| Written by Mark Buzinkay

A Position Detection System (PDS) is an essential tool for port operators who need to track containers and maintain an accurate inventory of containers.

In this article we explain why and how to choose a PDS to meet your port's specific needs.

Port Position Detection System

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As the world's trade has grown, so has the size and number of container ships. The average capacity of these vessels has increased from 5,000 twenty-foot equivalent units (TEU) in 1990 to over 10,000 TEU today – with some ships now able to carry over 20,000 TEU. As a result, ports have had to expand their operations and infrastructure to keep up with this demand.

Position Detection System: Traffic and operations

With the ever-increasing size of container ships and the number of containers being handled at port facilities, these operations must be run as efficiently as possible. One way to do this is using a Position Detection System (PDS).

Besides assuring visibility and integrity of the container inventory, a PDS can also be used to monitor container handling equipment (CHE) within the port – helping to ensure that the assets are being allocated in an efficient manner.

Several different position detection systems are available on the market today. Some systems use DGPS technology, while others utilize radio frequency identification (RFID) tags. In order to choose the right PDS for your needs, it is essential to consult with an experienced provider who can assess your specific requirements and recommend the best solution for your facility (learn more about implementing smart port technology).


What is a Position Detection System?

A position detection system is a computerized system that tracks the movement of assets within a port. A reliable PDS will enable accurate and reliable position detection of container handling equipment (CHE) and, consequently, containers in complex terminal environments. The system collects data on the location of each CHE, matches it with the yard position and passes it to the terminal operation system (TOS) where it will be asigned to the container being moved.. Port operators can then use this information to improve their operations' efficiency and provide better customer service.

When it comes to handover a container from an equipment to another, a a PDS can go the extra mile by automatic detecting the vehicle that approached the CHE to get the container. The operation can also be optimized by sending regular messages to the TOS informing the availability and current status of the CHE, which can then trigger the dispatch of new jobs and prepare equipments to execute their roles in the container handling process.



What are the main parts of a PDS?

A position detection system typically consists of three main components: Sensors and transponders, readers and software. Readers are placed at strategic points throughout the port and are used to track the movement of equipment to determine the position of the transponders. Readers create their own "satellite network" for geo-referencing.

Sensors and transponders are attached to each vehicle and transmit data on its location to the sensors. Software is used to collect and store data from the sensors and transponders and to generate reports that port operators can use.

The PDS referencing is based on a set of reference points at fixed, pre-defined positions. The mobile points, fitted on the container handling equipment, locate the CHE with the reference points' assistance using radio distance ranging. Additional local points or nodes can be equipped in the more complex areas to guarantee accurate position measurements. The mobile nodes can calculate their position autonomously, without server connection, and send their position to the TOS.


Why tracking containers with PDS is essential?

There are many reasons why tracking containers with a PDS is essential for port operators. First, it allows port operators to improve the efficiency of their operations by reducing the need for manual tracking of containers. Second, it enables them to provide better customer service by providing up-to-date information on the status of containers. Finally, it helps improve port security by providing a way to track suspicious activity.

Knowing where containers are dropped off or lifted highly contributes to the terminal's operational efficiency - during planning, moving or looking for containers. By measuring a container's registered position (i.e. the position where it will be picked up next), handling errors by crane operators or CHEs will be prevented, and lost containers will belong to the past (learn more about container handling terminal operations here...).

So the primary benefit is ensuring that the yard inventory is as accurate as possible by removing all assumptions about the position that a container was lifted from or dropped to a truck. Some solutions, for example, will report if an operator lifts a rear-mounted container rather than the forward-mounted container as planned and ensure the correct container is stowed in the reported yard destination.



Choosing the right PDS for your port

There are several different types of position detection systems available on the market. The most common type is the RTLS system (real-time location), which uses radio frequency tags to identify and track the movement of vehicles. Other position detection systems include DGPS (GNSS), infrared and optical character recognition (OCR) systems.

Technologies such as infrared have proved insufficient concerning reliable and precise position detection on terminals. Although DGPS will help measure positions, it lacks accuracy and will fail when the line of sight is obstructed. Even the latest version of DGPS receivers requires an unobstructed view of multiple satellites to get a good position reading. The position can be more or less guessed by using navigation aids such as INS, using accelerometers and gyroscopes. However, an accurate position reading is vital when containers are dropped off or picked up under cranes. That’s why it is important to find a customized solution that can be combined to cover all the challenges presented at the unique and complex environment of a container terminal.

When choosing a position detection system for your port, it is essential to consider the specific needs of your operation. Ultimately, the best position detection system for your port will depend on the specific needs of your operation (read more about PDS automation).



A PDS is an essential tool for port operators who need to track containers and maintain an accurate inventory of containers. By tracking containers with a PDS, port operators can improve the efficiency of their operations, provide better customer service, and improve security at the port. When choosing a PDS, selecting one that meets your port's specific needs is crucial.

Position Detection System in Ports Whitepaper

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