Azimuth measurements taken on transmitters of known position, i.e. check targets, can be compared with the 'ideal' answer, namely the true g.c. bearing, so that accuracy statistics can be compiled for various purposes described in Section 16.1.2 below. The same procedure cannot be used for measurements of elevation angles, where the 'true' answer is generally unknown. We shall therefore confine our attention in this chapter to azimuth measurements, which will now be referred to for brevity as bearings. It should be noted that bearing errors can, and do, arise from propagation effects as well as from instrumental effects, and that we are not directly concerned here with the physical causes of instrumental errors, which were discussed in Chapter 6.

Inspec keywords: radio direction-finding

Other keywords: DF plots; bearing accuracy; azimuth measurements; instrumental effects; propagation effects; elevation angles; bearing errors

Subjects: Radionavigation and direction finding