Tracking GSE location and status has a range of benefits for different users, and new technologies are making it easier to achieve. Chris Aaron looks at the communications technologies that underpin GSE fleet tracking
Tracking ground support equipment is now a commonplace function at larger airports, at least for motorised GSE units, and the benefits are proving to outweigh the costs of establishing the relevant infrastructure.
These benefits have been discussed in previous Airside articles but, to recap briefly, they include improved operational flexibility from having a real-time picture of the location of GSE units around the airport; utilisation efficiencies resulting from analysis of data on how different GSE units are used over time; fleet optimisation in terms of matching availability to demand, and scheduling vehicle maintenance; and safety and good-use monitoring through collection and correlation of vehicle and driver data.
Other unexpected benefits may arise from the collection of ‘big’ GSE data over time. For example, a recent study by a Dutch Master’s student (1) looked at the movement of baggage carts and dollies on the apron at Amsterdam Airport Schiphol. The study related to the perceived need for more space in parking bays to improve safety and efficiency. After physically observing movements in the area, the author concluded that more careful driving and parking, as well as better apron design, would in fact have more impact than extra space. While this study recorded vehicle movements manually, one can see how useful a database of all vehicle movements over time could be in improving apron design and driver behaviour.
More data, more users
When one considers all the benefits outlined above, it becomes obvious that collecting location information, while fundamental, is only one aspect of a wide range of performance measurement, data collection, display, and analysis functions that are tied up with ‘tracking’ GSE. Furthermore, the primarily one-way flow of data from vehicle to operator is likely to change as data is shared more widely between different users (handlers, airport management, security, etc), and as driverless and autonomous vehicles are eventually introduced onto the ramp, necessitating more two-way flows of data. In consequence, a large airport of the future is likely to see vastly more data being communicated between many more nodes than at present.
As the GSE tracking sector matures, solutions will also be needed for smaller airports that cannot currently justify the cost of installing the necessary infrastructure. Solutions that can be scaled down once the technology has been proven at large airports are therefore likely to be at an advantage. In a similar vein, solutions that can be used equally well on non-motorised as motorised GSE units will be attractive; this means that aspects such as unit cost and power consumption become more important.
Architecture
Given the factors outlined above, it may be that a particular system architecture will emerge that proves most successful. In terms of determining a unit’s location, speed, status, driver details and so on, the relevant sensors are well known. This is not to say that new technical solutions will not arise (for example, the use of ground-facing cameras along with markings on the ground may be an alternative to GPS), but they are unlikely to change the architecture of the system as a whole. An optimal solution at this level is likely to offer core parameter measurements (such as location), with additional plug-and-play features (such as a driver identification device). Similarly, at the display and analysis level, fleet management information systems are now familiar technology, with customisability being a prime driver among the competition. These two levels of the architecture are therefore fairly well established.
In contrast, the area that appears to be in flux, and which will be decisive in shaping the overall architecture of tracking solutions, is the communications system between vehicle and manager/user (or to put it another way, between data sensing and data usage)
Communication approaches
Several recently published patents illustrate two approaches to communication of GSE data at an airport.
The first, published in 2016 2, was filed by ADS-B Technologies LLC, and describes a system using an ADS-B OUT transmitter and a second transmitter using a non-ADS-B protocol, both mounted on a GSE unit, to transmit data from the unit to a control station. The ADS-B transmitter can be turned on and off depending on the location of the unit within the airport – specifically, whether it is in a safety/security priority area. In this way, the system utilises the ADS-B system that is being introduced in several countries, and would enable any user with an ADS-B receiver to see the location of GSE equipment in sensitive areas in real-time, while using a non-ADS-B protocol to communicate data when the unit is in a less-sensitive area. The logic seems to be to reduce clogging up the ADS-B frequency with less crucial transmissions, while using its broadcast potential when a GSE unit is in a sensitive area.
A similar patent was filed by THALES in 2005 3, in that case varying the regularity of ADS-B transmissions depending on the location of the GSE unit – frequent transmissions in more sensitive areas, less frequent updates in non-sensitive areas.
Both these patents describe a communications system that is essentially a direct, one-way broadcast from the GSE unit to a receiving ‘ground station’.
Another patent published in 2016, filed by Rockwell Collins 4, describes a different communications approach for GSE. This solution uses the presence of a large number of GSE units in a confined space (the airport) to create a network that communicates data across it. Thus transceivers are mounted on GSE units and low-power, line-of-sight radio transmissions pass data from one GSE unit to another. Networking protocols deliver the data to a fixed ‘node’ that then makes the data available to users over existing communications infrastructure.
This is essentially a mesh network solution using GSE units as nodes. The patent states that the solution involves “vehicle-mounted integrated end-device radio/GPS/power/antenna units, fixed or mobile router/repeater devices and fixed network gateways/coordinator units with Internet connectivity that may communicate near real-time end device (vehicle) position/track information for display on a situational awareness display device”.
The mention of fixed or mobile repeater devices indicates the possible use of autonomous mobile repeaters that can move around to ‘heal’ potential gaps in the network, although in the immediate future fixed repeaters are more likely to be installed based on analysis of real traffic-patterns.
This solution is similar to that of the Dutch company Undagrid, which has developed a tracking system called GSETrack. GSETrack is already being used at Schiphol Airport, Frankfurt, Dubai International Airport and Paris Charles de Gaulle. Their devices use a mix of Bluetooth low energy (Bluetooth SmartTM), LoRa, and Undagrid’s proprietary protocol to transmit data between units and then to the ‘Cloud’ for access by users, and claim to be able to function for several years on just two AA batteries.
The combination of low power consumption and automatic network configuration means the mesh-type solution is suitable for non-motorised GSE and is inherently scalable. ADS-B, on the other hand, is likely to become a worldwide standard that can be extended from the aircraft to GSE units if the right price points for units can be delivered.
Which direction?
What will determine the eventual proliferation of one solution or another? Price, reliability and scalability ought to be major factors, but other influences will come into play. The end user is more interested in the benefits that a system provides than the technology used. Therefore a provider with a great fleet management system may influence the communications infrastructure adopted, or a GSE unit manufacturer could choose whether or not to make certain data more or less openly available. The greater revenues are to be made at the major airports, and smaller airports will want to make as much use of any mandated systems like ADS-B that they can.
In the end, it might well depend on whether a mesh-like communications provider can form an appropriate alliance with a great fleet information management system supplier.
