T07 — Over the horizon radar

Summary form only given. Sky-wave over-the-horizon (OTH) radars operate in the HF band (3-30 MHz) where it is possible to exploit signal reflection from the ionosphere to detect and track targets at ranges of 1000 to 3000 km. For over half a century, OTH radars have provided cost effective early-warning surveillance over vast geographical areas, particularly in regions where conventional (microwave) radar coverage is either not feasible or convenient. This tutorial provides an introduction to the fundamental principles that underpin both sky wave and surface-wave OTH radar design. The unique challenges associated with the HF environment are explained and connected to motivate the architecture and operation of modern OTH radar systems. A distinguishing feature of the tutorial is the prolific inclusion of experimental results that illustrate the practical application of conventional and adaptive signal processing techniques to real-world OTH radar systems. The tutorial also provides insights for the way ahead and includes many references for those interested in delving further. It is expected to benefit scientists, engineers and students with little or no prior background in this field, as well as practitioners wishing to gain a broader understanding of emerging OTH radar technologies.