Airport gets 99% read rates on bag tags

Edited by the Engineeringtalk editorial team Feb 10, 2000

Manchester Airport is achieving a very high read rate thanks to its investment in Accu-Sort's Model 24i baggage scanning arrays.

The economy of air travel relies heavily on aircraft spending the minimum amount of time on the ground.

All the airport support systems therefore need to be geared to fast and efficient operation, without compromising security.

Baggage handling is a prime example.

Barcoding is the method used by all large airports to sort passengers' luggage to ensure its speedy delivery to the appropriate aircraft.

However, reading this barcode efficiently is a tricky process.

Baggage varies greatly in size and shape.

Its orientation on the conveyor is also unpredictable.

The item, though it may be inducted to the system upright, will usually be toppled over during its passage through the system.

This means the barcode tag can be presented to the reader at any angle.

Yet despite these pitfalls, Manchester Airport is achieving a very high read rate thanks to its investment in Accu-Sort's Model 24i baggage scanning arrays.

Manchester is the UK's third busiest airport.

During a typical day it will handle over 23,000 items of luggage from 208 check-in desks.

The new Accu-Sort systems are located in Terminal 1 which caters for International and Charter services.

After being weighed and tagged, an item of luggage is conveyed to one of the three Accu-Sort stations - each containing an array of eight Model 24i scanning heads - where its 10-digit IATA code is read.

This code comprises a general classification digit, a three-digit airline code and a unique identification number.

The Accu-Sort system then communicates the code to a set of computers which route the bag to the correct chute for loading.

A separate system reconciles the bar code against the baggage list to ensure a correct tally.

At its peak, the sortation system may have to process 2000+ items of baggage each hour.

To guarantee the effectiveness of this system, it is crucial that at least 94% of all barcodes are read at conveyor speeds of 1m/sec.

The importance of a high read rate is compounded by the fact that 'no-reads' are not retained in the system for a second pass.

'No-reads' are presented for manual handling, a process which can introduce delays into the system and add cost.

The Model 24i eight scanning head configuration was chosen as it provides the optimum reading field for the application.

It effectively gives a complete, 360� tunnel of vision.

Although most tags are attached to a luggage handle, they can be presented to the scanning array at almost any position and even upside down on the conveyor.

The Accu-Sort system ensures that regardless of unpredictable orientation, the coded tag will be read.

Given these variables, Accu-Sort's patented Data Reconstruction Technology - DRX - was considered a must as it vastly improves read rates compared with conventional laser systems.

The Model 24i system scans a code 4000 times per second.

In common with all laser scanners, it assesses a barcode after each scan.

Whilst ordinary systems refuse to accept a code unless it is read in its entirety during a single scan, DRX units store information as it is received, however incomplete.

With each new scan the picture is built up until a complete code is contained in its memory.

Even damaged codes rejected by ordinary laser systems are quickly recognised by the Model 24i.

In such a fast moving environment where high reliability is a pre-requisite, ease of maintenance is another important criterion.

To ensure minimum downtime, the Model 24i arrays are equipped with ADP, Accu-Sort's advanced diagnostics package which enables any fault to be identified and rectified quickly.

The man responsible for selecting the Accu-Sort systems is Manchester Airport's Senior Electronics Engineer, Geoff Densham, who concludes, "The Model 24i arrays were brought in to replace the Model 55B DRX arrays.

The 24i arrays have continued to perform with the high level of efficiency and reliability that can be expected from the Accu-Sort product".