Technical Session 8 – Emerging Technologies – Part 1
Chair: Mr Ma Jianshe (China)
Vice Chair Mr Seamus Doyle (Ireland)
New Solid State frontier on radar technologies, Mr Sergio Gollone and Professor Michele Fiorini, SELEX Sistemi Integrati - Italy
Presented by Mr Sergio Gollone
Traditionally ‘solid state’ is associated with Air Traffic Control (ATC) radars while tube technologies are synonymous with Vessel Traffic Service (VTS) and Homeland Protection (HP) radars. This historical division was based on the fact that the transmitted spectrum and dynamic resolution of solid state transmitters (TX) were not appropriate for VTS and HP applications. However, solid state technology is now mature to remove these limitations. The LYRA 50 series, thanks to a fully solid state architecture, gains coherent signal processing, low transmitting peak power, low voltage supply, high compactness, high reliability and capability of transmission on multiple frequencies.
In the LYRA radar family Wideband Frequency Modulation (WFM) is used to minimise the electromagnetic compatibility impact and is helpful in reducing interference from other radiating systems. The joint use of multi-frequency diversity and pulse compression (both digitally performed) allows low peak power long pulses, while a proprietary side lobe suppression algorithm reduces the pulse compression side lobe and its time stability at different environmental conditions is obtained by calibration algorithms.
The presentation showed results collected during the performance evaluation campaigns of the LYRA radar family and a demonstration of the achieved operational benefits on-live traffic recordings.
The key points of the presentation were:
1 Solid state radar technology had now advanced sufficiently to make it suitable for VTS application. Performance in terms of lower power, cost effective than existing marine radar systems.
2 Drawbacks of Magnetron radar include small operational life, non coherent processor and phase coded waveforms and Doppler filtering is not allowed;
3 Benefits of fully solid state final amplifier include a long, failure-free life, graceful degradation of system performance, coherent processing possible and high duty cycle. LYRA 50 doppler processing improves detection in presence of rain and sea clutter, scan to scan correlation tracking performances using proprietary scan to scan correlation algorithm is used for sea spikes suppression. Multi frequency transmission is especially effective in the case of rain clutter, where the number of scattering source is high.
4 LYRA 50 is operative in Yemen, (National Yemen VTS Project) where two radars sites monitor the Aden area. The radars detect the movement in the Gulf of large vessels and small wooden boats used by local fishermen
New Technology Radars and the Future of Racons, Dr Nick Ward and Mr Martin Bransby, General Lighthouse Authorities of UK and Ireland, and Captain Robert McCabe, Commissioners of Irish Lights
Presented by Dr Nick Ward.
In 2004 the International Maritime Organisation approved a new radar performance standard (MSC Resolution 192(79)), which from 1 July 2008 removed the requirement for new S-Band (10 cm) radars to trigger racons (radar beacons). This was intended to facilitate the introduction of cost effective, coherent processing techniques that should enable future radars to have an improved performance in sea and rain clutter. Potentially, it also allows more stringent limits to be considered on spurious and out of band emissions of marine radars, increasing the efficiency of radar spectrum use.
The removal of the requirement to trigger racons does not necessarily mean that racons will be unusable with NT Radars. They may work at a reduced, but acceptable range; NT Radars could be designed to trigger racons, whilst retaining their other performance advantages; alternatively existing racons could be modified to work with NT Radars or new racons designed to do so. Calculations of performance with the first of the NT Radars (Kelvin Hughes Sharpeye) indicate that existing racons will perform, but with reduced range. The extent of that reduction in range and its significance has now been determined in trials carried out using the Irish Lights vessel GRANUAILE.
The results of these trials were reported, with recommendations on the strategy that might be adopted on the future use and development of racons.
The key points of the presentation were:
1 Results of trials to compare S-Band racons with new technology radar compared to X-band radar. Six racons installed in various different sites (lighthouses, pier, buoy, LANBY etc), and either modern solid state or old design units were tested.
2 Results showed racon triggering ranges achieved by the NT were much less than X-Band radar except for a new technology racon with enhanced reception capability which achieved over double. The clarity of response was better for S-Band radar at short range in clutter than X-Band. Recommendations from the trials are:
• Modification of existing racons to improve their response to NT radars should be considered in consultation with racon manufacturers. Modifications could include: increasing the receive sensitivity, removing the scalable response, designing the racon to detect, and respond differently to NT radar.
• The differences in racon performance during these trials indicate that better standardisation of racons should be considered.
• IALA should be invited to consider the results of these trials when discussing its strategy for the future of racons.
A Next Generation Solid State, Fully Coherent, Frequency Diversity and Time Diversity Radar with Software Defined Functionality, Mr Jens C Pedersen, Terma AS - Denmark
Presented by Mr Jens C Pedersen.
Coherent, Solid State Radar technology has been available for military applications for decades, but it did not penetrate into VTS for cost and technical reasons.
Technically, the main challenge has been that the dynamic requirement to VTS radar is much higher than to other radar applications. However, new radar technology, virtually unrestricted by dynamic constraints, has now been developed and is in operation for military applications.
To make this affordable for VTS and other applications for professional users, well-renowned advantages and new functions are implemented on a new technology platform. Methods are further refined and the outcome is software defined radar series, tailored to individual market segments and featuring:
• Even smaller target detection;
• Improved resolution;
• Improved frequency diversity;
• Even better all-weather processing capability;
• Sub-clutter visibility for targets moving radially and having speeds different from clutter;
• Easy system configuration and integration into systems of systems;
• Substantially reduced requirements to maintenance.
The new technology includes faster processing than ever, novel low voltage - low temperature (long life) solid state transmitters, enhanced receiver technology, very high speed coherent sampling on IF, floating point representation of data, low time-sidelobe pulse compression, loss-free signal processing and several other improvements.
The key points of the presentation were:
1 Until now, technology did not allow fully coherent solid state radar to meet the requirements for VTS and Coastal Surveillance.
2 Handling clutter in a high elevated radar, looking into the waves from shore to the sea, is 10 fold more difficult than when being low on a ship.
3 Development of Terma’s marine solid state radar unit commenced 3 years ago and first production units are being delivered in 2010.
4 One performance goal was to meet and exceed the IALA V-128 recommendation, and also to be able to configure to all 3 recommendation levels, basic, standard and advanced. System implemented in advanced form rather than basic will generate more immediate cost benefits.
5 Transmits low power 20% of time. A mixture of long and short transmissions ensure simultaneous short and long range coverage.
6 The power can be varied in sectors to further reduce illumination of built up areas. This will reduce the cost associated with spectrum pricing which is becoming an issue in some countries.
7 Coherence means that the amplitude and phase of signals during transmission and reception is known. This is the base for pulse compression and for extracting doppler information from the signals. However, there are also new unwanted effects. Antenna side lobes are known in azimuth. By nature, side lobes will also occur in range in pulse compression radars. In this radar the side lobes are not suppressed. One of the big achievements made is that the side lobes are very low by design therefore able to see a small target near a large structure.
Four-Season Lighted Buoys, Captain Richard Moore, Canadian Coast Guard
Presented by Captain Richard Moore.
In Canada, AtoN service delivery is complex and costly due to the size of the country and particularly harsh winter conditions. The situation on the Saint-Lawrence River, in Eastern Canada, presents additional challenges with its 900-kilometre commercial waterway open all year-round and severe environmental conditions. The Canadian Coast Guard has developed a buoy that can remain in position for two (2) years without needing maintenance. This buoy provides lighted and radar service 9 months of the year and can withstand winter ice pressure for the remaining 3 months.
The key points of the presentation were:
1 Current buoying system involving ice-free and ice-withstandable buoys. St Lawrence river presents considerable climactic conditions for vessels including ice, strong currents and tidal variations. Retrieval prior to winter can be hazardous if delayed at all.
2 Project presentation and performance requirements for 4-season buoy development. Desired buoy performance specifications include being maintenance free for minimum of 2 years on station.
3 Trials results meets all performance criteria in <=5n current.
4 Challenges include better paint resistance to abrasion, adequate battery constraint within the buoy chamber.
5 The next step of this project is to further test the lantern performance. More testing will determine if water ingress was accidental or if the conditions in which the lantern must operate exceed its capacity.
6 Potential benefits of the new buoys include possible reductions in Floating Aids Program cost, replacement of two buoy systems, reduced stress on vessel’s operations and potential use elsewhere in Canada.
Ultra Capacitors as Energy Storage in Self Contained Lights, Mr Jonas Lindberg, Sabik Oy, Finland
Presented by Mr Jonas Lindberg
Conventional battery technologies have a number of limitations and issues when used as an energy storage in a high quality self contained lantern. The main issues are limited lifetime, limited number of charge cycles, reduced performance in high and low temperatures, environmental issues as well as problems related to long-time storage.
Ultra capacitors already outperform conventional batteries in all of the above areas but are larger in size and have a leakage current far beyond today´s conventional batteries.
This presentation describes how ultra capacitors can be used in self-contained AtoN by using a combination of new generation LEDs and ultra low power electronics with high efficiency.
The key points of the presentation were:
1 Optimizing optical and electrical performance to match ultra capacitor. Adding a filter in front of the step up converter can reduce ?. Power consumption between flashes is minimal (5MiW)
2 Ultra Capacitor leakage current vs. state of charge is very easy to measure.
3 Energy calculations. 14 days autonomy can be achieved
4 Ultra capacitors are still expensive compared to lead-acid batteryLow energy density so are about 10 times larger than equivalent lead-acid battery and have a high self discharge when fully charged. Liable to permanent damage in extremely high temperatures (>85°C)
5 Ultra capacitors can be stored empty, have an extremely short charge time and a very long lifetime (they do not limit service life of the lantern). They also have a very high charging efficiency (>99%)
Discussion – Technical Session 8 Part 1 (papers 1 - 5)
Nick Ward was asked if the GLAs undertake any trials with S-Band radars SARTs. However, Jens Pedersen from Terma responded that it would be less expensive to modify racons than to increase the sensitivity of S-Band radars
Jens Pedersen was asked if the new solid state radars were in production yet, to which he replied that they are; production started in January 2010.
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