Telemetry, Tracking, and Commanding (TT&C) Link Considerations for a LEO Sat123

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Telemetry, Tracking, and Commanding (TT&C) Link Considerations for a LEO Sat

¹²³

Jack K. Kreng, Michelle M. Ardeshiri, Oscar C. Barbosa, and Yogi Y. Krikorian The Aerospace Corporation

Communication Systems Engineering Department P.O. Box 92957

Los Angeles, California 90009-2957 310-336-1932

2 IEEEAC paper #1421, Version H, Updated December 21, 2004 3 2005 IEEE Aerospace Conference, Big Sky, MT, March 5–12, 2005

Abstract—Telemetry, Tracking, and Command are very important functions necessary for the proper operation of a satellite. It becomes a critical issue for the LEO-Sat program, however, when the command and control is provided from a small ground station with limited capabilities (low transmit EIRP and receive G/T), and when the satellite is in a contingency mode of operation, such as tumbling (antennas off pointed).

Previous link analyses [5] have shown that the satellite link would be adequate when commanding from large remote tracking stations (RTS) with a larger antenna (45- or 60-foot dish). This paper deals with command and control of this new LEO-Sat in its early orbit, using a small remote tracking station (RTS), with a 33-foot antenna.

Our analyses [2] have proven that the uplink and downlink can be closed even with a small RTS station with a 33-ft antenna. The details of these analyses are given in this paper. The communication link performance, both during normal operations as well as in contingency tumbling mode of operations, are presented here. Both the SNR (signal to noise ratio) and the threshold techniques were shown side- by-side, in the link analyses, for normal and anomalous tumbling cases, with similar results. The conclusion in Section 5 summarizes the analyses.

Aerospace personnel and the satellite contractor came to a similar conclusion: that the uplink and downlink (to and from the satellite) using a small RTS station with a 33-ft antenna have adequate link margin. In normal mode, worst- case LEO-Sat and nominal small RTS station parameters were used in the analysis. In contingency mode or tumbling mode, the worst worst-case parameters for LEO-Sat and for a small RTS station were used. A summary of the results of

the analyses performed for the uplink and downlink communication paths are given in this paper.

TABLE OF CONTENTS

1.INTRODUCTION... 1

2.U^PLINKA^NALYSIS... 2

3.DOWNLINK ANALYSIS... 3

4.DETAILED CALCULATIONS... 3

5.C^ONCLUSION... 4

REFERENCES... 9

BIOGRAPHY... 9

1. I

NTRODUCTION

The telemetry, tracking, and command (TT&C) enable for a full duplex commanding, and verification of the satellite’s health and status, from a remote tracking station (RTS). The overall spacecraft TT&C transponder is designed to receive, demodulate, and distribute ground command messages, and collect, format, modulate, and transmit satellite tracking, health, and status performance to ground. Link calculations are used to verify that the signal-to-noise ratio (SNR) is adequate in the uplink between the ground station and the space vehicle, as well as in the downlink between the space vehicle and the ground station. In the present study, the space vehicle uses SGLS (Space Ground Link System) Channel #6 (uplink at 1783.74 MHz and downlink at 2227.5 MHz) during normal and anomalous tumbling operations. There are at least two methods of determining the overall performance capability of a TT&C transponder over the program’s mission life. One method is through link calculations, using the derated parameters and worst-case

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conditions. The other is through end-to-end testing with simulated derated values and worst-case conditions added later.

In this paper, the former of the 2 methods, that is, the link analyses were used to evaluate the transponder performance.

In these link analyses it is not difficult to see the normal and anomalous tumbling operations (See Tables 1 & 2 respectively), using the threshold and the SNR techniques in the same tables.

A standard interface specification document for SGLS wave form was used as a guide [1] in the link calculations.

Assumptions

1) In the uplink as well as in the downlink analyses, calculations were made for both the Normal Operation as well as for the Anomalous Tumbling Operation conditions.

Figure 1. Normal and Anomalous Tumbling Operations

The drawing above defines a normal operation and anomalous tumbling operation. In the Normal Op shown in the top picture, the station and the satellite (also called space

vehicle or SV) antennas are pointed toward each other perfectly (bore-sight pointing, top picture). In the Anomalous Tumbling Op case (bottom picture, in dashed lines), the satellite or SV antennas are not pointed correctly toward the ground station antennas (off-bore-sight) resulting in a poor satellite or SV antenna gain. In this case we assume the lower gain Bicone antenna is pointed toward earth, instead of the high gain forward (FWD) or aft (AFT) antennas. No tumbling rate is involved in the link calculations.

2) In all link calculations for Normal Op, worst-case antenna gains and line losses were used. Similarly for Anomalous Tumbling Op, the worst of the worst in antenna gains and line losses were used. This is to insure that the link can close at different worst-case conditions.

2. U

PLINK

A

NALYSIS

The uplink is composed of (1) ground transmitter and antenna, (2) the path between ground and satellite antennas, and (3) the satellite antenna and satellite receiver. The uplink budget is determined by the transmission media, the ground station, satellite hardware, i.e., transmitter EIRP, space loss, receiver G/T, etc. The paragraph below describes the uplink budget for normal and for contingency tumbling modes of operation.

One way to assess link performance is based on computing the received SNR, which we will call “the SNR technique.”

The other way to assess link performance is solely based on specifying the minimum specified received signal power, which is called “the threshold technique.” In this latter case, noise level and required SNR are not considered.

a) Normal Operation: Table 1 shows the uplink performance for the carrier and command services in the normal operation case. The shaded areas indicate satellite or SV worst-case data, desired data, or specification values extracted from the program’s Performance Analysis Report [5]. The worst-case SV radio frequency assembly (RFA) line loss in front of the low noise amplifier (LNA) of 7.07 dB for the forward (FWD) antenna (from contractor data) is used here [5]. This input receive (Rx) line loss corresponds to a noise temperature of 1187 K, which is a portion of the system temperature Ts= 2943.8 K. Ts is in turn used in the command (CMD) noise floor calculation of –133.9 dBm.

The CMD data rate is assumed to be 1 kbps. The worst-case SV forward antenna (FWD) minimum gain of 5.21 dBi, at a look angle of 14.3°, was used in the calculation. The LEO- Sat program office is interested in the uplink performance using the smallest RTS station (with a 33-foot antenna), and a minimum transmit EIRP of 103.1 dBm (1 kW transmitter).

The carrier and CMD margins were calculated to be 41.58 and 27.28 dB, respectively, using the threshold technique.

0072-05

Normal OP

TX

S/V

R_X R_X

G/T EIRPT_X

S/V

Normal and Tumbling Anomaly OP

TX R_X

Normal Normal

Anormaly Anormaly

S/V S/V

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Using the SNR technique these, values are 40 and 32.09 dB, respectively.

b) Contingency Tumbling Operation: Table 2 shows the uplink performance for the carrier and command services in the tumbling case. The 6.29 dB SV RF Assembly (RFA) loss for the bi-cone antenna is used here. The worst worst- case SV Bicone antenna (Bicone) minimum gain of –9.7 dBi, at a look angle of 105°, was used in the calculation.

The carrier and CMD margins were calculated to be 26.7 and 12.37 dB, respectively, using the threshold technique.

Using the SNR technique these become 25.86 and 17.96 dB, respectively. The CMD margin, from the satellite contractor’s calculation, was 9.73 dB, and from our calculation it was 12.37 dB. These two CMD margin calculations are different because we calculate the –110 dBm threshold measured at the receive antenna hub while the contractor calculates this –110 dBm at the LNA input.

These two calculations would be the same if the loss between the antenna and the LNA were small. Using the SNR technique, the CMD margin is at 17.96 dB, which easily meets the 10 dB requirement (see bottom of Table 2).

In general, we believe that the SNR technique is the correct way to look at the CMD link performance, and the threshold technique is riskier since the CMD noise floor or the SNR was never measured or calculated. This CMD noise floor level should be at least 19 dB below the CMD signal to achieve a BER of 1E-5 (see Table 2 note). The actual CMD threshold can be calculated from the noise floor and the required SNR, to be kTB + SNR required = –114.8 dBm.

with the required CMD SNR of 19.1 dB and the CMD noise floor KTB = –133.9 dBm (B = 30 dB-Hz). The Required CMD SNR is 19.1dB, with 13.9 dB for 3-FSK with 1E-5 BER + 2.2 dB decryptor loss + 3 dB CMD demod loss. The CMD threshold requirement was set at –110 dBm by the contractor, with no information given on the SNR nor the noise floor.

3. D

OWNLINK

A

NALYSIS

Basically the downlink uses the same elements as the uplink. The downlink may be composed of (1) satellite transmitter and antenna (EIRP), (2) satellite-to-ground path loss, and ground antenna and receiver (G/T). The paragraphs below show the downlink budget calculations for the normal and for the contingency/tumbling mode of operations. The downlink budget is used to determine the carrier, telemetry and ranging services performance in the presence of space vehicle hardware, transmission media, and the receive ground station hardware in use. The paragraphs below are for the downlink budget calculations for the normal and for the contingency tumbling mode of operation.

a) Normal Operation: Table 3 shows the downlink performance for the carrier, telemetry, and ranging services.

The shaded boxes indicate SV worst-case data, desired data, or specification values, which are picked from the Milsat S- Band Performance Analysis Report. The worst-case SV forward antenna (FWD) minimum gain of 4.8 dBi, at a look angle of 14.3°, or a transmit EIRP of 38.38 dBm, was used in the calculation. The worst-case SV transmitter line loss of 3.41 dB was also used. The RTS 33-foot station with a minimum G/T (antenna gain to the system noise temperature ratio) of 21.59 dB/K was assumed. The carrier, telemetry, and ranging margins are 25.97, 19.16, and 25.59 dB, respectively. In this case, the contractor and Aerospace both used the SNR technique, and our results are within 1 to 2 dB of each other.

b) Contingency Tumbling Operation: When the satellite tumbles, we have a worst-case situation or minimum SV transmit EIRP when the satellite uses the bi-cone antenna and points it toward Earth. Table 4 shows the downlink performance for the carrier, telemetry, and ranging services.

The shaded boxes indicate SV worst-case data, desired data, or spec values taken from pages 8, 9, and 10 of the contractor’s S-Band Performance Analysis Report [5]. The worst worst-case SV Bicone antenna gain of –4.55 dBi at a 105° look angle, with the corresponding worst-case SV transmitter line loss of 2.65 dB, or a worst-worst transmitter EIRP of 29.79 dBm, was used. The 33-foot RTS station with a minimum G/T of 21.59 dB/K was assumed. The carrier, telemetry, and ranging margins were 17.38, 10.57, and 17.00 dB, respectively. The contractor and Aerospace both used the SNR technique, and the results were within 1 to 2 dB of each other.

4. D

ETAILED

C

ALCULATIONS a) LEO-Sat Uplink Received Residual Carrier, Ranging, and Command Calculations

The detailed derivations for uplink received residual carrier, ranging, and command can be found in [3 & 4].

A quick look at the theory for the uplink signal is shown below. The uplink SGLS signal is of the following form:

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( )

[

( ) ( )

]

( )

( ) ( ) ( )[ ]

( ) ( )[ ] ⁽⁴⁾

) sin(

).

cos(

) cos(

).

sin sin(

).

( 2

) sin(

. sin

) cos(

. cos

. 2

) sin(

).

( 2

) 3 ( ] ) 1 2 sin(

).

( 2 ) sin(

).

( 2 [ ) sin sin(

) ( )]

2 cos(

).

1 ( 2 ) ( [ ) sin cos(

: (4) equation have we (2), equation into (3) equation ng

substituti

and LPF, by rejected get that s order term higher

Neglecting

) 2 ( ]

sin(

).

sin cos(

) cos(

).

sin ).[sin(

sin(

)]

sin(

).

sin sin(

) cos(

).

sin ).[cos(

cos(

cos . 2

wave.

square filtered kHz 500 2 /

with Ranging Tone for sin X

detection.

synch AM after 1, for kHz 95 and 0, for kHz 76

tone, S for kHz 65 with CMD for sin

) (

(1) 2

cos . 2

2 2

2 2 1 1 1

2 2 1 0

2 2 1 0 1 1 1

1

1 1

1 2 1

1 1 1

1

1 2

1 1

2 2 1 1

2 2 1 1 2

2

2 2 2

1 1

2 2 1 1

⎪⎪

⎪

⎭

⎪⎪

⎪

⎬

⎫

⎪⎪

⎪

⎩

⎪⎪

⎪

⎨

⎧

⎥⎦

⎢ ⎤

⎣

⎡

− +

=

≈

+ +

=

≈ +

=

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

+

−

= −

=

+ +

=

∑

∞

= +

∞

=

t w X

t w t X

w J

X J

t w

X J

t w P

t S

t w J

t w k J

t w J

wt

J kwt J

J wt

X t

w

X t

w t

w

X t

w

X t

w t

w P

t S

w f

t w K t

f t

w K t X

t X t X t f P t

S

CUL CUL CUL

CUL s

UL

k k k

o k

o

CUL CUL

s UL

UL C s UL

β β β

β β

β β β

β β

β

β β

π

β β

π

The first term is the residual carrier, the second term is the ranging with X2, sine wave, or PRN signal, and the third term is the command tones (w1).

The uplink modulation losses for carrier, command, and ranging are, with ranging X2= ±1 random data, are

²

[ Tprn .( f − fc )]

^.

^]

= –82.72 dBm.

b) LEO-Sat Downlink Received Residual Carrier, Ranging, and Telemetry Calculations

₃)]

= –122.90 dBm.

5. C

ONCLUSION

Our link calculations show that there are sufficient uplink and downlink margins for normal as well as worst-case conditions using the small 33-foot RTS station transceiver (i.e., with a 33-ft transmit and receive antenna). The carrier tracking performance, as well as the CMD sensitivity, and the BER were tested at the TT&C transponder manufacturer laboratory. The successful BER test for the CMD uplink implies that the minimum requirement for the CMD signal- to-noise ratio (i.e., SNR of about 19 dB) is met.

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Table 1. TT&C Uplink (SNR MODEL, USING a 33-ft RTS Station) November 30, 04 Normal Operation Mode with SV Look Angle = 14.3 Deg.

Notes:

a. From an RTS Doc.

b. From a SGLS Interface Specification Doc.

c. Receiver spec for CMD BER=1E-5, or requirement data.

d. 19.1dB= 13.9dB (for Req'd Eb/No for Non-Coherent 3-FSK BER of 1E-5) + 2.2dB (for CMD Decryptor Loss) + 3 dB (for CMD Demod Loss)

e. Shaded Boxes are SV data, desired data, or spec values.

Parameters Comments

Frequency, fc (MHz) 1783.74

Orbit Heigh, ht (km) 20196.00 Apogee at Half GeoSync

Elevation Angle, Theta (Deg.) 5.00

Slant Range, SR (km) 25247.39 13632.50 n.mi.S.R.

Rx Antenna Diameter, D (ft) 0.21 181.34 DegOmniCov

Rx Antenna Efficiency, Eff 0.55 Equiv. For Dipole

Rx Antenna Temp., Ta (K) 290.00 Nominal Earth Temp

Rx Line Temp., Tl (K) 1187.00 7.07 dB (SV RF Assembly Loss For Ant)

Rx RF Amp. Temp., Tr (K) 288.00 3.00 dB NF Typical LNA NF

Rx System Temp., Ts (K) 2943.81 Ts=Ta+(L-1)Tg+L(NF-1)Tg

Max Tx Power, Pt (dBm) 60.00 1000 W TWT

Actual Tx Pk Ant.Gain, Gt (dBi) 43.50 a 33-ft Dish RTS Spec (a)

Tx Loss, Lo (dB) 0.4

Tx EIRP (dBm) 103.10 a Typical 33-ft RTS EIRP Spec (Pt*Gt-Lo) (b)

Space Loss, Ls (dB) -185.51

Other Loss, Lo (dB) 0.00

Misc.Losses, Lo (dB) 1.00 0.5dB Atmos & 0.5dB Polar losses

Rcvd Isotropic Pwr (dBmi) -83.41

Rx Antenna Gain, Gr (dBi) 5.21 SV FWD Min.Ant.Gain @ 14.3Deg.

Total RcvdCarrierPwr, Pr (dBm) -78.20 At Rx Ant.Feed Out (Not LNA In) L-Band Services Carrier Command Ranging

Modulation Index, Beta (Rad.) 1.00 0.30

Modulation Loss, Lmod (dB) -2.72 -4.52 -12.91

Rcvd Services Pwr, Pr (dBm) -80.92 -82.72 -91.12

Boltzmann Const., k (dBm/K-Hz) -198.60 -198.60 -198.60

Rx System Temp., Ts (dB-K) 34.69 34.69 34.69

Rcvd Noise Density, No (dBm/Hz) -163.91 -163.91 -163.91 No=k*Ts

Data Rate, Noise BW, B (kHz) 5.00 1.00 1000.00 (b) Rb=B

Rcvd Noise Power (dBm) -126.92 -133.91 -103.91 k*Ts*B

Rx Ant.Gain/Temp. (dB/K) -29.48 -29.48 -29.48 Gr/Ts

Rcvd CarrierToNoise(dB-Hz) 82.99 81.19 NA (Pr/No = C/No)

Rcvd Service C/N (dB) Pr/(NoB) 46.0 51.2 NA (C/N = SNR)

Min. Req'd Service C/N (dB) Req'd SNR 6.0 19.1 NA (d) Req'd Min.Service Pwr (dBm) PWR req'd -122.50 -110.00 NA (c)

Thermal Noise Margin (dB) M 41.58 27.28 NA

Using Req'd Min Service Pwr Threshold

Thermal Noise Margin (dB) M 40.00 32.09 NA Using M=Rcvd SNR - Req'd SNR

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Table 2. TT&C Uplink (SNR MODEL, USING a 33-ft RTS Station) November 30, 04 Contingency or Tumbling Operation Mode with SV Look Angle = 14.3 Deg.

Notes:

a. From an RTS Doc.

b. From a SGLS Interface Specification Doc.

c. Receiver spec for CMD BER=1E-5, or requirement data.

d. 19.1dB= 13.9dB (for Req'd Eb/No for Non-Coherent 3-FSK BER of 1E-5) + 2.2dB (for CMD Decryptor Loss) + 3 dB (for CMD Demod Loss)

e. Shaded Boxes are SV data, desired data, or spec values.

Frequency, fc (MHz) 1783.74

Orbit Heigh, ht (km) 20196.00 Apogee at Half GeoSync

Elevation Angle, Theta (Deg.) 5.00

Slant Range, SR (km) 25247.39 13632.50 n.mi.S.R.

Rx Antenna Diameter, D (ft) 0.21 181.34 DegOmniCov

Rx Antenna Efficiency, Eff 0.55 Equiv. For Dipole

Rx Antenna Temp., Ta (K) 290.00 Nominal Earth Temp

Rx Line Temp., Tl (K) 945.00 6.29 dB (SV RF Assembly Loss For Ant)

Rx RF Amp. Temp., Tr (K) 288.00 3.00 dB NF Typical LNA NF

Rx System Temp., Ts (K) 2461.48 Ts=Ta+(L-1)Tg+L(NF-1)Tg

Max Tx Power, Pt (dBm) 60.00 1000.00 W TWT (a)

Actual Tx Pk Ant.Gain, Gt (dBi) 43.50 a 33-ft Dish RTS Spec (a)

Tx Loss, Lo (dB) 0.4

Tx EIRP (dBm) 103.10 a Typical 33-ft RTS EIRP Spec (Pt*Gt-Lo) (b)

Other Loss, Lo (dB) 0.00

Misc.Losses, Lo (dB) 1.00 0.5dB Atmos & 0.5dB Polar losses

Rcvd Isotropic Pwr (dBmi) -83.41

Rx Antenna Gain, Gr (dBi) -9.70 SV Bicone Min.Ant.Gain @ 105 Deg.

Total RcvdCarrierPwr, Pr (dBm) -93.11 At Rx Ant.Feed Out (Not LNA In)

L-Band Services Carrier Command Ranging

Rcvd Services Pwr, Pr (dBm) -95.83 -97.63 -106.03

Boltzmann Const., k (dBm/K-Hz) -198.60 -198.60 -198.60

Rx System Temp., Ts (dB-K) 33.91 33.91 33.91

Rcvd Noise Density, No (dBm/Hz) -164.69 -164.69 -164.69 No=k*Ts

Data Rate, Noise BW, B (kHz) 5.00 1.00 1000.00 (b) Rb=B

Rcvd Noise Power (dBm) -127.70 -134.69 -104.69 k*Ts*B

Rx Ant.Gain/Temp. (dB/K) -43.61 -43.61 -43.61 Gr/Ts

Rcvd CarrierToNoise(dB-Hz) 68.85 67.06 NA (Pr/No = C/No)

Rcvd Service C/N (dB) Pr/(NoB) 31.9 37.1 NA (C/N = SNR)

Min. Req'd Service C/N (dB) Req'd SNR 6.0 19.1 NA (d)

Req'd Min.Service Pwr (dBm) PWR req'd -122.50 -110.00 NA (c)

Thermal Noise Margin (dB) M 26.67 12.37 NA Using Req'd Min Service Pwr

Threshold

Thermal Noise Margin (dB) M 25.86 17.96 NA Using M=Rcvd SNR - Req'd SNR

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Table 3. TT&C Downlink (SNR MODEL, USING a 33-ft RTS Station) November 30, 04 Normal Operation Mode with SV Look Angle = 14.3Deg

Note:

a. From an RTS Doc.;Carrier TrackThreshold (Pr/No)(1/B)=13 dB, with Carrier to Noise density Pr/No=29.6dB-Hz,B=50Hz. Carrier Acquisition with B= 2kHz, 1kHz or 500Hz.

b. From N. Elyashar's IOC on TRR Signal, No.91.3702.NNE.08. This 27dB SNR corresponds to Mode-1 operation with Residual Carrier C/No=29.7dB-Hz or RTS TRR in Mode-1.

c. Shaded Boxes are SV data, desired data, or spec values.

Frequency (MHz) 2227.50

Orbit Height (km) 20196.00

Elevation Angle (Degrees) 10.00

Slant Range (km) 24713.51 13344.23 nm Slant Range

Rx Antenna Diameter (ft) 33.00 0.94 Deg.FOV

Rx Antenna Efficiency 0.55

Rx Antenna Temperatue, Ta (K) 34.00

Rx Line Temperature, Tl (K) 35.50 0.50 dB LineLoss

Rx RF Amp. Temperature, Tr (K) 120.00 1.50 dB NF Rx System Temperature, Ts (K) 204.19 Ts=Ta+(L-1)Tg+L(F-1)Tg

(ARTS, Max Ts Spec for G=44.7, G/T=21.6)

Tx Power, Pt (dBm) 36.99 5.00 W Pwr Amp EOL

Tx Ant.Gain, Gt (dBi) 4.80 SV FWD Min.Ant.Gain @ 14.3Deg.

Other Tx Loss, Lt (dB) 3.41 SV FWD Ant.Transmit Line Loss

Tx EIRP (dBm) 38.38 SV Transmit EIRP (Pt*Gt-Lt)

Fade Loss, Lo (dB) 1.00 0.5dB Pol. & 0.5dB Atmosph.

Rcvd Isotropic Pwr (dBm) -149.88

Actual Rx Pk Ant.Gain, Gr (dBi) 44.69 A Typical 33-ft Dish RTS Spec (a) Rcvd Carrier Pwr, Pr (dBm) -105.19 At Ant.Feed Out.(not at LNA Input) S-Band Services Carrier Telemetry Ranging

Rcvd Services Power, Pr (dBm) -109.54 -108.02 -122.90 Boltzmann Const. (dBm/K-Hz) -198.60 -198.60 -198.60

Rx System Temp., Ts (dB-k) 23.10 23.10 23.10 (a)

Rcvd Noise Density (No) , (dBm/Hz) -175.50 -175.50 -175.50 (a) Data Rate, Noise BW, Rb=B (kHz) 0.500 4.00 0.001 (a) Rcvd Noise Power, kTsB (dBm) -148.51 -139.48 -175.50 Rx Ant.Gain/Temp., Gr/Ts (dB/K) 21.59 21.59 21.59 (a) Rcvd CarrierToNoise, Pr/No (dB-Hz) 65.96 67.48 52.59

Rcvd CNR or Eb/No= (Pr/No)(1/Rb) 38.97 31.46 52.59

Req'd Eb/No+2.7dB,for BER=1E-5 12.30

or SNR Threshold (dB) 13.00 (a) 27.00 (b)

Min.Req'd Service Pwr (dBm) -135.51 -127.18 -148.50

Thermal Noise Margin (dB) 25.97 19.16 25.59

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Table 4. TT&C Downlink (SNR MODEL, USING a 33-ft RTS Station) November 30, 04 Contingency or Tumbling Operation Mode with SV Look Angle = 14.3Deg

Note:

a. From an RTS Doc.;Carrier TrackThreshold (Pr/No)(1/B)=13 dB, with Carrier to Noise density Pr/No=29.6dB-Hz,B=50Hz. Carrier Acquisition with B= 2kHz, 1kHz or 500Hz.

b. From N. Elyashar's IOC on TRR Signal, No.91.3702.NNE.08. This 27dB SNR corresponds to Mode-1 operation with Residual Carrier C/No=29.7dB-Hz or RTS TRR in Mode-1.

c. Shaded Boxes are SV data, desired data, or spec values.

Frequency (MHz) 2227.50

Orbit Height (km) 20196.00

Elevation Angle (Degrees) 10.00

Slant Range (km) 24713.51 13344.23 nm Slant Range

Rx Antenna Diameter (ft) 33.00 0.94 Deg.FOV

Rx Antenna Efficiency 0.55

Rx Antenna Temperatue, Ta (K) 34.00 0.50 dB LineLoss

Rx Line Temperature, Tl (K) 35.50 1.50 dB NF

Rx RF Amp. Temperature, Tr (K) 120.00

Rx System Temperature, Ts (K) 204.19 Ts=Ta+(L-1)Tg+L(F-1)Tg

(ARTS, Max Ts Spec for G=44.7, G/T=21.6)

Tx Power, Pt (dBm) 36.99 5.00 W Pwr Amp EOL

Tx Ant.Gain, Gt (dBi) -4.55 SV Bicone Min.Ant.Gain @ 105 Deg.

Other Tx Loss, Lt (dB) 2.65 SV Bicone Transmit Line Loss

Tx EIRP (dBm) 29.79 SV Transmit EIRP (Pt*Gt-Lt)

Fade Loss, Lo (dB) 1.00 0.5dB Pol. & 0.5dB Atmosph.

Rcvd Isotropic Pwr (dBm) -158.47

Actual Rx Pk Ant.Gain, Gr (dBi) 44.69 A Typical 33-ft Dish RTS Spec (a) Rcvd Carrier Pwr, Pr (dBm) -113.78 At Ant.Feed Out.(not at LNA Input) S-Band Services Carrier Telemetry Ranging

Rcvd Services Power, Pr (dBm) -118.13 -116.61 -131.49

Boltzmann Const. (dBm/K-Hz) -198.60 -198.60 -198.60

Rx System Temp., Ts (dB-k) 23.10 23.10 23.10 (a)

Rcvd Noise Density (No) , (dBm/Hz) -175.50 -175.50 -175.50 (a)

Data Rate, Noise BW, Rb=B (kHz) 0.500 4.00 0.001 (a)

Rcvd Noise Power, kTsB (dBm) -148.51 -139.48 -175.50

Rx Ant.Gain/Temp., Gr/Ts (dB/K) 21.59 21.59 21.59 (a)

Rcvd CarrierToNoise, Pr/No (dB-Hz) 57.37 58.89 44.00

Rcvd CNR or Eb/No= (Pr/No)(1/Rb) 30.38 22.87 44.00

Req'd Eb/No+2.7dB,for BER=1E-5 12.30

or SNR Threshold (dB) 13.00 (a) 27.00 (b)

Min.Req'd Service Pwr (dBm) -135.51 -127.18 -148.50

Thermal Noise Margin (dB) 17.38 10.57 17.00

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R

EFERENCES

[1] A Standardized Interface Specification Document for SGLS wave form.

[2] J. Kreng and M. Ardeshiri, Uplink & Downlink Performance for the New LEO-Sat S-Band TT&C Transponder, ATM-2004(1540-23)-2, The Aerospace Corporation, January 2004.

[3] S. Raghavan and J. Kreng, Generalized Equations for Modulation Loss Calculations, Aerospace TOR-90(5485- 04).

[4] T. M. Nguyen, J. Yoh, and C. C. Wang, Assessment of S- Band Utilization for Future Satellite Operations, ATR- 99(1795)-1, The Aerospace Corp.

B

IOGRAPHY

Mr. Jack K. Kreng is an Engineering Specialist in the Communication Systems Engineering Department. He has been with The Aerospace Corporation since 1985. His areas of expertise include RF and digital communication hardware and systems. These areas of interest includes RF and digital communications, multi-rate multi- symbol modem design for secure and non-secure communications, digital signal processing and frequency synthesizer design techniques.

Prior to joining the Aerospace, Mr. Kreng worked at TRW Space Communications in Redondo Beach in the areas of modem, signal processing, and frequency synthesis (DSP, Milstar P/L, Spread-Spectrum Navy JTID Transponder). At Hughes Space and Communications (HSC) in El Segundo, Mr. Kreng was involved in communications and digital signal processing (Ku Band Space Shuttle Transponder, Mission 34 satellite P/L).

He has a BS and MS in Electrical Engineering from Ohio University (1967), and West Virginia University (1969).

Michelle M. Ardeshiri is a Senior MTS for Electronic Systems Division (ESD). She has been employed at The Aerospace Corporation since 2002. Her primary responsibility is technical requirements development for TT&C Dual/multiband Transponder for all future DOD, NASA, and other government-related space programs

Prior to joining The Aerospace Corporation in 2002, Ms.

Ardeshiri was a systems engineer for Boeing Space and Communications/Hughes company focusing on telemetry, tracking, and command (TT&C), payload communication systems engineering, flight hardware, and spacecraft harness design. She has over 10 years of related experience.

Ms. Ardeshiri received her MSEE degree in 2000 and BSME from, the University of Southern California in 1994.

She is currently a member of the International Council on Systems Engineering (INCOSE).

Yogi Y. Krikorian is the Manager of the System Design and Simulation Section of the Communication Systems Engineering Department. He rejoined The Aerospace Corporation in August 2000 after a 5-year absence; he had previously worked here for 8 years. Mr. Krikorian recently analyzed, simulated, and presented the susceptibility of ICO commercial satellite to pulsed radar frequency interference for GMSK and QPSK modems. He also received a Letter of Commendation for support of the STAR 37S Nozzle Anomaly Corrective Action Study, for which he analyzed nozzle radiographs using digital image processing for measurement of nozzle wall thickness.

Mr. Krikorian has 13 years experience in communications engineering, including 5 years in commercial companies, such as Hughes Space and Communication Company.

While at Hughes, he worked as a Payload System Engineer on the ICO Global Communication Satellite Program. He helped design and develop the LO Distribution Network, Communication Processors, Payload Control Processor (PCP), payload layout, and gain distribution of IF, RF, and LO signals. He also served as the Manager of Applications Engineering at Elanix, Inc. in Westlake Village, CA, where he provided technical expertise and support for SystemView, a PC-based software simulation on program for designing DSP algorithms, communications systems, and RF/analog systems. Other commercial experience includes serving as Senior Technical Engineer and Director of Engineering at RJS, Inc. in Santa Fe Springs, CA.

Mr. Krikorian received his BSEE and MSEE from the California Institute of Technology in Pasadena, CA. He is a member of IEEE and of several honor societies.

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Mr. Oscar Barbosa is a Senior Project Engineer for the Aerospace GPS Program Office. He graduated with a BSEE degree from California Polytechnic Institute in 1977. He joined The Aerospace Corporation in August 1987. He has 25 years of design and systems integration experience with a specialty in Radio Frequency (RF) communications systems that include processors and digital hardware. Mr. Barbosa’s involvement with various companies, organizations, and programs has equipped him with a broad-based knowledge in communication hardware. The majority of his experience has been in the Government space programs from the Space Shuttle to the current GPS program. Current responsibilities include oversight of the design and integration of uplink/downlink and crosslink RF communication subsystems for the GPS program.

Prior to joining Aerospace, Mr. Barbosa worked as Project Engineer for Rockwell International Corporation. In this capacity Mr. Barbosa was responsible for the design and integration of Special Test Equipment (STE) to verify and test GPS Block II RF and digital line replaceable units (LRUs). Duties also included technical management and liaison with the customer and internal matrix organization..