NavIC System and Applications –Status & Update
Akhileshwar Reddy
Satellite Navigation Programme Office
ISRO Headquarters
11 Jan 2022

ISRO1

NavIC Architecture• NavIC stands for ‘Navigation with Indian Constellation’• Regional navigation system of India* Civilian signal in L1 band is planned from upcoming NVS – 01 satellite

NavIC Constellation status Launch dates:55° E
IRNSS-1IIRNSS-1A• IRNSS 1A : 01 Jul 2013

• IRNSS 1B : 04 Apr 2014

83° E
IRNSS-1C

111.75° E
IRNSS-1D• IRNSS 1C : 16 Oct 2014
• IRNSS 1D : 28 Mar 2015

• IRNSS 1E : 20 Jan 2016

IRNSS-1B

IRNSS-1E• IRNSS 1F : 10 Mar 2016
• IRNSS 1G : 28 Apr 2016

• IRNSS 1I : 12 Apr 2018
 All launches using Polar Satellite
Launch Vehicle (PSLV) from Satish
Dhawan Space Centre (SDSC) at
Sriharikota••

GSO satellites (shown in blue) are with ~4 inclination
GSO satellites (shown in orange) are with 29 inclination

IRNSS 1A and 1E are providing NavIC based safety of life alerts

NavIC Coverage Area

NavIC being a regional
constellation, provides its services
to Indian mainland and 1500km
beyond the boundaryAccuracy (2σ, 3D)
 Position < 20 m
 Timing < 50 ns

Indian mainland and1500 km beyond

NavIC Documentation
NavIC Documentation on ISRO website:• NavIC SIS ICD for the L5, S SPS signal• Quarterly performance reports ofNavIC signals in the coverage region• SIS ICD for the new L1 civilian signal isgoing to be available soon

https://www.isro.gov.in/irnss-programmeNavIC System Updates
 NavIC System Advisory is planned to be launched shortly

 NVS-01/02/03/04/05 planned over the next few years beginning 2022
 Continuity of service with following new features:o Introduction of service in L1 bando Indigenous novel ranging code in L1 bando Inhouse developed space-grade atomic clocks
Centre Frequency
Frequency Band(MHz)
L5-band1176.45
S-band2492.028

L1-band1575.42

Band(MHz)
1164.45 – 1188.45
2483.5 – 2500

1563.42 – 1587.42

NavIC L1 signal
 Interoperable with other modernised GNSS signals
 Modulation: NavIC SBOC(6,1,1/11)
Power spectral density: MBOC (6,1,1/11)

 Channel coding: NavIC BCH and LDPC PRN code: Interleaved Z4-Linear Codes (IZ4)
 Data structure: Similar skeleton to GPS L1C

NavIC L1 signal - Modulation
 Implementation of MBOC (6,1,1/11)

 TMBOC: time multiplexed BOC
CBOC: composite BOC
QMBOC: quadrature multiplexed BOC

SBOC: synthesised BOC
 SBOC implementation:

Data & Pilot will have BOC(1,1) and BOC(6,1)

𝐒 𝐭 = 𝛂𝐒𝐩,𝐚 (𝐭) − 𝛃 𝐒𝐩,𝐛 (𝐭൯ + 𝐣 𝛄 𝐒𝐝,𝐚 𝐭 + 𝛈 𝐒𝐝,𝐛 𝐭

Coefficients are adjusted to make MBOC (6,1,1/11) PSD= 𝐒𝐈 𝐭 + 𝐣𝐒𝐐 𝐭

NavIC L1 signal - PRN Codes
 NavIC L1 signal shall use a family of Interleaved Z4 – Linear (IZ4) PRN spreading
codes implemented using coupled shift registers
 The PRN code length is 10230 chips with code period of 10 ms in both data andpilot channels. The pilot channel has a secondary overlay code of length 1800 and a
period of 18 s. Pilot and data signals are orthogonal.
 The IZ4 family of spreading codes are found to provide better or on-par
performance compared to the PRN code families used by GPS and BeiDou in the L1band

 The resources required for implementing the code generator are of the same orderas Weil codes

NavIC L1 signal - Data Structure Data structure of NavIC L1
signal is similar to GPS L1C
 The master frame is 18 sec induration with 3 sub-frames

1800 symbols (at 100 symbols/sec)
Subframe-1 (52 symbols)

Block Interleaving
46 x 38 (columns x rows)

 Total 1800 symbols:SF-1: 52 symbols

SF-2: 1200 symbols

SF-3: 548 symbols

 Symbol rate: 100 sps

 Error Correction Coding
scheme BCH(52,9) for SF-1
 Rate ½ LDPC for SF-2 & 3

Subframe-2 and Subframe-3 (1748 symbols)

Subframe-2 and Subframe-3 (1748 symbols)

Subframe-1 (52 symbols)
BCH Coding
Subframe-1 (9 bits TOI)

Subframe-2 (1200 symbols)
LDPC Coding

LDPC Coding

Subframe-2 (600 bits)

Primary Parameters(576 bits)

Subframe-3 (548 symbols)

CRC(24 bits)

Subframe-3 (274 bits)

CRC
Secondary Parameters(24 bits)(250 bits)

NavIC Applications
NMR

Railways

Atmosphere
Monitoring

UAVs

Automobiles

VLTs
2G-DATPower Grid

Geodesy
Precision Farming

Personal Trackers

Mobile Phones

Off-the-shelf standalone GNSS chips

A few of the off-the-shelf chips for standalone GNSS (NavIC enabled):
Telit, Allystar, Quectel, SkyTraQ, Broadcom, U-TraQ

NavIC based commercial vehicle safety• Ministry of Road Transport and Highway (MoRTH) has mandated use of AIS-140
compliant NavIC enabled vehicle tracking systems in all public and commercial vehicles
in India.

• ISRO has supported Automotive Research Association of India (ARAI), International
Centre for Automotive Technology (ICAT) to test and certify the NavIC enabled AIS-140
compliant vehicle tracking devices.
• ARAI & ICAT have certified products from >100 companies.
https://cms.araiindia.com/MediaFiles/List%20AIS%20140%20as%20on%2024th%20Feb%202021_11582.pdf
https://icat.in/storage/app/public/uploads/certificate_form_1564983033.pdf• Several tens of thousand vehicles are now plying the roads equipped with these devices.

NavIC based commercial vehicle safety
NavIC

Typical architecture

VehicleTargetinfo.

LAN /internet

User control room

Policecontrol room
Policepatrol

GSM/GPRSNavIC based Safety-of-Life Alerts
 Introduced to provide safety-of-lifealerts for fishermen when they
undertake deep sea fishing with noother means of receiving alerts.
 INCOIS broadcasts the messages related
to high wave, cyclone, and tsunami.
 One-way broadcasting system.

Short Messaging Services – NavIC Messaging
Services (One Way)

UserFeedback
Navigation
software @ISRO
Satellites

Navigation
centreformessaging

 Receiver technology transferred toIndian industries.
 Field Trials conducted. Feedback
received

Positioning
receiver

Satelliteuplink

NavIC based Safety-of-Life Alerts
 NavIC messaging service
provide acknowledgement ofdistress signals generated byfishermen.
 Prototype terminals have beensuccessfully tested

 Hub/server has been configuredat ISRO for final commissioning.
 Trans-receiver technology
transferred to Indian industries.

DAT-SG: Integrated Distress Alert Transmitter and NavIC
messaging Service(2-Way messaging system)NavIC based Safety-of-Life Alerts Documentation

NavIC Messaging Documentation on
ISRO website:• SIS ICD for the NavIC messaging
service used by INCOIS• SIS ICD for the second generation
Distress Alert Transmitter (DAT-SG)

https://www.isro.gov.in/irnss-programmeNavIC Enabled Mobile Phone SoC
800 Series(High end)

700 Series(Semi- High end)

600 Series(Mid-Range)

400 Series(Low-Range)

SD 888
SD 870SD 865+SD 865

SD 768G
SD 765G
SD 765SD 750G
SD 720G

SD 690SD 662SD 460Mediatek Dimensity:

1200, 1000c, 700

Huawei kirin:

9000, 990 5G

Samsung Exynos:

980

NavIC Enabled Mobile Phones
Sl.
No.
123
456Mobile
Poco m2 pro
Redmi Note 9 Pro
Redmi Note 9 Pro max
Real me 6 Pro
Mi 10iVivo v20

7891011

One Plus Nord
Vivo V20 pro
Mi 10T
Mi 10T pro
Real Me X50 pro 5G*

1213141516

Mi 10Huawei P40
Asus Zenphone 7 pro
Huawei p40 pro
Huawei Mate 40 Pro

Cost range(INR)
10K – 20K20K – 50K> 50K

NavIC in 3GPP
• NavIC has become a part of the latest specifications of 3GPP for Assisted- GlobalNavigation Satellite System (A-GNSS).

• Incorporation of NavIC into 3GPP Release-16 standards will ensure common
denominator performance of NavIC assistance among various telecom service
providers.
• Also, mobile handsets with NavIC capability will be able to obtain the benefits ofAssisted-GNSS.

NavIC in Standards
 International Maritime Organisation (IMO) has recognized NavIC as acomponent of the worldwide radio navigation system (WWRNS).
 Activities are underway for incorporation of NavIC in the appropriate IECstandards – IEC TC-80.
 NavIC has been incorporated in the latest National Marine Electronics
Association (NMEA) 0183 standard.
 NavIC L5 has been included in the latest release of Radio TechnicalCommission for Maritime Services (RTCM) 10403.3 standard.
 TED-14 committee under BIS has recently released standards for
Agricultural Drones which includes NavIC for position computation.

ISRO21NavIC RTK Proof of Concept Development
Base and Rover Antenna

NavIC Base and Rover RTK Rx• Carried out at Space Applications Center, ISRO
• Two receiver configuration, base receiver and roverreceiver.
• Real-time data link between base and rover receivers
using UHF Radio modem/GPRS Modem
ISRO22NavIC RTK PoC results

ISRO

23

Thank YouISRO24

Comparative Performance of L1 PRN codes

ISRO25