Provide a secure wireless communications system featuring high data bandwidth with compressed video streams in a compact design.
The planning and implementation of an integrated system utilising WaveMAX and WaveSPRINT units. The WaveMAX deployed on the terminal building are specially modified and are an example of the type of engineering that can be deployed rapidly to solve operational issues.
The purpose of the system is to ensure that all vehicle number plates can be read and identified on any of the approach roads to the airport complex.
The use of various methods of installation and communication were investigated, but due to the large area to be covered and the congestion problems that would occur if implementing traffic management or road closure during installation, the decision was taken to implement radio based wireless communication infrastructure.
Successful trials utilising equipment provided by Wavesight were conducted, the choice being based upon Wavesight’s ability to provide high data bandwidth with compressed video streams.
Size was also a major consideration as the authorities proposing the deployment wanted to minimise the visual profile of the radio units.
The deployment consists of 28 ANPR cameras and WaveSPRINT radio units. All images are relayed back to the police station located on the perimeter road.
These radios either link directly to WaveMAX base stations located on top of one of the terminal buildings, or repeat via secondary radios located along the perimeter roads.
The repeaters are located on lamp posts, the height of which are no more that 4 metres. The radio is therefore focused along the roads and avoids crossing the airport complex. The ability for the Wavesight radios to perform in such locations is primarily due to the excellent multipath handing capability provided by the system software. Multipath is the effect of echoes that occur when an RF signal is reflected by moving vehicles, local buildings and the road surface, as a consequence of the low mounting position on the lamp posts. To handle such echoes effectively, Wavesight ensured the available bandwidth is maintained and provided an assurance as to the minimum bandwidth available on any RF link.
All video streams are processed simultaneously and beamed towards the WaveMAX base stations on the terminal roof. At this location, there are a number of base stations, each one receiving images for the satellite units positioned with the ANPR cameras based on geographic sectors. The WaveMAX base stations are in turn interconnected via a LAN infrastructure to a final link which transmits all combined data from the terminal roof to the airport police station.
A number of installation issues were resolved by Wavesight engineers visiting the site and advising on the best practice for radio placement. The customer’s engineers had deployed many radios in very close proximity to each other, where the best practice, especially on repeater or relay positions, is to maintain at least a 1 metre separation. This ensures there is no cross talk between units.
The major installation issue involved interference between the WaveMAX base stations on the terminal roof and existing airport RF equipment.
A system used at the airport for some 20 years provides voice communications between the ground and aircraft. This system is not connected with air safety or ground handling and is involved with administrative functions between ground staff and the aircraft Captain.
When the ANPR was switched on for testing, the airport radio systems would cease to function.
The airport authority therefore contacted in Ofcom to assist in an investigation to determine the cause. At this time the ANPR engineers were unaware of the issue and the airport staff were unaware of the ANPR. Ofcom located the issue and Wavesight were called to a meeting to discuss a solution.
All Wavesight radios are fully type approved and operate inside the required limits. However, induced harmonics from the WaveMAX was affecting the airport radio system. As the airport system was quite old and could not be adjusted, Wavesight was asked by Ofcom to make modifications to enable both systems to coexist. Ofcom confirmed that whilst taking measurements, the WaveMAX was operating correctly and within legal requirements.
Wavesight undertook a thorough investigation and spent a number of days on site and successfully resolved the issue. Without the ability to respond immediately to this matter and find a quick resolution the ANPR system could not have been deployed. Being UK based and having local design and manufacturing capabilities enabled Wavesight to provide a unique service including systems advice and problem solving.
Following installation, local police services undertook a full security survey of the operational aspects of the ANPR system. During this survey, conducted over a period of two weeks, the police were at no time able to alter transmitted images or block the system.
Wavesight transmit data using inbuilt security handling by compressing data, striping all normal IP packet information, encoding that information and creating a ‘RF transmit’ that effectively streams the data. To outside RF ‘sniffing’, the data would not be identified as a Wi-Fi style transmission and under RF interrogation would not exist as packet transmitted data.