Radiolocators radiate a space, one or more beams of electromagnetic waves. If the number of beams is equal to the number of elements to be determined, then all the necessary data can be measured simultaneously. When the number of beams is less than the number of researched elements, the observation is made successively, by moving the antenna within the limits of the needs to cover the researched area. The observation area is the volume of space in which any target is observed on the radio station indicator. This area is determined by the maximum distance, the minimum distance, the azimuth (D βmax) and the elevation angle (D ε max). The observation period (Tobs) is the time when the observation of space reaches again a situation considered initial. For circular observation, Tobs is the time of an antenna rotation. The character of the observation largely depends on the shape of the directivity characteristic of the antenna. The use of a very narrow directivity feature achieves high accuracy, good separation capacity and increased range, but ensures the simultaneous observation of only a very small area of space. In order to cover the research area, the radiated beam must move in space in a certain way, ensured by its mechanical or electrical balancing. The width of the antenna directivity characteristic at half power can be considered:
where: λ, - wavelength; da-the antenna size in that plane. The observation of radiolocation can be done: - simultaneously (in parallel); - successively; - combined. Simultaneous observation is performed by investigating the solid angle of the observation area (Qo) at the same time. Successive observation is ensured by moving the radiated beam in the domain of the observation area. The combined observation uses several radiated beams, which cover the entire area. In case of simultaneous observation Tobs = Trad For successive observation the observation time is:
where: kobs> l- is a constant that takes into account the fact that during the target research the observation speed changes; Dmax - maximum distance ΔD - the portion of distance explored in each radiation period βL, εl - the width of the directivity characteristic in azimuth and elevation angle Δβmax, Δεmax - the fields in which the research is done horizontally and vertically. If targets are observed in the distance (Dmax), then the observation time is:
