INSAT SATELLITE BASED DATA COLLECTION TRACKING SYSTEM FOR

INSAT SATELLITE BASED DATA COLLECTION & TRACKING SYSTEM FOR OCEAN DATA BUOYS S. N. Satashia, Prem Kumar, M. Jeyamani & Tata Sudhakar Space Application Centre Ahmedabad & NIOT Chennai th BY Tata Sudhakar National Institute of Ocean Technology, Chennai

INSAT BASED DATA COLLECTION SYSTEM • The system uses Data Relay Transponder(DRT) of the Satellites • The satellite receives transmission from data buoy in UHF band(402 MHz) and retransmits to ground station in C band(4. 5 GHz). • There are two satellites having DRT transponders INSAT 3 A at location 93. 5 E and METSAT (KALPANA) satellite at location 74 E.

INSAT DRT coverage

FEATURES OF THE INSAT SATELLITES INSAT 3 A C band Transponder : 12 Ext C band Transponder : 6 Ku band Transponder : 6 DRT&SAS&R Transponders : 1 Met Transmitter(VHRR&CCD) : 1 METSAT(KALPANA) DRT & SAS&R Transponder : 1 Met Transmitter(VHRR) : 1

PRESENT DCP • India Meteorological Department • Central Water Commission • Snow& Avalanche Establishment • NIOT • State Agencies

CHARACTERISTICS OF THE TRANSMITTER (DCP) • Transmit power 10 W (Typ. ) • Transmit at 4. 8 Kbps in random mode in allotted time window. • Uses Directional antenna of gain 11 d. B (Typ. ) • Uses 3. 8 m Ground Receive station (Hub)

DRT TRANSPONDER CHARACTERISTICS Rx. Frequency Range : 402. 75 Mhz. 100 KHz. Rx. G/T : - 19. 0 d. B/ K Receive Polarization. Circular(RHCP : METSAT for &LHCP for INSAT 3 A) Down link frequency : 4505 MHz (Nominal) Transmit Polarization : Linear EIRP (EOC) : 18 d. BW

Satellite Link Design for Data Buoys • The Transmit power from the data buoy is 10 W. • The transmit data rate is 300 bps. • Forward Error Correction Coding (convolution Coding) for the satellite channel is employed. • Packet Error rate Probability(PEP)is kept as 0. 01. • Time Division Multiple Access(TDMA) transmission protocol employed with time synchronized to GPS received time.

Satellite Link calculation UP LINK: Up link frequency : 402. 710 MHz. Tx power : 10 d. BW Antenna gain (including cable loss) : -3 d. Bi Tx. EIRP : 7 d. BW Max. Slant range to satellite (at 5 deg. Ele) : 41130 Km Uplink path loss : 177 d. B Satellite G/T : -19 d. B/K : EIRP - path loss + G/T+K Uplink C/No : 39. 6 d. BHz DOWN LINK: Down link freq. : 4505 Mhz Down link path loss : 197. 0 d. B Satellite EIRP : -1 d. BW Down link path loss : 197. 0 db G/T of earth station (3 m) : 17 d. B/K Down link C/No : EIRP - Path loss+ G/T+k : 47. 6 d. BHz Total C/No : 39. 5 d. BHz Required C/No : 34 d. BHz Link Margin : 5. 5 d. B

INSAT UHF(402 MHz ) Data from Sensors C-BAND(4. 5 GHz) 3. 8 m Data Acquisition (CPU) UHF TRANSMITTER (10 W) LNA RF D/C BURST DEMOD (BPSK) To data processing system of NIOT GPS 70 MHz IF 300 b/s DATA COLLECTION FROM DATA BUOY THROUGH INSAT

402 MHz Data from CPU Message Generator 4. 8 Kbaud 300 bbps (1/2 rate) BPSK Modulator Power Amplifier (10 W) Frequency Synthesizer (UHF) Block Schematics of INSAT UHF Transmitter

BURST FORMAT OF TRANSMISSION F (8) MID (16) IINFORMATION (320) DATA FORMAT CR BTR UW 256 64 64 UP TO 752 SYMBOLS 1. 68 Sec sec CR Carrier Recovery BTR Bit Timing Recovery UW Unique Word SCRAMBLED AND ½ RATE CODED CRC (16) F (8)

Specification of Receive station(HUB) Receive frequency G/T of Receive station (3. 8 m) IF Input to BPSK demodulator Output data rate & level Output data frame format (Demod) Input to data processing unit : 4505 MHz : 22 d. B/K : 70 MHz (nominal) : 300 b/s, RS 232 : HDLC : 4800 baud

TEST RESULT OF SATELLITE LOOP TX power C/No (d. BHz) Packets % PEP Rx / Tx 1 W 32. 3 80/100 0. 2 1. 25 W 33. 3 90/100 0. 1 1. 5 W 34. 3 96/100, 95/100, 0. 04 96/100 2. 5 W 36. 3 98/100 0. 02 9 W 41. 8 98/100 0. 02

1. THE EXPERIMENT RESULTS SHOW THAT INSAT SUPPORTS DATA BUOY COMMUNICATION WITH ADEQUATE MARGIN 2. OCCASIONAL LOSS OF DATA DUE TO INTERFERENCE FROM OTHER GROUND SYSTEM IS TAKEN CARE OF BY DIFFERENTIAL CODING and REPEAT TRANSMISSION.

INSAT Transmitter and Antenna for data buoys

DATA BUOYS WITH INSAT COMMUNICATION INDIA Pipvav Off Paradip Mumbai Bay of Bengal Arabian Sea Machillipatnam DS 1 Goa Mangalore NIOT Chennai SW 6 DS 3 Tuticorin Data Buoy with Insat communication Buoy with Insat Position reporting system

NIOT Hub and INSAT DRT capacity A hub station has been commissioned at NIOT in association with SAC Ahmedabad to establish the INSAT link for buoy communication. Successfully carried out the preliminary tests INSAT (METSAT & INSAT 3 A) can handle communication up to 1200 platform/ hour/carrier.

TRACKING SYSTEM

MSS Terminal Specification Information Rate 300 BPS Format HDLC Message Length 40 Characters (Max) Error Protection 16 bit CRC Error correction rate 600 BPS Modulation BPSK, bust External Data RS-232 Interface (GPS, NMEA - 0183 D) Transmission 3 Packets/message randomized – Aloha mode. 1 Packet / Message - TDMA mode Transmission time 4 sec (Max) / Message Frequency band 2677. 56 to 2678. 56 MHz Freq. Uncertainty ± 2. 7 KHz Max. Antenna Coverage ± 45° Tx Ei. Rp 9 d. BW (min. ) Power Supply Li - Ion -12 V DC, 600 m. Ah, Rechargeable Battery Temperature 0 to + 50° C

MSS - TRANSMITTER Buoy fitted with MSS transmitter is ready for deployment.

Block Schematics of Alert Transmitter GPS Receiver Message Generator Emergency Switch BPSK Modulator Frequency Synthesizer Power Amplifier Battery

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