Weapons direction involves the management of torpedo flight from launch through to successful prosecution (a hit on the target).
A firing solution will likely have been calculated and the torpedo configured accordingly prior to launch. The torpedo will follow this configuration automatically, although it is highly likely that the torpedo's actual flight will vary from the firing solution at some point, requiring the weapons director to intervene and compensate.
Once torpedo launch procedures are completed, the torpedo can be launched when the vessel has reached the range and closing velocity to the target required by the firing solution.
There are a number of flight modes a torpedo may progress through. Each mode determines the targeting information available to the torpedo.
This mode utilises a direct data connection with the vessel, which allows the torpedo to be guided by the vessel's more powerful tactical sensors.
The data connection is not physical - the 'wire' is a tight-beam laser connection. This connection can only be maintained while the vessel's bearing to the torpedo's remains within a certain range. Once the connection is lost, it cannot be regained.
Each tube is equipped with two guidance transceivers which are assigned prior to launch. If necessary an assigned transceiver can be made available by manually disconnecting from the inflight torpedo. The disconnected torpedo will automatically shift to the next configured flight mode.
This flight mode uses a simplified EMDAR system onboard the torpedo to track the target by its EM output.
The torpedo is configured to select an EM band to detect. The sensors onboard torpedoes are narrowband and so so they have target tracking capabilities, but can only pick up detections from a narrow arc in space (a bearing of +/- 10° from the torpedo). The limitations of the torpedo-mounted sensors also mean detections can only be made from one EM band, selected during pre-launch configuration. but are narrowband sensors so they have tracking capabilities.
The torpedo will maintain a heading towards the EM source while it remains detectable. Typically the ambient EM output from magnetoplasma engines can be detected by a torpedo's passive system at up to 2000 GUs.
If the EM sources becomes undetectable the torpedo will fall back to the configured search pattern.
The torpedo guidance system falls back to a search pattern when it cannot find an EM contact to follow. The search pattern will be followed until a detection in the configured EM band is made.
A direct search pattern isn’t actually a pattern at all. In this search mode, the torpedo continues along the heading it was on when it entered passive mode.
A curve search pattern causes the torpedo to alter heading based on a specified held bearing.
The held bearing can be set to release after the torpedo’s heading has changed by a specified number of degrees (the scope), after which the torpedo will use the next specified search pattern (linear by default).
An alternating search pattern regularly changes the torpedo’s heading, alternating between port and starboard bearings and creating a zig-zag pattern.
There are three configurable variables in this mode which effectively define the search area:
Radial and alternating search pattersn are configured using these variables:
Bearing: The specifies the bearing that should be applied with each heading change. The number of degrees specified is alternately applied to port and starboard.
Scope: This specifies the range the torpedo travels over which the bearing should be applied (radial) or before an alternate beaing is applied (alternating).
When a target EM source is reacquired, the search pattern is suspended. If a target EM source has not been acquired by the completion of the search pattern, the torpedo will fall back to active mode.
In this mode, the torpedo uses onboard RADAR to scan for the target.
RADAR gives a highly accurate range and bearing and so is useful for closing on a target, but RADAR's active scanning makes the torpedo easy to detect by the target (and its countermeasure systems).
The torpedo will automatically enter active mode at the configured distance from the target, or if the configured passive mode search patttern fails to detect a target (unless configured with direct search mode or no passive mode at all).
The torpedo may also be manually put into active mode at any time by the weapons director.