Acciones Generales y Actividades Específicas

The RAR as seen in Chapters 3 & 5 was used in the TAT as a method of displaying the time available to re-task a weapon to a particular target. However, due to there being as many as 32 LRAGM in flight simultaneously, using a dynamic graphical over- lay of the RAR on the map overview would be computationally demanding as well as overwhelming for operators. Instead a system must be used that provides the operator the same level of information but in an easily interpretable format. As shown in the previous chapter, a numerical representation provides a useful way of representing the data that improves the accuracy of decision makers in time critical situations, whilst maintaining a comparable reaction time.

In the previous study the numerical data was presented as two numbers – the range to the target from the zero controls free-fall trajectory of the GBU, and the maximum possible range that the trajectory could be shifted in the direction of the new target. As shown this works sufficiently well for free-fall type weapons. However, the LRAGM is a powered missile, capable of cruising at a constant altitude whilst there is sufficient fuel to do so. This creates extra complexity in the method used to calculate the weapon’s ability to be re-tasked to different locations. Chapter 3 contains more detail about how the RAR is calculated for the LRAGM. The output of the calculations is the route and time it would take to reach the target, as well as the time spent in straight and level cruising flight.

This flight phase is important for predicting the time at which it will no longer be possible to reach a target. Figures 6.12, 6.13 and 6.14 show a number of approaches to a single target. The different flight phases are shown in different colours. For any flight, the optimum – minimum distance route to a target will be a combination of one or two turns, a section of gliding flight, a section of cruising flight, and the terminal phase. A normal weapon release from high altitude will typically have a glide, with or without a turn, followed by cruise. Then there will be a final turn towards the target (given the desired attack heading) followed by the terminal phase of flight to intercept it.

−3 −2.5 −2 −1.5 −1 −0.5 0 0.5 x 104 −1.5 −1 −0.5 0 0.5 1 1.5 x 104 East (m) RouteDist: 34.12km Ac Hdg: 000 Attk Hdg: 000 North (m) Tgt Pos Lnch Pos Terminal Transition Straight Flight Cntr Turn Tangent Launch Heading 1st Turn Centre 2nd Turn Centre 1st Turn Circle 2nd Turn Circle End 1st Turn Start 2nd Turn Straight Flight Terminal Flight Full Flight Glide Cruise Terminal

Figure 6.12: Approach Paths of Air-to-Surface LRAGM Given Launch and Approach Headings (North,North)

−3 −2.5 −2 −1.5 −1 −0.5 0 0.5 x 104 −1.5 −1 −0.5 0 0.5 1 1.5 x 104 East (m) RouteDist: 25.83km Ac Hdg: −45 Attk Hdg: −45 North (m) Tgt Pos Lnch Pos Terminal Transition Straight Flight Cntr Turn Tangent Launch Heading 1st Turn Centre 2nd Turn Centre 1st Turn Circle 2nd Turn Circle End 1st Turn Start 2nd Turn Straight Flight Terminal Flight Full Flight Glide Cruise Terminal

Figure 6.13: Approach Paths of Air-to-Surface LRAGM Given Launch and Approach Headings (North-West,North-West) −3 −2.5 −2 −1.5 −1 −0.5 0 0.5 x 104 −1.5 −1 −0.5 0 0.5 1 1.5 x 104 East (m) RouteDist: 24.50km Ac Hdg: −90 Attk Hdg: −90 North (m) Tgt Pos Lnch Pos Terminal Transition Straight Flight Cntr Turn Tangent Launch Heading 1st Turn Centre 2nd Turn Centre 1st Turn Circle 2nd Turn Circle End 1st Turn Start 2nd Turn Straight Flight Terminal Flight Full Flight Glide Cruise Terminal

The routes to each different target are calculated every time step for each different weapon, based upon the flight properties calculated from the Monte-Carlo simulations run in the LRAGM design phase to find the RAR of the weapon. A number of these flight properties are constant values, such as turn rate and cruise speed, which allows a simple routing solution to be generated, rather than running a complex, time-consuming Monte-Carlo analysis of the route for each potential weapon-target assignment. Given the turn rates and velocities, constant radius curved trajectories can be calculated for the flight path of the LRAGM during turning flight. This leads to a simplification of the route, and way-points, that are to be generated for the LRAGM. From each initial condition of the weapon, there are four possible trajectories to the target. A combina- tion of two turns, either left - left, left - right, right - left, or right - right, will bring the LRAGM to the target on the desired attack heading. Of these routes some may be impossible – i.e. the distance between the target and the missile may not provide sufficient distance to carry out the required turns – others will be too long, with cruise distances required that are beyond the range capability of the weapon.

From the four potential routes, the shortest achievable route to each target is found. This route can then be used to calculate the time until this route is no longer possible. The amount of TTG remaining in only the cruise phase of flight can be used to estimate the distance remaining until the LRAGM is too close to the target and needs to ‘Go Around’. A ‘Go Around’ occurs when the LRAGM can no longer make the necessary final approach turn to enter terminal guidance and hit the target. The estimation of the distance remaining can be used, along with the weapon’s velocity, to indicate to a Remote Operator how much time remains until they can no longer re-task a weapon to a target.

Preliminary prototyping of the interface found that the display would not be clear enough if the value presented in the re-task status boxes was a time value similar to the TTG displayed in the currently assigned status box for each weapon. Moreover, the operator needs to be able to quickly assess the available weapon-target pairings. For this reason, the time values were represented by a number of blocks each representing 5 second increments of time remaining until the re-task will no longer be available.

Colour coding was also used to infer the successful outcome of the re-tasking request. Green indicated that the re-tasking request will be successfully received by the weapon in time. Orange indicated that the re-tasking request would have a chance to be suc- cessfully received by the weapon before reaching the last point at which it could turn to the new target. Red indicates that the re-task request is unavailable and will not be received by the weapon, and hence will not be sent. The text ‘UNAVAILABLE’ is

also printed instead of the blocks to indicate this to the Remote Operator. Figure 6.9 shows the different forms of the RAR information as time progresses in a scenario.