Multifunction airborne radar

This article is dedicated to airborne radar, i.e. radar installed on an aircraft (manned or unmanned) or helicopter. To read it, you need to know the basics of Pulse-Doppler radar.

Because it is installed on a platform that moves relative to the ground, airborne radar has its own special characteristics in the world of radar. To fulfill its role, mainly the detection of flying or ground-based objects, these specificities lead to particular operating choices, sometimes very different from those made for a fixed radar in relation to its environment. This article explains the reasons for these choices.

The first section on air/air modes (detecting a flying object from a radar installed on an airborne platform) explains that the choice of waveforms and associated signal or information processing originate from the ground echoes received simultaneously with those of the object to be detected. These echoes have very high levels and a particular spectral distribution (in terms of Doppler frequencies). Analysis of this distribution enables us to understand the choice of waveform, which depends on the relative presentation of the radar and the object to be detected. This leads to the conclusion that a range of modes is needed, each optimized for a particular configuration. This section concludes with an illustration of the benefits of advanced radar management. This is made possible by the use of the latest generation of electronically scanned antennas (passive antenna, active antenna...) which, for identical performance in terms of hardware (transmitter, antenna...), improve detection performance compared with "simple" management, the only option available when using a mechanically scanned antenna.

The section on air/ground modes (detection of objects on the ground using radar installed on an airborne platform) describes how radar works to detect moving or stationary objects, the latter being detected using the platform's motion.

Air/sea modes (detection of objects on the surface of the sea by a radar installed on an airborne platform) will be the subject of a specific article, to which we refer.

The conclusion summarizes the previous sections and shows that an airborne radar is necessarily a multifunctional radar, with all the hardware and software consequences that this entails, because of the need to use a whole list of operating modes, both to carry out its different missions (air/air and air/ground, for example), but also because each mission (air/air, for example) alone requires a list of operating modes to cover the whole range of scenarios.