RU2531065C2 - Method of measuring pitch angle of aircraft and apparatus therefor - Google Patents

Abstract

FIELD: physics, navigation.

SUBSTANCE: invention relates to radio navigation and can be used in aircraft instrument landing systems. The method includes emitting, from a point with known coordinates, horizontally linearly polarised electromagnetic waves; receiving the electromagnetic waves on-board an aircraft in a lateral direction with respect to the direction of flight; and determining the pitch angle from measured amplitudes of in-phase orthogonally linearly polarised components of the received signal. This enables to prevent constant accumulation of measurement errors and insensitivity to overloading arising in a non-steady flight mode.

EFFECT: high accuracy.

2 cl, 3 dwg

Description

The invention relates to radio navigation and can be used in flight navigation systems for aircraft orientation (LA), for example, when approaching instruments.

Known methods and devices for measuring the pitch angle of an aircraft are based on the use of inertial navigation systems, in particular gyroscopic orientation systems [1-3]. A number of disadvantages are inherent in such measurement methods and devices implementing them. Firstly, over time, there is a constant accumulation of measurement errors and for one hour of flight it is a unit of degrees [1, 2]. Secondly, if an aircraft develops significant overloads, then the gyroscope’s own precession rate increases, which in some cases leads to a complete loss of its performance [1].

Since the known methods for measuring the pitch angle of an aircraft and devices that implement them are based on a different physical principle compared to the claimed ones, they cannot be considered as analogues, since they do not have common features.

The essence of the proposed method for measuring the pitch angle ξ of the aircraft is as follows.

излучаемых электромагнитных волн совпадает с горизонтальной плоскостью OZX и с положительным направлением оси ОХ, лежащей в этой плоскости.From the point (O) with known coordinates in the direction of the aircraft, horizontally linearly polarized electromagnetic waves are emitted (see figure 1). We choose a coordinate system in such a way that the direction of radiation of electromagnetic waves coincides with the axis OZ. The OY axis is perpendicular to the horizontal OZX plane, and the OX axis is in this plane. Together, they form the original fixed Cartesian rectangular coordinate system YOX. Electric field vector $$\dot{\overrightarrow{E}}$$

radiated electromagnetic waves coincides with the horizontal plane OZX and with the positive direction of the axis OX lying in this plane.

On board the aircraft located at the point O '(see Fig. 1), the movable Cartesian system of rectangular coordinates Y'O'X' associated with the hull is organized in such a way that in the initial state, when the pitch angle ξ of the aircraft is zero, the vertical O The 'Y' and the longitudinal O'X 'axes of the aircraft coincide respectively with the OY and OX axes of the fixed Cartesian rectangular coordinate system YOX of the electromagnetic radiation source. Thus, when the pitch angle ξ of the aircraft is zero, the vertical O'Y 'axis of the aircraft coincides with the perpendicular to the horizontal plane (or horizon plane), i.e. with the axis OY, and the longitudinal axis O'X 'of the aircraft is in this plane and coincides with the positive direction of the axis OX and the direction of movement of the aircraft.

и $${\overrightarrow{e}}_y^{\text{'}}$$

которого составляют угол θ=-45° с продольной O'X' и вертикальной O'Y' осями ЛА соответственно и в случае, когда угол тангажа ξ ЛА равен нулю, составляют также угол θ=-45° с горизонтальной ОХ и вертикальной OY осями неподвижной декартовой прямоугольной системы координат YOX соответственно. При этом угол θ отсчитывается по ходу движения часовой стрелки относительно оси OZ.On board the aircraft, the receiving antenna, the axis of symmetry of the radiation pattern of which is perpendicular to the direction of flight of the aircraft, performs lateral reception of horizontally linearly polarized electromagnetic waves in its own linear orthogonal polarization basis, unit vectors (unit vectors) $${\overrightarrow{e}}_x^{\text{'}\text{'}}$$

and $${\overrightarrow{e}}_y^{\text{'}\text{'}}$$

which make an angle θ = -45 ° with the longitudinal O'X 'and vertical O'Y' aircraft axes, respectively, and in the case when the pitch angle ξ of the aircraft is zero, they also make an angle θ = -45 ° with horizontal OX and vertical OY axes fixed Cartesian rectangular coordinate system YOX, respectively. In this case, the angle θ is counted in the direction of the clockwise movement relative to the axis OZ.

относительно продольной O'X' и вертикальной O'Y' осей ЛА позволяет на борту ЛА разделить принятые горизонтально линейно поляризованные электромагнитные волны, вектор напряженности электрического поля $$\dot{\overrightarrow{E}}$$

которых находится в горизонтальной плоскости, на две синфазные ортогонально линейно поляризованные составляющие вектора $${\dot{\overrightarrow{E}}}_x$$

и $${\dot{\overrightarrow{E}}}_y$$

, представить вектор $$\dot{\overrightarrow{E}}$$

как линейную суперпозицию в виде:The selected orientation of the receiving linear orthogonal polarization basis $$\left[{\overrightarrow{e}}_x^{\text{'}\text{'}},{\overrightarrow{e}}_y^{\text{'}\text{'}}\right]$$

relative to the longitudinal O'X 'and vertical O'Y' axes of the aircraft, on board the aircraft it is possible to separate the received horizontally linearly polarized electromagnetic waves, the electric field vector $$\dot{\overrightarrow{E}}$$

which are in the horizontal plane, into two in-phase orthogonally linearly polarized vector components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

present vector $$\dot{\overrightarrow{E}}$$

as a linear superposition in the form:

$$\dot{\overrightarrow{E}}={\dot{\overrightarrow{E}}}_x{\overrightarrow{e}}_x^{\text{'}\text{'}}+{\dot{\overrightarrow{E}}}_y{\overrightarrow{e}}_y^{\text{'}\text{'}},\left(\mathrm{one}\right)$$

и $${\overrightarrow{e}}_y^{\text{'}}=\left[\frac{0}{1}\right]$$

являются линейными ортогональными поляризациями и имеют значение базисных векторов (ортов) и называются базисными линейными состояниями поляризации. Эти векторы характеризуются единичной амплитудой и нулевой начальной фазой, и они ориентированы под углом θ=-45° относительно продольной O'X' и вертикальной O'Y' осей ЛА соответственно. Очевидно, что при выбранной ориентации приемного поляризационного базиса амплитуды A_x и A_y составляющих $${\dot{\overrightarrow{E}}}_x$$

и $${\dot{\overrightarrow{E}}}_y$$

будут определяться углом ориентации продольной оси O'X' ЛА относительно оси ОХ, лежащей в горизонтальной плоскости, или, иначе говоря, углом тангажа ξ ЛА. Так, например, если продольная ось O'X' ЛА находится в горизонтальной плоскости (см. фиг.1) и совпадает с осью ОХ неподвижной декартовой прямоугольной системы координат YOX, т.е. угол тангажа ξ=0°, то амплитуды A_x и A_y ортогонально линейно поляризованных синфазных составляющих $${\dot{\overrightarrow{E}}}_x$$

и $${\dot{\overrightarrow{E}}}_y$$

равны между собой и A_x=A_y. В общем случае, когда продольная ось O'X' ЛА находится ниже или выше горизонтальной плоскости, т.е. угол тангажа ξ≠0°, равенство амплитуд A_x и A_y не сохраняется и A_x≠A_y. Таким образом, амплитуды A_x и A_y синфазных линейно ортогонально поляризованных составляющих $${\dot{\overrightarrow{E}}}_x$$

и $${\dot{\overrightarrow{E}}}_y$$

вектора напряженности электрического поля $$\dot{\overrightarrow{E}}$$

на борту ЛА определяются углом тангажа ξ ЛА.where the vectors $${\overrightarrow{e}}_x^{\text{'}\text{'}}=\left[\frac{\mathrm{one}}{0}\right]$$

and $${\overrightarrow{e}}_y^{\text{'}\text{'}}=\left[\frac{0}{\mathrm{one}}\right]$$

are linear orthogonal polarizations and have the value of basis vectors (unit vectors) and are called basic linear states of polarization. These vectors are characterized by a unit amplitude and a zero initial phase, and they are oriented at an angle θ = -45 ° relative to the longitudinal O'X 'and vertical O'Y' axes of the aircraft, respectively. Obviously, for the selected orientation of the receiving polarization basis, the amplitudes A _x and A _{y of the} components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

will be determined by the angle of orientation of the longitudinal axis O'X 'of the aircraft relative to the axis OX lying in the horizontal plane, or, in other words, the pitch angle ξ of the aircraft. So, for example, if the longitudinal axis O'X 'of the aircraft is in the horizontal plane (see Fig. 1) and coincides with the axis OX of the fixed Cartesian rectangular coordinate system YOX, i.e. pitch angle ξ = 0 °, then the amplitudes A _x and A _{y of the} orthogonally linearly polarized in-phase components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

are equal to each other and A _x = A _y . In the general case, when the longitudinal axis O'X 'of the aircraft is below or above the horizontal plane, i.e. pitch angle ξ ≠ 0 °, the equality of the amplitudes A _x and A _{y is} not preserved and A _x ≠ A _y . Thus, the amplitudes A _x and A _{y of the in} -phase linearly orthogonally polarized components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

electric field vector $$\dot{\overrightarrow{E}}$$

on board the aircraft are determined by the pitch angle ξ of the aircraft.

и $${\dot{\overrightarrow{E}}}_y$$

углом тангажа ξ ЛА.We establish the relationship between the amplitudes A _x and A _y , as well as the phases φ _x and φ _y in-phase linearly orthogonally polarized components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

pitch angle ξ of the aircraft.

и $${\dot{\overrightarrow{E}}}_y$$

в собственном приемном линейном поляризационном базисе $$\left[{\overrightarrow{e}}_x^{\text{'}},{\overrightarrow{e}}_y^{\text{'}}\right]$$

, ориентированном под углом θ=-45° относительно вертикальной O'Y' и продольной O'X' осей ЛА на входе приемника, определяются, опуская временную зависимость сигналов, с помощью преобразований вида:To establish this connection, we use the well-known [4, 5] formalism of vectors and Jones matrices. Then the components of the signals $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

in own receiving linear polarization basis $$\left[{\overrightarrow{e}}_x^{\text{'}\text{'}},{\overrightarrow{e}}_y^{\text{'}\text{'}}\right]$$

oriented at an angle θ = -45 ° relative to the vertical O'Y 'and longitudinal O'X' axes of the aircraft at the receiver input, are determined by omitting the time dependence of the signals using transformations of the form:

$${\dot{\overrightarrow{E}}}_x=\left[\begin{array}{cc}\mathrm{one}& 0\\ 0& 0\end{array}\right]\left[\begin{array}{cc}\cos \theta & \sin \theta \\ -\sin \theta & \cos \theta \end{array}\right]\left[\begin{array}{cc}\cos \xi & \pm \sin \xi \\ \mp \sin \xi & \cos \xi \end{array}\right]\left[\begin{array}{c}\mathrm{one}\\ 0\end{array}\right],\left(2\right)$$

$${\dot{\overrightarrow{E}}}_y=\left[\begin{array}{cc}0& 0\\ 0& \mathrm{one}\end{array}\right]\left[\begin{array}{cc}\cos \theta & \sin \theta \\ -\sin \theta & \cos \theta \end{array}\right]\left[\begin{array}{cc}\cos \xi & \pm \sin \xi \\ \mp \sin \xi & \cos \xi \end{array}\right]\left[\begin{array}{c}\mathrm{one}\\ 0\end{array}\right],\left(3\right)$$

- вектор Джонса излучаемых горизонтально линейно поляризованных электромагнитных волн, записанный в исходном декартовом линейном поляризационном базисе $$\left[{\overrightarrow{e}}_x^{\text{'}},{\overrightarrow{e}}_y^{\text{'}}\right]$$

, единичные вектора (орты) которых совпадают с горизонтальной ОХ и вертикальной OY осями неподвижной декартовой прямоугольной системы координат YOX соответственно,Where $$\dot{\overrightarrow{E}}=\left[\frac{\mathrm{one}}{0}\right]$$

- Jones vector of emitted horizontally linearly polarized electromagnetic waves, recorded in the original Cartesian linear polarization basis $$\left[{\overrightarrow{e}}_x^{\text{'}\text{'}},{\overrightarrow{e}}_y^{\text{'}\text{'}}\right]$$

whose unit vectors (unit vectors) coincide with the horizontal OX and vertical OY axes of the fixed Cartesian rectangular coordinate system YOX, respectively,

- оператор поворота на угол тангажа $$\mp$$

ξ, $$\left[\begin{array}{cc}\cos \xi & \pm \sin \xi \\ \mp \sin \xi & \cos \xi \end{array}\right]$$

- pitch angle operator $$\mp$$

ξ,

-ξ - the pitch is negative when the longitudinal axis O'X 'of the aircraft is below the horizontal plane,

+ ξ - the pitch is positive when the longitudinal axis O'X 'of the aircraft is above the horizontal plane,

- оператор поворота по часовой стрелке на угол -θ (θ - ориентации собственного приемного линейного ортогонального поляризационного базиса $$\left[{\overrightarrow{e}}_x^{\text{'}},{\overrightarrow{e}}_y^{\text{'}}\right]$$

относительно продольной O'X' и вертикальной O'Y' осей ЛА подвижной декартовой прямоугольной системы координат ЛА Y'O'X' соответственно), $$\left[\begin{array}{cc}\cos \theta & \sin \theta \\ \sin \theta & \cos \theta \end{array}\right]$$

- operator of turning clockwise by an angle -θ (θ is the orientation of the intrinsic receiver linear orthogonal polarization basis $$\left[{\overrightarrow{e}}_x^{\text{'}\text{'}},{\overrightarrow{e}}_y^{\text{'}\text{'}}\right]$$

relative to the longitudinal O'X 'and vertical O'Y' axes of the aircraft of the moving Cartesian rectangular coordinate system of the aircraft Y'O'X ', respectively),

- оператор Джонса первого плеча линейного поляризационного разделителя, собственный орт которого совпадает с вектором $${\dot{\overrightarrow{E}}}_x$$

, $$\left[\begin{array}{cc}\mathrm{one}& 0\\ 0& 0\end{array}\right]$$

is the Jones operator of the first arm of the linear polarization separator, whose eigenmax coincides with the vector $${\dot{\overrightarrow{E}}}_x$$

,

- оператор Джонса второго плеча линейного поляризационного разделителя, собственный орт которого совпадает с вектором $${\dot{\overrightarrow{E}}}_y$$

. $$\left[\begin{array}{cc}0& 0\\ 0& \mathrm{one}\end{array}\right]$$

is the Jones operator of the second arm of the linear polarization separator, whose eigenmax coincides with the vector $${\dot{\overrightarrow{E}}}_y$$

.

и $${\dot{\overrightarrow{E}}}_y$$

на входе приемника вида:Having done the necessary matrix calculations in (2) and (3), we obtain analytical expressions for the orthogonally linearly polarized components $${\dot{\overrightarrow{E}}}_x$$

and $${\dot{\overrightarrow{E}}}_y$$

at the input of the receiver of the form:

$${\overrightarrow{E}}_x=\cos \left(\theta \pm \xi \right),{\overrightarrow{E}}_y=-\sin \left(\theta \pm \xi \right),\left(\mathrm{four}\right)$$

accordingly their phases:

$${\varphi }_x={\varphi }_y=0^{\circ }.\left(5\right)$$

и $${\overrightarrow{E}}_y$$

на выходе приемника, имеющего, например, линейную амплитудную характеристику:Find the ratio of the amplitudes A _x and A _{y of the} orthogonally linearly polarized components $${\overrightarrow{E}}_x$$

and $${\overrightarrow{E}}_y$$

at the output of a receiver having, for example, a linear amplitude response:

$$\frac{A_y}{A_x}=|\; |\; |\frac{\sin \left(\theta \pm \xi \right)}{\cos \left(\theta \pm \xi \right)}|\; |\; |=|\; |\; |tg\left(\theta \pm \xi \right)|\; |\; |.\left(6\right)$$

Substituting θ = 45 ° in (6), and also taking into account the definition of the pitch angle [6], we obtain the expression for measuring the pitch angle ξ of the aircraft in the form:

$$\xi =\mp \left({45}^{\circ }-arctg\frac{A_y}{A_x}\right),\left(7\right)$$

-γ - corresponds to a negative pitch angle when the longitudinal axis of the aircraft is below the horizontal plane,

+ γ - corresponds to a positive pitch angle when the longitudinal axis of the aircraft is above the horizontal plane,

,A _x is the amplitude of the linearly polarized component of the electric field vector $${\overrightarrow{E}}_x$$

,

.A _y is the amplitude of the linearly polarized component of the electric field vector $${\overrightarrow{E}}_y$$

.

, т.е. продольная ось O'X' ЛА находится в горизонтальной плоскости и совпадает с положительным направлением оси ОХ неподвижной декартовой прямоугольной системы координат YOX, то угол тангажа ξ=0°. Когда отношение амплитуд $$\frac{A_y}{A_x}<1$$

, т.е. продольная ось O'X' ЛА находится выше горизонтальной плоскости, то угол тангажа ξ положителен и ξ>0°, а если $$\frac{A_y}{A_x}>1$$

, т.е. продольная ось O'X' ЛА находится ниже горизонтальной плоскости, то угол тангажа ξ отрицателен и ξ<0° (см. фиг.1).From the analysis of (7) we see that if the ratio $$\frac{A_y}{A_x}=\mathrm{one}$$

, i.e. the longitudinal axis O'X 'of the aircraft is in the horizontal plane and coincides with the positive direction of the axis OX of the fixed Cartesian rectangular coordinate system YOX, then the pitch angle ξ = 0 °. When the ratio of amplitudes $$\frac{A_y}{A_x}<\mathrm{one}$$

, i.e. the longitudinal axis O'X 'of the aircraft is above the horizontal plane, then the pitch angle ξ is positive and ξ> 0 °, and if $$\frac{A_y}{A_x}>\mathrm{one}$$

, i.e. the longitudinal axis O'X 'of the aircraft is below the horizontal plane, then the pitch angle ξ is negative and ξ <0 ° (see figure 1).

и $${\dot{E}}_x$$

имеют логарифмическую амплитудную характеристику и используется линейное детектирование сигналов $${\dot{E}}_x$$

и $${\dot{E}}_y$$

, то отношение амплитуд $$\frac{A_y}{A_x}$$

двух сигналов $${\dot{E}}_x$$

и $${\dot{E}}_y$$

получается вычитанием значений логарифмов амплитуд этих сигналов, что, как известно [7], эквивалентно образованию логарифма отношения вида:In case the receiving channels of signals $${\dot{E}}_x$$

and $${\dot{E}}_x$$

have a logarithmic amplitude response and linear signal detection is used $${\dot{E}}_x$$

and $${\dot{E}}_y$$

, then the ratio of amplitudes $$\frac{A_y}{A_x}$$

two signals $${\dot{E}}_x$$

and $${\dot{E}}_y$$

obtained by subtracting the values of the logarithms of the amplitudes of these signals, which, as is known [7], is equivalent to the formation of a logarithm of a relationship of the form:

$$\lg A_y-\lg A_x=\lg \frac{A_y}{A_x}.\left(8\right)$$

The use of the claimed combination of features for measuring the pitch angle of an aircraft in known solutions by the author was not found.

Figure 2 presents the structural electrical diagram of a device that implements the proposed method for measuring the pitch angle of an aircraft. The device comprises a transmitter 1 and a transmitting antenna 2 located at a point with known coordinates. On board the aircraft, the device comprises a receiving antenna 3, a linear polarizing separator 4, an amplitude angular discriminator 5, and a computer 6.

Figure 3 presents the structural electric circuit of the amplitude angular discriminator 5, the receiving channels of which use intermediate frequency amplifiers (IFA) with a linear amplitude characteristic, and includes: a first mixer 7, a first linear IFA 8, a first amplitude detector 9, a local oscillator 10, division circuit 11, a second mixer 12, a second linear amplifier 13, a second amplitude detector 14.

The device operates as follows.

The transmitter 1 through a transmitting antenna 2 having a horizontal intrinsic polarization emits horizontally linearly polarized electromagnetic waves in the direction of the aircraft, the electric field vector E of which coincides with the horizontal plane.

на две синфазные ортогонально линейно поляризованные составляющие $${\dot{\overrightarrow{E}}}_y$$

и $${\dot{\overrightarrow{E}}}_x$$

, ориентации векторов которых составляют угол θ=-45° с вертикальной O'Y' и продольной O'X' осями ЛА соответственно. После чего ортогонально линейно поляризованные сигналы $${\dot{\overrightarrow{E}}}_y$$

и $${\dot{\overrightarrow{E}}}_x$$

поступают на соответствующие им входы амплитудного углового дискриминатора 5, т.е. поступают на соответствующие им первые входы смесителей 7 и 12 (см. фиг.3), а на их вторые входы поступает сигнал с выхода гетеродина 10. Затем сигналы промежуточной частоты с выходов смесителей 7 и 12 поступают соответственно на входы усилителей промежуточной частоты 8 и 13, имеющих одинаковые линейные амплитудные характеристики. Выходные сигналы линейных УПЧ 8 и 13 поступают на соответствующие им входы амплитудных детекторов 9 и 14, выходные сигналы которых однозначно связаны с амплитудами A_y и A_x ортогонально линейно поляризованных составляющих $${\overrightarrow{E}}_y$$

и $${\overrightarrow{E}}_x$$

соответственно. Затем выходные сигналы амплитудных детекторов 9 и 14 поступают на соответствующие входы схемы деления 11, на выходе которой формируется отношение амплитуд A_y/A_x ортогонально линейно поляризованных составляющих $${\overrightarrow{\dot{E}}}_y$$

и $${\overrightarrow{\dot{E}}}_x$$

. После чего по измеренному на выходе амплитудного углового дискриминатора 5 отношению амплитуд A_y/A_x двух сигналов вычислитель 6 в соответствии с соотношением (7) определяет угол тангажа ξ ЛА.On board the aircraft, the receiving antenna 3, the axis of symmetry of the radiation pattern of which is perpendicular to the direction of movement of the aircraft, performs lateral reception of electromagnetic waves. After that, the output signal of the receiving antenna 3 is fed to a linear polarizing separator 4, the eigenfunctions of which make an angle θ = -45 ° with the vertical O'Y 'and longitudinal O'X' aircraft axes, respectively. In the linear polarizing separator 4 there is a decomposition (separation) of the received electromagnetic waves with the electric field vector $$\overrightarrow{\dot{E}}$$

into two in-phase orthogonally linearly polarized components $${\dot{\overrightarrow{E}}}_y$$

and $${\dot{\overrightarrow{E}}}_x$$

whose vector orientations are at an angle θ = -45 ° with the vertical O'Y 'and longitudinal O'X' aircraft axes, respectively. Then orthogonally linearly polarized signals $${\dot{\overrightarrow{E}}}_y$$

and $${\dot{\overrightarrow{E}}}_x$$

arrive at the corresponding inputs of the amplitude angular discriminator 5, i.e. arrive at the corresponding first inputs of the mixers 7 and 12 (see Fig. 3), and a signal from the output of the local oscillator 10 is received at their second inputs. Then, the intermediate frequency signals from the outputs of the mixers 7 and 12 are respectively fed to the inputs of the amplifiers of intermediate frequency 8 and 13 having the same linear amplitude characteristics. The outputs of linear IF amplifier 8, and 13 provided to corresponding inputs of amplitude detectors 9 and 14, the outputs of which are uniquely associated with amplitudes A _y and A _x orthogonally linearly polarized components $${\overrightarrow{E}}_y$$

and $${\overrightarrow{E}}_x$$

respectively. Then the output signals of the amplitude detectors 9 and 14 are fed to the corresponding inputs of the division circuit 11, the output of which is formed by the ratio of the amplitudes A _y / A _{x of the} orthogonally linearly polarized components $${\overrightarrow{\dot{E}}}_y$$

and $${\overrightarrow{\dot{E}}}_x$$

. Then, according to the ratio of the amplitudes A _y / A _{x of the} two signals measured at the output of the amplitude angular discriminator 5, the calculator 6 in accordance with relation (7) determines the pitch angle ξ of the aircraft.

и $${\dot{\overrightarrow{E}}}_x$$

, что эквивалентно образованию логарифма отношения амплитуд A_y/A_x этих сигналов (8).In the event that the amplifiers 8 and 13 have a logarithmic amplitude characteristic, then the division circuit 11 (Fig. 3) is replaced by a subtraction circuit, and in this case, the difference between the logarithms of the amplitudes A _y and A _{x of} two amplitudes is generated at the output of the amplitude angular discriminator 5 (Fig. 2) orthogonally linearly polarized components $${\dot{\overrightarrow{E}}}_y$$

and $${\dot{\overrightarrow{E}}}_x$$

, which is equivalent to the formation of the logarithm of the ratio of the amplitudes A _y / A _{x of} these signals (8).

In the 3 cm wavelength range of the claimed device for measuring the pitch angle of an aircraft can be performed as follows.

As the transmitter 1 can be used, for example, a standard generator of high-frequency oscillations of the type ГЧ-83.

As the transmitting antenna 2, a horn antenna with a horizontal intrinsic linear polarization [8] can be used that is slightly directional in the horizontal plane.

The receiving antenna 3 can be made in the form of a weakly directed round speaker [9].

Linear polarizing separator 4 can be made in the form of a waveguide of circular cross section with the transition to two orthogonally located waveguides of rectangular cross section [10].

The amplitude angular discriminator 5, made in accordance with the functional diagram shown in figure 3, completely coincides with the same amplitude angular discriminator of the known amplitude-amplitude monopulse system [11].

The computer 6 can be performed on the basis of the on-board computer of the aircraft.

Compared with widely used in practice methods and techniques for measuring the pitch angle of an aircraft, based on the use of inertial navigation aids, the inventive method and device for determining the pitch angle of an aircraft allow eliminating the permanent accumulation of measurement errors inherent in all inertial navigation tools over time, as well as measurement errors not sensitive to overloads that occur in the case of unsteady flight mode of the aircraft.

Information sources

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Claims (2)

1. A method of measuring the pitch angle of an aircraft when it moves in a known direction, characterized in that horizontally linearly polarized electromagnetic waves, an electric field vector, are emitted from a point with known coordinates

which coincides with the horizontal plane, on board the aircraft, the receiving antenna, the axis of symmetry of which is perpendicular to the direction of movement of the aircraft, receives electromagnetic waves in its own linear orthogonal polarization basis, the unit vectors of which make an angle of -45 ° with the longitudinal and vertical axes of the aircraft, share the accepted horizontally linearly polarized electromagnetic waves into two in-phase orthogonally linearly polarized components

and

electric field vector

, measure their amplitudes A _x and A _y, respectively, calculate the pitch angle ξ between the longitudinal axis of the aircraft and the horizontal plane according to the formula:

,
where -ξ is the negative pitch angle of the aircraft when its longitudinal axis is below the horizontal plane,
+ ξ is the positive pitch angle of the aircraft when its longitudinal axis is above the horizontal plane,
A _x is the amplitude of the linearly polarized component of the electric field vector

,
A _y is the amplitude of the linearly polarized component of the electric field vector

. 2. A device for measuring the pitch angle of an aircraft, characterized in that a transmitter is located at a point with known coordinates, the output of which is connected to the input of the transmitting antenna, a receiving antenna is located on board the aircraft, the output of which is connected to the input of a linear polarizing separator, two outputs of which are connected to respective inputs of two angular amplitude discriminator, whose output is connected to the input of the calculator, wherein the measured relative amplitude a _y / a _x inphase ortogon linearly polarized components

and

electric field vector

received horizontally linearly polarized electromagnetic waves, the pitch angle ξ of the aircraft is calculated, and if the ratio A _y / A _x = 1, then the longitudinal axis of the aircraft is in the horizontal plane and the pitch angle ξ = 0 ° if A _y / A _x <1 , the longitudinal axis of the aircraft is above a horizontal plane and this corresponds to a positive pitch angle of the aircraft and ξ> 0 °, if the ratio of the amplitudes of the A _y / A _x> 1, the longitudinal axis of the aircraft is below the horizontal plane and that The appropriate negative pitch angle of the aircraft and ξ <0 °, where the electric field vector

radiated horizontally linearly polarized electromagnetic waves coincides with the horizontal plane, while the proper polarization of the transmitting antenna is horizontal, the axis of symmetry of the receiving antenna is perpendicular to the direction of movement of the aircraft, and the linear polarizing separator is oriented so that its own unit vectors into which it divides the received electromagnetic waves are an angle of -45 ° with the vertical and longitudinal axes of the aircraft, respectively.

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