CC BY
17
УДК 621.396.969.1
Alekseev M. V. student Molokanov A.A. undergraduate Tambov state technical university Russian Federation, Tambov
PHASE-ANTIPHASE METHOD OF RADIO DIRECTION FINDING
Annotation - in this article, the authors considered the phase-antiphase method of radio direction finding, otherwise called the sum and difference method, and also considered the principle of its operation. In particular, the main factors determining the instrumental accuracy of the two-channel amplitude-phase direction finder were considered.
Key words - phase method of radio direction-finding, methods of finding amplitude, amplitude-phase method of radio direction-finding, phase-antiphase method, DF, direction finding.
Increasingly, in the modern world, we are faced with a variety of unmanned aerial vehicles (UAVs) or drones of medium and small size. Whether it's a simple helicopter on the remote control or a full-fledged drone that can broadcast the image from the camera located on the drone, as well as take on Board small loads, all of them can pose a danger to human health and life. This is due not only to the deliberate use of drones for illegal activities, but also to the possible inexperience of the operator. This was the need to use various methods of radio direction finding for premature detection of unwanted drones and transfer its coordinates to the appropriate electronic warfare systems (EW). One of these methods is the phase-antiphase method, which will be discussed later.
Amplitude-phase methods of radio direction finding are based on the use of both amplitude and phase voltage ratios of two receiver antennas spaced apart in space.
An example of the amplitude-phase method of radio direction finding is the phase-antiphase method, otherwise called the sum-difference method. The essence of this method is as follows.
Let the two receiving antennas be switched on in phase. Then the voltage at the receiver input will be equal to the geometric sum of the antenna voltages:
U" = U" + U_2,
where U1 and U2 are the input voltages of the receiver from the first and second antennas.
If the antennas are identical, and the directions of the maxima of their radiation patterns are perpendicular to the base, then U1 = U2. Therefore, according to Fig. 4.5 the total voltage will be:
Uc = 2Ut cos^
где ф - разность фаз между напряжениями U1 и U2.
Figure 1 determination of total and differential voltage.
Substituting the value of the phase difference ф, we obtain:
nd
Uc = 2^ cos —— sin a Я
The voltage U1 can be represented as:
Ui = Uofa(a),
where U0 is the voltage at the receiver input when the direction of the maximum of the radiation pattern coincides with the direction to the target. Therefore:
n d
Uc = 2U0f(a) cos(—--sina)
Я
When the antennas are switched on in opposite phase, the voltage at the
receiver input will be equal to the geometric difference in the antenna voltages.
Under the above conditions, the difference voltage will be:
^ nd
Up = 2U sin— = 2U0f(a) sin(—-sin a) 2 Я
If we measure the ratio
Up nd
UC=Tsina
then we can determine the bearing of the target a.
Использованные источники:
1. Амплитудно-фазовые методы радиопеленгации / Электронный ресурс / http://rateli.ru/ 'rateli.ru: Радиотехника' (Дата обращения: 12.12.2019).
2. Кукес И.С., Старик М. Е., Основы радиопеленгации, М., 1964.
3. Радиопеленгация: Википедия - сводная энциклопедия [Электронный ресурс]. - Режим доступа: https: //ru.wikipedia. org/ wiki/Радиопеленгация#Амплитудный_метод (дата обращения: 04.12.2019).
