Terminal chassis or straddle carrier positioning in multiple lanes



In the total cycle time for STS crane, reduction of the time to place the spreader correctly above the chassis or straddle carrier is one important way to increase terminal productivity.  


This page describes a positioning system for a Shuttle Carrier (SC) or truck arriving under a quay crane. 

This system can give a X/Y position and makes simultaneously the positioning of 6 lanes between the crane legs and on 3 lanes on the back-reach. It can be used to position the carrier who will leave the container in a perfect position for an easier and faster pick-up by the spreader.



The system is based on our popular SIRRAH sensor : a multi-beacon sensor with a working range of 45 meters or more. Usually used on the RMQC trolley to measure the sway and the skew, this sensor is appropriated to check the SC position.

For the vertical shuttle carrier positioning system, three SIRRAH sensors are installed looking down on the STS beam. One beacon is installed at the top of the SC powered from the 24 VDC of the carrier batteries. The beacon lighting up is seen by the sensors.

This sensor measures the position of this beacon and calculates : 
- the lane number
- the X position on the long side
- the Y position on the transversal side of the lane.
On each crane, the system is composed of three SIRRAH sensors SI18. They are connected to a special computer provided by Arck through a RS422 serial line.
The measuring angle is +/- 11°.
On each Shuttle Carrier, a beacon should be installed.
This infrared beacon reference BMU-12 has a 24VDC power supply designed to be compatible with the truck battery specification. The angle of this beacon is +/-12°.
The system resolution is better than +/- 1 cm at low frequency (10Hz).
The absolute accuracy depends not only on the sensor accuracy but it is also related to the crane's flexibility. If the crane is not flexible, a good accuracy could be reached with a calibration made on the crane after installation. In this case, the accuracy will be +/- 20 mm for the X positioning.

The sensor field of view could cover various positions of the Shuttle Carrier, it can cover three lanes simultaneously.

SIRRAH sensor should be installed between 30 and 35 meters from the SC upper part to cover a larger zone with 3 lanes per sensor.


As a standard solution the sensors have an internal software doing the calculation of the X,Y of each Shuttle Carrier. They are able to communicate these positions to the specialized computer doing the display for the SC driver.

Two displays are available :

- a LED display with high luminescence : for this type of display, we can offer a 3-lane or a 6-lane display on the same screen. The lanes are illustrated in yellow with a transversal yellow barrier where is the optimal SC position. An additional green cross is also displayed where the SC is currently situated.The lane number is indicated at the left side of each lane representation.
Display size is 560mm*560mm.


- a 3-color column display :  we use one column with three LEDs lights for each lane.
The three lights are Red, Orange and Green. The Red is lighting when the SC is far away from the stop position, the Orange is lighting when the SC is near the final position and the green is lighting when it is at the final position. If the SC passes the stop position the Orange and Red lights are flashing to indicate an overpass.
The columns could be installed on the side beams of the crane of on the front beam (only in case of inter-legs position). For the back-reach only the side beam can be used.



3 SIRRAH SENSORS Ref. SI18 (TS18 Sensor included in BO35 protective housing including power and serial cables) + 1 SPC60 computer + 1 BMU-12 infrared beacon for each SC operating in the terminal. 

Download Application Note

Réalisation SYSTONIC 2008