Indian Navigation Constellation (NAVIC) aka IRNSS

[Blademaster]

For those who want to know how GPS works:

https://ciechanow.ski/gps/ (it goes into a LOT, I mean a LOT of details in a very interactive manner)

How did you find this link? This is one of the best explainers of how GPS system works.

 

[DumbPilot]

How did you find this link? This is one of the best explainers of how GPS system works.

Second page of google

 

[Blademaster]

Second page of google

Ah the bane of google search where good websites go to die.

 

[Varoon2]

Can anyone give an up to date status report on the IRNSS satellites. How are they functioning, who is using it, how accessible is the system. It's been 10 years since the first of the series was launched.

 

[Vamsi]

Can anyone give an up to date status report on the IRNSS satellites. How are they functioning, who is using it, how accessible is the system. It's been 10 years since the first of the series was launched.

before the launch of NVS-1, there are 7 sats, out of which only 4 are giving Navigation services, while remaining 3 are giving only timing services

 

[Indx TechStyle]

Exclusive: India's NavIC satellites offer 3-metre positioning accuracy, ISRO chairman tells WION

ISRO chief S Somnath Photograph WION Web Team )
STORY HIGHLIGHTS
Speaking to reporters after the successful GSLV-F12NVS-01 mission, Somanath said that only four of the existing fleet of seven NavIC satellites were operational now.

India's NavIC (Navigation for Indian Constellation) series of satellites offer a positioning accuracy of three metres, ISRO Chairman Dr S Somanath told WION.

He added that the position accuracy would vary if the signals are weaker and not all satellites are available. However, he said that the navigation, positioning and timing services offered by Indian satellites are superior, considering the architecture being used.

He further told WION that ISRO has the means to make the service global, as and when required.

ISRO recently launched the NVS-01 satellite, a next-generation satellite meant to meet India's requirements of navigation, positioning, and timing.

Launched on Monday, NVS-01 is the first in the series of five satellites that India's UR Rao Satellite Centre in Bengaluru is designing and building. The NVS series will augment India's existing fleet of NavIC satellites.

At present, India uses its Navigation with Indian Constellation(NavIC) series of satellites for civilian and defence navigation, positioning, and timing services within India and even 1500 kilometres beyond its borders.

ISRO Chief speaks to WION

"NVS series of satellites will sustain and augment the NavIC with enhanced features. This series incorporates L1 band signals additionally to widen the services. For the first time, an indigenous atomic clock will be flown in NVS-01," ISRO had said.

Highlighting the need for the indigenous navigation system, Somanath pointed out India's vast landmass, large population, booming digital services and business opportunities, and stated that it is important to have independent systems for navigation, positioning and timing.

Further, he touched upon the strategic perspective and said that India's armed forces are protecting the nation's borders and they require their own secured services for positioning, navigation and timing, thus giving them strategic autonomy.

ISRO's current series of NavIC satellites were placed in orbit in a phased manner between the years 2013 and 2018 using PSLV rockets. All satellites in the first-generation NavIC series weighed 1,425 kg and carried foreign-origin atomic clocks.

All IRNSS/NavIC series satellites carried two types of payloads – navigation payload and ranging payload. The navigation payload transmits signals for the determination of position, velocity and time. Rubidium atomic clocks are part of the navigation payload of the satellite. The ranging payload of these satellites consists of a C-band transponder which facilitates accurate determination of the range of the satellite.

Speaking to reporters after the successful GSLV-F12/NVS-01 mission, Somanath said that only four of the existing fleet of seven NavIC satellites were operational now.

Instead of replacing the three defunct satellites of the old generation, ISRO is launching a fleet of five next-gen NavIC satellites, of which NVS-01 would be the first, he added.

The rationale behind launching a new fleet of five satellites is due to the fact that the existing constellation would be defunct in a few years (owing to the completion of mission life). Hence, it would not be prudent to replace the old fleet. It is expected that two next-gen NavIC satellites will be launched every year.

 

[SUPERPOWER]

Exclusive: India's NavIC satellites offer 3-metre positioning accuracy, ISRO chairman tells WION

ISRO chief S Somnath Photograph WION Web Team )
STORY HIGHLIGHTS
Speaking to reporters after the successful GSLV-F12NVS-01 mission, Somanath said that only four of the existing fleet of seven NavIC satellites were operational now.


ISRO Chief speaks to WION

Yes i have heard 3 years back only 4 are operational thats due to failure of Atomic clocks supplied by switzerland so the priority was to make Atomic Clocks in India and we have made it Succefully ......Now Fuck Switzerland.....

 

[FalconSlayers]

 

[Swesh]

New NavIC clock outperforms previous generation
Est. reading time: 2:30

NVS-01 is the first second-generation satellite of the Indian Navigation Satellite System (IRNSS), also known as Navigation with Indian Constellation (NavIC). It was launched into geostationary orbit on May 20. The satellite is placed at 129.6° eastern longitude and will finally replace IRNSS-1G launched in April 2016.the first second-generation satellite of the Indian Navigation Satellite System (IRNSS), also known as Navigation with Indian Constellation (NavIC). It was launched into geostationary orbit on May 20. The satellite is placed at 129.6° eastern longitude and will finally replace IRNSS-1G launched in April 2016.

Whereas the first-generation satellites transmit navigation signals in the L5- and S-band, NVS-01 is the first IRNSS satellite also transmitting in the L1-band. The 1547.42 MHz frequency is also used by other satellite navigation systems, including GPS, Galileo, and BeiDou-3. However, a different modulation is used, namely a Synthesized Binary Offset Carrier (SBOC) signal. The IRNSS L1 SBOC signal has data and pilot components with and without navigation data. Data and pilot signals consist of BOC (1,1) and BOC (6,1) components with sub-frequencies of 1.023 MHz and 6.138 MHz. A quadrature multiplexing is applied for the data and pilot components with a power sharing of 41.82% and 58.18%. The navigation message on the IRNSS L1 signal has a different structure compared to those on the legacy L5- and S-band signals. The new L1 navigation message uses an advanced frame structure and forward error correction inherited from the CNAV-2 message of the GPS/QZSS L1C signal as well as a similar orbit model. Among other things, it provides inter-signal corrections for the L1 data and pilot signals with reference to the S band signal for single-frequency L1 band users.
NVS-01 started signal transmission on June 17, 2023, with the pseudo-random noise (PRN) code I10. The satellite’s L1 and L5 signals were tracked by a Septentrio PolaRx5 receiver located in Tokyo, Japan, with a prototype firmware that is capable of tracking the L1 pilot signal. Figure 1 shows the multipath linear combination of NVS-01’s L1 and L5 pilot signals. Whereas the short-term variations are smaller for L1 compared to L5, the overall RMS is 18 cm for both signals.

Whereas IRNSS-1’s rubidium clocks were provided by Spectratime, NVS-01 is the first satellite operating a new type of rubidium atomic frequency standard (RAFS) developed in India. The short-term performance of GNSS satellite clocks can be evaluated with the one-way carrier phase method. The receiver is connected to a highly stable external clock, e.g., a hydrogen maser. Thus, the receiver clock error is negligible. Measurement biases as well as the delays of ionosphere and troposphere on short time scales are removed by fitting a fourth-order polynomial. If no external clock is available, as is the case for the station in Tokyo, the precise clock information can be transferred from another station by a reference satellite jointly tracked by both receivers.

The Allan deviation based on this three-way carrier phase (TWCP) analysis is shown in Figure 2. The hydrogen maser of the IGS station USUD in Usuda, Japan, is used as the reference clock. At short integration times up to 20 s, the Allan deviation computed from the TWCP analysis is dominated by the GNSS measurement noise hiding the true clock performance. Above 20 s, the TWCP demonstrates that the NVS-01’s RAFS stability meets the performance of the ground tests and even exceeds them for longer integration times. At all integration times, the new RAFS outperforms the first generation IRNSS clocks.

Figure 2 IRNSS clock performance obtained from three-way carrier phase analysis as well as ground tests.
Figure 2: IRNSS clock performance obtained from three-way carrier phase analysis as well as ground tests.

 

[Swesh]

 

[Swesh]

Inside the box: New NavIC clock outperforms previous generation - GPS World

NVS-01 is the first second-generation satellite of the Indian Navigation Satellite System (IRNSS), also known as Navigation with Indian Constellation (NavIC).

www.gpsworld.com

 

[FalconSlayers]

 

[hurrians]

Is India’s NavIC Better Than GPS?

NavIC consists of a constellation of seven satellites and a network of ground stations and is touted to be more accurate than GPS. BY SOURABH LELE &

thenorthlines.com

Misleading headline but goòd info.