MH370: Is robotics technology ready for deep oceans SAR mission?
Volume 8 Issue 11 News & Resources | November 2015
MH370: Is robotics technology ready for deep oceans SAR mission?
On the 8th of March 2014, the Malaysian Airline System (MAS) flight MH370 lost communication from the main control tower in Kuala Lumpur International Airport (KLIA) after supposedly handing over the flight monitoring to the Vietnam Aviation Authority. The confusions that have arisen after the flight went missing for a few hours and the frantic search which followed in days and months onward has not ended in a solid and conclusive explanation. The final reliable location, via available satellite data, i.e. in the middle of the South Indian Ocean has lead investigators to believe the flight MH370 has ended in the deeper part of the Ocean. In this water the depth can vary from 3000m to a maximum depth of about 7000m. The uneven and unknown terrain on the ocean bed, coupled with the rough ocean surface and volatile weather have made the Search and Rescue (SAR) mission into a very difficult task. The use of underwater robotics with relevant sensors and instrumentation seemed to be appropriate. But, after more than 19 months, why have the SAR teams failed to detect or map any such debris or parts of the ill-fortuned flight? Has the available robotics technology failed us? Or are they due to other reasons? This talk will venture into discussing this specific issue.
2. Underwater Robotic Technology
The general aim of robotics techonology is to execute task/tasks within an application which is deemed to be dangerous, dirty, difficult dan dull, i.e. the 4Ds. A robotics system will have the necessary capabilities and capacity to tolerate the dangerous circumstances of the environment in which the task needs to be executed. Coupled with the extended duration of application where human operator will not be able to withstand and sustain reliable execution, a robotic system can certainly perform and also sustain its execution over a much longer deployment mission. Of course, all these assumptions are on the conditions that the power system and all the sub-systems for the chosen robotic system operate as they should. Underwater robotic technology includes the fixed and mobile types. For the mobile types robotic platforms, they include the land, underwater and aerial mobile robotic system. In terms of basic sub-system, all mobile robotics platforms will adopt similar modules. The differences will be on the platform design, mode of propulsion, sensing parameters and communication modules. The “brain” or controller module will follow similar design structure with suitable fine-tuning according to the targeted application. For underwater robotic platforms such as the Remotely-Operated Vehicle (ROV), Autonomous Underwater Vehicle (AUV) and Underwater Glider Platform (Gliders), they will be designed to cope with the underwater environment applications especially handling the high-pressure and corrosive marine conditions. As the average ocean depth of the world can go into thousands of meters, the design of underwater robotic platform will always be governed by the maximum depth rating (water density) and also the ability to cope with the varying temperature and salinity levels. The high dependence on acoustic medium for sensing and communication also limits the versatility of underwater robotics platforms.
3. The disappearing plane
Flight MH370 was a on its normal route flying from KLIA to Beijing. The sudden disapperance and frantic search for the whereabout of the aircraft till this day has been the one of the greatest aviation mystery the world has ever encountered. Nobody would have guessed or predicted that in the modern era of global aviation industry and the availability of advanced terrestial and satellite communication systems, an aircraft as big as MH370 could be lost and no concrete proofs are available to conclusively determine her final resting place. In one of the press briefing by the Malaysian authority, it was stated that there were two possible zones of SAR, i.e. northern and southern corridors. The northern corridor would have brought the plane over large area of the continent and across many countries. While the southern corridor would have brought in right into the South Indian Ocean, and possible into the large expanse of the unchartered water of the Southern Oceans, i.e. very near to Antartica. This would meant the wreckage would have submerged to the ocean-bed which can go down to 7000m depth. The southern corridor theory was finally accepted as the logical scenario due to the corroborated Inmarsat satellite data ping’s data. The initial estimated area of search was very large, i.e. it was about 320,000 km2. The assets needed to cover such search area would be tremendous. The search area was later revised to about 60,000 km2and the underwater ocean bed mapping tasks were conducted by multiple groups. The raw imaging data of the ocean-bed acquired were in abundances. The major tasks now is to reconstruct and make visual identification for potential pieces of the wreckage, assuming the plane did crash into the ocean and broken into pieces. The lighter parts would be drifted away, while the heavy pieces would have sinked to the bottom. Using the drift model, researchers have been trying very hard to identify the best possible location of the wreckage especially the fuselage where one would find the black-box.
4. Stages of SAR
In terms of SAR mission, the main objective is to recover the survivors and the aircraft black-box which consists of the FDR and CVR. Assuming that the plane did nose-dive into the ocean, one would safely assumed there will be no survivors. Now, the aim is to look for the black-box. The 1st stage was to look for floating debris. As the days kept increasing, the valuable floating debris were no where to be found. Images of floating debris were in abundance but none were found to be related to the flight MH370. The ocean-bed search continued for the following 30 days as the Black-box would be giving the acoustic signature (i.e a short pulse with carrier frequency of 37.5 kHz). False signals were detected and after the 30 days period expired, the ocean-bed mapping stage was triggered. The use of towed underwater mapping module or tow-fish was implemented. This module was towed using an elongated cable using a host ship which enabled the maping module to come close to the ocean-bed. An AUV System was also utised. This AUV (Bluefin) was utilised so that close and high resolution mapping was enabled. But, due to the wide expanse of the targeted search area, this ocean-bed mapping took months to complete. The purpose of using the tow-fish and AUV was to determine the exact location of the wreckage before an deep-water ROV system can be deployed. The deployment of ROV for mapping was not done because it was not practical and the logical step to take. An ROV is a local area inspection system, while an AUV is a global searching platform or wide-area mapping platform. The use of the right tools for the right job was critical as not to waste time and resources. The use of underwater robotics platform was mainly limited to ocean-bed mapping operation. The bottle-neck is not the on the technical side but on the time taken to cover the total search areas and the time taken to process the acquired raw data. Until this day, the complete and final analysis of the data gathered have not been released to the public.
5. What needs to be improved?
If we look at the use of technology for deep-water SAR, we can see the high dependency on limited number of deep-water technology assets. The use of one or two deep-water AUV, and the limited number of fully-equipped search vessels with towed and hull mounted ocean bed mapping module (Mult-Beam Echo Sounders) made the SAR missions too slow in relation to the total areas which need to be mapped. The unreliable weather conditions have also disturbed proper AUV deployment and recovery. The use of multiple AUV platforms with extended power sources would be useful for longer ocean-bed mapping mission. A smaller surface-based hull mounted for deep sonar imager would have allowed faster mapping of the designated search zones. On-board data analyser with super-computing capabilities would allow on-site ocean-bed reconstruction and determination of the reliable clues. The ability to do underwater docking for data transfer and power recharging are also very attractive features for the new generation of AUVS. Highly sensitive hydrophones with built-in signal processing modules would helped reduced the amount of post-processing needed. More coordinated mapping strategies would allow more cohesive and concrete data reconstruction and visualisation. The technology for all these are available for different applications, but yet to be adapted for deep-sea SAR applications. For the black-box, there should be a release mechanism which would allow the module to be detached from the fuselage and float to the surface. On top of this, the battery packs should allow for much longer signal activation time, possibly up to one year, compared to the current 30 days barrier. Deep-sea SAR mission requires more new and novel technology. The possibility of another incident like MH370 should not be ruled out. The important efforts now are to ensure the available deep-water technologies are further improved and ready for such an incident, if it every occur again.
6. A closure…
In my view, the current problem in the search for MH370 in the deep-oceans is biased towards the strategy adopted for SAR mission, rather than due to the limitations of the technologies adopted. The available underwater robotic technologies and platforms are relatively matured and stable. Some of the issues were the use of proper equipment/modules and the analyses of the data acquired. Admittedly, the cost of deploying an underwater robotic platform for ocean-bed mapping is not cheap. This is probably the reason on why the SAR mission are delayed and even after many months, the SAR mission has yet to find a satisfactory closure.
“Good Night Malaysian. THREE SEVEN ZERO”
Written by :
Prof. Dr. Mohd Rizal Arshad
School of Electrical & Electronic Engineering