Situational awareness and security during subsea interventions

Abstract

A method of monitoring the environment of a subsea structure 10, the method comprising: monitoring at least one optical transmission zone 20 extending into water from the structure; detecting incursio

Description

This invention relates to the challenges of monitoring and controlling interventions required to assess, maintain or repair subsea assets. For example, robotic or remotely 5 operated vehicles commonly perform tasks on hydrocarbon production installations in the subsea oil and gas industry and on renewable energy equipment installed underwater. The invention is particularly concerned with the challenges of situational awareness and security in that context, and especially with the difficulty of optically monitoring the environment of a subsea structure such as a wellhead or a manifold. 10 The prior art comprises numerous proposals for conveying optical information underwater or for conveying information underwater by optical means. For example, WO 2014 / 186034 discloses an example of underwater data communication in which light is emitted and received by transceivers on respective sides of a data link. 15 WO 2011 / 026233 describes an optical transceiver designed for adverse environments such as in subsea applications. US 9031413 describes a subsea optical communication protocol and exemplifies how 20 two optical emitter / receivers can communicate underwater. US 9231708 explains how to limit interference between underwater optical communication systems and light emitted from secondary sources deployed nearby, such as work lights or beacons. 25 In US 8179279, a subsea production tree or wellhead is monitored and controlled by wireless systems that could include a radio frequency modem, a sonar device, an infrared communication device, a light emitting diode or an optical modem. Such devices may use radio frequency waves, acoustic waves or electromagnetic waves. 30 In WO 2014 / 035749, an optical detector is positioned close to a wellhead to detect leaks using infrared light but there is no teaching that the detector could be used for communication. 35 Water near the seabed tends to be muddy and turbid, presenting the problem that particles in the water can obscure vision and absorb and scatter optical wireless 24 02 25 communication signals. Optical devices, such as cameras or lasers, have limited performance in this environment. A drawback of underwater optical communication is therefore limited range and unpredictability: the signal can often be interrupted, even if it is conveyed by a laser. 5 WO 2020 / 251364 notes this problem and attempts to address it by erecting a barrier to reduce entry of debris into a volume of seawater around items of subsea equipment. However, it is not possible to control turbidity entirely in that way. For example, turbidity will inevitably arise from the ingress and deposition of fine sediment that can then be 10 disturbed by the impeller wash of a subsea vehicle. Whilst perception and communication of optical information is difficult underwater, it remains attractive to use optical information wherever possible. Optical information differs from acoustic information derived from conventional acoustic means such as 15 sonar. In addition to giving a different perspective, optical information can be richer and more informative than sonar information and optical data transmission is possible at much greater bandwidth than acoustic transmission. Consequently, optical communication is sometimes used in combination with acoustic 20 detection or communication to convey more information at short range. One typical example is when docking an autonomous underwater vehicle (AUV) into a subsea garage or station. Whilst acoustic means are generally used for positioning, optical beacons may be used for docking. For example, a laser beam guides an AUV in CN 105182991. 25 Optical information, particularly when enabling a video signal to be displayed, is much easier and quicker than acoustic information for human operators to interpret. This allows for immediate, real-time interpretation and reaction by personnel on a vessel or in a control room onshore. Speed and accuracy of response to rapidly changing 30 circumstances can be crucial, especially if an incursion or an attempted intervention is unexpected and therefore unplanned. This applies all the more if an incursion ever takes place with malign intent because subsea infrastructure could be damaged or the state of valves, switches or other control elements could be altered covertly. 35 Additionally, the desirability of high-bandwidth data communication combined with the difficulty of transmitting data underwater has led to reliance on above-surface 24 02 25 communications such as 4G or 5G systems and satellite communication systems. However, such systems can suffer from data latency and could be vulnerable to hacking, jamming or other disruption. 5 Against this background, the invention resides in a method for monitoring the environment of a subsea structure. The method comprises: monitoring an optical transmission zone that extends into water from the structure; detecting incursion of a light source into the transmission zone; determining if the incursion into the at least one transmission zone is (i) unexpected or (ii) expected or authorised; and responding to 10 the detection by: in case (i) alerting a remote master control via a control system that controls the structure; and in case (ii), if the light source is an underwater vehicle, effecting optical data communication between the structure and the vehicle via a wireless communication link across the transmission zone. The transmission zone could, for example, be monitored passively. 15 Before responding to the detection, a determination may be made as to whether the detection is false. If the detection is determined to be false, the control system can be returned to a monitoring mode to continue monitoring of the transmission zone. 20 Data communication may be effected between the master control and the vehicle via the wireless communication link. For example, a live video feed can be provided from the vehicle to the master control via the wireless communication link. Moreover, data communication may be effected between the master control and a vehicle control via the wireless communication link and the vehicle in turn. In that way, the wireless 25 communication link can be used to communicate in real time between personnel located at the master control and at the vehicle control, for example via a live video feed carried by the wireless communication link. Additionally, data can be communicated via the wireless communication link to control the vehicle from the master control. 30 An alert at the master control could elicit the response of effecting optical data communication between the structure and the vehicle via the wireless communication link. 35 The transmission zone being monitored may extend from an intervention panel of the structure. For example, two or more transmission zones could extend from an 24 02 25 intervention panel of the structure. In that case, the transmission zones can overlap with each other laterally. Where an underwater vehicle is present, light may be emitted from the vehicle into a 5 transmission zone extending from the vehicle. Incursion of that light into a transmission zone extending from the structure could then be detected. In response, optical data communication can be effected between the structure and the vehicle via the wireless communication link across the overlapping transmission zones extending respectively from the structure and from the vehicle. At least one of the transmission zones may 10 flare outwardly from a transmitter, a receiver or a transceiver. Correspondingly, the inventive concept also embraces a system for monitoring the environment of a subsea structure. The system comprises at least one optical receiver on the structure for receiving light from an optical transmission zone extending into 15 water from the receiver and for detecting incursion of a light source into that transmission zone, which is thereby activated for data transmission. The system further comprises a control system that is configured to determine if the incursion into the transmission zone is (i) unexpected or (ii) expected or authorised and to control the structure and that is responsive to the receiver to respond to a detected incursion. The 20 control system responds by: in case (i) raising an alert; and in case (ii), if the light source is an underwater vehicle, by effecting optical data communication between the structure and the vehicle via a wireless communication link across the active transmission zone. 25 The receiver could be mounted on or beside at least one intervention panel of the structure. For example, the structure may comprise two or more faces, each fitted with an intervention panel and at least one receiver. In some embodiments, at least two receivers could be mounted on or beside an intervention panel of the structure. Such receivers could face away from the structure in outwardly divergent orientations. 30 The system may further comprise at least one optical transmitter on the structure for transmitting an optical data signal into the transmission zone. The or each transmitter could, for example, be implemented with the at least one receiver in at least one transceiver. 24 02 25 The structure may be configured to relay data between the control system and the transmitter and receiver of the structure. The control system may be in communication with, or could comprise an interface for communication with, a remote master control. 5 The system may further comprise an underwater vehicle that is fitted with at least one optical transmitter for emitting light into an optical transmission zone extending into water from the transmitter. The vehicle can also be fitted with a receiver for receiving light from the transmission zone extending from the transmitter of the vehicle. Again, the transmitter and the receiver of the vehicle are apt to be implemented together in a 10 transceiver. Where a vehicle is in communication with a vehicle control, the system may be configured to relay data between the vehicle control and the transmitter and receiver of the vehicle. Where the structure is in communication with a remote master control, the 15 system may be configured to relay data between the remote master control and the vehicle control via a wireless optical data link extending between the structure and the vehicle. The remote master control and the vehicle control could be be equipped with two-way real-time video communication systems that are operable via the optical data link. The vehicle may also be controllable from the remote master control via the optical 20 data link. In summary, the invention addresses challenges of subsea intervention, security and situational awareness. It presents alternatives to omnidirectional, free space optical transmission through water and to ROV- and vessel-deployed systems that rely upon 25 mobile telecommunications and satellite communications, if available. The invention can use the control network of a subsea production system (SPS) for live communications with an underwater vehicle such as an underwater inspection drone (UID) or a remotely operated vehicle (ROV) operating close to a subsea asset such as 30 a tree atop a wellhead. More generally, data can be passed between a control room and at-sea asset. For this purpose, the invention employs comms connectors in the SPS, located in control rooms and on a UID, ROV or other vehicle in the field, and creates a through-water link between the vehicle and the asset via short-range focused optical communications that eliminate crosstalk. Each area of interest, such as each 35 intervention panel of a subsea asset, may be equipped with one or more optical 24 02 25 transceivers and a comms connector. Each vehicle may also be also be equipped with an optical transceiver and comms connectors. Systems of the invention solve various problems, including that of real-time 5 communications between a IIID or other vehicle and a control room located onshore or otherwise above the surface. More generally, the invention enables direct communications between an offshore IIID or ROV system and an onshore control room. The invention also mitigates the risk of blind spots or crosstalk between optical systems for execution of intervention tasks. 10 In addition, systems of the invention can sense the presence of light in the vicinity of a subsea asset and sound an alarm in a control room if the presence of light at that location is unexpected, for example if no intervention was planned. Also, the invention does not rely upon surface telecommunications networks, such as 4G or 5G systems, 15 or upon satellite communications, all of which are subject to challenges of cyber security and data latency. By detecting risks of unauthorised intervention and by being resistant to cyber attacks, the invention provides an effective security system for subsea assets. 20 In embodiments of the invention, a device or system for monitoring the environment of a subsea structure such as a wellhead or a manifold comprises: at least one side panel comprising at least one optical receiver and transmitter able to detect light at short range, within a zone of vision that may be generally conical or pyramidal; and at least one onboard control system, wherein the control system is configured to trigger a 25 response when light is detected by the optical receiver. That response is or comprises one of, but is not limited to: sending an alarm message to a remote control room via a monitoring system of the subsea structure; going back to a passive reception mode; and activating a transmission mode. The system further comprises an interface to exchange information with a monitoring system of the subsea structure. Such an 30 interface can comply with electrical, acoustic or optical signal emission. The system may comprise enough panels to cover substantially the whole space immediately around the subsea structure, preferably with a substantial continuous perimeter of detection. The zone of vision of each panel may, for example, be up to 90° 35 wide and 5m long, creating a perimeter around the structure with a spacing or radius of up to 5m from the structure. There may be two or more optical transmitters and / or 24 02 25 receivers or transceivers on each panel, and the zones of vision of each could overlap with those of any neighbouring transmitters, receivers or transceivers. The system may also comprise at least one optical receiver / transmitter mounted on a 5 subsea vehicle, which could for example be an unmanned underwater vehicle (UUV) or an autonomous underwater vehicle (AUV) in addition to a IIID or an ROV. The optical receiver / transmitter can exchange optical signals with an onboard control system of the structure and / or of the vehicle, and could be embodied in a panel or other attachment fitted to the vehicle. 10 Correspondingly, embodiments of the invention implement a method to monitor the environment of a subsea structure. That method comprises providing a monitoring device or system by mounting on the subsea structure at least one side panel that has at least one optical receiver and transmitter able to detect light at short range, within a 15 zone of vision. The side panel or panels are connected to at least one onboard control system and an interface of the control system is connected to the monitoring system of the subsea structure. Initially, the monitoring system is placed in a passive mode in which light emanating 20 from outside the structure can be detected by the at least one optical receiver. Whenever such light is detected, the control system is triggered to generate a response. That response is or comprises one of, but is not limited to: sending an alarm message to a remote control room via the monitoring system of the subsea structure; reverting to the passive reception mode; or activating a transmission mode to emit and 25 receive optical signals within the zone of vision of an active panel. In summary, therefore, the environment around a subsea structure such as a wellhead or a manifold may be monitored by a system for observing one or more optical transmission zones that extend into water, for example beyond intervention panels of 30 the structure. On detecting incursion of a light source such as an underwater vehicle into a transmission zone, the system can respond by alerting a remote master control room via a preinstalled control system that controls the structure, such as a subsea production system acting on a wellhead or manifold 35 If the light source is an underwater vehicle, optical data communication can be effected between the structure and the vehicle via a wireless communication link across an 24 02 25 active transmission zone. The wireless communication link can effect data communication between the master control room and the vehicle and between the master control room and a vehicle control room, via the vehicle. 5 In order that the invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1a is a schematic plan view of an underwater vehicle approaching a structure on the seabed, showing transmission zones of light emitted by the 10 vehicle and the structure; Figure 1b corresponds to Figure 1a but shows the vehicle now close enough to the structure for light emitted from the vehicle to be within a transmission zone of the structure, and for optical data transmission to be established between the 15 structure and the vehicle in consequence; Figure 2 is a system diagram exemplifying how the structure and the vehicle interact with each other and with their respective control systems; 20 Figure 3 is a system diagram exemplifying how the structure and the vehicle communicate with each other and with their respective control systems; and Figure 4 is a flow diagram showing a mode of operation of the systems shown in Figures 2 and 3. 25 Referring firstly to Figures 1a and 1b of the drawings, a subsea structure 10 such as a wellhead tree is shown in plan view installed on the seabed 12. The structure 10 has a faceted shape, in this example cuboidal, defining faces that are apt to support respective control or intervention panels 14 as shown. Each intervention panel 14 30 comprises various control elements 16 such as switches, indicators or actuators for auxiliary operation of valves within the structure 10. In accordance with the invention, the structure 10 further comprises at least one optical transceiver 18 that can detect, emit and receive light in visible and / or other 35 wavelengths. Of course, separate transmitters and receivers could be provided instead of being integrated into transceivers 18, to similar effect. 24 02 25 Each transceiver 18 can emit light into, and receive light from, an outwardly-flared or splayed frusto-conical or frusto-pyramidal volume extending into the water surrounding the structure 10. That volume defines a transmission zone 20 of detection or of vision 5 of incoming optical signals, or conversely an effective range of emission of outgoing optical signals. The flare angle of the transmission zone 20 is determined by the design of the transceiver 18, for example up to about 90° in total or about 45° each side of a central 10 axis orthogonal to an outward face of the transceiver 18. Conversely, the outward extent of the transmission zone 20 is determined to a considerable degree by the turbidity of the water. In practical terms, the outward extent of the transmission zone 20, being the range of reliable visibility or detection or transmission of optical signals from the structure 10, may be about 5m from the related transceiver 18. 15 Conveniently, the optical transceivers 18 may be mounted on the intervention panels 14 as shown. One intervention panel 14 shown in Figures 1a and 1b has one transceiver 18 and the other intervention panel 14 shown in those drawings has a pair of transceivers 18. The transmission zones 20 of the paired transceivers 18 can 20 intersect or overlap with each other, as shown, to create a continuous peripheral boundary in combination with each other. In this example, the single transceiver 18 emits in a direction orthogonal to the plane of the associated intervention panel 14 whereas the paired transceivers 18 are oppositely inclined relative to the plane of their intervention panel 14 to maximise their combined angular coverage with minimal 25 overlap between their transmission zones 20. Figures 1a and 1b also show an underwater vehicle 22 such as an ROV. The vehicle 22 also supports a transceiver 18 that is capable of transmitting optical signals to the transceivers 18 of the structure 10 or of receiving optical signals from those 30 transceivers 18. Similarly, therefore, the transceiver 18 of the vehicle 22 can emit light into, and receive light from, an outwardly-flared frusto-conical or frusto-pyramidal volume extending into the water ahead of the vehicle 22. Again, that volume defines a transmission zone 20 of detection or of vision of incoming optical signals, or conversely an effective range of emission of outgoing optical signals from the vehicle 22. 24 02 25 The vehicle 22 is shown approaching the structure 10 in Figure 1b but the transmission zone 20 radiating from the vehicle 22 has not yet encountered or overlapped with the transmission zone 20 radiating from the opposed face of the structure 10. Conversely, Figure 1b shows the vehicle 22 now close enough to the structure 10 for its 5 transmission zone 20 to overlap with the transmission zone 20 radiating from the opposed face of the structure 10. Consequently, optical signals emitted from the vehicle 22 are now detectable and receivable via the relevant transceiver 18 of the structure. In accordance with the invention, as will be explained, the system can respond by enabling optical data transmission via a two-way wireless data link 24 10 extending across the overlapping transmission zones 20 between the opposed transceivers 18 of the structure 10 and the vehicle 22. This short-range optical communication between the opposed transceivers 18 is stable, reliable, high in bandwidth and mitigates the risk of crosstalk. 15 Turning next to Figures 2 and 3, these drawings show how the structure 10 and the vehicle 22, exemplified here by an ROV, are controlled respectively by a master control room 26 and an ROV control room 28, both being at respective locations above the surface 30 such as onshore or aboard a vessel. Figure 2 shows that the master control room 26 comprises or is connected to an SPS control system 32 that communicates 20 via a power and data link 34 with an SPS pod 36 hosted by the structure 10. As shown in Figure 3, the SPS pod 36 interfaces via a comms connector 38 with respective transceivers 18 of the intervention panels 14 of the structure 10. There could be one, two or more such intervention panels 14 on the structure 10. 25 Returning to the master control room 26 as shown in Figure 2, the SPS control system 32 communicates with a comms converter 40 that communicates, in turn, with equipment required to support and interface with one or more human controllers 42 supervising the master control room 26. That equipment comprises a live video feed 44 accompanied by a web cam 46, a vehicle control 48 and an alarm 50. 30 The video feed 44 and webcam 46 enable the controller 42 to communicate with an ROV pilot 52 in the ROV control room 28, who is similarly equipped with a corresponding video feed 44 and webcam 46. Thus, the ROV pilot 52 has live communications with the controller 42 or other operators in the master control room 26. 24 02 25 The alarm 50 is activated to alert the controller 42 that a vehicle 22 in the vicinity of the structure 10 has been detected approaching the structure 10, causing the transmission zones 20 of the structure 10 and the vehicle 22 to overlap as shown in Figure 1b. The vehicle control 48 enables the controller 42 to assume control of the vehicle 22 if 5 required. For this purpose, the video feeds 44 can also display a video signal from a camera 54 of the vehicle 22. More generally, operators in the master control room 26 can control a UID, employ live video, effect human-in-the-loop control or remote-pilot an ROV. 10 The alarm 50 can also alert the controller 42 of any other light detected within the transmission zones 20 of any of the transceivers 18 of the structure 10, thus detecting light emitted from another vehicle or, in sufficiently shallow water, from a diver in the vicinity. 15 The ROV pilot 52 in the ROV control room 28 can control the vehicle 22 via an ROV control 56 that interfaces with the vehicle 22 via a comms controller 58, an ROV multiplexer 60 and a comms connector 62. If the vehicle 22 is instead a UID, a UID control system 64 interfaces with the vehicle 22 via the comms connector 62 as shown in Figure 3. 20 Turning finally to Figure 4, the SPS control system 32 is initially in a passive standby mode at 64, in which the transceivers 18 of the structure 10 are enabled to detect light within their respective transmission zones 20. When such a detection is made at 66, the system 32 interprets the detected light signal at 68. For example, the system 32 25 may conclude that the light signal is spurious, for example if the signal is faint or transient, is not maintained or repeated or does not brighten over time. In that case, the system 32 flags a false detection at 70 and returns to the passive mode at 64. Where the system 32 concludes that the light signal represents an incursion into a 30 transmission zone 20, it then considers whether the light signal arises from an expected or an unexpected incursion. For example, the system 32 may previously have been updated to expect a scheduled intervention by a vehicle 22 around a particular time, or prior authority for the incursion may have been requested and granted. In that case, a communication signal issued or received at 72 leads to an instruction from the 35 system 32 for the transceiver 18 of the structure 10 to enter an active mode at 74, whereupon optical communication is established at 76 between the structure 10 and the vehicle 22. When communication at 76 is complete, the system reverts to the passive mode at 64. If the system 32 concludes at 78 that the incursion is unexpected, it raises an alert at 5 80, in this case by activating the alarm 50 in the master control room 26 at 82. Operators in the master control room 26 can then consider what to do before issuing instructions to the system 32 at 84 accordingly. For example, the incursion may in fact be authorised or operators in the master control room 26 may, if the vehicle 22 is an ROV, wish to communicate with the ROV control room 28 via the optical data link 24 to 10 determine the reason for the incursion, to warn the ROV pilot 52 or to assume control of the vehicle 22. In that case, the instruction to the system 32 may be to enter the active mode at 74 before effecting optical communication between the structure 10 and the vehicle 22 at 76. 24 02 25 24 02 25

Claims

1. A method of monitoring the environment of a subsea structure, the method comprising:5monitoring at least one optical transmission zone extending into water from the structure;detecting incursion of a light source into the at least one transmission zone10determining if the incursion into the at least one transmission zone is (i) unexpected or (ii) expected or authorised; andresponding to the detection by: in case (i) alerting a remote master control via a 15 control system that controls the structure; and in case (ii), if the light source isan underwater vehicle, effecting optical data communication between the structure and the vehicle via a wireless communication link across the at least one transmission zone.20 2. The method of Claim 1, comprising passively monitoring the at least onetransmission zone.

3. The method of Claim 1 or Claim 2, comprising determining whether the detection is false before responding to the detection.

254. The method of Claim 3, comprising returning the control system to a monitoring mode for continued monitoring of the at least one transmission zone, if the detection is determined to be false.30 5. The method of any preceding claim, comprising effecting data communicationbetween the master control and the vehicle via the wireless communication link.

6. The method of Claim 5, comprising providing a live video feed from the vehicle to the master control via the wireless communication link.24 02 257. The method of Claim 5 or Claim 6, comprising effecting data communication between the master control and a vehicle control via the wireless communication link and the vehicle.5 8. The method of Claim 7, comprising using the wireless communication link tocommunicate in real time between personnel located at the master control and at the vehicle control.

9. The method of Claim 8, comprising providing a live video feed between said 10 personnel via the wireless communication link.

10. The method of any of Claims 7 to 9, comprising using data communicated via the wireless communication link to control the vehicle from the master control.15 11. The method of any preceding claim, comprising responding to an alert at themaster control by effecting optical data communication between the structure and the vehicle via the wireless communication link.

12. The method of any preceding claim, comprising monitoring the at least one 20 transmission zone extending from at least one intervention panel of the structure.

13. The method of Claim 12, wherein at least two of the transmission zones extend from an intervention panel of the structure.25 14. The method of Claim 13, wherein the at least two transmission zones overlap witheach other laterally.

15. The method of any preceding claim, comprising emitting light from the vehicle into another transmission zone extending from the vehicle; detecting incursion of that light 30 into the at least one transmission zone extending from the structure; and effecting optical data communication between the structure and the vehicle via the wireless communication link across the transmission zones that extend from the structure and from the vehicle.35 16. The method of any preceding claim, wherein the or each transmission zone flaresoutwardly from a transmitter, receiver or transceiver.24 02 2517. A system for monitoring the environment of a subsea structure, the system comprising:5 at least one optical receiver on the structure for receiving light from an opticaltransmission zone extending into water from the receiver and for detecting incursion of a light source into that transmission zone; anda control system configured to determine if the incursion into the transmission10 zone is (i) unexpected or (ii) expected or authorised control the structure andresponsive to the receiver to respond to said detection by: in case (i) raising an alert; and in case (ii), if the light source is an underwater vehicle, effecting optical data communication between the structure and the vehicle via a wireless communication link across that transmission zone.1518. The system of Claim 17, wherein the at least one receiver is mounted on or beside at least one intervention panel of the structure.

19. The system of Claim 18, wherein the structure comprises two or more faces, each 20 fitted with an intervention panel and at least one receiver.

20. The system of Claim 18 or Claim 19, wherein at least two receivers are mounted on or beside an intervention panel of the structure.25 21. The system of Claim 20, wherein the receivers face away from the structure inoutwardly divergent orientations.

22. The system of any of Claims 17 to 21, further comprising at least one optical transmitter for transmitting an optical data signal into the transmission zone.3023. The system of Claim 22, wherein the or each transmitter is implemented with the at least one receiver in at least one transceiver.

24. The system of Claim 22 or Claim 23, wherein the structure is configured to relay35 data between the control system and the transmitter and receiver of the structure.24 02 2525. The system of any of Claims 17 to 24, wherein the control system is in communication with, or comprises an interface for communication with, a remote master control.5 26. The system of any of Claims 17 to 25, further comprising an underwater vehiclefitted with at least one optical transmitter for emitting light into an optical transmission zone that extends into water from the transmitter.

27. The system of Claim 26, wherein the vehicle is fitted with a receiver for receiving 10 light from the transmission zone extending from the transmitter of the vehicle.

28. The system of Claim 27, wherein the transmitter and the receiver of the vehicle are implemented together in a transceiver.15 29. The system of Claim 27 or Claim 28, wherein the vehicle is in communication with avehicle control and is configured to relay data between the vehicle control and the transmitter and receiver of the vehicle.

30. The system of Claim 29, wherein the structure is in communication with a remote 20 master control and the system is configured to relay information between the remote master control and the vehicle control via a wireless optical data link extending between the structure and the vehicle.

31. The system of Claim 30, wherein the remote master control and the vehicle control 25 are equipped with two-way real-time video communication systems that are operable via the optical data link.

32. The system of Claim 30 or Claim 31, wherein the vehicle is controllable from the remote master control via the optical data link.

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