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Radar Video Signal Enhancer (RVSE) Questions & Answers

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• Is there a block diagram of the systems design architecture used for the Norwich Airport demonstration?

  Yes, the specific Norwich system block diagram may be found here.  A more typical operational configuration is to be found here.

• How many in-fill radar sources can the RVSE take?

  The RVSE has the hardware in place to accept two separate infill radar sources, but currently only one is used. Further software development will be required to use the second input but this is entirely feasible.

• Why is the number of ‘gated areas’ restricted to 4 and could more be added?

  Four areas were chosen for the initial product specification. There is existing processing capacity for additional areas to be incorporated, but this will require further software development but, again, this is entirely feasible.

• It was understood that the remote site data input into the RVSE during the demonstration was 'combined' i.e. both primary and SSR information. If this is the case does the RVSE use both the SSR and primary data in the processing to provide the synthetic video?

  The RVSE reads the ASTERIX Target Report Descriptor messages from the infill radar. Target types which are ‘PSR only detection’, ‘SSR only detection’ and ‘Combined detection’ are each configured to be either accepted or rejected. The current NATS Cromer feed to Norwich is populated with Combined and SSR-only target reports. The RVSE was configured to accept the combined targets and reject the SSR-only messages on the basis that synthetic PSR video should only be generated from targets which have been seen by a primary radar.

• What data sources does the RVSE need?

  The RVSE accepts HDLC radar data in ASTERIX or RDIF formats. ASTERIX was developed in the 1990’s and is the European radar format mandated for all new radars under the Interoperability regulations. Older systems within the UK may still employ RDIF.

• Can the RVSE take other than NATS data sources?

  The RVSE can use any radar source (or other sensor) as long as the format is ASTERIX or RDIF. Several UK non-NATS airports now operate new digital radars that can provide ASTERIX data feeds.

• Could the RVSE take data from MoD radar?

  The majority of MoD radars still use analogue video. Where these are being used as the infill radar source, a Plot Extractor will need to be fitted at the radar head. In the past this has been costly but this is no longer the case. Furthermore, sending plot extracted serial data is easily accommodated over a basic 64KB BT link or an IP based network.

• Will the RVSE accept and work with data from NERL sources e.g. the en-route radar?

  Yes; this was a major consideration as many airports already have a feed of data from the NATS en route radar network. All NATS en-route radars provide ASTERIX message formats.

• Will the RVSE accept data from radar sources with slower RPM?

  The RVSE infill radar RPM can be lower than the main radar. It has been designed with the airport radar in mind, typically turning at 15RPM, with infill from the likes of en route radar which may be as low as 7.5RPM. This demonstration Video shows 15 and 12 rpm sensors being used. (The video runs in Windows Media Player - you may need to download ActiveX to view it)

• How does the RVSE cope with RF saturation, for example jamming?

  In the enhancement area, the RVSE simply displays as synthetic video the target messages sent by the radar. It does not have additional processing to deal with jamming. However, the amount of jamming that would be displayed from the airport radar within the enhancement areas depends on the level of enhancement set by the controller using the RCU. In all other areas it will be transparent.

• MoD radar uses filters – what effect does this have on the RVSE?

  This has no effect on the operation and performance of the RVSE. There may be wider system implications to be considered from the use of the filters e.g. a process of informing remote users of the radar data that filters are being used.

• How does the RVSE deal with the slant range issue from the in-fill data source?

  The RVSE uses the target report Mode C code data item, where available, in its processing to apply slant range correction when working out the ground range and position in X, Y, Z coordinates. The ground position is transposed to give the ground range with respect to the local primary radar origin. The height data is then reapplied in the conversion from X, Y, Z Cartesian to slant range and azimuth Polar coordinates. Target data which lacks valid Mode C or is from a PSR-only will have a configurable default altitude assigned for the process just described. This default value can be selected to best suit the particular circumstances around the Enhancement Areas, the type of infill radar and the use of the airspace.

• Does the SSR detail assist in providing any elevation and slant information to ensure the smooth transition between the enhanced zone areas and the local radar display?

  The availability of SSR height information increases the accuracy of the slant range correction, but is not essential to meet the necessary accuracy requirements. The implications of this are included in our performance modelling tool which will be used in our Phase 1 assessment (see the following question)

• What is the process for procuring a RVSE and the cost of the solution?

  To assure a successful outcome, it is strongly recommended that a 3-phase approach be taken by any customer who considers that the RVSE will resolve an aviation objection. The phases are:

  • Phase 1 – invest in a feasibility study to establish the:
    • Candidate in-fill radar source and geometry are suitable to meet the Operational Requirement e.g. 3nm separation
    • Pd of the turbines from the in-fill radar lies within acceptable limits
    • Overall system architecture, including data communication links, plot extractors, power supplies etc.
  • Phase 2 (optional)
    • Trial the RVSE to confirm expected performance from the feasibility study is realised
    • Provide recordings for evaluation.
  • Phase 3
    • Full implementation
  Phase 1 will cost approximately £6K. Phase 2 will cost in the region of £20k. Together these will demonstrate that the RVSE is an acceptable mitigation. There are many other aspects to an implementation project to be considered (e.g. safety and project management, data comms links, plot extraction requirements, training, documentation etc.) It is therefore difficult to give a fixed price for the RVSE installation, but it is envisaged that it will lie somewhere between £60k and £150k per installation. The cost of the infill radar data is not included in this cost and will be subject to an annual charge to be agreed between the airport and the radar data provider. Note that if a Plot Extractor is fitted to an infill radar source, this would be a ‘one-off’ cost as the radar could then serve multiple RVSEs.
• Is the line used to define the ‘gated area’ on the radar screen to demarcate the boundary between the main radar and the in-fill source data a ‘hard line’?

  Yes, but....The RVSE is processing infill radar targets into synthetic video using a much larger ‘volume of interest’ which encompasses all of the gated areas. It is only within the gated areas that the local PSR is attenuated and the synthetic video is admitted to the RVSE output.

• Was the RVSE demonstrated at Norwich Airport a production model? What additional work, if any, is required to bring the RVSE into operation?

  The RVSE and RCU demonstrated at Norwich are built to a production standard. The product certification process needs to be completed. This requires the unit to be EMC tested for CE approval, but is a minor task that will be completed within the next few weeks.

• Would the RVSE work with the future Cambridge Consulting holographic radar proposal?

  Yes. This is an ideal source of infill data because the target messages include height data and the update rates of several times per second. Furthermore, Cambridge Consulting confirmed that they output ASTERIX data formats. The RVSE provides the interface between their holographic radar system and the operational radar display system.

• What performance criteria were applied to the speed and turning ability of aircraft within a ‘gated area’?

  The RVSE is able to process reports from infill targets with speeds up to 800kts and turning at up to 3g. This aligns with the radar specification for the new NATS En route radars and the EUROCONTROL SURVEILLANCE STANDARD. The accuracy of the synthetic video is determined by a number of system variables, primarily the radar turning rates and report delays, plus the spatial relationship between the radars and the target.

• Have any safety requirements been accounted for? What work needs to be done to complete a safety case for the RVSE?

  Each implementation of the RVSE will need its own safety case. Performance is determined by both the system configuration and the wider system variables such as the radar involved, the spatial relationship between them and the enhancement areas, and the airspace involved. Cyrrus have addressed the product failure modes and Human Factors requirements in the RVSE design. This together with the reliability data, will be the product related assurance required to develop a site specific system safety case.

• When will the RVSE become operational?

  The final qualification evidence will be completed within the next few weeks. The timescales for implementation are more dependent on the duration of the three phases mentioned 6 points above. It is anticipated that a fully approved RVSE could be operational within 6 months from receipt of an order.

• Can the RVSE output data into a processed display?

  No. However, Cyrrus is currently working on a unique solution for processed radar. Work on this innovative solution is not as mature as the RVSE but it is hoped to have a demonstration model ready by Q1 – 2011.

• What will be the support and maintenance required for the RVSE?

  Typically annual maintenance contracts would cost between £5k and £12k per annum depending on the level of support required.

• Have any other procurement options been considered?

  The capital cost can be reduced if a leasing option is taken up. The leasing arrangements could include maintenance and support through an annual payment plan.