Summary

Class of GLONASS satellites

GLONASS-K

Model of Glonass-K satellite at CeBIT 2011
Manufacturer	ISS Reshetnev
Country of origin	Russia
Operator	JSC «Navigation-Information systems»
Applications	Navigation
Specifications
Bus	Ekspress-1000K
Launch mass	935 kg
Power	1600 watts
Batteries	NiH2
Equipment	FDMA signals: L1OF, L1SF, L2OF and L2SF CDMA signals: L3OC
Regime	Medium Earth orbit (MEO)
Design life	10 years (planned)
Dimensions
Production
Status	In production
Built	3
On order	9 [1]
Launched	3
Operational	3
Maiden launch	26 February 2011
Last launch	25 October 2020

GLONASS-K is the latest satellite design intended as a part of the Russian GLONASS radio-based satellite navigation system. Developed by ISS Reshetnev (Information Satellite Systems Reshetnev) and first launched on 26 February 2011, it is a substantial improvement of the previous GLONASS-M second-generation satellites, having a longer lifespan and better accuracy.

History

The Federal Targeted Program "Global Navigation System" 2002–2011, introduced in 2001, stipulated the development of a third-generation navigation satellite design, called GLONASS-K, as part of the overall GLONASS upgrade program in the time frame 2005–2011. The new satellite followed the second generation GLONASS-M, introduced in 2003.^[2] The Roscosmos initially ordered 27 GLONASS-K satellites from ISS Reshetnev, the developer of all the previous GLONASS satellites.^[3] On 7 December 2010, the company announced it had completed ground tests of the first GLONASS-K satellite.^[4] The satellite was launched to orbit on 26 February 2011.^[5] On 30 November 2014, the second and supposedly last GLONASS-K1 development satellite was put to orbit as Kosmos 2501.^[6]

On 28 May 2014, interview, Nikolay Testoyedov (president of ISS Reshetnev) stated that production of GLONASS-M would end in 2015, with GLONASS-K being exclusively produced after that final batch.^[7] On 14 December 2014, an interview with GPS World, he stated that because of Western sanctions that limited the supply of radiation resistant electronics, they had decided to launch nine additional GLONASS-K1 as fleet replacement while they finished the GLONASS-K2 design.^[8] In May 2015 presentation, Mr. Testoyedov expected the serial production of GLONASS-K1 to start flying in early 2018, just after the launch of the first GLONASS-K2 prototype. The presentation showed at least eleven additional GLONASS-K1 satellites flying until 2020.^[9]

Satellites

GLONASS-K is the first unpressurised GLONASS satellite — all of its equipment is able to operate in a vacuum. Due to this, the satellite's mass has been substantially reduced: GLONASS-K has a mass of just 935 kg compared to its predecessor GLONASS-M, which had a mass of 1450 kg.^[10] The new satellite has an operational lifetime of 10 years, three years longer than that of GLONASS-M and seven years longer than the lifetime of the original GLONASS satellite. It also increased the power supply from GLONASS-M's 1400 watts to 1600 watts.^[10]

GLONASS-K will transmit additional navigation signals to improve the system's accuracy.^[2] Existing FDMA signals, 2 military and 2 civilian, will be transmitted on the L1 and L2 bands, and additional civilian CDMA signals will be transmitted in the L1, L2, L3 and L5 bands.^[11][12][13]

GLONASS-V

GLONASS-V is a planned modification of GLONASS-K for use in highly elliptical orbit.^[14][15] Roscosmos plans to launch six GLONASS-V satellites in two orbital planes in 2023-2025. The new satellites will improve location accuracy in urban canyons and increase redundancy in longitudes between 20° and 160° East covering most of Russia.

Launches

For launching the satellites, two options are planned: six satellites simultaneously from Baikonur Cosmodrome on the heavy-lift Proton-M, or two simultaneously from Plesetsk Cosmodrome on a Soyuz-2 with a Fregat upper stage.^[16] In comparison, the previous GLONASS-M satellites could only be launched three at a time on a Proton-M. The new launch scheme is expected to cut orbiting costs by 50%. The new satellite's advanced equipment — made solely from Russian components — was expected to allow doubling the accuracy.^[13] The launch of the first GLONASS-K satellite did however not conform to the general plan, as it was launched alone on a Soyuz-2.1b instead of in a pair.

At 03:07 UTC on 26 February 2011, the first GLONASS-K satellite, Kosmos 2471, was launched. The launch took place from Plesetsk Cosmodrome on a Soyuz-2.1b rocket with a Fregat upper stage.^[17] The satellite reached the correct orbit at 06:39 UTC.^[5] At 06:44, ground stations established control over the satellite.^[18] A Space Forces spokesman told Interfax: "We have established and are maintaining steady telemetry communications with the spacecraft... the on-board systems of the Glonass-K satellite are functioning normally".^[17] Successful reception of the CDMA signal in L3 band has been reported by independent researchers.^[19][20]

At 21:52:26 UTC on 30 November 2014, the second GLONASS-K satellite, Kosmos 2501 was launched. The launch took place from Plesetsk Cosmodrome on a Soyuz-2.1b rocket with a Fregat upper stage.^[21][18] The spacecraft separated from the launch vehicle at 01:25 UTC of 1 December 2014.^[22]

A third GLONASS-K satellite, Kosmos-2547 was launched on 25 October 2020 at 19:08:42 UTC by a Soyuz-2.1b launcher from the Plesetsk Cosmodrome.^[23]

Photogallery from CeBIT 2011 in Hannover

Russia has exhibited the Glonass-K spacecraft during the CeBIT 2011 fair, that took place in Hannover from 1st to 5 March 2011.

References