China launches Compass duo via Long March 3B

[shuttler]

CZ 5 (Long March 5) Will Have World's Second Largest Carrying Capacity
.

With a maximum payload capacity of 25 tonnes, Long March 5 is expected to be able to send lunar rovers, large satellites and space stations into space after 2014.

.

Long_March_5_Will_Have_World_Second_Largest_Carryi ng_Capacity
.
.
Computer Simulation CZ 5
.

 

[peaceful]

That is only to prevent ridicule and loss of image in case of a failure......
Most failiures are hidden using these propaganda tactics , you know.....
Since India is not a communist state, it unfortunately cannot hold it's media's tongue and is subject to ridicule everytime

you must be kidding yourself if you think someone can hide a launch failure in 2012. both the US and China have satellites called ballistic missile launch early warning satellites, they are well capable of detecting missile and rocket launches.

 

[ephone]

I hope this GPS system will be free to those around the world. Let's make it free to those in Asia first. Isn't it working to cover all of Asia quite soon?

 

[Safriz]

i wonder what positioning technique the chinese will use?
is it the samecas american? or different..
one very obvious difference is that american GPS is a MEO satellite constellation while chinese is geo stationary?

 

[Safriz]

ok...just has a quick read on the Beidou system...
the second generation is superior than american GPS.

The archelies heel of any such navigation system is the Ground station which tracks the satellites and inputs the necessary data for pisitioning..
USA has theirs in an airbase and its a high security area..only uniformed military personnel work there ...

American GPS needs an input from ground station every 12 hours..
dont know about Beidou..

but if an enemy nation wants to destroy the navigation system of a country./
all they have to do is take out the ground tracking station..
there is only one usually....

 

[shuttler]

ok...just has a quick read on the Beidou system...
the second generation is superior than american GPS.

The archelies heel of any such navigation system is the Ground station which tracks the satellites and inputs the necessary data for pisitioning..
USA has theirs in an airbase and its a high security area..only uniformed military personnel work there ...

American GPS needs an input from ground station every 12 hours..
dont know about Beidou..

but if an enemy nation wants to destroy the navigation system of a country./
all they have to do is take out the ground tracking station..
there is only one usually....

GPS swung into operation in 1994. Its been upthere for quite a while and subsequent upgrade can improve its functions. I have read a description on the Beidou N System that it can serve a 2-way communication, between earth and satellite while GPS goes one way. i need further info about how the "2-way" communication work!

 

[Safriz]

GPS swung into operation in 1994. Its been upthere for quite a while. I have read a description on the Beidou N System that it can serve a 2-way communication, between earth and satellite while GPS goes one way. i need further info about how the "2-way" communication work!

Beidou-1 is based on two way communication..
the user has to transmit a signal to get a position fix..
but that increases cost of the receiver as you need a powerful transmitter at hand to send signal all the way to a geo stationey satellite 30,000 kilometers away.....and limits the amount of time you can get position uodate due to time lapse....

Beidou 2 is passive navigation system similar to american gps..and you dont need to transmit a signal to the satellite for a fix.
and the speed of update iscfar better than Bedou 1 due to satellites being nearer at lower orbits and more numerous..
Another difference i noticed was the signal encryption..
Americal gps has little encryption and is easier to jam or spoof..
Last time i checked they had a 4 gb signal packet..while chinese has a muvh larger packet and has key encryption similar to mobile phone networks....This makes it harder to jam or spoof.

But a military receiver always has two way communication with
positioning satellite..be it GPS.GLONASS.BEIDOU or any other system...thats is for avoiding spoofing

Beidou is still a work in progress and we have to see how the final shape comes out to be

 

[shuttler]

Beidou-1 is based on two way communication..
the user has to transmit a signal to get a position fix..
but that increases cost of the receiver as you need a powerful transmitter at hand to send signal all the way to a geo stationey satellite 30,000 kilometers away.....and limits the amount of time you can get position uodate due to time lapse....

Beidou 2 is passive navigation system similar to american gps..and you dont need to transmit a signal to the satellite for a fix.
and the speed of update iscfar better than Bedou 1 due to satellites being nearer at lower orbits and more numerous..
Another difference i noticed was the signal encryption..
Americal gps has little encryption and is easier to jam or spoof..
Last time i checked they had a 4 gb signal packet..while chinese has a muvh larger packet and has key encryption similar to mobile phone networks....This makes it harder to jam or spoof.

But a military receiver always has two way communication with
positioning satellite..be it GPS.GLONASS.BEIDOU or any other system...thats is for avoiding spoofing

Beidou is still a work in progress and we have to see how the final shape comes out to be

the signal encryption is an advantage of Beidou. But it is rotating on low orbit, more visible to the eyes so more vulnerable to missile attacks. There are more to the 2-way communication in addition to what you describe about the additional cost and time for transmission and reception. I am searching for it. But thanks for the input!

 

[shuttler]

The advantages of Beidou over GPS are:

1. it is GPS compatible and provides about the same all weathered free services to global users on speed monitoring, positioning and time sychronization etc.. It also provides broader and more sophisticated services under Beidou operators' authorization.
2. it can communicate not only in signals but also in short messages
3. it has lesser blind spots
4. the "2-way" communication is user A can communicate via Beidou with user B on the planet in different remote positions apart with each other by texting short messages. GPS cannot do this yet. So controllers can direct and change commands to their intended receivers more efficiently.
5. system security is enhanced by the encryption feature unique to Beidou
6. In respect of precision, reliabilty, and stability, Beidous is just as good as GPS and it is better than GPS when operating in Asia Pacific.
7. it is China's baby!

 

[Safriz]

The advantages of Beidou over GPS are:

1. it is GPS compatible and provides about the same all weathered free services to global users on speed monitoring, positioning and time sychronization etc.. It also provides broader and more sophisticated services under Beidou operators' authorization.
2. it can communicate not only in signals but also in short messages
3. it has lesser blind spots
4. the "2-way" communication is user A can communicate via Beidou with user B on the planet in different remote positions apart with each other by texting short messages. GPS cannot do this yet. So controllers can direct and change commands to their intended receivers more efficiently.
5. system security is enhanced by the encryption feature unique to Beidou
6. In respect of precision, reliabilty, and stability, Beidous is just as good as GPS and it is better than GPS when operating in Asia Pacific.
7. it is China's baby!

Ok..so they have integrated a communication system in the Navigation satellite..That is something new.But the fature mey be restricted to military users only.Not for civilian use.

Beidou-2 will also use European Galelio satellites becuase china has significant investment in Galelio system..
When that happens the contellation will be combination of Beidou and Galelio satellites and thats a whopper 70+ satellites.
That means we will have much better signal reception in cvities..as in cities the buildings stop sinal and induce error by bouncing them off...This will be cured by the Beidou+Galelio hybrid.
Beidou-1 is geostationery and thats why 30,000+ kilomerters up and not susceptible to any Missile attack...
Beidou-2 had to be put in lower orbits for ease of use and to reduce the cost of receiver as Beidou-1 receiver was very expensive...
Here are excerpts from wiki which will explain the two way communication i was on about and the costs...relating to Beidou-1..It has akll to do with the method of position calculation used in Beidou-1...

Position calculation

To calculate a position, the following procedure is used:[5]

A signal is transmitted skyward by a remote terminal.
Each of the geostationary satellites receive the signal.
Each satellite sends the accurate time of when each received the signal to a ground station.
The ground station calculates the longitude and latitude of the remote terminal, and determines the altitude from a relief map.
The ground station sends the remote terminal's 3D position to the satellites.
The satellites broadcast the calculated position to the remote terminal.

In 2007, the official Xinhua News Agency reported that the resolution of the BeiDou system was as high as 0.5 metres, considerably better than unaided GPS.[23] With the existing user terminals appears that the calibrated accuracy is 20m (100m, uncalibrated).[24]
Terminal

The terminal can communicate with the ground station by sending and receiving short messages.

As of 2008, one BeiDou-1 terminal costs about ¥20,000RMB (US$2,929), almost 10 times the price of GPS counterpart.[25] It's said that the reason why is the terminal so expensive is due to "using expensive imported Chips"，but China seemed to have found replacement and the price could lower to less than ¥1,000RMB.[26] By the China High-Tech Fair ELEXCON 2009 (November 16–21, 2009) in Shenzhen, China, a terminal solution costing no more than ¥3,000RMB was presented.[27]

 

[timetravel]

how many foreign payloads has china's space agency launched and how many has ISRO launched ?? is there any member who has such information. would be interesting to know. thanks..

 

[shuttler]

Ok..so they have integrated a communication system in the Navigation satellite..That is something new.But the fature mey be restricted to military users only.Not for civilian use.

Beidou-2 will also use European Galelio satellites becuase china has significant investment in Galelio system..
When that happens the contellation will be combination of Beidou and Galelio satellites and thats a whopper 70+ satellites.
That means we will have much better signal reception in cvities..as in cities the buildings stop sinal and induce error by bouncing them off...This will be cured by the Beidou+Galelio hybrid.
Beidou-1 is geostationery and thats why 30,000+ kilomerters up and not susceptible to any Missile attack...
Beidou-2 had to be put in lower orbits for ease of use and to reduce the cost of receiver as Beidou-1 receiver was very expensive...

Just come back for the 3 points above buddy:
1. Beidou is open for both global civilian usages free of charge for designated scope of service. Upgraded usage needs Operator's authorization. That may imply charge of fees.
2. I think they hit a snag over more involved co-operation so the reason for the birth of Beidou
3. Agreed. Reaching of 30,000 km geostationary orbit is too far-fetched in foreseeable future.

 

[Safriz]

Just come back for the 3 points above buddy:
1. Beidou is open for both global civilian usages free of charge for designated scope of service. Upgraded usage needs Operator's authorization. That may imply charge of fees.
2. I think they hit a snag over more involved co-operation so the reason for the birth of Beidou
3. Agreed. Reaching of 30,000 km geostationary orbit is too far-fetched in foreseeable future.

well...Navigation part is free,and is free in American GPS also...But they too have certain part of the satellite signal which cannot be decoded by Civilian or non susbcribed receivers....That includes restriction of position update above certain speeds.So that non authorised users cannot use it for miliytary purpose such as missile navigation...
Same is the story of Beidou...Can be used freely by civilian for Navigation..but certain services will be restricted to Military and subscribed users only...and I dont think messaging service will be open to public for free....and may well need extra hardware to use...

Boeings's Iridum and that Middle eastern venture Thuraya are two examples here..Both need special Mobile phones for the services..Although theirs is a full fledged Mobile phone service via satellite...

I am not sure what type of Messaging service Baidou is offering..Sounds more like a Packet data service than normal texting and i am not sure if Packet data service will be of any use for public,and may not have been designed for public use in the first place..
If you have more details,please share.

how many foreign payloads has china's space agency launched and how many has ISRO launched ?? is there any member who has such information. would be interesting to know. thanks..

China's space program is for personal use and has too many home grown projects to keep them busy...
while India's space program is commercial and aimed at foreign customers as they dont have many home grown satellites to launch..
so i wont be surprised if ISRO has more foreign launches than China.

 

[shuttler]

well...Navigation part is free,and is free in American GPS also...But they too have certain part of the satellite signal which cannot be decoded by Civilian or non susbcribed receivers....That includes restriction of position update above certain speeds.So that non authorised users cannot use it for miliytary purpose such as missile navigation...
Same is the story of Beidou...Can be used freely by civilian for Navigation..but certain services will be restricted to Military and subscribed users only...and I dont think messaging service will be open to public for free....and may well need extra hardware to use...

Boeings's Iridum and that Middle eastern venture Thuraya are two examples here..Both need special Mobile phones for the services..Although theirs is a full fledged Mobile phone service via satellite...

I am not sure what type of Messaging service Baidou is offering..Sounds more like a Packet data service than normal texting and i am not sure if Packet data service will be of any use for public,and may not have been designed for public use in the first place..
If you have more details,please share.

I think I have described the free and restricted access parts already.

Sure if I have more info, I will spill the beans on PDF.

China's space program is for personal use and has too many home grown projects to keep them busy...
while India's space program is commercial and aimed at foreign customers as they dont have many home grown satellites to launch..
so i wont be surprised if ISRO has more foreign launches than China.

the Chinese satellite launching programs are going commercial vigorously too.
I dont have their business details

 

[chauism]

how many foreign payloads has china's space agency launched and how many has ISRO launched ?? is there any member who has such information. would be interesting to know. thanks..

Here is a comprehensive list of foreign satellites Launched by China Great Wall Industry Corporation. It has launched 39 satellites which 6 of them were piggyback mission for foreign customers.

Long March International Commercial Launch Record
No. Payload/SC Launch Vehicle Customer Launch Date Ref.
1* Micro-gravity Test Instrument LM-2C F09 MartraMaconi, France 5 Aug. 1987 Piggyback
2* Micro-gravity Test Instrument LM-2C F11 Intospace ,Germany 5 Aug. 1988 Piggyback
3 AsiaSat-1 LM-3 F07 AsiaSat, HK 7 April 1990 Dedicated
4* BADR-A/ Aussat Dummy Payload LM-2E F01 SUPARCO, Pakistan 16 July 1990 Piggyback
5 Aussat-B1 LM-2E F02 Aussat, Australia 14 Aug. 1992 Dedicated
6* Freja LM-2C F13 SSC, Sweden 6 Oct. 1992 Piggyback
7 Optus-B2 LM-2E F03 Aussat, Australia 21 Dec. 1992 Dedicated
8 APSTAR-I LM-3 F09 APT, HK 21 July 1994 Dedicated
9 Optus-B3 LM-2E F04 Optus, Australia 28 Aug. 1994 Dedicated
10 APSTAR-II LM-2E F05 APT, HK 26 Jan. 1995 Dedicated
11 AsiaSat-2 LM-2E F06 (EPKM) AsiaSat ,HK 28 Nov. 1995 Dedicated
12 EchoStar-1 LM-2E F07 (EPKM) EchoStar, USA 28 Dec. 1995 Dedicated
13 INTELSAT-7A LM-3B F01 INTELSAT 15 Feb. 1996 Dedicated
14 APSTAR-IA LM-3 F10 APT, HK 3 July 1996 Dedicated
15 ChinaSat-7 LM-3 F11 ChinaSat, China 18 Aug. 1996 Dedicated
16* Micro-gravity Test Instrument LM-2D F03 Marubeni Corp., Japan 20 Oct. 1996 Piggyback
17 MabuhaySat LM-3B F02 Mabuhay,
The Philippines 20 Aug. 1997 Dedicated
18 APSTAR-IIR LM-3B F03 APT, HK 17 Oct. 1997 Dedicated
19 Iridium LM-2C/SD F02 Motorola, USA 8 Dec. 1997 Dual
20 Iridium LM-2C/SD F03 Motorola, USA 26 Mar. 1998 Dual
21 Iridium LM-2C/SD F04 Motorola, USA 2 May 1998 Dual
22 ChinaStar-1 LM-3B F04 China Orient ,China 30 May 1998 Dedicated
23 SinoSat-1 LM-3B F05 SinoSat, China 18 July 1998 Dedicated
24 Iridium LM-2C/SD F05 Motorola, USA 20 Aug. 1998 Dual
25 Iridium LM-2C/SD F06 Motorola, USA 19 Dec. 1999 Dual
26 Iridium LM-2C/SD F07 Motorola, USA 12 Jun. 1999 Dual
27 CBERS-01 LM-4 F04 INPE, Brazil 14 Oct. 1999 Dedicated
28* SACI LM-4 F04 INPE, Brazil 14 Oct. 1999 Piggyback
29 CBERS-02 LM-4 F08 INPE, Brazil 21 Oct. 2003 Dedicated
30 APSTAR-VI LM-3B F06 APT, HK 12 April 2005 Dedicated
31 NigComSat-1 LM-3B F07 NSRDA, Nigeria 14 May 2007 Dedicated
32 ChinaSat-6B LM-3B F08 ChinaSat, China 5 July 2007 Dedicated
33 CBERS-02B LM-3B F09 INPE, Brazil 19 Sept. 2007 Dedicated
34 ChinaSat-9 LM-3B F10 ChinaSat, China 9 June 2008 Dedicated
35 VeneSat-1 LM-3B F11 Venezuelan Ministry
of Science and
Technology 30 Oct. 2008 Dedicated
36 PALAPA-D LM-3B F12 PT IndonisiaTbk 31 Aug 2009 Dedicated
37 Paksat-1R LM-3B F15 SUPARCO 12 Aug. 2011 Dedicated
38 W3C LM-3B F17 Eutelsat 07 Oct. 2011 Dedicated
39 NigComSat-1R LM-3B F18 NSRDA, Nigeria 20 Dec 2011 Dedicated

Long March International Commercial Launch Record --- CGWIC