A Perimeter Intrusion Detection System (PIDS) that alarms when small boats enter the ferry terminal at Amsterdam port. The system should not alarm when ferry boats enter or exit the terminal. The system should be impervious to alarms from tidal motion, wakes from passing nautical traffic and animals such as sea birds.
Amsterdam Ferry Port required protection at the entrance to the terminal.
Numerous systems were trialled at the site but issues such as sea animals and fog prevented these systems from being able to perform successfully. Microwave systems are not typically installed over water, however, Sensuritys unique design components (antenna, operating frequency and advanced algorithms) together allow the system to perform in locations unsuitable for competitive microwave PID systems.
Traditional microwave bistatic radar Perimeter Intrusion Detection (PID) systems typically use amplitude based algorithms to trigger alarms based on a change detected in the received signal level when an object enters the detection zone of the system. The strength of the signal received due to reflections from an object entering the detection zone is dependent on the scattering properties of the object at the radar operating frequency, i.e. its Radar Cross Section (RCS). This determines how easily the radar system can ‘see’ an object. RCS is proportional to the size of an object; therefore larger objects will have a greater RCS and cause a greater change in the received signal. This presents an obvious problem for customers who wish to ensure an alarm is not raised due to the movement of a large object, such as a ferry boat, through the detection zone of the system.
Competing technologies, such as infrared beams (which use a binary state whereby the beam is either broken or not broken) and motion capture cameras (which will inevitably trigger due to the movement of a large object, such as a ferry boat), suffer from the same problem.
The Sensurity Halo system uses an asymmetric planar antenna and a 5.8 GHz radar operating frequency. The wider antenna beamwidth and lower radar operating frequency, relative to competing systems, gives more information about an object intruding into the detection zone of the system, i.e. more non-amplitude based information such as changes in the frequency content of the receive signal. Halo analyzes the received signal in more advanced ways than typical amplitude-based bistatic radar PID systems
Data was collected at a number of sites (including the proposed installation site) to develop a specific algorithm for the port. The algorithm performs as follows:
- Alarms when a small boat enters the terminal (sensitivity adjustable)
- Does not alarm when a large ferry boat enters the terminal (sensitivity adjustable)
- Does not alarm on tidal movement
- Does not alarm in the presence of sea birds
The algorithm was applied in January 2017 and following a six week test procedure, was deployed at the port in the locations marked in Figure 1.
Outcomes and Impact
The Halo system has significantly outperformed all other systems evaluated at this location and the Authorities have opted to permanently install the system. The developed configuration has proven the system’s ability to:
- Work in unique environments not traditionally suitable for microwave PIDs
- Work over water
- Host multiple algorithms to suit unique environments
This algorithm has the potential to solve the issue for other locations who wish to secure their ferry terminal entrance.
However, the algorithm also has wider potential, for instance:
- Installations across train-tracks where trains should not cause an alarm but human traffic should cause an alarm.
- At gateways or roadways where vehicles are allowed entry but human traffic should create an alert.
- Other instances where a system is required near or over water.
For further information on this Case Study or any other related topic, please contact Sensurity on firstname.lastname@example.org or +44 (0) 28 9039 4270.