RU2013787C1 - Phase method of measurement of range of two aerial targets - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: device for implementation of method has receiving-transmitting aerial 1, aerial switch 2, receiver 3, high-frequency generator 4, modulating voltage generator 5, modulator 6, amplitude limiters 7, 8, narrow-band filters 9, 10, phase-meter 11, target range computer 12. Resolving power is improved thanks to increased duration of pulses. Accuracy of measurement of range of two targets grows due to attenuation of effect of distortions of pulse edges. EFFECT: increased accuracy of measurement of range. 1 dwg

Description

 The invention relates to radar and can be used in tracking and guidance radars for measuring ranges of two targets (for example, an intruder aircraft and a missile aimed at it). It allows you to increase the accuracy of measurements and improve resolution in range when using probing radio pulses of long duration.

 The aim of the invention is to improve the resolution and increase the accuracy of measuring the ranges of two targets (for example, an intruder and a missile aimed at it) when using relatively long duration probing radio pulses in a phase range finder.

The drawing shows a simplified block diagram of a phase range finder implementing the method, and two targets and their inclined ranges R ₁ , R ₂ are schematically shown.

The phase range finder contains the following elements: transmit-receive antenna 1, antenna switch 2, receiver 3, transmitter high frequency generator 4, modulating voltage generator 5, transmitter modulator 6, two amplitude limiters 7, 8, two narrow-band filters 9, 10, phase meter 11 , the calculator 12 range targets R ₁ , R ₂ .

,

на выходах фильтров 9, 10, дополнительно использовать также измерение отношения амплитуд U/U_o этих напряжений. Амплитуда гармонического напряжения U_o частоты F, выделенного фильтром 9 из протяженной периодической последовательности прямоугольных импульсов генератора модулирующего напряжения 5, определяется известным соотношением
U₀=

sinΠFτ , (1) где A - амплитуда импульса, равная порогу ограничения амплитудных ограничителей 7, 8;
F - частота следования модулирующих импульсов генератора 5;
τ- длительность модулирующего импульса.In the general case, the phase of the harmonic voltage of frequency F at the output of the narrow-band filter 10 depends on the delay time t _z1 , t _{z2 of the} echo signals of two targets and the amplitudes of these echo signals. However, if the video signals of the two targets are aligned in amplitude using the limiter 8, then the voltage phase will depend on the delay time t _s1 , t _{s2 of the} echo signals of these targets, i.e. the phase will contain unambiguous information on the ranges of the targets R ₁ , R ₂ . Moreover, to determine two unknown ranges R ₁ , R _{2 is} not enough just one phase measurement. Therefore, it is proposed to determine the ranges of two targets R ₁ , R ₂ in addition to measuring the phase shift Δ φ

,

at the outputs of the filters 9, 10, in addition, also use the measurement of the ratio of the amplitudes U / U _{o of} these voltages. The amplitude of the harmonic voltage U _o frequency F, selected by the filter 9 from the extended periodic sequence of rectangular pulses of the modulating voltage generator 5, is determined by the known relation
U ₀ =

sinΠFτ, (1) where A is the pulse amplitude equal to the limit threshold of the amplitude limiters 7, 8;
F is the repetition rate of the modulating pulses of the generator 5;
τ is the duration of the modulating pulse.

,

на выходах фильтров 9, 10 будет
Δ φ=π F(t_з1+t_з2), (2)
а гармоническое напряжение U на выходе фильтра 10 равно
U =

sin(ΠFτ)

cos2ΠF

t-t

+ cos2ΠF

t-t

, (3) где t_з1,t_з2 - время запаздывания эхо-сигналов первой и второй цели соответственно;
t - текущее время.When the echoes of two targets are resolved in range, the phase shift Δ φ of harmonic voltages

,

at the outputs of the filters 9, 10 will be
Δ φ = π F (t _z1 + t _z2 ), (2)
and the harmonic voltage U at the output of the filter 10 is
U =

sin (ΠFτ)

cos2ΠF

tt

+ cos2ΠF

tt

, (3) where t _z1 , t _z2 is the delay time of the echo signals of the first and second targets, respectively;
t is the current time.

= 2 cos 2ΠF

t

t

. (4)
Находя из системы двух уравнений (2) и (4) время запаздывания t_з1,t_з2 и соответствующие дальности целей R₁, R₂, получим формулы для определения дальностей целей в случае, когда эхо-сигналы двух целей разрешаются по дальности.The ratio of the amplitudes of the stresses U / U _o at the outputs of the filters 10, 9 will be

= 2 cos 2ΠF

t

t

. (4)
Finding from the system of two equations (2) and (4) the delay time t _z1 , t _z2 and the corresponding target ranges R ₁ , R ₂ , we obtain formulas for determining the target ranges in the case when the echo signals of two targets are resolved by range.

=

(7)
Находя из системы двух уравнений (6) и (7) время запаздывания t_з1,t_з2 и соответствующие дальности целей R₁, R₂, получим формулы для определения дальностей в случае, когда цели не разрешаются по дальности.In the case when the echoes of two targets in range are not allowed, the video pulses of the echoes of two targets at the output of the receiver 3 merge and the duration of the resulting pulse τ _Σ will be
τ _Σ = τ + (t _z2 -t _z1 ) / 2 (5)
In this case, the phase shift Δ φ and the ratio of the amplitudes U / U _o harmonic voltages at the outputs of the filters 9, 10 will be
Δ φ = 2 π F t _z1 , (6)

=

(7)
Finding from the system of two equations (6) and (7) the delay time t _z1 , t _z2 and the corresponding target ranges R ₁ , R ₂ , we obtain formulas for determining the ranges in the case when the targets are not resolved by range.

 Thus, the proposed method can be practically implemented, and the distinguishing features noted are essential and fundamentally necessary.

 The repetition rate F of the probe pulses is chosen from the same considerations as in a conventional pulsed range finder. The pulse duration τ is less than the pulse repetition period, but can be chosen much longer than in a conventional pulse range finder. The use of long pulses is advisable to attenuate the harmful effect of distortions of the pulse fronts on the accuracy of range measurement. The use of long pulses in the proposed method can improve the accuracy of measuring ranges in contrast to the conventional pulsed method of ranging, in which the use of long pulses reduces the resolution and accuracy of the range finder. In addition, the use of long pulses additionally reduces the necessary pulse power of the transmitter and simplifies the design of the feeder system of the pulse range finder.

 The device operates as follows.

на частоте следования F зондирующих импульсов. Амплитудный ограничитель 7 ограничивает амплитуды импульсов генератора модулирующего напряжения 5 до того же уровня, что и ограничитель 8. Узкополосный фильтр 9 выделяет из ограниченного по амплитуде модулирующего сигнала гармоническое напряжение

на частоте следования импульсов F. Фазометр 11 измеряет сдвиг фаз Δ φгармонических напряжений

,

. Вычислитель 12 определяет по результатам измерения сдвига фаз Δ φи отношению амплитуд напряжений U/U_o дальности двух целей R₁, R₂.A transmitter with a transmit-receive antenna 1 emits a probing signal in the form of a periodic sequence of rectangular radio pulses. Receiver 2 receives echoes from two air targets. The amplitude limiter 8 at the output of the receiver 3 limits the amplitude of the video pulses of the received echo signals of the targets to the same level. The narrow-band filter 10 extracts the harmonic voltage from the received signal

at a repetition rate F of probe pulses. The amplitude limiter 7 limits the amplitudes of the pulses of the modulating voltage generator 5 to the same level as the limiter 8. The narrow-band filter 9 extracts the harmonic voltage from the amplitude-limited modulating signal

at a pulse repetition rate F. The phasometer 11 measures the phase shift Δ φ of harmonic voltages

,

. The calculator 12 determines from the results of the measurement of the phase shift Δ φ and the ratio of the voltage amplitudes U / U _{o the} range of two targets R ₁ , R ₂ .

Claims (1)

PHASE METHOD FOR MEASURING THE RANGE OF TWO AIR TARGETS, namely, that they emit a sounding signal in the form of rectangular radio pulses of duration τ, where τ <T, T is the repetition period of rectangular radio pulses, τ is the duration of the radio pulses of the probe signal, receive target echo signals, emit video signals received echo signals, targets, identify the harmonic components at a frequency F from the modulating pulse signal of the transmitter and the video signals of the targets, measure the phase shift Δ φ of these components, characterized in that then the video signals and the modulating pulse signal are limited in amplitude to the same level, the ratio of the amplitudes of the extracted harmonic components is measured, and the ranges to the targets R ₁ , R _{2 are} determined by the formulas
R ₁ =

-

arccos

;
R ₂ =

-

arccos

,
when targets are resolved by range and by formulas
R ₁ =

,
R ₂ = R ₁ -Cτ +

arcsin

sinπF

,
when range targets are not allowed,
where C is the speed of light;
U, U ₀ are the amplitudes of the harmonic components of the frequency signals F, extracted from the video signals of the targets and the modulating pulse signal, respectively.