FLTSATCOM

There are four FLTSATCOM satellites in service. These satellites are positioned at 100 W, 72.5 E, 23 W, and 172 E longitudes. They serve the Third, Sixth, Second, and Seventh fleets and the Indian Ocean battle groups. These four satellites provide worldwide coverage between 70 N and 70 S latitudes (figure 2-5).

Each FLTSATCOM satellite has a 23-RF-channel capability. These include 10 25-kHz channels, 12 5-kHz channels, and 1 500-kHz channel. The 500-kHz and the 10 25-kHz channels are reserved for Navy use. Of the 10 25-kHz channels, channel 1 is used for the fleet broadcast. All charnels use SHF for the uplink transmission. SHF is translated to UHF for the downlink transmission.

There is a separate UHF downlink transmitter for each channel. Each of the 23 channels has 3 different frequency plans in which the uplink or downlink may be transmitted. This capability precludes interference where satellite coverage overlaps.

LEASAT

The latest generation of Navy communications satellites is leased; hence, the program name LEASAT. As we mentioned earlier, these satellites replaced 2 of the 3 GAPFILLER satellites and augment the FLTSATCOM satellites.

CONUS LEASAT (L-3) is positioned at 105 W longitude, LANT LEASAT (L-1) is positioned at

Figure 2-5.-FLTSATCOM coverage areas,

15 W longitude, and 10 LEASAT (L-2) is positioned at 72.5 E longitude (figure 2-6).

Each LEASAT provides 13 communications channels using 9 transmitters. There are 7 25-kHz UHF downlink channels, 1 500-kHz wideband channel, and 5 5-kHz channels. The 500-kHz channel and the 725-kHz channels are leased by the Navy. One of the 725-kHz UHF downlink channels is the downlink for the Fleet Satellite Broadcast.

The broadcast uplink is SHF, with translation to UHF taking place in the satellite. The remaining 625-kHz channels function as direct-relay channels with several repeaters. Currently, the LEASAT channels provide for the following subsystems:

Channel 1 for Fleet Satellite Broadcast transmissions;

1 25-kHz channel for SSIXS communications;

1 25-kHz channel for ASWIXS communications; and

2 25-kHz channels for subsystems that transmit or receive via DAMA (Demand Assigned Multiple Access) (for example, CUDIXS/NAVMACS, TACINTEL, and secure voice).