersatellite links in radio frequency and optical bands;
- transition to PZ-90.11 Geodetic Reference System aligned to the International Terrestrial Reference Frame (ITRF) at the millimeter level;
- synchronization of the GLONASS time scale with Coordinated Universal Time UTC (SU, for Soviet Union) at the level of less than 2 nanoseconds while keeping the UTC (SU) own long-term stability at 10-17.
Augmentations play an important role in improving GLONASS performance. With the launch of Luch-5V into an orbital position of 95° E in 2014, the first phase of the System of Differential Correction and Monitoring (SDCM) constellation deployment will be completed. SDCM will provide satellite-based augmentation services (SBAS) in L1 (1575.42 MHz). Simultaneously, the deployment in the Far East of the Russian Federation of uploading and monitoring facilities for Luch-5A positioned at 167° E will be completed. Special attention is being paid to ensuring compatibility of Luch-5B satellite (16° E) and Inmarsat-3F2 satellite (15.5° W) carrying a European Geostationary Navigation Overlay System (EGNOS) payload.
With the purpose of improving the quality of SDCM services, the ground network consisting of several dozen sites will be deployed over the Russian territory, and more stations will be deployed along the Russian border to improve the accuracy of generating the vertical ionospheric delay map.
Apart from SBAS technology development, a system for ensuring Precise Point Positioning (PPP)service is planned for development. PPP service will be provided using geostationary Earth-orbit (GEO) satellites transmitting in L1/L3 GLONASS bands. The L1/L3 transponders are planned to be installed on board future GEO satellites. Considering the common parameters (carrier frequency, pseudorandom noise pulse rate, data rate) of PPP and GLONASS’ own signals, the informative capacity of the former is an order of magnitude greater to ensure rapid broadcast of high-precision orbits and clocks.
For PPP technology development, the global network of measuring facilities is of extreme importance. The global network ensures global monitoring of navigation signals and generation of initial data for high-precision determination and prediction of orbits and clocks.
Cooperation with GNSS providers focuses on protecting the spectrum allocated to radionavigation satellite service, pursuing compatibility and interoperability of GLONASS and SDCM with other GNSSs and augmentations, creating an international GNSS monitoring system.
One of the priority directions of international scientific cooperation is the cooperation with the International GNSS Service through the exchange of measurement information between its members. At the same time, GLONASS measuring and monitoring facilities will receive and monitor all open navigation signals of all GNSSs.
A lot of attention is paid to enhancing GLONASS awareness. Since 2009, the International School on Satellite Navigation has been held annually in the Russian Federation. The Russian Federation has been preparing to host the United Nations Workshop on the Applications of Global Satellite Navigation Systems.
Denis Lyskov is state-secretary, deputy head of the Federal Space Agency of Russia (Roscosmos). He started his carrier in the Russian space industry after graduation from the Moscow Aviation Institute in 1996. He has been working in Roscosmos for the last two years and supervising the GLONASS program since June 2013.