PCM/PSK/PM S-Band TC & R (GEO: Geostationary Earth Orbit) (GTO: Geostationary Transfer Orbit) (SSTO: Super Synchronous Transfer Orbit). SSTO S

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1 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE Nov.; 25(11), ISSN (Print)ISSN X (Online) PCM/PSK/PM S-Band TC & R TC & R Communication Link Performance Analysis of Geostationary Satellite Employing PCM/PSK/PM on Super Synchronous Transfer Orbit 이선익 염경환 Sun-Ik LeeKyung-Whan Yeom* 요약 PCM/PSK/PM () S-band. PCM/PSK/PM TC & R(Telemetry, Command and Ranging). Heritage., EIRP 65 dbw 3 db. (3 db), G/T. 65,000 km 70,000 km. Abstract The classical PCM/PSK/PM scheme has been commonly used for TC & R applications between satellites and ground stations in the S-band. We analyzed TC & R link performance between ground station and the geostationary satellite which employs PCM/PSK/PM, when the satellite are particularly on the Super Synchronous Transfer Orbit(SSTO). The satellite parameters on SSTO are assumed to be those operating on the geostationary orbit, considering heritage aspect. In the uplink, the results shown indicate that sufficient margins over 3 db are obtained when the EIRP of ground station is greater than 65 dbw. The down link performance is of great interest. By adjusting the telemetry modulation index and ranging modulation index, we could obtain the required margin of 3.0 db in the down link, and find out the minimum G/T of ground station. In conclusion, the previously operated ground stations during LEOP at COMS launch, can be operational when GEO injection is made using SSTO(65,000 km and 70,000 km). Key words: PCM/PSK/PM, TC & R, Geostationary Satellite, Modulation Loss, SSTO, Link Budget. 서론 35,786 km. (Korea Aerospace Research Institute) * (Department of Radio Science & Engineering, Chungnam National University) Manuscript received August 25, 2014 ; Revised October 8, 2014 ; Accepted October 8, (ID No ) Corresponding Author: Kyung-Whan Yeom ( khyeom@cnu.ac.kr) 1142 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.

2 PCM/PSK/PM S-Band TC & R (GEO: Geostationary Earth Orbit) (GTO: Geostationary Transfer Orbit) (SSTO: Super Synchronous Transfer Orbit). SSTO SSTO GTO, Proton M, Falcon 9 Atlas V, Delta V SSTO. GTO, SSTO. S-band SSTO PCM/PSK/PM, TC & R(Telemetry, Command and Ranging). [1] (Telemetry, TM) (Command, TC), (Modulation Index: MI) (, Ranging: RG). [2]. S-band 1980 TC & R. (Launch Early Operation Phase: LEOP) [3]. SSTO,. TC & R PCM/PSK/PM PCM/PM/Bi-phase. PCM/PSK/PM 60 Ksps, PCM/PM/Bi-phase Ksps. PCM/PM/Bi-phase PCM SPL/PM [3]. 100 Ksps2 Msps BPSK QPSK. 10 kbps, PCM/ PSK/PM. PCM/PSK/PM SPL/PM (Residual carrier), BPSK QPSK (suppressed carrier) [4]. (PLL: Phase Locked Loop) [5]. PLL. PCM/PSK/PM [6][10],[12].,. 2 PCM/PSK/PM,. TC & R, PCM/PSK/PM.,,. PCM/PSK/PM (Sine wave) (Square wave) [4],[8],[9],[11]. SSTO (WARC ORB km,. CCSDS, Category A, Category B [8],[11] ),. 3, 4 Heritage,., SSTO,.. PCM/PSK/PM 신호모델 1143

3 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 11, Nov 그림 [9] Fig. 1. A block diagram for simultaneous command-ranging and telemetry-ranging operation [9]. PCM/PSK/PM, 1. Turn-around. PCM/PSK/PM. PCM/PSK/PM [7],[8]. sin (1),, ( ),, NRZ (±1). ( ), 1 PCM/PM. (1) sin cos cos sin (2), (PSD: Power Spectral Density) (3). 짝수 홀수 (3), 1 0, NRZ PSD, (4). (3),,,. sin, (data rate). 2-1 상향링크신호모델과변조손실 (4) 1144

4 PCM/PSK/PM S-Band TC & R (1) (5) [9]. sin sin (5),,.,, NRZ (±1),. (5),,., (6a)(6c) [11]. (6a) sin (7),, (rad), NRZ (±1), (rad),. Turn-around 1,, (AGC: Automatic Gain Control).. 'Command feedthrough' [13],[14].. AGC (8) [9]. (6b) sin, 1 1. (6c) (6a) (6c). (6a) (6c) 1, 하향링크신호모델과변조손실 sin 0, (feed through noise).,, (9a)(9e) [11]. (8) (9a) (9b) (9c) [9],[12]. sin (9d) (9e) 1145

5 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 11, Nov ,, Feed through,, (Power Spectral Density),., (10a)(10c) [9],[11]. (10a) (10b) (10c), Command,,, (11a)(11c). (11a) (11b) (11c) (),,,, (12a) (12d). (10a) (10c),, (13a)(13c). max max m in max m ax min max m in max m ax max max m in min m ax (13a) (13b) (13c),, min, max,. 3-1 전송방정식. 링크분석식 Friis [15] (14a) (14b). (14a) max min max min (12a) (12b) (12c) (12d) (14b),,.,,,, 1146

6 PCM/PSK/PM S-Band TC & R. ( ) ( ) [16].. (15) ( ), RF (, db), (16) [17]. (16) [18] (17). cos (17),,,. 3-2 레인징오차 (range error, range noise error) (measurement error) (range accuracy), (m, rms) [19]. (18) Major tone. (18),, Major,,, Tracking loop (PLL) bandwidth.. TC & R 시스템모델및링크분석 4-1 TC & R 시스템구성 TC & R 2 2 S-band, 2 S-band, RF. RF 3 db- (). S-band (hemispherical coverage). (LHCP), (RHCP). S-band 4 steradians 99 %. 5.0 dbi. S-band., PM, PM. PLL, Coherent ( coherent carrier transfer) (240/221).. LNA,,, AGC, PLL, ADC, DAC. PM. SSTO S-band 5.6 W.. (noise figure) 4.5 db., SSTO S-band TC & R GTO LEOP Fucino( 11 m antenna), Santiago( 9 m), Dongara( 13 m). G/T dbi/k, EIRP 65 dbw. SSTO LEOP, (ESA) NASA 1147

7 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 11, Nov 그림 2. TC & R RF Fig. 2. Satellite TC & R RF system coceptual block diagram 지상국과 SSTO간거리 65,000 km SS- TO, 80,000 km90,000 km SSTO.,. SSTO, GEO., SSTO. SSTO 40,000 km 90,000 km. 4-3 전송특성 S-band TC & R, PCM/PSK/PM,, BER 1 [2],[11],[22]. 2 kbps, 8 khz 표 1. Table 1. Transmission characteristics for a GEO satellite. RG Items Uplink Downlink Freq. 2,0252,110 MHz 2,2002,290 MHz Modulation PCM/PSK/PM PCM/PSK/PM MI(nominal) 1.4 rad for TC rad for TM MI variation ±5 % ±10 % Subcarrier type sine wave sine wave Subcarrier freq. 8 khz khz Data rate 2 kbps(tc) 4.1 kbps(tm) Modulation PM PM Tone freq. MI(nominal) major: 100 khz, minor: 1620 khz 1.4(0.7, 0.7) rad 0.45(0.32, 0.32) 0.7(0.5, 0.5) rad MI variation ±5 % +10 %, 15 % Channel coding BCH Convolution coding(r=1/2, k=7) Channel encoding Error detection Viterbi(soft) BER kbps 1148

8 PCM/PSK/PM S-Band TC & R 그림 3. BER Fig. 3. Theoretical BER curve of convolution coding., Convolution, Viterbi. Convolution BPSK BER db (coding gain). (soft decision). (hard decision) 2.7 db. 3 (Matlab) rad(peak) [20] rad, 0.45 rad [21]., rad. Major tone, Major tone Minor tone RG. [21]. 2. 표 2. Table 2. Uplink & downlink parameters. Parameters Units Values G/S Tx. EIRP dbw 65.0 Pointing loss db 0.2 Atmospheric loss db 0.6 Polarization loss db 2.1 S/C antenna composite gain dbi 5.0 S/C circuit loss(rx. & Tx.) db 5.4 Transponder Rx. Noise figure db 4.5 S/C Carrier recovery PLL loop BW Hz 800 C/N)req for carrier tracking(uplink) db 10.0 TC E b /N o required at BER 10 6 db 10.5 Implementation loss(up & down) db S/C EIRP dbw 2.1 G/S G/T dbi/k 2426 G/S Carrier recovery PLL loop BW Hz 300 G/S Ranging noise BW for SSTO Hz 4.0 S/No required on major & minor dbhz 20.0 TM E b /N o required at BER 10 6 db m, S-band 0.2 db. (polarization loss) db, 1 db. (atmospheric loss) db. (simulation tool),.,. 4-4 링크분석결과 상향링크 (TC only) (RG only) 1149

9 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 11, Nov 그림 4. TC carrier RG S/No Fig. 4. Uplink TC, carrier marginss and range S/No. (a) 4. TC 1.4 rad, Major RG 1.4 rad, major minor 0.7 rad, 0.7 rad, 5 dbi, 4.5 db, EIRP 65 dbw. TC db 3 db, S/No 42.5 db. EIRP 65 dbw. (b) 하향링크 (simultaneous TM and RG). TM 1.0 rad, RG 0.45(0.32, 0.32) rad. 2 (EIRP: 2.92 dbw) (G/T: 24.0 dbi/k) 10 SSTO 5. 5(a) SSTO 70,000 km TM RG ambiguity 2.3 db, 1.6 db 3 db. Carrier, 9 db. (c) 그림 5. (a), (b), (c)., TM 1.0 rad, RG 0.45 (0.32, 0.32) rad, G/S G/T 24 dbi/k Fig. 5. (a) Link margins, (b) Range errors, (c) Modulation losses, where TM MI of 1.0 rad, RG MI of 0.45 (0.32, 0.32) rad, G/S G/T of 24 dbi/k. 1150

10 PCM/PSK/PM S-Band TC & R 그림 6. SSTO 70,000 km., TM 1.0 rad, RG 0.45(0.32, 0.32) rad, G/S G/T 24 dbi/k Fig. 6. Link margins and range errors versus elevation angle (in degrees) on SSTO of 70,000 km, where TM MI of 1.0 rad, RG MI of 0.45(0.32, 0.32) rad, G/S G/T of 24 dbi/k. SSTO 40,000 km (5.6 m, rms) GEO S-band (6.0 m, rms) [22]., 100 khz. 5(b) RG Major (range noise error) 70,000 km 13 m, 90,000 km 20 m. 5(c) Carrier TM, RG SSTO. RG, S/No. 6 70,000 km RG Major. TM RG ambiguity db db. 7(a) SSTO 70,000 km G/T 24 dbi/k TM 1.0 rad 1.4 rad Carrier TM,. 7(a) (a) (b) 그림 7. (a) TM ( rad), (b) TM 1.3 rad RG., SSTO 70,000 km, G/S G/T 24 dbi/k Fig. 7. (a) Link margins and range error with TM MI variation from 1.0 to 1.4 rad, (b) Link margins and range error with RG MI variation(when TM MI of 1.3 rad fixed), where SSTO apogee is assumed 70,000 km, and G/S G/T of 24.0 dbi/k. 1151

11 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 11, Nov 표 3. SSTO 80,000 km Table 3. Link performance example to convince link performance for SSTO apogee of 80,000 km. Parameters & results Units Values Slant Elevation 10 ) km 85,041 S/C EIRP dbw 2.9 G/S G/T dbi/k 25.5 TM mod. index rad 1.2 RG major only mod. index rad 0.7 RG major & minor mod. index rad 0.5 Carrier mod. loss db 5.6 TM mod. loss db 4.9 RG mod. loss(major only) db 19.6 RG mod. loss(major & minor) db 27.0 Carrier tracking margin db 9.7 TM margin db 3.1 RG major tone noise error m 11.3 RG ambiguity margin db 3.1 TM TM Carrier RG. TM 1.0 rad 1.3 rad TM 2.3 db 4.3 db, Carrier 11.5 db 8.2 db, RG ambiguity 1.6 db 1.7 db. TM Carrier (3 db) RG ambiguity. TM 1.3 rad, RG 0.45(0.32, 0.32), 0.5(0.35, 0.35), 0.64(0.45, 0.45), 0.7(0.5, 0.5) rad 7(b). RG Major 17.2 m 11.8 m. RG Carrier 9.2 db 8.4 db, TM 3.9 db 3.2 db, RG 0.7 db 2.8 db. RG 0.64(0.45, 0.45) 0.7(0.5, 0.5) TM 3.4 db 3.2 db, RG 2.0 db 2.8 db 표 4. SSTO 90,000 km Table 4. Link performance example to convince link performance for SSTO apogee of 90,000 km. Parameters & results Units Values Slant range(@ Elevation 10 ) km 95,066 S/C EIRP dbw 2.9 G/S G/T dbi/k 27.0 TM mod. index rad 1.15 RG major only mod. index rad 0.7 RG major & minor mod. index rad 0.5 Carrier mod. loss db 5.2 TM mod. loss db 5.2 RG mod. loss(major only) db 20.0 RG mod. loss(major & minor) db 27.5 Carrier tracking margin db 10.7 TM margin db 3.4 RG major tone noise error m 11.1 RG ambiguity margin db 3.1. G/T 24.5 dbi/k TM 1.3 rad, RG 0.7(0.5, 0.5) rad TM RG 3 db (TM : 3.7 db, RG : 3.3 db). SSTO 80,000 km 90,000 km G/T, TM RG Carrier, TM, RG ,000 km G/T 25.5 dbi/k, TM 1.2 rad, RG 0.7(0.5, 0.5) rad TM RG 3.1 db. SSTO 90,000 km 4 TM 1.15 rad, RG 0.7(0.5, 0.5) rad G/T 27 dbi/k 3 db. TM RG 3 db SSTO 12 m. 100 khz Major 10 m [22], SSTO 12 m 1152

12 PCM/PSK/PM S-Band TC & R SSTO. SSTO, 10 m,., SSTO 2 [23],., (9) (10) S/N (effecive range modulation index, ),..,, Convolution. Reed solomon Convolution, 2 db.. 결론 S-band 10 kbps PCM/PSK/PM (SSTO) TC & R. (G/T)., EIRP 65 dbw. 3 db.,.,., 70,000 km G/T 24.5 dbi/k 80,000 km 90,000 km G/T 25.5 dbi/k, 27 dbi/k 3 db. SSTO 65,000 km 70,000 km 80,000 km 90,000 km GTO LEOP (:, ).,,.. References [1],,,,,,, " S- ", 2014, pp , [2],, " ",, 34 (11), pp , [3] R. Garcia, S. Marti, F. Schwartz, C. Bainier, and L. Martineau, "Compact TT&C equipment for small satellites", European Space Agency, TTC 2001, 2nd ESA Workshop on Tracking, Telemetry and Command Systems for Space Applications, Oct [4] W. L. Martin, T. M. Nguyen, "The joint CCSDS-SFCG modulation study-a comparison of modulation schemes", Jet Propulsion Laboratory, [5] M. K. Simon, S. Million, "Residual versus suppressedcarrier coherent communications", Jet Propulsion Laboratory, TDA Progress Report , pp. 1-9, Nov [6] T. K. Foley, B. J. Gaumond, "Optimum power division for phase-modulated deep-space communication links", 1153

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14 PCM/PSK/PM S-Band TC & R : () : : () : () : () () : : : [ 주관심분야 ] RF, TTC & R : () : () : () : () MIC : () : () : ()LTI : [ 주관심분야 ], MMIC 1155