Calculation Results for Aggregate System EPFD for the Tenth Resolution 609 (Rev. WRC-07) Consultation Meeting

1 Introduction The purpose of this contribution is to provide the results of “equivalent power flux density” (epfd) calculations performed by the United States of America (U.S.) in preparation for the “Tenth Resolution 609 Consultation Meeting” (10th CM) in Los Angeles, 10-12 September 2013, as well as some proposals for the work of the 10th CM. The following relevant materials are presented in this document:

• A summary of U.S. calculations is presented in Section 2. • The U.S. calculation of the maximum RNSS “aggregate epfd” (aepfd), according to

§ 11 d) of the “CM Terms of Reference (MOD Geneva, September 2011)” (ToR), based on input data provided by each operator/administration regarding the epfd of its own system, is provided in Section 3 below.

• In Section 4 below, the single-system epfd results, obtained using a U.S. simulation tool, are compared to other operator/administration results.

• Finally, in Section 5 below, some U.S. proposals for CM work are provided.

2 Summary of Calculation Results

2.1 Maximum Aggregate EPFD Results For the maximum “aggregate epfd” (aepfd) results provided in this report, the single-system epfd results provided by notifying administrations were used. Based on this assumption, the U.S. obtained the following results:

• Excluding GLONASS CDMA, ARABSAT, and NIGCOMSAT systems in the calculation, the maximum aggregate epfd level is -121.93 dB(W/(m2∙MHz)), 0.43 dB below the Resolution 609 limit of -121.5 dB(W/(m2∙MHz)). This value occurs at 1 207 MHz. The U.S. currently believes this value is the correct aepfd value to report out of the 10th CM. (See Section 3.1 below for more details.)

• Including GLONASS CDMA, ARABSAT, and NIGCOMSAT systems in the calculation, the maximum aggregate epfd level is -121.76 dB(W/(m2∙MHz)), 0.26 dB below the Resolution 609 limit of -121.5 dB(W/(m2∙MHz)). This value also occurs at 1 207 MHz.

The details of maximum aepfd results are discussed in Section 3.

2.2 Tenth Consultation Meeting Single-System EPFD Results The main conclusions from U.S. calculations of single-system epfd results, incorporating new inputs to the 10th CM, are as follows:

• For the following systems, the U.S. epfd results are in very good agreement with those

provided by the notifying administrations: o QZSS GSO at 123°E (GS3) and 127°E (GS4) longitude o QZSS (7 HEOs) o INSAT-NAV(55), INSAT-NAVR(83), INSAT-NAV(93.5): INSAT-NAV(93.5)

will be an in-orbit backup satellite for GAGAN at 55°E and 83°E. For the purpose of maximum aepfd calculation INSAT-NAV(93.5) need not be considered.

o INSAT-NAV(32.5), INSAT-NAV(83), INSAT-NAV(131.5) • For the following systems, the U.S. epfd results do not agree with those provided by the

notifying administrations: o INSAT-NAVR-GS + INSAT-NAV-NGSA (IRNSS): Although INSAT-NAVR-

GS and INSAT-NAV-NGSA include a total of 8 non-GSOs, Table I-2 of IRNSS systems characteristics lists 11 non-GSOs. The U.S. believes that satellites 1-4 correspond to INSAT-NAVR-GS and 8-11 correspond to INSAT-NAV-NGSA. The U.S. epfd results based on this assumption do not agree with the single-system epfd results provided by India.

The details of single-system epfd results are discussed in Section 4.

3 Maximum Aggregate EPFD Results

3.1 RNSS Systems Taken into Account in the Aggregate EPFD Calculations The list of RNSS systems considered for maximum aepfd calculations is shown in Table 1. It is worth noting that:

1. bis aepfd calculations – GLONASS-M CDMA data was provided for information only. In addition, the current status of ARABSAT and NIGCOMSAT systems are unknown. Therefore, the U.S. has not included these in the primary aepfd calculation for the 10th CM. Instead they are included in the bis (i.e., secondary) aepfd calculations.

2. For the 10th CM, the new QZSS filing (7 HEO + GS3 + GS4) replaces the previous QZSS (6 HEOs + GS4) system.

3. Japan confirmed that the MTSAT satellite networks no longer satisfy the criteria defined in the Annex to Resolution 609 and, therefore, these satellite networks are not included in the maximum aepfd calculation.

4. INSAT-NAV(55), INSAT-NAVR(83), INSAT-NAV(93.5), INSAT-NAVR(32.5), INSAT-NAVR(84), and INSAT-NAV(131.5) replace INSAT-NAV-(34E, 55E, 82E, 83E, 131.5E). INSAT-NAV(93.5) is intended as an in-orbit backup satellite to GAGAN satellites at 55°E and 83°E and, therefore, is not included in the aepfd calculations.

5. INSAT-NAVR-GS + INSAT-NAV-NGSA replace INSAT-NAV-GS-1 from the 9th CM. INSAT-NAVR-GS covers the four IRNSS geo-synchronous satellites in two orbital planes with an inclination of 29° and equatorial crossings at 55°E for two satellites and 111.75°E for the other two satellites. INSAT-NAV-NGSA covers the four IRNSS geo-synchronous satellites in four orbital planes with an inclination of 42° and equatorial crossings at 46.5°E, 65.5°E, 94.5°E and 119.75°E respectively. Because the U.S. tools

could not replicate the single-system epfd data set provided by India for INSAT-NAVR-GS + INSAT-NAV-NGSA, India’s epfd data was used for the U.S. calculations of maximum aggregate epfd.

Based on the above, the maximum aepfd levels were calculated for the following two cases:

• CM10 – All RNSS systems in Table 1 excluding INSAT-NAV(93.5), GLONASS-M CDMA, ARABSAT-5C-20E, and NIGCOMSAT-1G/-1R

• CM10bis – All RNSS systems in Table 1 excluding INSAT-NAV(93.5).

3.2 Maximum Aggregate EPFD results using U.S. Tool The maximum aepfd results for CM10 and CM10bis cases, as a function of frequency, are summarized in Tables 2 and 3, respectively. The plots of these two results are shown in Figure 1. The maximum aepfd results are -121.93 and -121.76 dB(W/(m2∙MHz)) for CM10 and CM10bis, respectively. For these two cases, the remaining margins before exceeding the Resolution 609 limit of -121.5 dB(W/(m2∙MHz)) are 0.43 and 0.26 dB, respectively. In both cases, the worst 1 MHz aepfd level occurs at 1 207 MHz. It is also noted that these are the same maximum aepfd values as those computed for the 9th CM.

Table 1. RNSS Systems and aepfd Calculation Sets N° RNSS System Name Administration Input Data

Source CM10 CM10bis

1 MSATNAV-2 F/GLS 8th CM X X 2 NAVSTAR GPS U.S.A. 8th CM X X 3 GLONASS-M (FDMA) Russia 8th CM X X

4 COMPASS-H/-M/-MEO China 8th CM X X

5 LM-RPS-133W U.S.A. 8th CM X X 6 LM-RPS-107.3W U.S.A. 8th CM X X 7 INMARSAT-4 25E/-XL1/-4A 25E Great Britain 8th CM X X 8 INMARSAT-4 143.5E/-4A 143.5E Great Britain 8th CM X X 9 INMARSAT-4 98W/-4A 98W Great Britain 8th CM X X

10 COMPASS-58.75E China 8th CM X X 11 COMPASS-80E China 8th CM X X 12 COMPASS-110.5E China 8th CM X X 13 COMPASS-140E China 8th CM X X 14 COMPASS-160E China 8th CM X X 15 LUX-G6-2-E Luxembourg 8th CM X X 16 LUX-G7-9-E2 Luxembourg 9th CM X X 17 COMPASS-M/-MEO (F2) China 9th CM X X 18 COMPASS-H/-IGSO (F2) China 9th CM X X 19 COMPASS-58.75E (F2) China 9th CM X X 20 COMPASS-80E (F2) China 9th CM X X 21 COMPASS-110.5E (F2) China 9th CM X X 22 COMPASS-140E (F2) China 9th CM X X 23 COMPASS-160E (F2) China 9th CM X X 24 QZSS (7 HEOs) Japan 10th CM X X 25 QZSS GS3 (123E) Japan 10th CM X X 26 QZSS GS4 (127E) Japan 10th CM X X 27 INSAT-NAV(55) India 10th CM X X 28 INSAT-NAVR(83) India 10th CM X X 29 INSAT-NAV(93.5) (Note 1) India 10th CM 30 INSAT-NAVR(32.5) India 10th CM X X 31 INSAT-NAVR(83) India 10th CM X X 32 INSAT-NAV(131.5) (Note 1) India 10th CM X X

33 INSAT-NAVR-GS + INSAT-NAV-NGSA India 10th CM X X

34 GLONASS-M (CDMA) Russia 8th CM X 35 ARABSAT-5C-20E ARS/ARB 8th CM X 36 NIGCOMSAT-1G/-1R Nigeria 8th CM X

Note 1: INSAT-NAV(93.5) will be an in-orbit backup satellite for GAGAN at 55°E and 83°E. For the purpose of maximum aepfd calculation this satellite network should not be considered.

Figure 1. Maximum aepfd results CM10 and CM10bis. The maximum aepfd values calculated using the U.S. tool for CM10 and CM10bis are -121.93 and -121.76 dB(W/(m2∙MHz)), respectively,

and both occur at 1207 MHz.

1160 1170 1180 1190 1200 1210 1220-155

-150

-145

-140

-135

-130

-125

-120

Frequency (MHz)

Agg

rega

te e

pfd

(dB

(W/(m

2 *M

Hz)

))

CM10A (-121.93 dB(W/(m2*MHz))

CM10Abis (-121.76 dB(W/(m2*MHz))

Table 2. Maximum aepfd calculation results for CM10

Table 3. Maximum aepfd calculation results for CM10bis

Frequency (MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))1164 -139.665 1177 -123.005 1190 -135.699 1203 -125.9871165 -143.080 1178 -123.433 1191 -134.705 1204 -124.9221166 -152.314 1179 -124.295 1192 -134.617 1205 -124.5201167 -144.208 1180 -124.762 1193 -135.435 1206 -123.5001168 -137.190 1181 -126.038 1194 -136.615 1207 -121.9321169 -132.865 1182 -127.732 1195 -139.428 1208 -123.1631170 -129.537 1183 -130.117 1196 -143.201 1209 -125.0281171 -127.153 1184 -132.963 1197 -147.932 1210 -125.5581172 -126.196 1185 -137.406 1198 -140.513 1211 -126.7031173 -124.769 1186 -144.768 1199 -135.749 1212 -127.9471174 -124.151 1187 -150.571 1200 -131.856 1213 -129.8331175 -123.300 1188 -141.477 1201 -129.290 1214 -132.1301176 -122.140 1189 -137.906 1202 -127.273 1215 -135.542

Frequency (MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))Frequency

(MHz)

Max. aggregate epfd

dB(W/(m2·MHz))1164 -139.032 1177.000 -122.857 1190.000 -135.460 1203.000 -125.4081165 -140.547 1178.000 -123.279 1191.000 -134.522 1204.000 -124.4451166 -140.827 1179.000 -124.110 1192.000 -134.446 1205.000 -124.0901167 -139.584 1180.000 -124.612 1193.000 -135.168 1206.000 -123.1601168 -136.050 1181.000 -125.862 1194.000 -136.130 1207.000 -121.7631169 -132.647 1182.000 -127.559 1195.000 -138.046 1208.000 -122.9631170 -129.370 1183.000 -129.910 1196.000 -139.326 1209.000 -124.7471171 -126.996 1184.000 -132.717 1197.000 -139.061 1210.000 -125.3161172 -126.002 1185.000 -136.117 1198.000 -136.215 1211.000 -126.4621173 -124.616 1186.000 -139.516 1199.000 -133.344 1212.000 -127.7191174 -123.975 1187.000 -141.982 1200.000 -130.462 1213.000 -129.5941175 -123.150 1188.000 -139.859 1201.000 -128.311 1214.000 -131.8721176 -122.018 1189.000 -137.464 1202.000 -126.562 1215.000 -135.182

4 Tenth CM Single-System EPFD Results For the 10th CM Japan and India submitted updated information for their respective RNSS systems. The single-system epfd results for these systems are presented in this section.

4.1 QZSS For the 10th CM, Japan announced changes to the QZSS system.

• The total number of QZSS HEOs is seven. In addition QZSS has a plan for two GSOs located at 123°E and 127°E.

4.1.1 QZSS-GS3 123E GSO The epfd results for QZSS-GS4 GSO using Japan and U.S. tools are shown in Figure 2. The QZSS results obtained by Japan and the U.S. are in very good agreement.

4.1.2 QZSS-GS4 127E GSO The epfd results for QZSS-GS4 GSO using Japan and U.S. tools are shown in Figure 3. The QZSS results obtained by Japan and the U.S. are in very good agreement.

4.1.3 QZSS (7 HEO satellites) The maximum epfd results from both Japan and the U.S. for QZSS (7 HEO satellites) are shown in Figure 4. The QZSS results obtained by Japan and the U.S. are in very good agreement. The U.S. would like to further note that the equatorial crossings of the satellites also agree (see Figure 5 and Figure 6).

Figure 2. Comparison of the maximum epfd results from U.S. and Japan for QZSS GSO at 123°E

-80 -60 -40 -20 0 20 40 60 80-136.5

-136.4

-136.3

-136.2

-136.1

-136

-135.9

-135.8

-135.7

-135.6

-135.5

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - QZSS GS4 123E

Japan ToolU.S. Tool

Figure 3. Comparison of the maximum epfd results from U.S. and Japan for QZSS GSO at 127°E

Figure 4. Comparison of the maximum epfd results from U.S. and Japan for QZSS

-80 -60 -40 -20 0 20 40 60 80-136.5

-136.4

-136.3

-136.2

-136.1

-136

-135.9

-135.8

-135.7

-135.6

-135.5

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)Max epfd - QZSS GS 127E

Japan ToolU.S. Tool

-80 -60 -40 -20 0 20 40 60 80-134

-133

-132

-131

-130

-129

-128

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - QZSS

Japan ToolU.S. Tool

Figure 5. Japan calculated epfd values for QZSS (7 HEOs)

Figure 6. U.S. calculated epfd values for QZSS (7 HEOs)

Longitude [deg]

Latit

ude

[deg

]

-150 -100 -50 0 50 100 150

-80

-60

-40

-20

0

20

40

60

80epfd [dB

W/m

2/MH

z]

-138

-137

-136

-135

-134

-133

-132

-131

-130

-129

-128

Longitude [deg]

Latit

ude

[deg

]

-150 -100 -50 0 50 100 150

-80

-60

-40

-20

0

20

40

60

80

epfd [dBW

/m2/M

Hz]

-138

-137

-136

-135

-134

-133

-132

-131

-130

-129

-128

4.2 India For the 10th CM, India submitted information on GAGAN (3 GSOs) and IRNSS (3 GSOs + 8 non-GSOs).

4.2.1 India GSO (GAGAN) The epfd results GAGAN GSO at 55°E, 83°E, and 93.5°E using India and U.S. tools are shown in Figure 7 through Figure 9. The epfd results obtained by India and the U.S. are in very good agreement.

Figure 7. Comparison of the maximum epfd results from U.S. and India for INSAT-NAV(55)

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - GAGAN GSO 55E

India ToolU.S. Tool

Figure 8. Comparison of the maximum epfd results from U.S. and India for INSAT-NAVR(83)

Figure 9. Comparison of the maximum epfd results from U.S. and India for INSAT-NAV(93.5)

Note again that the INSAT-NAV(93.5) satellite is intended to be an in-orbit backup satellite for GAGAN at 55°E and 83°E and was not included in the aepfd calculation.

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - GAGAN GSO 83E

India ToolU.S. Tool

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - GAGAN GSO 93.5E

India ToolU.S. Tool

4.2.2 India GSO (IRNSS) The epfd results IRNSS GSO at 32.5°E, 83°E, and 131.5°E using India and U.S. tools are shown in Figure 10 through Figure 12. The epfd results obtained by India and the U.S. are in very good agreement.

Figure 10. Comparison of the maximum epfd results from U.S. and India for INSAT-NAVR(32.5)

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - IRNSS GSO 32.5E

India ToolU.S. Tool

Figure 11. Comparison of the maximum epfd results from U.S. and India for INSAT-NAVR(83)

Figure 12. Comparison of the maximum epfd results from U.S. and India for INSAT-NAV(131.5)

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - IRNSS GSO 83E

India ToolU.S. Tool

-80 -60 -40 -20 0 20 40 60 80-139

-138

-137

-136

-135

-134

-133

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - IRNSS GSO 131.5E

India ToolU.S. Tool

4.2.3 India non-GSO (IRNSS) INSAT-NAVR-GS comprises four of eight IRNSS geo-synchronous satellites. These are in two orbital planes with an inclination of 29° and equatorial crossings at 55°E for two satellites and 111.75°E for the other two satellites. INSAT-NAV-NGSA comprises the other four IRNSS geo-synchronous satellites in four orbital planes with an inclination of 42° and equatorial crossings at 46.5°E, 65.5°E, 94.5°E and 119.75°E. However, India listed 11 non-GSO satellites in Section I-2 of their IRNSS submission (see Table 4). For the purpose of this document, the U.S. assumed that satellites 1-4 correspond to INSAT-NAVR-GS and 8-11 correspond to INSAT-NAV-NGSA while ignoring the entries for satellites 5-7 (see Comments column in Table 4). The single-system U.S. calculation epfd results based on this interpretation of Table 4 are shown in Figure 13 along with a plot of the epfd data provided by India. It is quite clear that these two curves are dissimilar. The epfd values over all longitudes and latitudes are shown in Figure 14 and Figure 15. In particular, the equatorial crossings do not agree, most likely due to differences in assumed orbit epoch time. One approach to align equatorial crossings is to use the same orbit epoch time. Another is to add an offset angle to the RAAN values. Since the orbit epoch time used by India is unknown, the U.S. used the latter approach to accomplish the alignment. The image plot in Figure 16 shows the epfd results when 160 degrees offset is added to the RAAN values in Table 4. The resulting maximum epfd data is shown in Figure 17. It should be noted that the U.S. results are up to 2 dB higher in some latitudes than those provided by India. Because the U.S. tool could not replicate India’s INSAT-NAVR-GS + INSAT-NAV-NGSA single-system epfd data set, the U.S. used India’s epfd data for maximum aepfd calculations. It should be noted that using U.S. tool results in place of India’s data did not change the maximum aepfd values presented in Section 3. This is because the maximum single-system epfd (over a 1-MHz bandwidth) for India’s system occurs at 1176 MHz, while the maximum aepfd is at 1207 MHz.

Table 4. IRNSS non-GSO satellite system constellation parameters provided by India and U.S. comments

Satellite index RAAN Argument of latitude U.S. comments

1 135 120 INSAT-NAVR-GS Equatorial Crossing 55° E

2 135 176.75 INSAT-NAVR-GS Equatorial Crossing 111.75° E

3 310 305 INSAT-NAVR-GS Equatorial Crossing 55° E

4 310 1.75 INSAT-NAVR-GS Equatorial Crossing 111.75° E

5 270 13 GSO 83° E (Note 1) 6 270 322.5 GSO 32.5° E (Note 1) 7 270 59.5 GSO 131.5° E (Note 1)

Satellite index RAAN Argument of latitude U.S. comments

8 318.5 288.25 INSAT-NAV-NGSA Equatorial Crossing 46.5° E

9 110 155.5 INSAT-NAV-NGSA Equatorial Crossing 65.5° E

10 290 4 INSAT-NAV-NGSA Equatorial Crossing 94.5° E

11 279 40.75 INSAT-NAV-NGSA Equatorial Crossing 119.75° E

Note 1. It appears that these three rows are GSO’s and should be removed from the table in Section I-2 of Attachment 1 for IRNSS.

Figure 13. Comparison of the maximum epfd results for INSAT-NAVR-GS + INSAT-NAV-NGSA

-100 -80 -60 -40 -20 0 20 40 60 80 100-140

-138

-136

-134

-132

-130

-128

-126

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - IRNSS NGSO

India ToolU.S. Tool

Figure 14. India calculated epfd values for INSAT-NAVR-GS + INSAT-NAV-NGSA

Figure 15. U.S. calculated epfd values for INSAT-NAVR-GS + INSAT-NAV-NGSA

Longitude [deg]

Latit

ude

[deg

]

-150 -100 -50 0 50 100 150

-80

-60

-40

-20

0

20

40

60

80epfd [dBW

/m2/M

Hz]

-138

-137

-136

-135

-134

-133

-132

-131

-130

-129

-128

Longitude [deg]

Latit

ude

[deg

]

-150 -100 -50 0 50 100 150

-80

-60

-40

-20

0

20

40

60

80

epfd [dBW

/m2/M

Hz]

-138

-137

-136

-135

-134

-133

-132

-131

-130

-129

-128

Figure 16. U.S. calculated epfd values for INSAT-NAVR-GS + INSAT-NAV-NGSA with 160

degrees offset in RAAN

Figure 17. Comparison of the maximum epfd results for INSAT-NAVR-GS + INSAT-NAV-NGSA

with 160 degrees offset in RAAN

Longitude [deg]

Latit

ude

[deg

]

-150 -100 -50 0 50 100 150

-80

-60

-40

-20

0

20

40

60

80epfd [dB

W/m

2/MH

z]

-138

-137

-136

-135

-134

-133

-132

-131

-130

-129

-128

-100 -80 -60 -40 -20 0 20 40 60 80 100-140

-138

-136

-134

-132

-130

-128

-126

Latitude (Deg)

Max

imum

epf

d dB

(W/(m

2 *M

Hz)

)

Max epfd - IRNSS NGSO

India ToolU.S. Tool

5 Proposals for CM Work

5.1 Clarifying the Format of the Input Data for a Single System with Multiple Signals At the 9th CM, the meeting discussed how to treat COMPASS-H/-M/-MEO epfd data from the 8th CM and the new COMPASS MEO and IGSO inputs to the 9th CM for a new signal at 1207.14 MHz. In particular:

• The COMPASS –H and –M at 1191.795 MHz center frequency was considered as a single network. Consequently, the epfd data used during the 9th CM represents the sum of –H and –M systems. At the 9th CM, it was agreed that –H and –M should be treated as separate systems. (Note, -H is IGSO and –M is MEO)

• For the 9th CM, China submitted parameters for COMPASS MEO, IGSO and GSOs for a new signal centered at 1207.14 MHz. At the 9th CM, it was agreed that China should treat all planned transmissions in the 1 164-1 215 MHz band as a single signal and provide one epfd result for MEO, IGSO, and for each GSO.

The U.S. understood that China would provide new input to the 10th CM taking these discussions into account. In particular, the U.S. expected that China would submit Section 9 epfd data for all signals of COMPASS M/MEO as one system, and separate epfd data for all signals of H/IGSO as another system. Consequently, it was expected that Section 8 would contain only one table for COMPASS (MEO and IGSO) providing the SAF for a combined signal rather than separate tables for the “original” signal and “additional” signal. Likewise, there should be only one table in Section 8 for COMPASS GSOs. Similarly, for Section 4 (space station pfd versus the elevation angle) the expectation was that there should not be separate tables for the “original” signal and “additional” signal. Instead a single maximum pfd value for each elevation angle representing the combined signals was expected. Hence the U.S. proposes the CM should discuss the appropriate format for multiple RNSS signals of a single system. Furthermore, the CM should consider if appropriate changes should be made to the ToR to reflect the conclusions of such discussions.

5.2 Providing the Epoch Time for Non-GSO Systems At the 9th CM, the meeting discussed the importance of providing accurate constellation parameters for the IGSO satellite system in Table IV-2. The values of RAAN and argument of latitude are specified at some time “t” (orbit epoch time). The orbit epoch time is needed to allow proper modeling of the orbit. Specifying the longitude of the equatorial crossings also allows proper calculation of the orbit, but each administration would have to do additional calculations to determine the epoch times that result in the corresponding longitudinal crossings. So the U.S. recommends that operators of IGSO provide orbit epoch times when t ≠ 0, in addition to the given RAAN and argument of latitude. The CM should discuss this and other possible options to ensure consistency in simulation results.