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Cambridge Pixel Customer Login


Frequently Asked Questions

This page features the frequently asked questions that we receive from our customers related to Cambridge Pixel products and services. If you need help and support, please get in touch with us at: [email protected]

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General Questions

What is ASTERIX? 

ASTERIX is a set of Eurocontrol Specifications for the exchange of surveillance information such as radar plots, tracks and video. Different categories are available for different types of information, e.g. CAT-48 for plots and tracks, or CAT-240 for radar video. More information can be found at


What is CAT-240? 

CAT-240 is a category within the ASTERIX specification which is dedicated to the exchange of radar video data across a network. (Plots and tracks are supported by other categories such as CAT-48.)

What is CAT-48? 

CAT-48 is a category within the ASTERIX specification which is dedicated to the exchange of radar plot and track messages, typically across networks. It is usually used in conjunction with CAT-34, the category used for radar status messages. Other categories for radar target messages include CAT-1, CAT-10 and CAT-62, whereas radar video uses CAT-240.

What does PIM stand for? 

PIM is an acronym for Polar Interface Module. This is one of the classes (SPxPIM) within Cambridge Pixel’s SPx Development Library and is used for the storage of radar video data for processing and display.

What format of navigation data does the SPx software support? 

The SPx software supports the NMEA-0183 standard for navigation data such as position, velocity, heading etc., via either serial or network interfaces (including the Light Weight Ethernet (LWE) protocol).

Is it possible to get an electronic version of the documentation? 

In addition to printed hard copies of documentation, soft copies of all documents are also available. These are usually in the “Docs” sub-directory of an SPx software installation, or can be requested by emailing [email protected].

What does RPM mean, for example "scan rate up to 120 rpm"? 

RPM stands for Revolutions Per Minute. Typically it is used to describe how fast a radar rotates, i.e. how many times it sweeps through 360 degrees in 60 seconds. It is inversely related to the Period.

What does Period mean, for example “a radar period of 2 seconds”? 

Period is the number of seconds that an event takes to repeat. It is often used to describe how long a radar takes to sweep through 360 degrees. For example, a 2 second period means a radar rotates completely every 2 seconds, which is the equivalent of a 30RPM rotation rate.

How can I get a copy of your licence terms, end user agreement or general terms of use? 

Please email us at: [email protected] with your request.

Where can I find the manual for my SPx software? 

Product specific manuals are supplied with purchases of SPx software, but can also be requested directly from our website, or by emailing your request to: [email protected]

Do you have a training course? 

Yes, we can offer training courses on Cambridge Pixel’s SPx software products. Please email us to arrange this, providing us with your company name and product of interest.

Do you have Cambridge Pixel's SPx Software Library Training course? 

We can offer a training course, yes. Please email us to arrange this, providing us with your company name and country in the first instance? 

Do your products work with airborne radar? 

The quick and simple answer is yes. This assumes the airborne radar can either provide plot reports (ideally in CAT-48 with CAT-34 status messages, or CAT-1 and CAT-2 resp.), or there is an ICD to enable us to convert a proprietary format to ASTERIX, or can provide analogue or digital radar video that can be processed by our SPx Server to produce ASTERIX plot reports.

SPx Tracker-3D is initially aimed at static radars, such as CUAS, with a roadmap for supporting moving platforms, such as airborne platforms. We have interfaced to many radars, including airborne radars on aerostats including both primary and IFF radars.

How does your software handle the intersection of tracks for collision avoidance purposes? 

The SPx Tracker product produces track reports with optional CPA/TCPA (Closest Point of Approach and Time to CPA) values, relative to own ship.

However, we also have a product called the Alarm Server that can be integrated into a solution to provide CPA/TCPA and other alarms for targets.

Which display applications can support the display of S57 Electronic Navigation Charts? 

Currently RadarView, RadarWatch and the Maritime Display Framework support the display of S57 ENCs

I have two SPx Servers and one SPx Fusion Server on my PC, what physical runtime licence options are there? 

Runtime licences can be supplied on one or more USB dongles. Multiple runtime licences for different applications/functionality can be combined in a single USB dongle, and runtime licences for multiple instances of the same application/functionality can be combined in a single USB dongle too. For example one USB dongle can enable two instances of SPx Server and one instance of SPx Fusion Server; or three separate USB dongles can enable each of the two instances of SPx Server and the instance of SPx Fusion Server respectively. Any USB port(s) on the host computer can be used for any of the USB dongles. See document reference CP-25-110-13.

Runtime licences can be supplied as licence files. Multiple runtime licences for different applications/functionality can be combined in a single licence file, and runtime licences for multiple instances of the same application/functionality can be combined in a single licence file. For example one licence file could enable two instances of SPx Server and one instance of SPx Fusion Server, or three separate licence files can enable each of two instances of SPx Server and the instance of SPx Fusion Server. A runtime licence file has an associated host MAC address. Multiple runtime licence files can use the same host MAC address. Host MAC addresses from any valid adaptor, e.g. Ethernet, Wireless including WLAN and WI-FI, Bluetooth can be used for any of the runtime licence files. See document reference CP-25-110-12

Are there any export restrictions on Cambridge Pixel products? 

With only one or two exceptions, Cambridge Pixel’s products are not subject to UK export control. However, Cambridge Pixel may be unable to supply its products to countries which are subject to UK Government sanctions or other special measures.

Which browsers do you support in your web-enabled clients? 

We support the following minimum versions:

  • Chrome v90
  • Edge v89
  • Firefox v90
  • Safari v14.1 (desktop), v15 (mobile)

HPx Hardware FAQs

Do you have a product to convert analogue radar signals to an ASTERIX CAT-240 network stream? 

Yes, the HPx-346 product is a small form factor, combined analogue radar input and network radar video distribution unit.

Can you interface to a Furuno series 2xx8 radar? 

Yes, we are familiar with FAR-2xx8 radars and our HPx radar interface products can be used to connect to the "sub display" output from them.

Can you interface to other radars (e.g. JRC, Furuno, Simrad, Raymarine, etc.)? 

Almost always yes. A list of radars we are known to have interfaced to can be found on our Supported Radars page, but there are almost certainly many others our customers have used that we’re not aware of at present. If you have a radar that’s not on the list, please get in touch for more information.

Do you have a product to convert a LAN radar stream to analogue signals, i.e. ethernet in, video, trigger, ARP and ACP out? 

Yes, we can accept many different ethernet radar protocols as inputs (including ASTERIX CAT-240 as well as various proprietary formats from radar manufacturers) and the HPx-310 radar output card can be used to drive analogue signals as outputs.

Where can I find the newest device drivers for your HPx radar cards? 

The latest HPx drivers for Linux and Windows are available free of charge within your warranty period. Please contact us for details.

How do you connect to a Sperry DCU? 

Sperry output is bespoke but we can either interface to the Sperry radar’s transceiver directly, or to the DCU.

The transceiver’s signals are directly compatible with the HPx-346 and cable P/N 346-800.

The DCU’s signals are slightly different so would need some conditioning and a different radar input cable would be required, however the same HPx-346 enclosure applies.

Feel free to contact us for options.

Can I use one HPx radar interface card to acquire data from two radars? 

The HPx-410 dual channel radar interface card supports two independent sets of radar inputs and can either assist with dual redundancy from a single radar, or can acquire two streams of data simultaneously. If you want to perform tracking from two different radars, you'll need two instances of the SPx Server.

How can I distribute network video from 2 different radars (with different rotations) connected to the same HPx-410 dual channel radar input card? 

Cambridge Pixel's HPxToNet program manages two independent radar sources and can distribute two channels of radar video for processing.

Can the HPx-346 distribute radar video as a multicast stream? 

Yes, the HPx-346 can send multicast video on the network. This would normally be ASTERIX CAT-240.

What versions of Windows are supported by the HPx radar input cards? 

Cambridge Pixel generically supports Microsoft Windows 10 and 11 Operating Systems.

I have an old HPx radar input card that I need to replace - what are my options? 

The HPx family of cards are backwards compatible so upgrading to the latest generation (currently the HPx-410 PCI Express card) is relatively simple. The correct device drivers will be required and your application may need to be recompiled against the current SPx library.

Can you supply cables for use with your HPx radar cards? 

Yes, we have a variety of options for all our radar cards so please contact us for more information

Do you have power consumption details for your radar interface cards? 

The HPx-180 uses around 2W.  The HPx-346 uses around 5W.  The HPx-410e and HPx-450 use around 10W.

What does "highest-wins to reduce the data rate" mean? 

The HPx radar input cards can combine consecutive samples in range if desired, to reduce the number of samples per spoke of data, e.g. down to 2048 or 4096 bytes. Where samples are combined, the highest value is used so that returns from small targets are not lost.

Does the HPx-346 support dual redundant Ethernet output? 

Yes, there is a variant of the HPx-346 which has dual Ethernet capability. Contact us for details.

RadarView FAQs

Why can’t I see tracks displayed on my radar video? 

It is important to understand that RadarView does not create tracks. It displays tracks that it receives as input. To create tracks from video you need SPx Server.

Is RadarView available for Linux? 

No, RadarView is a Windows application. There are a number of options for displaying radar video under Linux - please consult our sales team.

What kind of maps does RadarView support? 

RadarView supports raster maps, tiled maps and ENC charts (needs an extra licence). Most situations use tiled maps which are automatically downloaded from the Internet for an area of interest. The maps are stored locally (cached), so that revisiting the same location does require internet access. For ENC charts, you need an additional licence and then the charts need to be purchased for the area of interest. Consult our sales team for more details.

What is a B-Scan or B-Scope display? 

This is a specialised format of radar display that shows radar against azimuth. It is used in naval fire control situations.

What is an A-Scan or A-Scope display? 

This form of display shows signal amplitude as a function of range for each radar return. It is the display you would see if you connected the radar video to an oscilloscope. It can be useful when looking at radar video signal levels to verify that the radar is correctly configured.

What is an RHI display? 

An RHI (Range Height Indicator) is a display that shows range along the X axis and altitude on the Y axis. Unlike other displays in RadarView, an RHI only displays Tracks, not radar video.

Why does it take a long time for AIS symbology to appear? 

It depends on the rate at which AIS messages are being sent. Some AIS messages, including those that define the size and details of a target, are sent less frequently, so it may be many 10s of seconds before the details of an AIS target can be displayed by RadarView.

Can RadarView display camera video? 

Yes, RadarView can be configured to display camera video received as an RTSP stream over the network or from a DirectShow compatible video capture device. A maximum of two video windows can be displayed simultaneously. RadarView also supports controls of up to two PELCO compatible PTZ cameras.

ASD-100 & ASD-View FAQs

What format of weather radar data does the SPx software accept? 

We support ASTERIX CAT-8 weather radar receipt and display in ASD-100, RadarView, and our SPx Development toolkit.

What software accepts ADS-B reports (ASTERIX CAT-21) on an Ethernet interface and provides a display on a computer? 

Cambridge Pixel can provide several applications that can do that, including RadarView, ASD-100 and ASD-View.

RadarView can receive an ADS-B input for display of track reports. RadarView can also receive, process and scan convert multiple channels of radar video into PPI, A-Scan and B-Scan formats.

ASD-100 is an air situational solution for the display of primary radar video, track reports (including ADS-B) and CAT-4 safety alerts.

ASD-View is an air situational solution for the display for ADS-B reports only.

Can I hide the side panel and menu bar in ASD-100? 

Yes, ASD-100 has configuration options to show/hide  the menu bar and side panel.

What maps are supported in ASD-100 and ASD-View? 

ASD-View supports world vector map, tiled and terrain contour maps. ASD-100 also supports raster maps, user maps and aeronautical charts.

How do I get SkyVector chart display on ASD-100? 

SkyVector charts are set up as described in the ‘Tiled Map Display’ section (3.24) of the ASD-100 User manual. A subscription to SkyVector is required and this needs to be procured directly from SkyVector (contact SkyVector directly at The SkyVector licence key number can be entered in ASD-100 via a setup dialogue or directly by editing the config file.


What support does VSD have for video tracking? 

VSD has the option for a built-in video tracker and supports interfaces to a number of third-party video trackers including Vision 4CE

For counter-UAV applications, where Radar, RF detector, camera and jammer are used - what is the ideal management software? 

We have a display application called VSD, which could be useful for this.

What radars does VSD support? 

Cambridge Pixel supports a wide range of radar types and most of these are supported within VSD. For applications of security and drone detection radars from Echodyne, Blighter, Navtech, Navico, Furuno, Spotter-RF are relevant. A key feature of Cambridge Pixel’s solution is that the processing and display capabilities are independent of the radar sensor. This makes it possibly to deploy different radars in different situations, whilst retaining the same software architecture.

How should I choose between VSD and RadarWatch for a Coastal Surveillance application? 

Whilst VSD and RadarWatch have overlapping features, VSD is simpler to operate and is aimed at smaller mobile or single operator systems, systems which require integration with a video tracker, laser range finder, RFDF sensor or other such accessories, or ‘camera only’ systems.  RadarWatch is designed for more complex larger systems with multiple operators, multiple long range radars, more complex alarm handling, and where ENC chart support is required.

Can VSD support proprietary plot and track reports ? 

VSD supports the receipt of track reports, which can be used to trigger alarms, control cameras and laser range finders.

Proprietary plot and track formats can be converted using SPx Track Manager

SPx Server and SPx Tracker-3D can be used to generate track reports from plot reports.

Can VSD be customised? 

There are a significant number of capabilities in VSD that can be customised, including the display presentation and controls. Support for new devices can be added as needed by our engineering team.

What cameras are supported by VSD? 

VSD supports industry-standard camera interfaces based on PELCO-D and ONVIF. Camera control can be manual using a physical joystick or on-screen controls, or cameras may be controlled automatically to follow a detected radar track. A video tracker can be incorporated to permit camera control direct from the camera video.  Using the optional SPx Camera Manager software, camera control can be shared and prioritised between multiple display applications.

Does VSD display mapping information? 

Yes, VSD shows a georeferenced map to indicate the position of radars, cameras and targets of interest. Maps are automatically downloaded from an active internet connection (or can be cached to permit operation without an internet connection) or custom maps can be loaded.

Can VSD be used to locate a target with radar and then follow with camera video? 

Yes, this is a typical application for VSD. A wide range of radar types are supported as input. Once acquired on radar, a camera may then be moved to the reported position and the camera position updated from each radar detection. This is called slew-to-cue.

Maritime Display Framework FAQs

Do you have development toolkits aimed at maritime displays? 

Yes, the Maritime Display Framework is a good starting point for this kind of application.

How is CPA/TCPA handled in MDF? 

CPA/TCPA (Closest Point of Approach and Time to CPA) values and related alarms are handled natively in MDF, via use of the SPx .NET library.

Is MDF just for developers or can it be used as a turnkey application? 

MDF is available both as a turnkey application, and (in conjunction with SPx Development) as a ‘source code supplied’ framework for developers to modify and extend.

What inputs does MDF require? 

MDF usually requires an NMEA-0183 navigation data input, an ASTERIX CAT-240 radar video input and an ASTERIX CAT-48, SPx or TTM  radar track input.  AIS input is also supported, and SPx Fusion can be optionally used to combine this with the radar tracks.  An H.264 camera video input can also be supported.

Is MDF an ARPA, ECDIS or Integrated Bridge System Display? 

MDF could be the basis of any of these systems for a system developer who uses it as the starting point for their development.

If I am developing a new maritime application what can MDF offer? 

MDF can be supplied with source code (for the application layer), meaning the standard MDF can be used as a starting point for further custom development. It is generally much easier for software developers to start with an application that implements the core functionality and then modify/expand the application for custom requirements. The final product may look very different to the initial MDF, but having the framework there from the beginning is generally a productivity boast for development.

What radars does MDF support? 

The radar is normally input to SPx Server which converts video to ASTERIX CAT-240 and generates tracks for input to MDF. SPx Server supports a very wide range of radar types from Simrad, Furuno, Raymarine, Kelvin Hughes, Terma, JRC and most other maritime radars (consult Cambridge Pixel's support team for details).

SPx Track Manager FAQs

What is ‘slant range’ correction? 

When radars measure the range to an airborne object, this is the ’Slant Range’ (the range measured at a slant, because the object is not on the ground).  When the track for an airborne object is displayed on a PPI display at its Slant Range, it will appear to be further away from the radar than it really is.  When the radar has a 3D capability and can measure the elevation of the target, as well its range, then basic trigonometry can be used to convert the Slant Range to corrected range. This will show the true position of the track over the ground on the PPI display.  Slant Range effects are more significant when targets are closer to the radar and the elevation angle is higher.  For example, if a radar measures the range to a track at a 45 degree elevation, then the Slant Range would need to be multiplied by cos(45), or 0.7071, to get the ground range of the object from the radar. If the object had an elevation of, say, just 5 degrees, then the correction factor would be 0.9962 meaning that the Slant Range and corrected range would be within 0.5% of each other.

My track source has a lot of false tracks all coming from an area of permanent clutter. These clutter tracks die out after a few revs of the radar. Can I filter out these false tracks using SPx Track Manager? 

Yes you can. This is achieved by setting up two filter areas, one where the false tracks are started (inner zone), and another enclosing the area where the tracks usually die out (outer zone). The filter settings are then set to exclude tracks which are in the outer zone AND started in the inner zone. Tracks started outside the inner zone will not be filtered, and neither will tracks which make it to the outside of the outer zone (even if they started in the inner zone).

My track source doesn’t seem to be on the list of supported track formats. The track format is documented. What should I do? 

Contact us - we have designed Track Manager to be extended to accommodate new track formats quickly and easily.  There may a small NRE charge, but if you can share the track format documentation (under NDA, if necessary) we will be able to provide a fixed price quote quickly.

I have five radar ASTERIX track sources. All track sources require track filtering and format conversion. Track reports are supplied using the same network address:port details, but each radar has its own SAC/SIC codes. What variant of SPx Track Manager is required? 

Although all the track reports are supplied on the same network address:port, there are five independent inputs distinguishable by the SAC/SIC codes. Each input can be processed and converted and output. A single input can have multiple outputs. Track filtering can be enabled/disabled on a per output channel basis, but the filter parameters are global to all channels. Track format conversion can be applied to each output and one input can have multiple outputs.

The variant requires a runtime licence based on the number of output streams required.

SPx Server FAQs

Why is there a user-interface for a server product? 

The user-interface is provided to assist with configuration and analysis. When operating as a server the user-interface is not required and SPx Server can be configured to start without one if desired.

Why does my SPx Server not support target tracking? 

SPx Server supports several different radar processing functions according to a license. If you have purchased SPx Server for radar distribution, for example, it will not enable plot extraction and target tracking.

What is the MBT? 

The MBT (Model Based Tracking) module is a component of SPx Server for target tracking. It provides options for creating a set of tightly coupled tracking parameters (the model) that allow the track processing to look specifically for certain types of target. The MBT can be used for small target detection, for example, or models can be configured to look for air and surface targets in the same data set. It is very similar to having multiple trackers processing the same data with different parameters,

Does SPx Server automatically adapt to changing sea-state or weather conditions? 

Yes it should, provided it is configured correctly. The dynamic thresholding process will automatically adjust the detection threshold to accommodate changing clutter levels (CFAR). Other parameters in the track processing provide automatic adaption to conditions. There are limits though to this adaption.

How can I monitor SPx Server across a network interface? 

There are two options to this. One is to use a remote desktop to permit the SPx Server user-interface to be seen on a remote computer. However, the preferred way is to use the browser interface option. This allows a standard web browser to connect to SPx Server. There are some limitations of control through the web browser versus the native interface.

Can SPx Server be used to distribute radar video and track targets at the same time? 

Yes, subject to having the licences. It is important to note that there is only a single processing chain and that processing should be optimised for the track processing function, rather than the display. If it is desired to process the radar video for display (for example to threshold it for reduced bandwidth or simplified display) then that cannot use the same processing chain as the tracking.

What type of tracking filter is used by SPx Server? 

SPx Server uses an adaptive alpha-beta tracker. The gains for the tracking filter are automatically adjusted so that lower gains are used for steady-state tracking and higher gains are used when there is increased uncertainty or manoeuvring. This is similar in principle to the behaviour of the Kalman filter.

How do I configure SPx Server to get the best tracking results? 

This is a difficult question, because it depends on the radar, what types of targets are being processed and what is most important in the processing (for example acquisition speed or reduced false alarms). The SPx Server manual set provides a reference and explains the controls but it does not, and realistically cannot, provide a step-by-step procedure. Cambridge Pixel engineers are available to provide assistance for tracker configuration and often this means that our engineers will provide a customised configuration file as a starting point, with suggested parameters to adjust to. SPx Server provides a radar recording capability which can be used to capture radar video that can be sent to our engineers for initial advice.

Can SPx Server be used to combine radar tracks with AIS? 

Yes, to a limited degree. There is a built-in capability in SPx Server to associate a radar track with an AIS track and the associated AIS ID appears in the track report. There is more flexibility and options using a separate SPx Fusion Server, but simple association of tracks and AIS if possible within SPx Server.

How can I use area-dependent parameters? 

This is an important capability of SPx Server. By default, tracking parameters affect the behaviour of tracking everywhere. However, sometimes it is desirable to use different parameters in restricted areas, perhaps to solve a local problem. To do this, create new area objects, for example as polygons or segments. These named area objects can then be used to give tracking parameters different values in those areas. For any track processing, the value of a tracking parameter to use is found by first checking any area-dependencies. If there are non, the global value is used. Most tracking parameters can be area dependent. Note that area dependency only relates to tracking parameters, not plot extraction or processing parameters.

What are hypotheses? 

The tracker is a multi-hypothesis tracker. This means that it is able to consider different possible interpretations of how new plots associate with tracks.. Each interpretation is called a hypothesis. The best hypothesis is the one with the highest confidence and that is the one that gets reported. Sometimes it is not possible to get the right interpretation based on limited data, so holding multiple hypotheses allows the correct interpretation to be deduced as soon as new data is received. It is possible to switch the tracking into single hypothesis mode if desired. Note also that the tracker will automatically switch into single hypothesis mode as part of load reduction if it gets overloaded.

What are clusters? 

A cluster is a collection of one or more tracks that are close enough together that the processing considers them as a group. A cluster may comprise one track if that track is sufficiently isolated from any others. It is necessary to process close tracks as a group to ensure that all possible associations of plots and tracks are considered.

What are provisional tracks? 

When a track is first created, which occurs when a plot is unassociated with any existing track, it is provisional. It remains in the provisional state for a number of detections, until confidence has built up and it can become an established track. There are typically many more provisional deleted because they are associated with noise or clutter. Provisional tracks can be displayed in the user interface, which is useful for analysis. The amount of time a track remains provisional before being promoted to established is configurable.

How can I reduce the bandwidth of distributed radar video with SPx Server? 

SPx Server can be used to distribute radar video over a standard network using UDP/IP protocols, allowing any number of clients to receive the video. Radar video can be compressed with one of two built-in compression schemes, which are lossless, but the degree of compression achieved is dependent on the radar video and may change over time. There are several processing options that may be configured to simplify the video and make it more compressible, albeit with some loss of video content. For example, the video can be thresholded to a single bit, optionally taking out low-level background noise. Note that SPx Tracking processing stages are also used by the target tracker, which normally takes priority for the settings of processing.

SPx Server appears overloaded and not keeping up. What should I do? 

When configured for track processing it is possible that SPx Server cannot keep up with incoming radar. This is the case if the processing, plot extraction or tracking are incorrectly configured. SPx Server will attempt to take some steps to self-correct by automatically switching to simplified processing, but this may not be enough or it may not be the desired behaviour. The situation must be considered by first disabling tracking and looking at the radar processing and plot extraction to ensure that plots are being extracted only for possible targets and not for excessive clutter or noise. Changes to the video or plot processing should be first used to restrict the number of plots being generated. Then for the track processing, ensure that tracking parameters are not unreasonable, i.e. track dynamics, acquisition time, acquisition area etc are all reasonable. For areas of high plot density, for example, track processing may be disabled or area-dependent parameters may be used to increase the acquisition time.

Can I update SPx Server to the latest version? 

SPx Server is under active development and we are continually making improvements. You may upgrade to the latest version of the software for one year after initial delivery. After that time you need to have in place a support contract. Contact our sales team for details.

We recommend you register your product to receive notifications when updates are available.

Can I record radar video in SPx Server? 

Ensure that the ProRecord.Available parameter is set to 1. Use the ProRecord to set a file prefix if required (note that if a directory name is specified, the directory will not be automatically created).

Can the recording capability of SPx Server be used to provide continuous recording? 

The recording capability of SPx Server is not intended to support continuous recording. There is no capability to manage the recording session to maintain the last N days, for example. The recording capability of SPx Server is to support the capture of recordings during trials. This permits offline analysis and configuration of the software. The recording capability is a licenced option. Without the license only a short recording time permitted. For continuous recording with managed storage, please consider our RDR Data Recorder software.

The track IDs from SPx Server appear to have some numbers missing. Why is this? 

A track ID is allocated when a track is created as a provisional track. The same track ID is used when the track becomes established. If the provisional track is deleted before becoming established the track ID may never be used in a track report. For example, you may see track ID 1, 2 and 4 appearing for 3 tracks. This will mean that ID 3 was used for a provisional track, which never became established.

How are track IDs allocated? 

Track IDs are allocated on a least recently used basis with valid IDs are from 1 to 4095. If Track ID 1 is used and then that track is deleted no new track with same ID will be used until all other track IDs have been used.

What format of track reports are available? 

SPx Server can output SPx, ASTERIX and TTM track reports. SPx format is Cambridge Pixel’s own format and this provides the most comprehensive set of data for a track. The ASTERIX format (CAT-48 or CAT-10) is the Eurocontrol standard format. TTM format is the NMEA Maritime standard.

Does SPx Server support any specific international standards? 

SPx Server has been verified by simulation against the standardised test scenarios in IEC 62388 section 10.3.14 (target motion and tracking accuracy).

Does SPx Server support 3D radars? 

SPx Server has very limited support for 3D radars. It is able to tag height information into the track report, but the tracking is 2D. For true 3D tracking, or for radars with variable update rates, please consider our SPx Tracker 3D product.

What is the maximum speed of target that can be tracked with SPx Server? 

There isn’t a maximum speed built into the software. It is possible to track high-speed targets with appropriate configuration. An important consideration is how far the target moves in the data store and this depends on the radar’s maximum range. It is difficult to track high-speed targets with short range radars, for example.

Why is the estimated speed/heading of a track varying more than expected? 

Since measurements of a track’s position by the radar are always subject to error, the estimated speed and heading will, to some extent, reflect that measurement error. The gains of the tracking filter are key to improving the estimated values for speed and course, on the assumption that the target is moving at a constant heading and speed. Reducing the steady state filter gains will apply more filtering and the estimated speed and heading will, eventually, stabilise as the noise is filtered out. If the tracking filter starts to observe a significant error in the position of the track it will start to increase the filter gains to track the target through a manoeuvre. Once the target has completed the manoeuvre the filter gains will automatically reduce again to improve the estimated speed and heading. Refer to the manual for guidelines on the steady-state filter gains for different tracking situations.

What’s the difference between manual and automatic track acquisition? 

In manual track acquisition, it is the responsibility of something outside of SPx Server to define a position where a new track should be created. For example, this could come from a user-interface, where the user observes video from a target and then clicks that location, resulting in a message being sent to SPx Server to initiate a track. SPx Server will continue to maintain the track with subsequent updates of the radar video. In automatic track initiation (ATI), SPx Server creates new tracks automatically by examining the radar video to look for target-like returns. ATI can be turned off if manual (external) initiation alone is required. Manual initiation offers the option of creating tracks with additional information, if known. For example, if it is known that the target to be tracked is a highly manoeuvrable target, SPx Server can create a track and associate a model with appropriate parameters.

What’s the purpose of SPx Server’s Screen Recording capability? 

The built-in screen recorder is able to capture images from the PPI window at regular intervals and save in a directory. This can be useful during analysis of problem cases when it is desired to capture images showing detailed information on the screen.

Why are my radar echoes not aligned with real world objects e.g. coastline or AIS targets? 

Some radars may show a small bias in the range of radar video. This can be corrected where necessary using one of our standard plugins to support a fixed range offset and a range multiplier. Contact us for further details.

Please can you confirm whether there are any export controlled parts (e.g. ITAR) for the SPx Server or the SPx Fusion server? 

Those products are manufactured in the UK and are not subject to export control, including ITAR.

SPx Fusion Server FAQs

Can we install SPx Server, SPx Fusion & RadarWatch on a modern Windows 11 workstation? 

Yes, that should be fine, as long as the PC has reasonable performance (at least an i5 processor with 8GB memory and a dedicated graphics card).

Can more than one application receive track reports from the same SPx Fusion server? 

Track reports are normally sent as multicast UDP messages, allowing you to have multiple subscribers on a network.

Is there any limit to the number of sensors that SPx Fusion can combine? 

The limit is imposed by the licence purchased for use with fusion, but there is no intrinsic limit in the software itself.

Can SPx Fusion Server correlate track reports for drone detection solutions? 

SPx Fusion Server uses the 3D positional data within track reports, e.g. latitude/longitude/height, during the correlation process. Each sensor is also assigned a relative priority and score which determines the number of sensor observations required in an output report.

Please can you confirm whether there are any export controlled parts (e.g. ITAR) for the SPx Server or the SPx Fusion server? 

Those products are manufactured in the UK and are not subject to export control, including ITAR.

SPx Radar Simulator FAQs

How can I generate simulated analogue radar video? 

SPx Radar Simulator combined with HPx-310 radar output card can generate realistic simulated radar scenarios with radar returns from terrain and moving targets. Analogue radar video is supplied in standard four-wire format: video, trigger, ACP, ARP.

Does the Simulator calculate the detectability of targets, based on radar power and target RCS? 

SPx Radar Simulator is intended to provide a controllable source of realistic-looking radar video. It does not model the RF characteristics of real radars, instead it allows control over high-level settings, such as beam width and pulse length, which may be adjusted until the video picture looks as wanted.

SPx Radar Simulator will account for terrain obscuration and radar end range when generating target video returns. Also, the targets’ RCS values are used to determine the amplitude of their returns as a function of range from the radar.

How can I combine synthetic targets with real radar video? 

SPx Radar Simulator can combine radar video from an auxiliary source with simulated targets. The auxiliary source may be a CPR radar recording file, a network input (SPx or ASTERIX CAT-240 format), or directly from an HPx hardware capture card. When using an auxiliary source, the simulated radar properties such as period and end range will be set based on the auxiliary source.

What can I do if the terrain data available within SPx Radar Simulator is not accurate enough or missing important structures? 

SPx Radar Simulator uses SRTM terrain data by default, which provides reasonable resolution terrain data for the whole world. If you have DTED or GeoTIFF terrain data available then this can be used in addition to or instead of the SRTM data, configured within the terrain configuration dialog. Alternatively buildings may be drawn manually or loaded for Shapefiles to be combined with terrain information, when a static radar is being simulated.

My simulated target is not appearing within generated radar video. How can I find out why? 

Use the visibility status dialog from within the target configuration dialog to debug target visibility issues. If a target is not visible, then one of the indicators within the visibility dialog will be red. A tooltip will be available indicating how to resolve the issue. When multiple radars are being simulated, separate visibility status indicators will be available for each radar.

What options are available for simulating noise within SPx Radar Simulator? 

Various types of noise can be simulated - background noise and near noise within generated radar video, noise in detected target positions, noise in detected target size and noise in measured platform position, course, heading and speed.

How can I view ASTERIX CAT-240 radar video on my phone or tablet? 

You could connect your phone’s web browser to the SPx Radar Web Server if you have a network connection to it.

Why does the Simulator accept radar as an input? 

The Simulator generates radar as an output, but optionally is can accept radar as an input to combine with the simulated radar. This allows simulated targets to be inserted into existing radar recordings.

What types of target does the Simulator generate? 

Targets are created within the simulator. Each target can be configured to generate any combination of AIS, primary or secondary video. For example, a target could be designated as AIS only, or can be configured to generate AIS and primary radar, both as video and a track.

Is there a Linux version of the Simulator? 

The Simulator is Windows only at present.

Can the Simulator be controlled from a separate application as a server? 

Yes, there is an API to remote control.

Can the Simulator be used with my existing scenario generator to control the motion of targets? 

Yes. The Simulator has a built-in scenario generator, but this does not need to be used. If target positions are controlled by an existing scenario generator, the Simulator can be used to convert target positions into radar video, tracks or AIS. The existing scenario generator will need to report changes in target positions to the Simulator at regular intervals.

SPx Radar Web Server FAQs

How can I display scan-converted radar in a web browser? 

SPx Radar Web Server allows web clients to request scan-converted radar video for a defined geographical area using a REST interface. The scan-converted image is supplied as PNM or BMP images which can then be mixed with other layers generated by the web client.

What operating systems are supported by SPx Radar Web Server? 

SPx Radar Web Server is a client-server technology. Server distribution is supported under Windows and Linux, and client display is browser based with support for all five operating systems, Windows, Linux, macOS, IOS and Android OS.

What format are track reports provided in SPx Radar Web Server? 

SPx Radar Web Server servers track reports in an extended GeoJSON format.

RDR Data Recorder FAQs

What kinds of data can RDR capture? 

RDR can capture radar video, radar tracks, AIS and ADS-B reports, camera video, audio and arbitrary network packets. It can also record the contents of a screen.

How long can RDR record for? 

There is no intrinsic limit to the length of recordings; it is limited by available disk space. RDR supports rolling recording where data older than, for example, 30 days is automatically deleted.

How can I analyse the radar video data in and RDR recording? 

RDR’s replay capability synchronously outputs network streams from each of the individual data sources in the original recording. Analysis of the radar video can be performed in MATLAB using SPx Open Access.

How can I analyse track movements from an RDR recording? 

RDR populates an SQL database with track messages while recording. Results can be filtered using SQL structured queries, and the results can be exported to a .csv file for import into Microsoft Excel or alternate packages for analysis. The SQL feature and its use is fully described in Section 22 of the User Manual, including examples.

I want to record data from my own proprietary sensor or system simultaneously with radar data. Can RDR do this? 

Yes, an open RDR channel can be set up to record network data, so provided that your sensor or system outputs to a network, the traffic can be recorded and replayed, like any other channel. If your sensor outputs on an RS232, 422 or 485 serial channel, and your computer has a suitable interface, Cambridge Pixel can also provide a serial-to-network utility, to allow the data to be recorded.


Can I export the coverage data from Radar Coverage Tool? 

Exporting of coverage data requires the Pro or Geo versions of the software, which allow the information to be exported as a KML file. These versions also support simultaneous coverage calculation for up to 10 radar sites.

Can I convert between serial data and UDP, or between TCP and UDP, or between unicast and multicast? 

Our toolkit includes a number of useful standalone applications. This includes spxserialtonet, which can convert between serial and UDP and between TCP and UDP, often useful for converting serial AIS or GPS feeds into UDP messages. It also includes spxnetrepeat which can convert between unicast and multicast packets and is often useful at the boundaries of a site in a WAN where multicast over WAN is not supported.

What Free Download Tools does Cambridge Pixel Offer? 

Radar Coverage Tool, for visualising radar coverage

Navigation Data Monitor, for analysing NMEA-0183 Navigation messages

AIS Data Monitor, for analysing NMEA-0183 AIS messages

ADS-B Data Monitor, for analysing ADS-B messages

RadarView-240 for the display of ASTERIX CAT-240 radar video