Engineering Insights

What is SAPIENT? A Guide to the Open Standard for Sensor Integration

SAPIENT (Sensing for Asset Protection with Integrated Electronic Networked Technology) is an open standard developed by UK’s Defence Science and Technology Laboratory (DSTL). It is designed to allow for a number of different devices (referred to in SAPIENT as edge nodes) to...

ASTERIX CAT 048 vs CAT 062: A Comparison

Two of its most critical categories are Category 048 (CAT-48/CAT 048) and Category 062 (CAT-62/CAT 062). While both carry target (e.g. aircraft) position, velocity and identification data, they represent two entirely different stages of the surveillance processing chain. This...

How to Choose the Right Radar for Your Application

Radar is often the principal sensor for long-range/wide-area target detection. Getting the radar choice right for a project is absolutely critical; it can be the difference between "seeing" targets in time and missing them completely. While highly specialised military...

A Guide to Camera Video and Control Protocols

Historically, video cameras have presented an analogue or at least wired interface to present a video signal to a display or recorder. Dedicated wired interfaces are often on coaxial cable (e.g. analogue composite for standard definition or serial digital HD-SDI for...

Understanding Slant Range in Radar Systems

Radars measure the distance to targets based on the direct line-of-sight path from the sensor to the target. This distance is known as the slant range. When targets are at a different elevation than the radar, the slant range will differ from the ground range, which is the...

Reader-Writer Locks for Data Protection in High Performance Radar Processing

In modern parallel processing systems, ensuring efficient, safe and secure access to shared data is a fundamental requirement to protect the data from corruption or inconsistency. This is a particular challenge in real-time radar processing systems with in-memory databases if a...

Understanding Radar Video, Plots and Tracks

This article explains the difference between radar video, radar plots and radar tracks. A radar sensor transmits beams of RF energy and detects and measures the returned energy to provide an indication of objects in the direction the radar is pointing. The returned data is...

Introduction to ASTERIX CAT048 for Software Engineers

ASTERIX (All Purpose Structured Eurocontrol Surveillance Information Exchange) is a set of standards developed by Eurocontrol to support the exchange of surveillance data between air traffic control systems. It is widely used in radar systems, providing a common structure for...

Testing Radar Trackers for IMO Compliance

The development of radar displays and radar processing for maritime navigation systems is subject to minimal performance requirements defined by IEC 62388 (Edition 2.0). This document defines requirements for equipment, including radars and AIS, as well as defining methods of...

The Importance of High-Frequency Heading Updates In Ship-based Radar Tracking

For applications of radar tracking on a ship, the heading of the ship hosting the radar must be taken into account when processing the data from the radar. By heading we mean the direction that the ship is pointing (as opposed to course which is the direction the ship is...

Radar Signal Filtering: STC, FTC and CFAR

In this paper we look at the common radar processing functions of STC, FTC and CFAR and explain their role in radar processing. Sensitivity Time Control (STC) The power of a radar signal reaching a distant target diminishes with range according to the well-known radar range...

Thread Safety in C++ Radar Software Development

Modern computer programs will often use multiple parallel threads of execution in order to fully utilise the performance available with modern multi-core processors. For example, in radar processing applications, one thread will manage user interface display and interactions,...

Interfacing to Open Collector Radar Signals

When connecting radar signals to radar interface hardware, such as the HPx series of cards from Cambridge Pixel, consideration has to be given to the type of signal being connected. There are single-ended signals, which have a single signal wire referenced to ground, there are...

Fusing Video and Radar Tracks in Multi-Sensor Military Security

Effective fusion of multiple sensors such as radar video and cameras is the key to presenting a situational display in military security applications that informs an operator and supports critical decision-making. However, while track display with track fusion offers the...

Simulation – The Key to Effective Testing of C2 Applications

Ad-hoc testing of software products is no substitute for controlled testing using a set of precise and repeatable data sources that allow systematic verification. This is true for initial system development and also for ongoing regression testing, where it is desired to ensure...

Avoiding Ground Loops in Radar Signal Connections

When connecting an interface card (for example one of Cambridge Pixel’s HPx series of cards) to a radar or simulator, the possibility arises of ground loops. These can introduce noise into the signals, but more seriously they can permit large currents to flow into sensitive...

Using Multiple Hypotheses to Improve Target Tracking

If the measurement of a target's position by a surveillance radar were perfect and precise, tracking would be much easier. Changes in position would be easily converted into speed, course and accelerations, allowing motions and manoeuvres to be followed. The problem of matching...

Challenges and Compromises of Radar Video Distribution Over Networks

Distributing radar video over a standard Ethernet network has many advantages in terms of simplified cabling and ease of integration. Radar systems that generate analogue signals, including many legacy radars, may convert to digital to simplify the distribution process....

Understanding Radar Synchro Converters

Fundamental to the correct operation of a conventional radar system is the concept of direction. Radar video must be correlated with the direction of the antenna before further processing, to ensure that detected targets can be referenced to real-world locations and are...

Bayesian Estimation - From Fork Handles to Radar Tracking

Most people living in the UK over a certain age will be familiar with the Four Candles sketch from the 1976 Two Ronnies comedy show. For others, a quick education is available on the Wikipedia page for the sketch or simply watch it on You Tube. The essence of the sketch that we...

Radar-only Autonomous Navigation in GPS Denied Environments for USVs

Jammed or Spoofed GPS is a critical problem for Uncrewed Surface Vessels which rely on GPS for navigation. On-board radars can be used to detect spoofed GPS and provide a radar-based navigation alternative. The Typical USV System Configuration Small USVs typically use...

Understanding ACP and ARP Radar Signals

The radar equipment receiving the ACP and ARP signals has the task of interpreting the signals to correctly label each radar return with the azimuth that it was derived from. To do this it needs to know the number of ACP signals in one revolution of the radar, ie the...

Overcoming the Challenges of Interfacing to Legacy Radars

Upgrading radar systems, whether for surveillance, air defence, maritime security or naval applications, is expensive. Although a full system upgrade of antennas, transceivers, radar processing and displays may be desirable, it may also be cost-prohibitive and unnecessary if...

How to Measure Latency from Radar Interfacing to Display

In the case of radar video, latency is the time it takes for data to go from the radar source to a display screen. Radar video latency is typically measured in milliseconds and the closer it is to zero the better. Why measure it? A large latency could result in a...

A Guide to Multicast Network Distribution for Radar Video Data

Many system designers and architects digitise and distribute radar video over Ethernet networks. This approach, rather than the use of older analogue splitter and distribution technology, makes use of common infrastructure to carry many different types of data (for example,...

How to Track and Detect Small Targets with Radar

Small target detection is necessary in coastal waters for performing search and rescue operations or for any situation requiring the detection of hard-to-see targets. Detecting targets in radar video involves separating the signal-of-interest from noise. There are many sources...

How Do We Test Our Radar Processing Cards

One of Cambridge Pixel’s major product lines is radar interface hardware, also known as the HPx card range. These cards perform a range of radar processing tasks, such as signal conversion, radar input and output. They are available as bare cards or built into a variety of...

Radar Scan Conversion: The Hows, Whys and Where Nexts?

Radar scan conversion is the process of converting a sequence of radar returns into an image for display. Each radar return is an array of amplitude values corresponding to different range values for a specific angle. As the radar rotates, a new array of values is created for...