Ground Sensor Computer

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Description

The Ground Sensor Computer is a high-level operations computer for ground-based sensor systems. This component manages the coordination between a Tracking Mount and various sensor payloads including optical (CCD), electromagnetic, and radar systems. The computer automatically discovers and connects to available sensors, manages their operational states based on target accessibility, and enforces elevation constraints to prevent operations below the horizon or minimum elevation limits.

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Example Use Cases

• Space Surveillance: Coordinate optical and radar sensors to track orbiting objects during visibility windows.
• Satellite Tracking: Manage sensor activation based on target access and elevation constraints.
• Ground Station Automation: Provide autonomous sensor control for unattended ground station operations.

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Module Implementation

The Ground Sensor Computer is a Computer component that attaches to a Ground Station and provides centralized control of tracking and sensor systems.

Initialization

During initialization, the computer discovers and connects to available subsystems on the ground station:

Component	Description
Tracking Mount	Provides pointing capability and access information
Charge Coupled Device	Optical sensor for visible-light detection
Electromagnetic Sensor	Passive RF sensor for signal detection
RADAR	Active RF sensor for target detection and ranging

If no tracking mount exists, one is automatically created. A placeholder access message is configured if none is connected.

Access-Based Control

The computer manages sensor states based on target accessibility provided by the tracking mount’s access message:

$$\text{sensors enabled}=\{\begin{array}{ll}\text{true}& \text{if IsAccessible}=\text{true}\\ \text{false}& \text{otherwise}\end{array}$$

When the target becomes inaccessible, all sensors are shut down to conserve resources.

Elevation Constraints

An additional check enforces the ground station’s minimum elevation limit:

$$\text{valid elevation}=ϵ\ge {ϵ}_{\text{min}}$$

where:

• $ϵ$ is the current target elevation angle
• ${ϵ}_{\text{min}}$ is the ground station’s configured minimum elevation

Sensors are disabled when the target elevation falls below this threshold, even if geometric access exists.

State Management

The computer follows a standard operational state machine:

State	Behavior
Startup	Transition to running state
Running	Process access checks and manage sensors
Other	Attempt startup recovery

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Assumptions/Limitations

• The computer assumes all sensors are mounted on the tracking mount as child objects.
• Sensor discovery occurs during initialization; sensors added later are not automatically detected.
• Only CCD sensors have full shutdown capability implemented; EM and RADAR shutdown is pending implementation.
• The tracking mount access message must be externally configured to provide valid access data.
• The computer does not generate pointing commands; it only responds to access information.
• Minimum elevation is read from the parent ground