Thursday, 30 June 2016

Comms-crabs.


In the late 20th century special reconnaissance missions would normally be performed by small parties of highly trained men. In the TS-era the same mission is more commonly performed by a collection of diverse robotic systems.

A reconnaissance/ surveillance force will usually contain a variety of systems. Some of these systems such as surveillance dust, surveillance fluff, bumblebots, robo-roaches, snakebots and birdbots have been described on other pages.

One of the drawbacks of using small robotic systems is that they are limited to broadcasting in the microwave range. The systems are physically too small to use antenna suitable for longer radio wavelengths. Such microwave transmissions are often limited to line of sight use since microwaves cannot pass around hills or mountains like longer radiowaves can. These relatively low power transmissions are often limited in range too. In populated fifth-wave urban areas this may not be a problem since there are abundant signal boost and relay systems designed to facilitate the operation of wearable computing systems. In abandoned or rural areas buildings and other terrain features may have a significant effect.

Often it is not practical for a reconnaissance system to transmit a continuous, real-time feed. Transmissions are often highly directional short duration bursts.

Due to these practicalities a reconnaissance force will include at least one relay centre. Such a system collects transmissions from reconnaissance systems and passes them on using its more sophisticated broadcast capabilities. One form of relay system in common use is known as a “comms-crab”.

The comms-crab is a small cybershell about the size of a small dog (SM -4). It has four short, stocky legs. Very little detail of the crab will be visible since it is covered with a tangle of varicloth strips. The crab often looks like a bush or patch of forest floor. The crab includes a number of satellite robot systems. This include a repair cyberswarm, utility robo-roaches, a mecho-gecko and a snakebot. The snakebot is of the variety that has graspers at each end and can be used as a manipulative limb by the comms-crab. It is also used as a periscope and as an auxiliary monopole antenna.

At the top of the comms-crab is a folding parabolic antenna. This is primarily used for satellite communications but can also be directed to communicate with high flying aircraft. It can be repositioned to transmit to lower receiving stations.  

Comms-crabs can climb tree trunks to attain better broadcast positions. They are not so adept at climbing rockfaces or narrow trees. In such a situation the comms-crab will attach its satcom antenna to a snakebot or mecho-gecko and send it to climb as high as possible. A hardwire controls the satellite robot and feeds transmissions to the antenna.

Alternately the comms-crab can use HF/shortwave transmissions. HF transmissions can have a global range since shortwaves reflect from the ionosphere. Unfortunately this requires an antenna that takes several minutes to deploy or recover. A HF antenna is a T-shaped construction of wire that may be tens of metres across. The comms-crab deploys this using three small helibots; one at the centre and one at each end. The helibots are designed so their systems minimize interference with the antenna’s performance. If possible the terminal helibots will anchor themselves to a high point. Robo-roaches are used to adjust the antenna.

The comms-crab has a secondary SIGINT role, monitoring and recording local transmissions.  

The comms-crab's main defence is its ability to hide. The legs can be used for digging but it is more common that existing hollows or animal burrows are used. Comms-crabs are also likely to hide in the high boughs of trees. A comms-crab may have several hiding places some distance from the areas from which it broadcasts.

There are many models of comms-crab in service with various nations and organizations. Variants optimized for operation in various environments exist. The basic design is also highly adaptable. A system deployed in an urban environment may be fitted with legs suited to climbing walls, or a unit uses in a desert may be fitted with solar-powered cooling systems.

If enemy surveillance is suspected security detachments may be sent on “crab-hunts”. Ideally a crab is to be captured before it can broadcast its collected reports. Examination of the memory banks may indicate how much the enemy may know. The crab’s hiding abilities make such operations highly challenging. A crab may incorporate a thermite self-destruct charge which it will activate if it is likely to be captured and is not quickly disabled.