Satellite Navigation

dongdong2 · #1 6th November 2006, 05:53

China officially announces that it is building its own Beidou (Compass) Navigation Satellite System. (via Xinhua News Agency: (Chinese) http://news.xinhuanet.com/mil/2006-1...9932.htm?rss=1)
The news is released during Zhuhai Airshow and the system diagram and the important Onboard Rubidium Atomic Frequency Standard are displayed in Zhuhai Airshow. I personally think this is the greatest news in the Airshow. This is more important than the demo of JDAM/JSOW of Chinese version (LS-6,FT-1,etc) in Zhuhai . This is a symbol that China is holding the capability of big system warfare.

Three trial Beidou Navigation Satellites have been launched since 2000 and have served lots of civilian and military users in China. The two formal satellites will be launched by end of 2006 or start of 2007. By 2008, Beidou's service can cover China territory and surrounding Asia/Pacific countries. And it will be gradually expanded to global service. The final Beidou space segment will consist of 5 GEO and 30 non-GEO satellites(35 in total).

Besides passive navigation service, a very useful feature of Beidou system is a Beidou terminal/PDA can send and receive two-way short text message (for authorized users only). CCTV news has shown PLA soldiers in patrol using Beidou teminal to send message to Headquarters.

Pinko · #2 6th November 2006, 07:11

Hardcore news, well, I think the initiatives behind the "Beidou-2" are EU's reluctance to accept China as a equal share-holding member of Galileo Navigation system, apparently because of the strong pressure from the other side of Atlantic. Did them mention they will shoot down Galileo should there be a confrontation between them and Chinese and Chinese are to use Galileo signal to "kill their soldiers"?

Well. Blockage from the lonely earth dictator serves little to halt Chinese progress because the initiatives are within Chinese not from everybody else. Good news, No pressure, no progress.

Distiller · #3 6th November 2006, 07:42

Really cute. Other countries need years to put up a GPS satellite system, China just announces that in a couple of month they will have their own. Really cute ...

Showtime 100 · #4 6th November 2006, 07:45

I think this is one of the reason why PRC JADM like LS-6 and Self propel Gun like PL-45 has enter service since their guidance r heavily rely on GPS. Soon they will not restricted by US satelite and can even use by PRC friendlies countries in wartime!

Showtime 100 · #5 6th November 2006, 07:47

Quote:

Originally Posted by Distiller

Really cute. Other countries need years to put up a GPS satellite system, China just announces that in a couple of month they will have their own. Really cute ...

Hopefully u don turn from cute to horror!

crobato · #6 6th November 2006, 07:54

Quote:

Originally Posted by Distiller

Really cute. Other countries need years to put up a GPS satellite system, China just announces that in a couple of month they will have their own. Really cute ...

What's cute? The network has been building up for some years now. Beidou 1A was launched early in October 2000 followed by Beidou 1B in December of the same year. Beidou 2A was launched in May 24, 2003.

That's more than 3 years ago, dude, and six years ago for the first satellite.

http://en.wikipedia.org/wiki/Beidou_navigation_system

With the minimum of 3 trial satellites for triangulation, apparently you have 3 years to throroughly work out the system, and the announcement to put 2 formal satellites means the system is going into the next phase. The appearance of GPS guided bombs in the PLA, and GPS receivers in the PLAAF are obvious signs of a practical working system.

Like the guy said this is a genuine hard core news.

This attitude of dismissing projects currently happening as photoshop will someday come back to haunt you and bite you in the ass. Whatever happened to the idea of "vigilance"?

WisePanda · #7 6th November 2006, 08:06

EU galileo will imo be a victim of political, funding and workshare battles. nobody should hang their hat on that hook.

Distiller · #8 6th November 2006, 09:17

Quote:

Originally Posted by crobato

What's cute? The network has been building up for some years now. Beidou 1A was launched early in October 2000 followed by Beidou 1B in December of the same year. Beidou 2A was launched in May 24, 2003.

That's more than 3 years ago, dude, and six years ago for the first satellite.

http://en.wikipedia.org/wiki/Beidou_navigation_system

With the minimum of 3 trial satellites for triangulation, apparently you have 3 years to throroughly work out the system, and the announcement to put 2 formal satellites means the system is going into the next phase. The appearance of GPS guided bombs in the PLA, and GPS receivers in the PLAAF are obvious signs of a practical working system.

And talking about global services: The orbits 8x3 plus 5 (Navstar 6x4 circular) will provide only for a relatively small area

Like the guy said this is a genuine hard core news.

This attitude of dismissing projects currently happening as photoshop will someday come back to haunt you and bite you in the ass. Whatever happened to the idea of "vigilance"?

I do not belittle the fact that China has ambitions to build such a system. Ground stations on Cuba, Kiribati (dropped), and that contract with Sweden and the number of planned reference stations tell a story of long-term planing.

I say cute because of the apodictic way those news from China are communicated. Having three close trailing geostats on 0.1° over Indonesia don't give you GPS capability and is *very* different from having an operationally useable constellation of geosync sats flying. And the four additional geostat Beidou-2 slot they reserved will not dramatically change the usability of the current system. And nobody did eliptical geosync GPS so far. We shall see. Anyway, 3x8 will cover only a certain part of the globe, no way to do a full-coverage system that way. Again, we shall see.

Plus I also say cute cause I always ask myself if they developed, or bought, or stole the technology when reading such news! So far their space programme still heavily depends on the help of (idiotic) foreign countries and companies. (Although China claims to have done the Bei Dous all alone. Who am I to judge.).

Btw, GLONASS/Kosmos is down to 11. Let's see how Bei Dou does.

chinawhite · #9 6th November 2006, 10:32

Another example of mistrust between countries. One GPS system is enough for the world but major nations need to secure their lines of communication.

- Russian GLONASS was because the americans wont let them use theirs
- US GPS is just US GPS
- Galileo was created to ensure better accuracy for civillan use which the Americans wont give
- If No trust anyone else, the chinese sure as hell arent going to trust anyone

Beidu 1 has only 2 satellites for the Asian region and seems to be good enough for the chinese military. You really need more than 2 so they can reference back to each other to make them more accurate for an guidence system

Blueshark · #10 6th November 2006, 15:56

The Beidou satellite navigation system will have 35 satellites in orbit and have global coverage.

The Beidou system will have 2 tiers. One tier will be for commercial and civilian use. Another tier will be for authorised users only.

young · #11 6th November 2006, 20:54

I guess when a nation has 1trillion US$ in reserves, with a fully-fledged
manned-space programme ( which is something we Europeans have not
achieved yet on our own), a Beidou 2 , 3, 4, (or more..) will obviously
be within their capacity. Good luck to them.

crobato · #12 7th November 2006, 01:28

Quote:

Originally Posted by Distiller

I do not belittle the fact that China has ambitions to build such a system. Ground stations on Cuba, Kiribati (dropped), and that contract with Sweden and the number of planned reference stations tell a story of long-term planing.

I say cute because of the apodictic way those news from China are communicated. Having three close trailing geostats on 0.1° over Indonesia don't give you GPS capability and is *very* different from having an operationally useable constellation of geosync sats flying. And the four additional geostat Beidou-2 slot they reserved will not dramatically change the usability of the current system. And nobody did eliptical geosync GPS so far. We shall see. Anyway, 3x8 will cover only a certain part of the globe, no way to do a full-coverage system that way. Again, we shall see.

Plus I also say cute cause I always ask myself if they developed, or bought, or stole the technology when reading such news! So far their space programme still heavily depends on the help of (idiotic) foreign countries and companies. (Although China claims to have done the Bei Dous all alone. Who am I to judge.).

Btw, GLONASS/Kosmos is down to 11. Let's see how Bei Dou does.

No one is saying the Beidou is a full fledged GLOBAL system. 3 satellites is the minimum you need to cover China and their side of the hemisphere, and that's what they got. And it does appear to be usable within this coverage, and so it seems, they have satisfied their short term ambitions and goals and this is a signal they're moving to the next stage.

GoldenDragon · #13 7th November 2006, 03:27

Quote:

Originally Posted by crobato

No one is saying the Beidou is a full fledged GLOBAL system. 3 satellites is the minimum you need to cover China and their side of the hemisphere, and that's what they got. And it does appear to be usable within this coverage, and so it seems, they have satisfied their short term ambitions and goals and this is a signal they're moving to the next stage.

The user can figure out whether he is on the right course with even two satellite. It gives you direction if you know the position of the satellite and a fixed location like a city. With three satellites you have the location of the user and that gives you something completely functional. Beidou is just the beginning and is centered on China. The US' GPS system is 24 satellites but it is a constellation spread around the globe.

As stated in this and the article in the other thread, the Chinese Compass system will eventually have 35 satellites.

dongdong2 · #14 7th November 2006, 04:13

The fact is based on the three trial Beidou satellites(Beidou-1), a Beidou industry chain has already been formed in China, from chipsets, user terminals to system application solution. If you type "Beidou" in Chinese google, you will find many Chinese companies are selling Beidou products such as navigation terminals for personnel, vehicle and ship, timing products and OEM boards as well as group management and control system.
http://www.unistrong.com/product/beidou/index.asp
http://www.51gps.com/Shop/ShowProduct.asp?ProductID=334

Compared with GPS, a unique feature of Beidou is its two-way text communication capability. A Beidou terminal can report or can be asked to report its position and sent message to remote center without the help of any other datalink. In China, a Beidou terminal can even send and receive short message to/from normal GSM/CDMA mobile phones! This is very useful in exploration, lifesaving, group management and military command and control. This is an interesting example: a Chinese company provides solutions for Army's command system. By this system, a general can even send command to a tank or a single soldier carrying Beidou terminal:the thorough flat organization :-)
http://www.spacestar.com.cn/new/show...id=52&unid=192

Beidou receiver and antenna looks bigger than GPS's. This will be improved after Beidou-2 is ready.

The pictures are snapshots of web pages of existing Beidou products.

tphuang · #15 7th November 2006, 04:17

Quote:

Originally Posted by GoldenDragon

The user can figure out whether he is on the right course with even two satellite. It gives you direction if you know the position of the satellite and a fixed location like a city. With three satellites you have the location of the user and that gives you something completely functional. Beidou is just the beginning and is centered on China. The US' GPS system is 24 satellites but it is a constellation spread around the globe.

As stated in this and the article in the other thread, the Chinese Compass system will eventually have 35 satellites.

you know, the weird part is that I read some Chinese articles that said Beidou 2 would have 12 satellites.

GoldenDragon · #16 7th November 2006, 04:47

Well, the article said the final Beidou version will have "5 GEO and 30 non-GEO satellites."

Just as the Beidou-1 configuration has just three satellites, the Beidou-2 configuration might very well have 12 before the final version of 35 satellites are put in place. Considering that the US uses a constellation of 24 (three are spares) for the full global coverage, by the time China reached 12 for Beidou-2, they would have coverage equal to GPS for China's neighborhood. So 12 would seem a good milestone for a country focused regionally like China.

chinawhite · #17 7th November 2006, 06:07

dongdong2,

I forgot to thank you for posting all these pictures

totoro · #18 7th November 2006, 08:55

Unless they're in geosync orbits over china, 12 satellites are not enough to provide contiuous coverage for chinese at usual altitudes. Only if orbiting at much higer altitudes could 12 be enough to cover entire globe.

Distiller · #19 7th November 2006, 09:39

Ok, CURRENTLY there are 3 Bei Dou up there in a geostat orbit over Indonesia, and they are closely spaced. Since we all know (I hope!) that a GPS system works via triangulation, one can easily see, that three in a tight row will now give you a very good angular resolution. Plus you have to know your exact altitude, otherwise you need four sats. (Or you have your own atomic watch, then two are sufficient. It would even work with just one sat, but not if that sat is geostat). It just can't be very precise. Simple.
And talking about "finding directions": There's a thing called compass and I'm sure the Chinese have a magnetic map of their country.

That SMS feature of the current Bei Dous is just a gimmick, or probably a trial balloon for some later system.

Future Bei Dous - as of current assumptions - will have 1x5 geostat + 3x8 elliptical orbits. ELLIPTICAL orbits. Navstars are 6x4 on circular 20.200km 55° orbits, GALILEO will be 3x9 on circular 23.222km 56° orbits. Nobody ever did elliptical orbits for a GPS. That will cause tremendous problems, plus you do not get global coverage. Again, if the data currently available is correct.

crobato · #20 8th November 2006, 02:43

Its not a tight row, that's like 90 degrees from one satellite to another, and 45 degrees to the one in the center. That's probably enough to service one hemisphere. Hard to say if its accurate or not, unless you're in the front row, but all indications at least, it has passed the PLA's requirements.

Distiller · #21 8th November 2006, 06:36

Quote:

Originally Posted by crobato

Its not a tight row, that's like 90 degrees from one satellite to another, and 45 degrees to the one in the center. That's probably enough to service one hemisphere. Hard to say if its accurate or not, unless you're in the front row, but all indications at least, it has passed the PLA's requirements.

Current Bei Dous are at 80 - 104 - 131 east.
http://www.n2yo.com/

crobato · #22 8th November 2006, 07:49

Quote:

That SMS feature of the current Bei Dous is just a gimmick, or probably a trial balloon for some later system.

Gimmick? SMS for mainland Chinese and much of Asia is both an unprecedented craze that has become a vital fact of life. It's everything for them. Maybe it will be expanded later with additional options. Well in a way, this is becoming a gimmick crazy country with an insatiable appetite for the latest technology items.

Showtime 100 · #23 11th November 2006, 14:27

Translate from the Chinese character! "Beidou code one system"

Pic of PLA troops using Beidou GPS system!

Distiller · #24 14th November 2006, 19:42

Competition still alive.
Undiluted GLONASS from 2007 on.

http://www.gpsdaily.com/reports/Russ...n_Use_999.html

AdmarilZhengHe · #25 15th November 2006, 01:12

Quote:

Originally Posted by Distiller

Competition still alive.
Undiluted GLONASS from 2007 on.

http://www.gpsdaily.com/reports/Russ...n_Use_999.html

but Russia do not have Kazakistan to use anymore, so fees to send civilian product up will be required from both country. not cheap. Other Russia launch pad is in cold areas. China can send them from sunny Xinjiang. it is the area you see in Crouching Tiger and Hidden Dragon where the barbarain lives. good place for rocket sending. cheaper too.

Satellite Navigation

Monday, October 22, 2007

China is building its Beidou Navigation Satellite System

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