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These sites are Remote Tracking Stations (RTSs) of the AF Satellite Control Network (AFSCN). As such, they have equipment compatible with the Space/Ground Link Subsystem (SGLS) DMSP satellite links. Presently shared AFSCN communications are not adequate to support the wideband (2.66 Mb/s) DMSP mission data and EST in real time. Special equipment and communications have been installed at these sites to allow the DMSP SOCs to send and receive data directly through these RTSs to provide the required data communications capacity and minimize commanding delays.

DMSP interface equipment

DMSP interface equipment at Hawaii Tracking Station (HTS), New Hampshire Station (NHS), and Thule Tracking (TTS) allows these AFSCN Remote Tracking Station (RST) sites to be used directly by DMSP's dedicated MPSOC and FSOC.

These sites are all dual RTSs with Automated Remote Tracking Station (ARTS) installations. The ARTS design has been modified to include a DMSP Enhancement (DMSPE), which allows baseband interface of commands, EST, mission data, limited site status, and antenna pointing data in the form of NORAD two-card set ephemeris data for the DMSP satellites.

The DMSP dedicated Wideband Network extends to these sites as DOMSAT links. Each of these sites receives two DOMSAT links, one from FSOC and one from MPSOC. Data from one or the other of these links is selected by the RTS personnel to control which SOC is interfacing with the DMSP satellite. Data to be returned to the SOCs is transmitted over a single link and received at both SOCs, and at the strategic user sites (AFGWC and FNOC).

DMSP interface equipment rack
A single-standard rack houses the DMSP interface equipment at these RTSs. The terminal is for maintenance only.

A single rack of dedicated DMSP equipment, the DMSP Interface (DMSPI), interfaces to the selected DOMSAT data and to the DMSPE. These racks are virtually identical at each site except for markings. External patch panels allow selection of the other side of the dual RTS (other antenna, receivers, and transmitters) as backup.

The ARTS is set up and tested by the AFSCN Range Control Center (RCC) and released to DMSP control for a scheduled DMSP contact. Up to the point at which the ARTS is released to DMSP control, this follows normal AFSCN procedures. The selected DMSP SOC interfaces with the ARTS through the Wideband Network and the DMSPI in a manner that is nearly indistinguishable to the DMSP operators from interfacing to the dedicated DASs at FSOC. Full commanding, EST, and mission data capabilities are supported by this linkage. At completion of the scheduled contact, or in the event of an overriding emergency, the RCC resumes control of the ARTS and proceeds with normal AFSCN operations.

At the HTS and NHS, the DMSP DOMSAT link was piggybacked on an existing DOMSAT terminal. Because of the surrounding mountains and low-look angle to the DOMSAT at the TTS, the existing DOMSAT terminal was located atop a nearby mountain. It was necessary to provide a fiber-optic link between the DOMSAT terminal and the DMSPI.

Additional recorders were also provided at these sites to allow mission data to be recorded and played back at a later time as necessary, without affecting the use of the ARTS recorders by other AFSCN users.

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Designed and Developed by

The Aerospace Corp.

John Bohlson, Leonard Daly, and Charles Simmons
The Aerospace Corporation
Last modified on July 03, 1997

Please send any questions or comments regarding this service or content to
DMSP WebMaster - James Dixon