SU1115586A1 - Doppler speed meter and altimeter - Google Patents

Abstract

DOPLER SPEED AND HEIGHT FLIGHT METER containing serially connected modulating voltage generator, frequency modulated oscillator transmitter and transmitting antenna serially connected receiving antenna, receiver, first phase detector, integrator and speed recorder connected in series second phase detector, lower filter frequency and height recorder, as well as a controlled oscillator, the output of which is connected to the reference -input of the first phase detector, and a flexible phasor the generator, the output of the modulating voltage generator is connected via a controlled phase shifter to the reference input of the second phase detector, and the output of the low-pass filter is connected to the control input of the controlled phase shifter, while the transmitting and receiving antennas are at a constant angle to the underlying surfaces, so that, in order to improve the accuracy of measuring the speed and altitude of the carrier, a filter, modulation frequencies, a scaling amplifier and an adder, the output of the first phase cell are introduced torus connected via a frequency filter with the modulation input of the second phase detector, the integrator output is connected through an adder to a control input e .mogo controlled oscillator, and an output controlled fasl zovraschatel soedinencherez scaling amplifier to a second input of the adder.

Description

The invention relates to radio navigation and can be used as a measure of the speed and altitude of flight of aircraft.

A Doppler velocity and altitude meter, containing a modulated voltage generator, a frequency modulated oscillator and a transmitting antenna, a serially connected receiving antenna, a receiver, a first phase detector, an integrator and a speed recorder, are connected in series with a second phase detector, filter low pass and height recorder, as well as a controlled oscillator, the output of which is connected to the reference input of the first phase detector, and controlled by zovrascha "OD Tel, wherein the generator effluent moduliruyuSL voltage is connected through

with controlled phase shifter with reference

The C0 OS input of the second phase detector, and the output of the low-pass filter are connected to the control input of the controlled phase shifter, with the transmitting and receiving antennas being directed at a constant angle to the underlying surface.

However, the known meter has insufficient accuracy in measuring the speed and altitude of the carrier.

The purpose of the invention is to improve the accuracy of measuring speed and altitude

carrier.

To do this, a Doppler velocity and altitude meter containing serially connected modulating voltage generator, transmitter of frequency modulated oscillation and transmitting antenna, serially connected receiving antenna, receiver, first phase detector, integrator and speed recorder, serially connected second phase detector, filter low pass and height recorder, as well as a controlled oscillator, the output of which is connected to the reference input of the first phase detector, and a controlled a phase shifter, the output of the modulating voltage generator is connected via a controlled phase shifter to the reference input of the second phase detector, and the output of the low-pass filter is connected to the control input of the controlled phase shifter, with the transmitting and receiving antennas being directed at a constant angle to the underlying surface, modulation frequency filter, scaling amplifier and adder, output of the first are introduced. the phase detector is connected via a modulation frequency filter to the input of the second phase detector, the integrator output is connected via a sum generator to the control input of the controlled oscillator, and the output of the controlled phase shifter is connected via a scaling amplifier to the second input of the adder.

The drawing shows a structural electrical circuit meter.

The meter contains transmitter 1 frequency-modulated oscillation, modulating voltage generator 2, receiver 3 ,. first phase detector 4, integrator 5. adder 6, transmitting antenna 7, receiving antenna 8, controlled oscillator 9, modulation frequency filter 10, second phase detector 11, low-pass filter 12, controlled phase-shifter-13, scaling amplifier 14, speed recorder 15 and height recorder 16.

The meter works as follows.

Transmitter 1 emits a signal modulated in frequency by a signal from a modulating voltage generator 2.

 ei (t) Ei cds (t -f cos Qt), (1)

where 1%, Aw, Q are the known carrier frequency, frequency deviation and modulation frequency.

The reflected signal at the output of the receiver 3 has the form

l2 (t) -E2COS 0npt

2 (2)

X cos (Q t - -7 ---- f- N) and C cos Go -

where ftJnp is the intermediate frequency; H - flight altitude;

Go - the installation angle of the antenna beam relative to the vertical:

(p is the phase of the reflected signal, which 0 takes into account the Doppler effect and is equal to

(p 0) gt-ry}. (3)

where Shd 2 Wo W / C is the Doppler frequency shift;

W is the velocity of the aircraft 5 (LA) in the direction of the radiation; 1 /; - random phase.

The signal of the controlled oscillator 9 is modulated in frequency by the signal of oscillator 2, phase-shifted in the controlled 0 phase channel 10, by an amount corresponding to the estimated value of the height H of the aircraft, and the frequency of the controlled generator 9 is shifted relative to the intermediate one by the estimated value of the Doppler 5 s. moving frequency corresponding to the estimated value of the speed of the slope W.

13 Ez cos Ыpp t + n

2, - and)

Xcos (Qtry-H) + v5

C cos

where 1/9 f {JoW t / C. (5)

The output signal from the receiver 3 is multiplied with the signal of the controlled oscillator 9 in the phase detector 4 of the velocity change channel 5. The output voltage of the phase detector 4 averaged over the modulation period is

, 2 Ai) .. QS

fi q I o -o-sin -f:, (6)

: S I n.

Cos go

.

0 where and (-tracking errors;

 - Bessel function of the first kind, nth order;

q is the coefficient characterizing the ratio of the signal power to the power of the noise arriving at the device input.

The output voltage of the phase detector 4 through the integrator 5, the adder 6 acts on the control element

0 of the generator 9, which adjusts the frequency of the generator 9 to the frequency of the output signal of the receiver 3, thereby reducing the magnitude of the error, / to zero. At the same time, the voltage at the output of the integrator 5 is proportional to the estimated Doppler frequency shift, which is converted in the Doppler frequency converter of the speed recorder 15 to a voltage proportional to the estimated speed W.

Claims (1)

A DOPPLER SPEED AND FLIGHT MEASURER, comprising a modulating voltage generator, a frequency modulated oscillation transmitter and a transmitting antenna, a receiving antenna, a receiver, a first phase detector, an integrator and a speed recorder, a second phase detector, a low pass filter and a height logger in series as well as a controlled generator. the output of which is connected to the reference input of the first phase detector, and the controlled phase shifter, the output of the modulating voltage generator being connected via a controlled phase shifter to the reference input of the second phase detector, and the output of the low-pass filter connected to the control input of the controlled phase shifter, while the transmitting and receiving antennas are directed At a constant angle to the underlying surface, they are distinguished by the fact that, in order to increase the accuracy of measuring the speed and height of the carrier’s flight, a filter is introduced, often modulation outputs, the scaling amplifier and adder, the output of the first phase detector is connected through the modulation frequency filter to the input of the second phase detector, the integrator output is connected through the adder to the control input of the controlled generator, and the output of the controlled phase shifter is connected through the scaling amplifier to the second input of the adder.