The new GLONASS-K2 navigation satellite was successfully launched into orbit on March 3, 2025, from the Russian military cosmodrome Plesetsk in the Arkhangelsk region. American sources promptly reported this, while Russian sources did not formally identify the satellite, instead employing the terms “a spacecraft in the interests of the Russian Ministry of Defense” or “a satellite manufactured by JSC Reshetnev.”
The first test launch of a GLONASS-K2 satellite was successfully carried out from Plesetsk in August 2023. According to American sources, the March 3, 2025, launch was the second for this type of spacecraft. If this is true, it fits the logic of testing—at the beginning of any project, the quality characteristics are worked out, and the performance of new systems is analyzed.
In the early 2020s, reports indicated that the first four GLONASS-K2 satellites were under construction in Krasnoyarsk, and 13–15 such satellites were planned to be built by 2030. Nevertheless, the launch program has not been made public. It is worth noting that the military launched both of the first GLONASS-K2 satellites, labeled “Kosmos-2569” and “Kosmos-2584,” which implies that not all details and specifications will be disclosed.
In the past, Russian media reported that GLONASS-K2 is a significant improvement over the GLONASS-K satellites, as it provides a higher degree of precision in determining user coordinates (less than 30 cm) as a result of the transmission of CDMA signals on three L-band frequencies (L1, L2, and L3) and the use of modern radio-electronic apparatus. The number of navigation signals has increased compared to previous models. The GLONASS-M has five signals, the GLONASS-K has seven signals, and the GLONASS-K2 has nine signals.
Let us discuss this satellite series in more detail.
The GLONASS-K2 satellites represent the fourth significant upgrade in the Russian GLONASS navigation satellite system, following the original Uragan, GLONASS-M, and GLONASS-K models. ISS Reshetnev manufactures the unpressurized Ekspress-1000 satellite bus, upon which these satellites are built. They use a new-generation thermal control system with electrically powered thermal panels and optical thermal coating, allowing precise temperature control within 0.1°C.
In terms of navigation signals, the GLONASS-K2 satellites transmit three types of signals: two signals in the L1 and L2 ranges for specialized users, such as the military, and one channel in the L1 range accessible to the general public. Additionally, they feature CDMA signals on L1, L2, and L3 frequencies, enhancing accuracy and compatibility with other systems. This upgrade significantly improves the navigation accuracy, providing it at less than 30 cm, which is a notable improvement over previous models.
Each GLONASS-K2 satellite has a design life of 10 years and weighs approximately 1,645 kg. They have 170% more power compared to their predecessors, which supports their enhanced capabilities. The satellites are also equipped with instruments for the COSPAS-SARSAT international search and rescue system and may include unidentified military payloads. The development of GLONASS-K2 involved significant efforts in import substitution due to sanctions, aiming to use Russian-made radiation-hardened components.
The first GLONASS-K2 satellite was launched on August 7, 2023, from the Plesetsk Cosmodrome. The GLONASS-K2 series is being developed as part of the ongoing endeavor to modernize the GLONASS system, thereby guaranteeing its competitiveness with other global navigation systems such as Galileo and GPS. These satellites are crucial for sustaining Russia’s position in the global navigation market and providing reliable services for both civilian and military applications.
It is launched using the modern Soyuz-2.1b medium-class rocket with a Fregat upper stage. The operational orbit is approximately 19,000 km above Earth, and the satellite’s lifespan is at least 10 years.
Let us compare it with the latest GPS satellites.
When comparing the GLONASS-K2 satellites with the latest GPS satellites, several key aspects come into play, including signal structure, accuracy, and operational capabilities. The GLONASS-K2 satellites will transmit both legacy FDMA (Frequency Division Multiple Access) signals and new CDMA (Code Division Multiple Access) signals on L1, L2, and L3 frequencies. This improvement enables improved interoperability with other GNSS systems, such as GPS and Galileo, thereby enhancing the accuracy and resistance to multipath.
On the other hand, the most recent GPS satellites, including those in the GPS III series, also employ CDMA signals, specifically the L1C and L5 signals, which are engineered to enhance performance and compatibility with other systems. These signals are centered at 1575.42 MHz (L1) and 1176.45 MHz (L5), respectively.
In terms of accuracy and performance, the GLONASS-K2 satellites aim to provide navigation accuracy of less than 30 cm, significantly improving upon previous GLONASS models. They also feature a clock stability of ~5-1×10^-14.
On the other hand, GPS III satellites offer improved accuracy and signal strength, with position accuracy generally ranging from 2 to 8.76 meters. The L5 signal, in particular, is designed for “Safety of Life” applications, providing robust performance in challenging environments. While both systems have made significant strides in accuracy, GPS III satellites maintain a slight edge in overall precision.
The operational lifetime and design of these satellites also draw attention to certain distinctions. The design life of each GLONASS-K2 satellite is 10 years, and it is equipped with improved thermal and power management systems. In contrast, GPS III satellites are engineered with sophisticated propulsion systems to enhance maneuverability and longevity, and their operational lifespans typically exceed 15 years. This extended lifespan and enhanced propulsion system give GPS III satellites an advantage in terms of durability and flexibility.
Finally, the orbital configuration and coverage of these satellites exhibit substantial differences. The K2 series, which is part of the GLONASS satellite constellation, is located at higher latitudes, providing more comprehensive coverage in northern regions than GPS. This makes GLONASS particularly effective for users in high-latitude areas. On the other hand, GPS satellites are distributed globally with a lower orbital inclination, providing broader coverage but potentially less effective at high latitudes compared to GLONASS. Overall, both systems have their strengths and weaknesses, with GLONASS excelling in high-latitude coverage and GPS offering broader global coverage and slightly superior overall accuracy.
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