RU1809400C - Method of measuring tangential component of object speed - Google Patents

Abstract

Usage: measuring the speed of an object. SUMMARY OF THE INVENTION: a pulse is emitted of a timp duration, a repetition period of T0, a reflected pulse is received, a range D to the object is measured, direction 0 | the arrival of the received signal, after a time T0, a second pulse is emitted, a reflected one is received, the direction of arrival 2 is measured, the tangential component of the velocity of the object VT is determined by the above formula. 3 il ..

Description

The invention relates to radar and radio navigation and can be used to measure the tangential velocity of objects in superscan systems.

A differential method for measuring the tangential velocity of a spacecraft is known, which consists in measuring the Doppler frequency td for several positions of the spacecraft in the traverse range rm and generating a signal proportional to the tangential speed of the spacecraft based on the obtained system of equations

fds - - f s

VT

V1 - (Gt / G |) W

There is a method of measuring the tangential velocity VT (3, p. 314), which consists in emitting a signal with a wavelength of A in the direction of the target, receiving a signal reflected from a moving target by two antennas spaced apart by interval d, measuring the direction © of the target, measuring the frequencies fi and f2 of the signals ( from the outputs of both antennas), followed by subtracting the results fi-f2, - measuring the distance D to the target and generating a signal proportional to the tangential velocity, in accordance with the expression

Yo

00

about

 2

Oh Oh

VT 0

fi -f2

d / A cos 0

(2)

This differential method has limited capabilities (measurement in the region of Tm) and low measurement accuracy when using the fast scanning method due to the non-uniformity of the scanning law t (0) (or 0 (t)).

However, this method has a low measurement accuracy, because requires high identity of both receive and f channels. as well as in the case of using the fast scanning method due to the neglect of differences in the durations of emitted (received) signals in different directions and requires large antenna sizes d.

Closest to the proposed one is a method of measuring the tangential velocity VT, which consists in emitting a radio signal with a wavelength of I, receiving two points of the reflected signal spaced apart by a distance d, measuring the direction to target 0, and directly measuring the frequency AF of the beats of two received signals (fi and fa ), measuring the distance to the target D and generating a signal proportional to the tangential velocity of the target VT, in accordance with the expression

.

- ° - sgU g: I

However, this method has a low accuracy of VT measurement, since it does not take into account differences in the durations of emitted (received) signals (when measuring D and 0) and requires two spaced receiving points or one antenna with a large base d.

The purpose of the invention is to increase the accuracy of measuring the tangential velocity of an object with a one-point location system based on quick scanning by taking into account the change in the duration of the emitted pulses with a change in direction.

This goal is achieved by the fact that in the known method of measuring the tangential velocity by directly measuring the beat frequency of two received signals, which consists in emitting a radio pulse, receiving a radio pulse reflected from the object, measuring the distance D to the object, measuring the receiving direction 01, additionally again after time T0 emit and receive a radio pulse, measure the direction 02 of receiving a pulse and generate a signal proportional to the tangential velocity VT of the object, according to the expression

VT D.

That is tnep (01) + tnep (02.)

-.(4)

where tnep (0) is the law of scanning the beam of the antenna when radiating a radio pulse.

The essence of the method is as follows.

The antenna beam scans according to the law tnep (0) (or © nep (t)) and during the duration of the emitted pulse, the gypsum rotates in the sector (0n, 0n + 0obz). After a certain period of time, the GPS in the same sector begins to scan the antenna beam along

tnp (0) (or 0np (t)) to receive the signal reflected from the object

tnp (O) 0; tnp (0be) GPR,

those. the sector review time (0n. 0n + 0be) at reception is equal to gpr. During scanning of the antenna beam, a signal reflected from a moving target is received from a certain direction 01. Signal reception direction 01 is measured.

01 0pr (TI) - 0o,

(5)

where ri is the moment of termination of the pulse reflected from the target

TI tnp (0i + 0b);

0o - beam width (radiation pattern) of the antenna. The distance to the DI target is measured.

Dl-J- Gimp - tnep (01) + GLP + ti. (6)

After a certain time rp after the end of the scan to receive tnp (0o6a) rp. the antenna beam scans again in the field of view (0n. 0n + © review) BY the Law tnep (0) AND

the antenna emits a radio pulse (Fig. 1, 2)

That Gimp + TPP + GPR + Gp.

(7)

After the time of the hfp, at the end of the radiation of the radio pulse tnep (0o6a), the gimp antenna beam begins to scan according to the law tnp (0) to receive signals: tnp (o) 0. During scanning, the reflected signal is received from some direction 02 (in the general case 0i 0g) pulse. The receiving direction (02) is measured (FIG. 1)

(8)

where G2 is the moment of termination of the action of the received impulse

T2 tnp (02 + 0o).

According to the obtained data, a signal is generated proportional to the value of the tangential component of the target velocity, in accordance with the expression

VT D

01-0

t;

, (9)

WHERE TO TO - tnep (0l) - tn «p (0z),

(YU)

where VTT0 is the segment of the path that the object traverses during the time T0 along the tangent to a circle of radius D and the center at the point of the phase center of the antenna (point 0 in Fig. 2);

0 (01 - 02) - the length of the arc, determined by the central angle equal to (0i - 0g) radians.

Due to the smallness of VrTo, we can assume that the length of the arc D (© i - © 2) and the segment of the tangent to this circle are equal.

Consider the accuracy characteristics of the proposed method in comparison with the prototype.

Let the prototype determine VT at one point from two measurements at time instants tio and t20, with t20 being tio To. Then

V / D

d sin ©

I 1 dAy d sin 0 2 d t

-D

2 dVe-gr () D

Afc

d sirT0 d

L (Acose) D-Af

"D

F

 D

Tn

The resulting expression (11) in form coincides with the proposed (9), because in the prototype measurements are made with errors

5D -i- 5T -§- ti-tnep (0i); (12)

 1

(thirteen)

.- 2 L Eo + 0pr (q) - © pr (ri);

b That I That - That I I tnep (02) - tnep (0l) I, (14)

where 0b is the beamwidth of the antenna. Expression (14) is written for the absolute error of measuring the angle 0 in comparison with the traditional measurement of direction by the fork method

(r-,) + 0np (ti) rs ri ti (15)

where TS is the duration of the received signal. The dispersion of the measurement of the tangential velocity component in the linear approximation is

((Th-Ch ™ Ґ

 2 Dlaj + egab + D2 0Spto / T and

(sixteen)

Toi

Taking into account errors (12) - (14), we can write

twenty

M (x-x0-dx) 2 ± M (x-x0) 2 + (d x) 2, x (D.Th, 0) t.

(17)

25 Then the increase in the accuracy of VT measurement by the proposed method in comparison with the prototype is determined by the value

 - (A /, rvT

VT

021 ((3p) 2 + 2p (a0) 2 + p21v2, (3t0) 2 / t:

Toy

preerem t20

y t

(eleven)

vaipe

(12)

thirteen)

(14)

noah and no

(fifteen)

ala. Noah at16)

40

10

(eighteen)

35 where "3D, b ©, dT0 are determined according to (12H14).

Thus, the proposed method allows to increase the accuracy of measuring the tangential velocity of an object with a one-point location system using fast scanning methods by (18) by taking into account the change in the duration of the emitted pulses (Fig. 1) with a change in the direction of their arrival due to the tangential movement goals (taking into account the scanning laws tnep (0), 0np (t) in expressions (12) - (14).

In FIG. 3 presents a system that implements the proposed method of measurement

50 tangential velocity of the object.

A system that implements the proposed method for measuring the tangential velocity of an object consists of an antenna 1, an antenna control system (SUA) 2, an antenna switch 55 (transmitter) 3, a transmitter 4, a receiver 5, pulse termination pulse shaping devices (UVIS) 6 and 7, triggers 8, 9 and 10, time interval meters (IVI) 11, 12 and 13, the processor 14, counters-dividers by 2 (CT) 15 and 16, the element Exclusive OR 17 and the clock generator 18, and the information input of the antenna 1 is connected to the output of the AP -3, the first input of the AP 3 is connected to the input of the receiver 5, the output

5 of receiver 5 is connected to the inputs of UVIOS 6 and 7, the output of UVIOS b is connected to the inputs of the zero setting of triggers 8 and 9, the output of UVIOS 7 is connected to the input of the installation to the zero state of trigger 10, the outputs of triggers 8, 9 and 10 are connected to IVI inputs 11. 11 and 13, respectively, IVI outputs 11. 12 and 13 are connected respectively to the third, second and first inputs of the processor 14, the processor output

15 14 is the output of the VT system, the start-up input of the device is connected to the inputs of the initial installation of triggers 8, 9 and 10 and the start-up input of the clock-18, the output of the clock 18 is connected to the clock inputs of the AP 3, transmitter 4 and SUA 2 and to the input of CT 15 , the output of the ACS 2 is connected to the control input of the antenna 1. the output of the transmitter 4 is connected to the second input of the AP 3, the output of CT 15 is connected to the first input of the exclusive OR 17 element and to the input of CT 16, the output of CT 16 is connected to the unit input to the unit state trigger 8 and the second input of the element Exclusive OR 17, output d XOR element 17 is connected to the setting inputs of a single state of flip-flops 9 and 10.

A system implementing this method operates as follows.

The start pulse at the start input of the system transfers the triggers 8, 9 and 10 to the initial (zero) state and starts the clock generator 18. On the first pulse from the clock generator 18, the AP 3 connects the output of the transmitter 4, which generates the emitted pulse with the duration of the gyms (Fig. 1), to the input of the antenna 1, and the SUA 2 at the same time provides a scan of the beam of the antenna 1 during the pulse duration of the transmitter 4 timp in a given sector He, He + Sbz) according to the law tnep (69 {or GViep (t). This is the first pulse from the output of the clock 18 goes to the input of CT 15. At the end action of the pulse of the transmitter 4 SUA 2 translates the beam of the antenna 1 in the initial & direction. After time inn (Fig. 2), the clock generator 18 generates a second pulse. On the second pulse of the clock generator 18 AP 3 connects the output of the antenna 1 to the input of the receiver 5, and SUA 2 provides scanning the beam of antenna 1 during the time of scanning in the field of view (E, E +) according to the law tnp (©) (or GVip (t). The same second pulse is fed to the input of CT 15, the output of which is a pulse. The pulse from the output of CT 15 is supplied to the first input of the element EXCLUSIVE OR 17, and since at its second input, there is a zero level from the output of CT 1 b, this pulse appears at the output of the EXCLUSIVE OR element 17 and sets the triggers 9 and 10 to the single state. A single signal from the outputs of the triggers 9 and 10 is supplied to the inputs of the IVI 12 and 13, respectively. The IVI 11, 12 and 13 operate, for example, according to the method of counting pulses. From the moment of supply of a single signal, IVI 12 and 13 begin the measurement. The radio pulse reflected from the target (Fig. 1, 2) is received by the antenna 1 and through the AP 3 it is fed to the input of the receiver 5. From the output

0

of the receiver 5, the video pulse is fed to the inputs of the UVIOS 6 and 7 (for example, single-vibrators). Moreover, UVIOS 6 forms a pulse whose front corresponds to a decline,

and UVIOS 7 is the pulse whose front corresponds to the front of the video pulse of receiver 5. The pulse from the UVIS 7 output is fed to the setup input to the zero state of trigger 10, the output of which has zero potential. The zero potential from the output of the trigger 10 is fed to the input of the IVI 13, which corresponds to the moment the measurement is completed. The measurement result (for example, code) ti from the output of IVI 13 is fed to the first input

5 of microprocessor 14. A pulse from the output of UVIOS 6 will transfer trigger 9 from a single to a zero state. The zero potential from the output of the trigger 9 will go to the input of the IVI 12, which will correspond to the moment the measurement is completed. The measurement result n from the output of IVI 12 is supplied to the second input of the processor 14.

After a certain period of time after the end of scanning the antenna beam on

5 receiving tnp (6b63) fnp clock 18 generates a third pulse. This pulse from the output of the clock generator 18 is fed to the input of the AP 3, which connects the output of the transmitter 4 to the input of the antenna 1, and to the input of the ACS 2, which scans the beam of the antenna 1 during the pulse width of the transmitter Timp 4 in a given sector (Ok EVi + wobz) under the law tnep (6) (or GViep (t)). The same third pulse from the output of the clock generator 18 is supplied to the input of CT 15. At the end of the pulse of the transmitter 4 (tnep () Timp. (Timp) bbz) ACA 2 transfers the beam of antenna 1 to the initial direction Ey. After time Tpp, the clock 18 generates a fourth pulse. On the fourth pulse of the clock generator 18 AP 3 connects the output of the antenna 1 to the input of the receiver 5, and the ACS 2 provides scanning of the beam of the antenna 1 for the time of geodesy in the field of view according to the law tnp (3) (or (t)). The same fourth pulse from the output of the clock generator 18 is supplied to the input of CT 15, the output of which is transmitted to the second pulse. This second pulse from the output of CT 15 is fed to the input of CT 16 and the first input of the exclusive OR element 17. At the same time, the output of CT 16 receives a pulse that arrives at the second input of the exclusive OR 17 element, therefore, the output of the exclusive OR 17 element is not wits impulse, i.e. there will be zero potential. This zero potential from the output of the exclusive OR 17 element is supplied to the inputs of the installation in

0

5

0

5

0

5

the single state of the triggers 9 and 10, therefore, the triggers 9 and 10 will remain in the zero state. The pulse from the output of CT 16 is input to the unit in the single state of trigger 8 and will transfer it from zero to the single state. A single signal from the output of trigger 8 is supplied to the input of IVI 11, which begins the measurement. The radio pulse reflected from the moving target (Figs. 1, 2) is received by the antenna 1 and fed through the AP 3 to the input of the receiver 5. The video pulse from the output of the receiver 5 is fed to the inputs of UVIOS 6 and 7, the outputs of which are pulses through. Pulses from the outputs of UVIOS 6 and 7 are fed to the installation inputs to the zero state (Reset) of triggers 8, 9 and 10. As a result, triggers 9 and 10 will not change their zero state, and trigger 8 will go from single to zero state . This transition will occur at the moment of arrival of the pulse from the output of UVIOS b, which generates a pulse whose front coincides with the fall of the video pulse at the output of receiver 5. The moment of occurrence of the zero potential at the output of trigger 8 (i.e., at the input of IVI 11) corresponds to the moment the measurement is completed for IVI 11. The measurement result T2 from the output of IVI 11 goes to the third input of the processor 14. After the signal arrives at the third input, the processor 14 calculates in accordance with the algorithm

,, with VT - -tg

01 - © 2) Gimp - tnep (© 1) TPP + M j

Then tnep (© 1) + tnep (© 2)

(nineteen)

where © о is the beam width of the antenna (for example, in terms of half power); 40

D -§- Gimp - tnep (© 1) + GLP + tl. (twenty)

- range to the target (Fig. 1, 2).

Thus, compared with the known method of measuring the tangential velocity of an object, it is possible to increase the accuracy of measuring VT by a value of (18) by a single-point location system using the super scanning method by taking into account differences in the durations of emitted signals with a change in the direction of their arrival due to the tangential movement of the target, t .e. The object of the invention has been achieved.

Claims (1)

SUMMARY OF THE INVENTION A method for determining the tangential component of an object’s speed, including emitting a pulse with a duration of Gimp and a repetition period of To, receiving a reflected signal during ultrafast scanning of an antenna beam in sector © bbz during a Timp, and determining the speed from the results of processing the received signals, characterized in that, in order to increase the accuracy of the measurement, the distance D to the object and the direction 0i of arrival of the received signal are measured, a second pulse is emitted after the time T0 after the pulse is emitted and received The reflected signal is received, the direction of its arrival 02 is measured, and the tangential component of the object’s speed VT is determined by the formula 35 VT That - tnep (07) + tnep (© 2) where tnep (0) is the law of scanning the beam of the antenna when radiating a radio pulse, feJ