Below are some tables of data pertaining some of the Big LEOs (Odyssey, ICO (formerly Inmarsat-P), Globalstar, Constellation (formerly Aries), Iridium, Teledesic and Ellipso). The tables are compiled from various general sources, all publically available. The tables are thus a compilation of other peoples work, only spiced with my own occasional error here or there.
Where conflicting data entries were found, the most recent sources were used. As data are gathered from a number of diverse sources, consistency between entries for the same system is not guaranteed, nor even aimed at. Figures for e.g. system cost may entail different elements for the different systems, and serve at best as an indication only. The tables ought nonetheless be usable for comparing the systems, provided great care is taken. Blank entries corresponds to cases where no data was available to me at the time of writing.
Standard disclaimers apply; I accept no responsibility of any sort for the contents of these tables!
| Odyssey | ICO (formerly Inmarsat-P) | Globalstar | Constellation (formerly Aries) | Iridium | Teledesic | Ellipso | |
|---|---|---|---|---|---|---|---|
| Service types | Voice, data, fax, paging, messaging, position location | Voice, data, fax, paging | Voice, data, fax, paging, short message service, position location | Voice, data, fax | Voice, data, fax, paging, messaging, position location | Voice, data, fax, paging, video | Voice, data, fax, paging, messaging, position location |
| Voice (kbps) | 4.8 | 4.8 | Adaptive 2.4 / 4.8 / 9.6 | 4.8 | 2.4 / 4.8 | 16 | 4.15 |
| Data (kbps) | 9.6 | 2.4 | 7.2 sustained throughput | 2.4 | 2.4 | 16 - 2048 | 0.3 - 9.6 |
| Modulation | QPSK | QPSK | QPSK | -- | QPSK | -- | OQPSK |
| Voice circuits / satellite | 2300 | 4500 | 2000 - 3000 | -- | 1100 (power limited) | 100000 16 kbps channels | -- |
| Dual mode User Terminals? | Yes | Yes | Yes | -- | Yes | No | Yes |
| Hand-held User Terminals? | Yes | Yes | Yes | Yes | Yes | Portable | Yes |
| System cost (Million US$) | 1800 | 2600 | 2000 | 1700 | 3700 | 9000 | 750 |
| User Terminal cost, US$ | 300 | "Several hundred" | 750 | -- | 2500 - 3000 | -- | 1000 |
| Satellite lifetime (years) | 10 | 10 | 7.5 | -- | 5 | 10 | 5; 5 |
| Call rates, US$/ min. | 0.65 | 1-2 | 0.35 - 0.55, wholesale | -- | 3 | -- | 0.5 |
| Operations scheduled | 2000 | 2000 | 1998 | 1998 | 1998 | 2001 | 1998 |
| Odyssey | ICO (formerly Inmarsat-P) | Globalstar | Constellation (formerly Aries) | Iridium | Teledesic | Ellipso | |
|---|---|---|---|---|---|---|---|
| Orbit class | MEO | ICO | LEO | LEO | LEO | LEO | HEO; MEO |
| Altitude (km) | 10354 | 10355 | 1400 | 1018 | 780 | 695-705 | 7846 x 520; 8040 |
| Number of Satellites | 12 + 3 spare | 10 + 2 spare | 48 + 8 spare | 48 | 66 +6 spare | 840 + up to 84 spare | 10; 6 |
| Number of planes | 3 | 2 | 8 | 4 | 6 | 21 | 2; 1 |
| Inclination (deg.) | 55 | 45 | 52 | 90 | 86.4 | 98.16 | 116.5; 0 |
| Period (minutes) | 359.53 | 358.9 | 114 | 105.3 | 100.13 | 98.77 | 180; 280 |
| Average sat. visibility time, minutes | 47.27 | 57.80 | 8.21 | -- | 5.54 | 1.74 | ; 41.77 |
| Min. User Terminal elevation angle (deg.) | 22 | 10 | 10 | -- | 8.2 | 40 | 10; 10 |
| Min. mobile link one-way propagation delay (ms) | 34.6 | 34.5 | 4.63 | 3.39 | 2.60 | 2.32 | -- |
| Max. mobile link one-way propagation delay (ms) | 44.3 | 48.0 | 11.5 | -- | 8.22 | 3.40 | 38.7; 38.7 |
| Min. LES / gateway elevation angle (deg.) | -- | -- | 10 | -- | -- | 40 | -- |
| Number of LESs /gateways | 10 - 11 | 12 | ~100 | -- | 15 - 20 | -- | -- |
| Coverage | Major land masses | Global | Within +/- 70 deg. latitude | Global | Global | Nearly global (2 degree hole at each pole) | North of 50 deg south latitude |
| Odyssey | ICO (formerly Inmarsat-P) | Globalstar | Constellation (formerly Aries) | Iridium | Teledesic | Ellipso | |
|---|---|---|---|---|---|---|---|
| Multiple access method | CDMA | TDMA | CDMA | CDMA | FDMA / TDMA / TDD | TDMA, SDMA, FDMA and ATDMA (see note at foot of table) | CDMA |
| Beams pr. satellite | 61 | 163 | 16 | 7 | 48 | 64 | 61 |
| Total # beams | 732 | 1630 | 768 | 336 | 3168 | 53760 | -- |
| Beam diameter, km | -- | -- | 2254, average | -- | 600 (min.) | 25 | -- |
| Footprint diameter, km | 10540 | -- | 5850 | -- | 4700 | 1412 | ; 11960 |
| Antennae? | Steerable, earth-fixed cells | Fixed | Staring, moving cells | -- | Staring, moving cells | Steerable, earth-fixed cells | Staring, moving cells |
| Reuse pattern (cells per cluster) | 3 | 4 | 1 | -- | N/A | N/A | 1 |
| Reuse factor | -- | -- | 768 | -- | 180 | 20000 | -- |
| Dual satellite visibility | More or equal to 2 satellites in coverage area | Usually more or equal to 2 satellites | "Substantial" | -- | At poles | More or equal to 2 satellites most of the time | More or equal to 2 satellites north of 40 deg. south latitude |
| Satellite diversity exploited? | No | Yes | Yes | -- | No | No (gateways only) | Yes |
| Odyssey | ICO (formerly Inmarsat-P) | Globalstar | Constellation (formerly Aries) | Iridium | Teledesic | Ellipso | |
|---|---|---|---|---|---|---|---|
| Mobile downlink freq. (MHz) | 2483.5 -2500.0 (S-band) | 1980 - 2010 | 2483.5 -2500.0 (S-band) | 2483.5 -2500.0 (S-band) | 1616.0 -1626.5 (L-band) | Ka-band | 2483.5 -2500.0 (S-band) |
| Mobile uplink freq. (MHz) | 1610.0 -1626.5 (L-band) | 2170 -2200 | 1610.0 -1626.5 (L-band) | 1610.0 -1626.5 (L-band) | 1616.0 -1626.5 (L-band) | Ka-band | 1610.0 -1626.5 (L-band) |
| Feeder uplink freq. (GHz) | 29.50 - 30.00 (Ka-band) | 5 (C-band) | 5.091 -5.250 (C-band) | 6.555 (C-band) | 19.400 -19.600 (Ka-band) | Ka-band | C-band |
| Feeder downlink freq. (GHz) | 19.700 - 20.200 (Ka-band) | 7 (C-band) | 6.875 -7.055 (C-band) | 5.160 (C-band) | 29.100 -29.300 (Ka-band) | Ka-band | C-band |
| On-board processing (OBP)? | No | -- | No | -- | Yes | Yes | -- |
| Inter-satellite Link (ISL) frequencies, GHz | N/A | N/A | N/A | -- | 23.180 -23.380 | 60 | -- |
| Handover performed? | Yes (only rarely) | Yes | Yes, seamless | -- | Yes | Yes | Yes (User Terminal not involved) |
| Link (fade) margins, dB | -- | 8 - 12 | 11 - 16 dB equivalent margin | -- | 16 voice, 35 paging | -- | -- |
| Satellite output power (W) | -- | -- | -- | -- | -- | -- | 200 Ave., 500 peak |
| Satellite mass (kg) | -- | 1925 | < 450 | -- | -- | -- | -- |
2) The data for Ellipso before the semi-colon pertain the Borealis elliptical constellation; values after the sem-colon correspond to the Concorida circular constellation.
3) I'm in the process of contacting each of the systems in an attempt to get updates and corrections and amendments from them. These updates will be included as soon as possible.