D. FUNCTIONAL ANALYSIS
1. Decomposition
A functional decomposition seeks to draw out additional stakeholders or requirements by categorizing the functions a system will perform. This process is accomplished by identifying the components that make each function.
a. Top Level
The distributed surface force function is “to prevail in an A2AD environment.”
This will be accomplished by dispersing capability over a group of ships. A view is shown in Figure 14.
Figure 14. Top-level functional decomposition.
The top-level design is further broken down into the detailed design in the next section.
b. Detailed
(1) Function 1.1 is “to sense.” This function defines the vessel’s systems;
utilizing both organic and off-vessel sensors, shall detect, locate, and track seaborne contacts. Information provided to system operators at a minimum shall include:
• For radar: course, speed, and bearing (both true and relative)
• For electronic warfare equipment: frequency, bearing, and signal strength Under Function 1.1 we have three sub-functions: “to detect,” “to classify,” and
“to track.” Details for these sub-functions will be explained below and are shown in Figure 15.
Figure 15. “To sense” sub-functional decomposition.
Function 1.1.1 is “to detect.” This function defines that the system automatically receive inputs actively from own-ship and passively from off-ship radar, providing feedback to sensor operator.
Function 1.1.2 is “to classify.” This function defines the radar system that provides raw radar data to the signal processing system and sensor operator to assist in classification. An electronic warfare system will assist the operator in classifying contacts through the use of database and pairing likely vessels through emitted frequencies.
Function 1.1.3 is “to track.” This function defines organic radar system’s Automatic Radar Plotting Aid (ARPA), which actively tracks the history of detected radar contacts and provides closest point of approach (CPA). Off-ship assets may provide contact position and, if capable, video images of contacts to aid operators in classification.
(2) Function 1.2 is “to engage.” This function defines the action in three sub-functions specific to a firing sequence. The system, after the target is acquired and classified as hostile, produces a fire-control solution. The fire-control solution is established from the radar system and operator inputs. The weapon system shall engage with missile or main gun to intercept the target of interest. Additional means to engage contacts will be through crew-served weapons such as machine guns, grenade launchers, and small arms. The operators using on and off-ship sensors will assess weapon effectiveness. A breakdown of function 1.2 is shown in Figure 16.
Figure 16. “To engage” sub-functional decomposition
Function 1.2.1 is “to target.” This function defines that the radar and off-ship sensors shall provide track data to the sensor operator in order to establish a fire control solution on the target of interest. Fire-control solutions will provide a fine bearing resolution on the target of interest. This information will be provided to the weapon prior to engagement.
Function 1.2.2 is “to launch weapon.” This function defines the act of the weapon leaving the ship and specifically pertains to missiles, and primarily surface-to-surface
missiles. The function may also apply to main gins, machine guns, and defensive missiles. After a fire-control solution is received from the radar system, the weapon will launch and fly towards the contact of interest. Target location is updated to the weapon for the longest duration possible.
Function 1.2.3 is “to conduct battle damage assessment (BDA).” This function defines the ability of sensors to accurately report lost contacts due to combat. BDA may pertain to on and off-ship sensors including electronics and the human eye.
Figure 17. “To move” sub-functional decomposition.
Function 1.3 is “to move.” This function defines the ability of the vessel to travel under the control of the crew.
Function 1.3.1 is “to transit.” This function defines how the vessel operates from its initial starting point to a designated location.
Function 1.3.2 is “to maneuver.” This function defines the ability of the vessel to avoid static and moving obstacles such as ships, islands, and navigational aids. The maneuvering will be done through operator interaction.
Function 1.3.3 is “to navigate.” This function defines the ability for a vessel to know its current and projected location and plan to transit to new locations.
Function 1.4 is “to communicate.” This function defines the transmitting and receiving of data or voice information required to conduct the operations of sensing,
engaging, and moving. These communications must be effective in both network optional warfare environments and network centric environments. A breakdown of Function 1.4 is shown in Figure 18.
Figure 18. “To communicate” sub-functional decomposition.
Function 1.4.1 is “to transmit.” This function defines actively sending signals from the vessel these signals may be data or voice signals. This information may be sent via radio, light, visual cues, and lasers.
Function 1.4.2 is “to receive.” This function defines actively or passively obtaining radio, laser, or other electronic information and conversion to pictorial, data, or voice information. Radio, light, visual cues, and lasers must be receivable by the system.
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