For customers and integrators intending to use Asterix Cat-10, the documents assume a reasonable working knowledge of UDP network communication. They are targeted at technical teams, typically with software development skills, who are integrating the output from Witness into external systems.
Technical Overview
When Witness processes targets into tracks, it passes all this information to Witness Canary. Witness Canary then converts this information into a suitable data format to send to external systems.
CAT-10 Specification:
On this page:
The CAT-10 Plugin
Witness Canary supports integration with many different types of external systems through the use of plugins. These are stand-alone software libraries which are dynamically loaded by Canary and contain code which knows how to convert the Witness data into the required format for the external system. Navtech Radar can easily develop bespoke plugins to interface with a specific type of equipment or application. The Asterix CAT-10 plugin has been developed to provide integration to a common standard using in Airport system communication.
The Asterix plugin file is entitled Witness.Plugin.CAT10.dll and must be present in the Witness Plugin folder which is inside the main application folder.
The plugin can be selected during setup and will automatically be installed in the correct location.
Configuring the CAT-10 Plugin
When the plugin is installed and Canary starts, the plugin configuration settings are saved to the PluginConfiguration.xml file. This file is located in the Witness main application folder. To change the settings this file should be opened in a text editor, such as Notepad, however we would recommend an editor which is XML aware, such as Notepad++.
Once the file is open, locate the CAT10 section, as illustrated below:
<?xml version="1.0" encoding="utf-8"?>
<Config>
<Plugins>
<CAT10>
<PluginConfig>
<TimerTick>500</TimerTick>
<SystemIdentificationCode>1</SystemIdentificationCode>
<UdpServer RemoteIPAddress="239.192.86.0" Enabled="True" Port="8600" />
<SendCAT10>True</SendCAT10>
<ListenCAT10>True</ListenCAT10>
<CAT10SourcePositions>
<SourcePositions>
<Sic>23</Sic>
<Sac>0</Sac>
<X>10</X>
<Y>49</Y>
</SourcePositions>
</CAT10SourcePositions>
<HeartbeatInterval>0</HeartbeatInterval>
<BufferTracks>False</BufferTracks>
</PluginConfig>
</CAT10>
</Plugins>
</Config>
Once you have made changes to the plugin configuration file then you must restart the Canary application / service for the new settings to be applied. No other modules need to be restarted.
The setting options are as follows:
TimerTick
Timer used to control sending status messages and cleaning up buffers in milliseconds. A CAT-10 status message is sent on this timer if Sending CAT10 is enabled.
SystemIdentificationCode
Unique number identifying the Witness system in an Asterix network. SIC Must be smaller or equal to 255. Witness cannot share a SIC with another system.
UdpServer
- Enabled - Should always be set to true
- RemoteIPAddress - The IP address used for clients to access the UDP data. Only Multicast IPs (starting in range 224 to 239) are supported.
- Port - The port used for the UDP communications.
SendCAT10
- True - Sends all confirmed tracks in Witness as CAT-10 messages to the UdpServer address.
- False - Tracks are not sent out.
ListenCAT10
- True - Listens to CAT-10 messages on the udpserver address and port and inserts tracks detected as friendly tracks into Witness.
- False - Does not listen to CAT-10 messages.
One or both of ListenCAT10 or SendCAT10 should be true.
CAT10SourcePositions
Source positions are used to configure displacements of origins between systems.
- List of displacement locations based on system SIC and SAC for other systems.
- SIC: System Identification Code - uniquely identifies each systems within the airport.
- SAC: should normally be 0 for other systems in the same airport.
- X: System origin is located east from witness origin by X meters.
- Y: System origin is located north from witness origin by Y meters.
This does not need to be configured for systems who's origin coincides with Witness origin.
Examples
Example 1: A multilateration detection system has it's origin set at the airport control tower. Witness is configured with origion the control tower as well.
In this case, we do not need a SourcePosition record for the system.
Example 2: A single detector also sends CAT-10 messages relative to its own location - 150 meters north and 200 meters west from the control tower. This detector is assigned SIC153.
For this detector we will need a CAT10SourcePositions record of:
<SourcePositions>
<Sic>153</Sic>
<Sac>0</Sac>
<X>-200</X>
<Y>150</Y>
</SourcePositions>
External System tracks should be within Witness radar coverage to appear in Sentinel.
HeartbeatInterval
- Period, in seconds, between each heartbeat being sent to every connected client. Default is 10 seconds.
BufferTracks
- Buffer tracks to send in batches on TimerTicks
Custom specification for Data Item I010/020
Spare bits in Data Item I010/020 "Target Report Descriptor" Structure of Second Extent is re-purposed in Witness CAT-10 to enable additional classification information.
The I010/020 item will always be included in Witness CAT-10 track reports and will always include at least 3 octets - 1 octet in the standard First Part and 1 octet in a First Extent as per CAT-10 specification and 1 octet in the Second Extent with the spare bits used for Witness classification as per specification below:
Structure of Second Extent:
CAT-10 Original specification:
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
|---|---|---|---|---|---|---|---|
| SPI | 0 | 0 | 0 | 0 | 0 | 0 | FX |
SPI = Special Position Identification
FX = Extension into next extent
Witness CAT-10 repurposed specification
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
|---|---|---|---|---|---|---|---|
| SPI | Classification | FX | |||||
Classification = 6 bit unsigned integer (0-32) indicating the classification:
| Bit representation | numeric value | classification |
|---|---|---|
| 000001 | 1 | Any |
| 000010 | 2 | Unclassified |
| 000011 | 3 | Person |
| 000100 | 4 | Debris |
| 000101 | 5 | Boat |
| 000110 | 6 | Vehicle |
| 000111 | 7 | Aeroplane |
Vehicle and Aeroplane classifications can also be obtained from the standard Target Report Descriptor First Extent as per CAT-10 specifications.
Related information