Three localisation challenges in port logistics

Port logistics autonomy is a hot topic right now, as the drive to respond to the global competitive landscape and maximise TEU throughput is forcing port owners to change how they store, move and manage their inventory. This has led to a sharp focus on finding ways for autonomous port vehicles to navigate without the need for infrastructure such as buried magnetic strips, which limit the ability to reconfigure the layout of container storage. 

In this blog, we’re examining three major localisation challenges that port robots face – and discussing how they can be overcome, based on our experience supporting customers to create high-performing autonomous navigation systems. We’ll also be sharing our new product, WayFinder, designed for environments with ever-changing GNSS conditions like ports.

As with any autonomous vehicle, one of the most vital pieces of a port AMR’s control stack is the localisation solution. It gives the robot data about where it is, its heading, orientation, and so on, which are used in a few different ways:

+ It uses localisation data to follow a path, and detect when it has deviated from that path.

+ It gives the robot vital information for obstacle avoidance, by enabling the robot to situate itself within a (usually pre-surveyed) map of its environment.

+ Information such as pitch, roll, and heading can also be used to improve the safety of the vehicle by detecting if it might be at risk of tipping over.

A popular localisation solution for autonomous vehicles is a GNSS-aided inertial navigation system, or GNSS/INS. The port environment, however, presents some unique challenges that a localisation solution will need to overcome. 

In a port environment, there are large areas where the GNSS signal that most localisation solutions rely on for position is patchy or completely unavailable. The most obvious areas are in between the tall stacks of shipping containers, which block the port AMR’s line of sight to the satellites in the sky above it, but storage sheds where autonomous vehicles may be kept overnight are also GNSS blackspots. Even the overhead gantries and cranes can cause issues with GNSS navigation. 

This is one of the reasons that solutions like magnetic strips or paint are popular, as they don’t rely on GNSS. But, as we’ve said previously, the goal for many ports is to move away from infrastructure-based navigation. Infrastructure such as magnetic strips or even paint on the ground are labour-intensive and expensive to alter if the layout of container storage changes, making them unsuitable for forward-thinking ports.

The solution: real-time sensor fusion for infrastructure-less navigation.

Sensor fusion is the science of combining data from multiple sensors to give you a more robust navigation output – and doing it in real time on board your port robot enables it to navigate with precision and accuracy in any environment, and seamlessly transition between them. That’s where WayFinder comes in. 

WayFinder is a standalone unit that enables you to get accurate localisation data in GNSS-denied environments with no additional hardware. It uses LiDAR boost, a world-first real-time localisation enhancement solution for any land-based activity in harsh GNSS conditions. Simply put, LiDAR Boost uses data from a LiDAR scanner in real time to improve real-time navigation accuracy in areas where GNSS signal is poor. With LiDAR Boost, you can even use WayFinder in a pre-surveyed space to completely replace GNSS, guaranteeing completely repeatable accuracy within that space. As long as the port is re-surveyed whenever the layout changes, you can use LiDAR Boost to give you a robust localisation solution with no infrastructure at all.

Learn more: LiDAR Boost closeup blog.

Ports have always been complex environments, but since many operators are pursuing autonomy in the hope of enabling their layouts to be even more adaptable to change, that complexity is only going to increase. Rudimentary systems for path following and navigation will struggle to keep pace with the rate of change in these environments. If the layout of your container storage is changed, for instance, the work required to programme the port AMRs to navigate the new layout could be considerable, and they may be unable to handle ‘on-the-fly’ changes such as obstacles in their path.

The solution: tight integration of localisation data through the control stack

An advanced port robot should include modules for obstacle avoidance, that allow the robot to detect an obstacle and calculate a route around it and back to its path. Vital to this is having localisation data that’s precise enough for the other modules in the control stack to do their job, and a way of passing that data between control modules. 

With OXTS, you can easily integrate your localisation data into a robotic control stack that runs on the ROS2 framework using our pre-built drivers. That means you can use information from your GNSS/INS wherever you need to in your port AMR, making it resilient to changing environments. On top of this, reliable obstacle avoidance capabilities powered by accurate localisation help to make your port safer, reducing accidents and injuries.

It’s also worth highlighting the completely repeatable accuracy within a surveyed environment that you can achieve with WayFinder. As long as the map is updated whenever you change your layout – something that can be done quickly and easily with a LiDAR scanner – your port AMR will be able to cope with any layout change you can throw at it.

Although your port AMR is an investment for any port operator, it still needs to be commercially attractive as possible. That means looking for ways to deliver the best possible performance for the best price, but also making sure that your end product is easy for your customers to buy and use.

The solution: a holistic solution based on powerful localisation

The first thing to note here is that your localisation solution doesn’t have to be a complete vehicle. If you can create a flexible navigation solution that can be retrofitted to existing autonomous guided vehicles (AGVs) then you have a very different commercial proposition to buying a whole new port AMR.

Whether you choose to retrofit or build a new platform, the best way to create a commercially attractive localisation solution is to create something greater than the sum of its parts. For example, using OXTS technology – including WayFinder – gives your AMR localisation data that’s comparable with what you might get from a far more powerful FOG inertial navigation system, but using more cost-effective MEMS components. That’s because our devices benefit from 20 years of experience building inertial navigation systems.

You can also ship WayFinder anywhere with no export costs or paperwork, since all our hardware is ITAR-free – important for if you plan on selling your port AMR globally.

When helping prospects build their business case for a port AMR, you can consider the increased uptime you should see from an autonomous solution that can adapt to changing layouts. The capacity to process more TEUs this brings could be a powerful addition to any business case.

You can learn more about how OXTS can help you build accurate localisation data into port AMRs, including discovering more about WayFinder here. Alternatively complete the form below and a member of the team will be in touch to discuss your port autonomy project.