Author Topic: ISRO NavIC/IRNSS and GAGAN SBAS - General Discussion  (Read 76282 times)

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #60 on: 02/03/2017 01:50 am »
The earlier plan apparently was to have the IRNSS-1H (and 1I) built as ground spares by the private Alpha consortium under guidance from ISRO. Is it likely there would be change in those plans now in the aftermath of IRNSS-1A failure?

Offline vyoma

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Re: NavIC/IRNSS discussion
« Reply #61 on: 02/03/2017 02:12 am »
As per this report, 1H was anyway supposed to be built by March 2017 with ISRO handholding private contractors. So, I guess, they may have already started building it.

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #62 on: 02/22/2017 10:03 am »
From the Annual Report 2016-17

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The space agencies of India and Japan have agreed to further enhance cooperation by signing a new MoU, which enables inclusion of satellite navigation and planetary exploration as additional areas ofcooperation. Both agencies have also agreed to conduct a joint experiment to study Venus atmosphereby collecting signals from JAXA’s Akatsuki mission by ISRO’s ground stations (IDSN). JAXA has agreedto support ISRO to establish a ground station in Japan to support NavIC satellite constellation.

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #63 on: 03/05/2017 07:26 am »
Interview with Nilesh M Desai, Deputy Director, SATCOM & Navigation Applications Area, SAC, ISRO
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Currently, the main challenge is miniaturization. ISRO has already made receivers for both standard and restricted services. We have also shared information such as frequency and other aspects with private vendors and students to work on projects. However, the receiver being used currently is the size of a box. It will reach common people only when it can be embedded in a chip for mobile phone use. We hope that by the year-end, it will have commercial applications.
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Within India and 1500 km of its periphery, we have observed up to 5 meters accuracy. Out of around five to six applications today, only Galileo has messaging interface embedded - a feature one will be able to use in NavIC. This feature will be helpful when a command center wants to send warnings to a specific geographic area. For example, fishermen using the system can be warned about a cyclone.
That '5m accuracy' mentioned above must be for the civilian Standard Positioning Service signals.
« Last Edit: 03/05/2017 07:30 am by vineethgk »

Re: NavIC/IRNSS discussion
« Reply #64 on: 03/12/2017 04:12 pm »
India now includes those countries who have own navigation system.
Find Best comparison between all countries Navigation system below.
http://newser.in/good-news/indias-own-navigation-system-navic/

:) i dont know when NAVIC will be operational, have any idea ?
is available for public or only for governmental use ?

Offline sportyfailure

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Re: NavIC/IRNSS discussion
« Reply #65 on: 04/21/2017 04:19 pm »
India now includes those countries who have own navigation system.
Find Best comparison between all countries Navigation system below.
http://newser.in/good-news/indias-own-navigation-system-navic/

:) i dont know when NAVIC will be operational, have any idea ?
is available for public or only for governmental use ?

NAVIC is reportedly operational.

It has both public and military modes.

Reports say regular GPS/GLONASS receivers are not compatible with NAVIC due to different frequency of operation and protocols. ISRO was sponsoring development of public receivers for various types of hardware like mobile devices, civil aircraft, merchant ships etc. but progress is unknown.
« Last Edit: 04/21/2017 04:20 pm by sportyfailure »

Offline worldtimedate

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Re: NavIC/IRNSS discussion
« Reply #66 on: 05/30/2017 06:17 am »
Get ready! India's own GPS set to hit the market early next year

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India's very own desi Global Positioning System (GPS) is operational and is set to hit the market for public use in early 2018.

"The Indian Regional Navigation Satellite System (IRNSS) with an operational name of NavIC is currently being tested for its accuracy and is most likely to be available in the market for public use early next year," said Tapan Misra, the director of Ahmedabad-based Space Application Centre (SAC).

"Though American GPS with 24 satellites in a constellation has wider reach and covers the entire world, NavIC with seven satellites covers only India and its surroundings but is more accurate than the American system. NavIC will provide standard positioning service to all users with a position accuracy of 5 metre. The GPS, on the other hand, has a position accuracy of 20-30 metre," the SAC director said.

We have developed digital chips to miniaturise technology (for use in mobiles and handsets) and experiments are on them. The system is being tested all across the country." He said,

Explaining the scientific reasons for NavIC's superiority over GPS, Misra said, "Our system has dual frequency (S and L bands). GPS is dependent only on L band.

"NavIC will cover the entire country, Indian Ocean and its surroundings. In the west, the system will have a reach till eastern parts of Arabian peninsula and in the east, some parts of China. In the south, NavIC signals will work till Malaysia," Misra said.

--- [ --- ]

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #67 on: 05/30/2017 07:02 am »
Is the GPS accuracy as bad as 20-30 metres as implied in the article? I thought it was more in the range of 4-7 metres.

Offline dusky

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Re: NavIC/IRNSS discussion
« Reply #68 on: 05/30/2017 08:01 am »
Quote
For example, GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft.) radius under open sky
http://www.gps.gov/systems/gps/performance/accuracy/

With better antennas and dual frequency receivers accuracy can be much better. By using local reference stations <10cm and even <1cm is doable.

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #69 on: 06/10/2017 03:29 pm »
Bad news. More IRNSS sats have started showing trouble if reports are to be believed.

http://wap.business-standard.com/article/current-affairs/navigation-satellite-clocks-ticking-system-to-be-expanded-isro-117061000273_1.html

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Sources close to ISRO, on the condition of anonymity, told IANS that two more atomic clocks in the satellite system started showing abnormalities thereby taking the total number of failed clocks to five.

"Hence as a precaution and also to extend the operational life of satellites, the ISRO is running the NavIC system with one clock switched on instead of two. If the running clock fails then the standby clocks will be switched on," sources said.

The initial plan was to keep two clocks in the satellite on while keeping the third one on standby.
Since the trouble started with IRNSS-1A, the first satellite that has been in operation for the longest among the bunch, I fear the issues might be starting to appear in the rest as they operate for progressively longer periods time. They might seriously need to consider the prospect of having to replace the entire constellation and make their contingency plans accordingly.
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"We are already using the NavIC system for several applications. The replacement satellite for IRNSS-1A will be launched in July or August. There are also plans to expand the NavIC system by taking the number of satellites to 11 from seven," Kumar said.
If the atomic clocks keep failing, they are going to busy replacing existing satellites in the near future, rather than expanding the constellation.
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It is learnt that ISRO has got the atomic clocks replaced in the two standby NavIC satellites.
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Misra said it is not only the atomic clocks in the Indian satellite navigation systems that have failed, the clocks in the European system Galileo too have failed as per reports.
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The NavIC system was performing well till the three clocks in IRNSS-1A — the first satellite — failed some months back.
Government would very likely be ready to fund a host of replacement satellites, if it comes to that, considering the strategic importance of the project. But ISRO can expect hard questions from them.
« Last Edit: 06/10/2017 03:31 pm by vineethgk »

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #70 on: 06/14/2017 05:01 pm »
This report quotes the ISRO Chairman as denying there has been further failures of atomic clocks on the constellation other than 1A.
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He rubbished reports that said more atomic clocks have started showing abnormalities.

Either the earlier report of further failures was incorrect, or ISRO has chosen not to acknowledge them for the moment.

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #71 on: 06/16/2017 05:44 pm »
PSLV C39 carrying IRNSS-1H scheduled for late July or early August
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In an attempt to keep India’s regional navigation satellite system fully operational, the Indian Space Research Organisation (ISRO) is preparing to launch a back-up for IRNSS-1A, one of the seven satellites in the constellation, that has been hobbled by the failure of the atomic clocks on board.

The PSLV C39 mission, scheduled for late July or early August, will carry the new satellite named IRNSS-1H into orbit, K. Sivan, Director of Vikram Sarabhai Space Centre, told The Hindu.

Replacing IRNSS-1A became a priority for the ISRO after it was confirmed in January this year that all the three rubidium atomic clocks on board had stopped functioning. The space agency had decided on launching one of the two spare satellites after initial efforts to restart the clocks failed.



Offline vyoma

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Re: NavIC/IRNSS discussion
« Reply #72 on: 06/18/2017 05:18 am »
Centre to make indigenous navigation system mandatory for new aircrafts

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CHENNAI: The Centre is soon expected to issue the notification to make GAGAN, the indigenously developed navigation system, mandatory for new aircraft registered in the country from January 1, 2019.

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Speaking to Express, sources in the Ministry of Civil Aviation confirmed that GAGAN (or GPS Aided GEO Augmented Navigation), jointly developed by Indian Space Research Organisation (ISRO) and the Airports Authority of India, is ready for full optimisation and has obtained an international certification for approach and precision landing operations (APV1/1.5) over the subcontinent.

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Data from this three-satellite constellation for GAGAN – GSAT 8, 10 and 15 – is also useful in perimeter monitoring and identifying boundaries. “It is accurate to one metre,” said Kumar. He added that other user segments such as intelligent transportation, maritime, highways, railways, surveying, geodesy, security agencies, telecom industry and personal users of position location applications can make use of it.

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The system is interoperable with other international systems like the US’ WAAS, European EGNOS, and Japanese MSAS etc. GAGAN’s geo footprint extends from Africa to Australia and has expansion capability for seamless navigation services across the region.

GAGAN provides the additional accuracy, availability, and integrity necessary for all phases of flight, from en route through approach for all qualified airports within the GAGAN service volume.

Offline vineethgk

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Re: NavIC/IRNSS discussion
« Reply #73 on: 06/26/2017 01:06 am »
More reports (quoting 'anonymous' ISRO sources) coming in that 4 more atomic clocks may have failed on IRNSS system other than the three on IRNSS-1A, but other satellites remain functional for now perhaps because the new failures are distributed across multiple satellites.

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ISRO had announced in July last year that all three atomic clocks on IRNSS-1A, the first of the seven satellites that was launched on July 1, 2013, had malfunctioned, rendering that satellite ineffective. Now, sources associated with ISRO’s satellite navigation programme say four more atomic clocks on the other six satellites are not performing as required.
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The subsequent malfunction of four more atomic clocks , sources have indicated, has not incapacitated any other satellite. “Measures are being taken to correct the problems caused by the clocks in the launch of future satellites. The atomic clocks to be used in the other satellites have been modified to prevent malfunction,” a senior official in the programme said.

There is no official acknowledgement of more failures as of now.
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Asked about the failure of the additional clocks, an official ISRO spokesperson said, “We have not been told of any failures other than what has been stated by the ISRO chairman, which is three clocks on IRNSS-1A.”
Source

Offline vyoma

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Re: NavIC/IRNSS discussion
« Reply #74 on: 07/05/2017 02:44 am »
Europe's Galileo satnav identifies problems behind failing clocks

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Investigators have uncovered the problems behind the failure of atomic clocks onboard satellites belonging to the beleaguered Galileo satnav system, the European Commission said Monday.

For months, the European Space Agency—which runs the programme—has been investigating the reasons behind failing clocks onboard some of the 18 navigation satellites it has launched for Galileo, Europe's alternative to America's GPS system.

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"The main causes of the malfunctions have been identified and measures have been put in place to reduce the possibility of further malfunctions of the satellites already in space," commission spokeswoman Lucia Caudet said.

ESA found after an investigation that its rubidium clocks had a faulty component that could cause a short circuit, according to European sources.

Offline vyoma

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Re: NavIC/IRNSS discussion
« Reply #75 on: 07/05/2017 02:48 am »
ISRO all set to offer desi GPS for mobile users from next year

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The crucial miniaturisation of chipsets that go into wireless devices such as cell phones and wifi receivers has been achieved by the ISRO.

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As per different applications two different kinds of hardwares are required – digital and RF (radio frequency) front end. “Our semiconductor laboratory (SCL) in Chandigarh has developed the digital hardware and tested it. Now, the RF front end hardware is expected to hit the markets next month,” said Tapan Misra, director of Ahmedabad-based SAC to the Express.

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Initially ISRO invited the industry to design and develop the chipsets. However there was little interest shown because of high investment costs. “The market didn’t want to take the first step. So we took it on ourselves to do it. Our SCL has developed the digital chips and for manufacturing prototypes of RF Front End hardware, we gave the order to Tower Jazz, a US-based firm specialised in silicon germanium technology suited for increasing bandwidth. We are planning to set-up a fabrication facility with silicon germanium processing technology in SCL,” Misra said.

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Misra said the final version would be an 11-channel chipset (7 NavIC satellites and four GPS satellites) operating under dual frequency (S and L bands). This actually delivered higher accuracy than GPS.
“GPS is dependent on L band and atmospheric disturbances affected its performance. To assess the errors, atmospheric models are used which would go erratic. In our case, we measure the difference in delay of dual frequency (S and L bands) and can assess the actual delay. Therefore NavIC is not dependent on any model to find the frequency error and is more accurate than GPS. To be precise, NavIC will provide standard positioning service to all users with a position accuracy of 5 metres. The GPS on the other hand, has a position accuracy of 20-30 metres,” Mishra said.

Offline kanaka

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Re: NavIC/IRNSS discussion
« Reply #76 on: 07/05/2017 05:50 am »
ISRO all set to offer desi GPS for mobile users from next year

Quote
The crucial miniaturisation of chipsets that go into wireless devices such as cell phones and wifi receivers has been achieved by the ISRO.

Quote
As per different applications two different kinds of hardwares are required – digital and RF (radio frequency) front end. “Our semiconductor laboratory (SCL) in Chandigarh has developed the digital hardware and tested it. Now, the RF front end hardware is expected to hit the markets next month,” said Tapan Misra, director of Ahmedabad-based SAC to the Express.

Quote
Initially ISRO invited the industry to design and develop the chipsets. However there was little interest shown because of high investment costs. “The market didn’t want to take the first step. So we took it on ourselves to do it. Our SCL has developed the digital chips and for manufacturing prototypes of RF Front End hardware, we gave the order to Tower Jazz, a US-based firm specialised in silicon germanium technology suited for increasing bandwidth. We are planning to set-up a fabrication facility with silicon germanium processing technology in SCL,” Misra said.

Quote
Misra said the final version would be an 11-channel chipset (7 NavIC satellites and four GPS satellites) operating under dual frequency (S and L bands). This actually delivered higher accuracy than GPS.
“GPS is dependent on L band and atmospheric disturbances affected its performance. To assess the errors, atmospheric models are used which would go erratic. In our case, we measure the difference in delay of dual frequency (S and L bands) and can assess the actual delay. Therefore NavIC is not dependent on any model to find the frequency error and is more accurate than GPS. To be precise, NavIC will provide standard positioning service to all users with a position accuracy of 5 metres. The GPS on the other hand, has a position accuracy of 20-30 metres,” Mishra said.


Hope failed clocks issue will be resolved by that time.

Offline sanjaykumar

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Re: NavIC/IRNSS discussion
« Reply #77 on: 07/06/2017 04:17 am »


India Israel MOU  between ISRO and ISC

1) Building Atomic Clocks
2) Electric propulsion for small sats
3) Geo Leo Links - (no idea what it means)



Offline Steven Pietrobon

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Re: NavIC/IRNSS discussion
« Reply #78 on: 07/06/2017 08:06 am »
3) Geo Leo Links - (no idea what it means)

Could mean a TDRS like system using either radio or laser communications.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline sanjaykumar

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Re: NavIC/IRNSS discussion
« Reply #79 on: 07/07/2017 01:06 am »
^^^

Makes sense, given the fact India & Israel are already collaborating  in Radar technology.


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