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The DMSP Operational Concept

Operational control of the DMSP is accomplished by transmitting command and load data to the DMSP satellites and collecting telemetry and meteorological data from them. Meteorological data is relayed to specialized processing centers. The telemetry/sensor data is ingested and the telemetry data is processed to determine the status of the spacecraft.

The functions performed by the DMSP Command, Control, and Communications Segment (C3S) are shown in the DMSP Command Control and Communications Diagram.

Operational Concept

The DMSP C3S performs all functions required to control and maintain the DMSP satellites

DMSP Mission Planning

Mission Planning accomplishes all tasks associated with scheduling and generation of control data for both the ground system and satellite operation. It synthesizes the users' scheduled data needs and accepts requests for special satellite status information to create the data files for control of the DMSP satellite system.

The Mission Planning function receives requests from users for stored and real-time mission data. In addition, mission requirements and constraints on the current capabilities of the satellite are received. These are processed to automatically produce the data files used to control the DMSP satellites.

DMSP Mission Commanding

Mission Commanding transmits and verifies commands and satellite memory loads, updates spacecraft clocks, and monitors selected telemetry parameters in real time.

The Commanding function incorporates a macrocommand capability for use in constructing command sequences. This capability allows operations to be viewed at a very high level. For instance, the macrocommand "Load and Verify Ephemeris" is a collection of many individual spacecraft commands.

DMSP Real-Time Telemetry Processing

The Real-Time Telemetry Processing subsystem ingests and displays satellite equipment status telemetry (EST) in an easy to use form for the operator. Two types of EST data are received for processing: real-time EST, which is only available while the spacecraft is within a station's visibility circle; and stored-mode EST, which is recorded outside the station circle.

The telemetry data can be received either concurrent with, or independent of, the commanding activity.

Computers integrate the real-time EST, commanding, and stored EST functions to support a specific satellite.

Real-time EST processing provides parameter display for analysis. Satellite subsystems, out-of-limits, and dwell (single-point monitoring) telemetry displays are provided to the analysts on color-graphic terminals. In addition, telemetry values can be presented graphically on these terminals, and on hard-copy strip charts.

A virtual playback capability is also provided to enable the analyst to replay significant events. The replay allows slow-motion viewing of the EST. Once contact with the satellite has ended, the stored telemetry and real-time telemetry are merged into a single database for postpass computer analysis.

DMSP Stored Telemetry Processing (Postpass Analysis)

The Stored Telemetry Processing System (STPS) allows analysis of spacecraft health and welfare. The system operates in either the interactive or batch modes.

In the interactive mode, the analyst can retrieve information from the telemetry database and perform analyses. Menus lead the data analyst through the system. Results are displayed on the operator's terminal.

In the batch mode, repetitive and time-consuming processing can be executed more rapidly. The batch mode can be initiated directly from the console, or be delayed awaiting a specific event, e.g., completion of the current pass.

Engineers/analysts can search the database for out-of-limit parameters or other significant situations. Multiple orbits of data can be scanned. Special user-defined retrieval algorithms are available to the analyst to aid in searching.

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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

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DMSP WebMaster - James Dixon