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Glonass - does it work?

32 Posts

23-Apr-22 05:43

AFAIK missiles use inertial guidance, like this.

You could build your own GPS which then has no limitations, but it would not be of much use in any real conflict.

Administrator

Shoreham EGKA, United Kingdom

22-Apr-22 22:03

I was going to say something smart-alec about them having to stick to subsonic missiles in that case, but Google says that amateurs have found ways round the speed/altitude limits on commercial receivers.

22-Apr-22 18:58

Looking on the bright side, it means it’s unlikely the Russians will shoot down the GPS constellation, since they’re just as dependent on it as everyone else. Presumably using smuggled Garmin devices.

LFMD, France

22-Apr-22 14:45

Peter wrote:

Speaking from experience, there is a significant risk that within 5 years the Russian GLONASS constellation will simply cease to exist.

I don’t see any risk there I believe it’s guaranteed. Like in probability theory, that’s sure event.

Last Edited by Emir at 22 Apr 14:48

LDZA LDVA, Croatia

22-Apr-22 11:32

The news from Russia is that Glonass is soon going to come to a sticky end.

The system originally used Glonass satellites developed in the Soviet Union, which began to be replaced in 2001 by the more modern Glonass-M, still based on Soviet design and know-how.

The replacement of GLONASS-K1 satellites, which were supposed to bring GLONASS up to the level of the US GPS navigation system, was started in 2011.

However, after the invasion of Ukraine in 2014, the first sanctions were imposed on Russia, and because GLONASS is formally a fully military system (the Russian Ministry of Defence is the customer and operator), GLONASS came under full force of these sanctions. After that, it suddenly turned out that a significant part of the satellite hardware was imported, and apart from three completed experimental satellites and one unfinished K1, nothing could be produced. And the satellites in orbit degrade and require periodic replacement. As a solution to the problem, they announced “rapid substitution of imports” that was “bound to succeed” and lead to the creation of a super-advanced all-domestic K2 satellite.

The K1 satellites were planned for an emergency upgrade, removing as many imported components as possible, the missing things to be smuggled in. The domestic K2 was due to launch as early as 2018.
However, it immediately became clear that removing imported radiation-hardened components reduced the lifespan of the satellite by a factor of 3 or 4. Nine satellites had to be launched to maintain the constellation instead of two!
The situation was so critical that old Glonass-M satellites that were taken out of production back in 2015 were retrieved from storage and launched. They even thought of launching old Soviet Glonass ones, but those had already reached the end of their service life and proved incompatible with the new system.

Of course, no K2 happened in 2018.

In 2019 it turned out that the new K1s could not be produced either, and there were problems with upgrading the old ones. It was decided to accelerate the work on K2, which by that time should have been ready for two years.

There was no sign of K2 in 2020. In spite of tales of continuous success, the situation became even worse and to maintain the constellation, they even had to launch the ancient Glonass-M that was used as a ground testbed.

However, there should be 24 satellites in orbit at the same time, not counting the reserve, plus several reserve satellites in case of breakdowns. These satellites have to be replaced periodically. Now, the Sun is entering its active phase and “greeting” us with record solar storms, each of them greatly reducing the service life of satellites.

In general, because of the mess, squandering, arrogance, and sanctions, the satellites were in short supply and to maintain the constellation in 2021 it was necessary to launch at least five satellites: one more renovated ancient Glonass-M, two Glonass-K with smuggled components and some others replaced with Russian ones, and two new “import-substituted” Glonass-K2 (which no one has ever seen).

By mid-year 2021, there were no launches, and the plans had changed from five to four satellites to be launched. Or maybe two, or possibly one, with an overall sour-grapes attitude.

None were actually launched, but for 2022 they promised to launch two ill-fated K1s and one or two K2s that would be ready “really soon”. The old Glonass-M testbed seems to have disintegrated in the meantime, and nobody remembers it anymore.
The promises were somewhat unconvincing – the “inevitable success” was due in the early 2022, then postponed until the end of the year.
Then Rogozin (head of the Russian Space Agency) promised a fantastic success with launching 18 additional K2 satellites at once… but only in 2030, yet immediately started sobbing about a catastrophic shortage of satellites in orbit (who would have thought?)

By now, there is some talk that the current GLONASS is obsolete and useless and that Russia will make an even better GLONASS literally tomorrow, that is, in 2028.

As a result, there are 22 satellites operating out of 24 required for the GLONASS space constellation, and there is a total deficit of six launches.

Meanwhile, many GLONASS satellites have long exhausted their service life and even if all the declared plans are fulfilled (which is highly unlikely), the deficit of satellites will inevitably increase within a year or two with a corresponding reduction in system performance.

Speaking from experience, there is a significant risk that within 5 years the Russian GLONASS constellation will simply cease to exist.

Administrator

Shoreham EGKA, United Kingdom

31-Aug-18 12:14

AndroiTS
Not sure if it is still available.
Simon

31-Aug-18 11:24

Jan Olieslagers wrote:

But is there a real advantage to receiving Glonass on top of GPS? THAT was my question!

Yes, at high latitudes. This is primarily due to Glonass’ higher orbital inclination compared to NAVSTAR.

Other advantages are higher repeatability of DOP values on a daily cycle and, theoretically, a slightly higher resistance to narrow-band interference.

There is also their contribution to the Cospas-Sarsat space segment as a secondary mission, along with NAVSTAR and Galileo.

A disadvantage (as of ten years ago, things may have changed since) is a lower density of ground stations so anomalies in individual satellites may go undetected for longer than with other constellations. This is a political, not a technical drawback.

Finally, in terms of having GLONASS on top of GPS (i.e., alongside, which I believe was your question) there is the redundancy offered by two independently developed and operated technologies. Same applies for Galileo and Beidou.

Last Edited by 1521 at 31 Aug 11:28