JPS58123484A - Radar height-measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve accurate measurement of the altitude in a low altitude flight by extropolative calculation between two beams when the amplitude difference of beams exceeds a specified max. amplitude difference. CONSTITUTION:Amplitude values[AL, AL+1]from a height measuring radar 10 are inputted into an amplitude comparator 11 to inform a data section 16 of the center beam 3 larger in the amplitude, the elevation angle of which is outputted to an elevation angle calculating section 17. The comparator 11 feeds the amplitude values AL and AL+1 of two beams to an amplitude substactor 12 to compute the difference therebetween and an absolute value¦AL-AL+1¦is taken and inputted into a comparator 13 to compare the difference in the amplitude values of the beams with AMAX value. When the comparator 13 shows AMAX<AL-AL+1, the amplitude value¦AL-AL+1¦is fed to an amplitude extrapolation section 15 to calculate an extrapolated elevation angle thereof. Elevation angles phiL and phiL+1 from the data section 16 and the extrapolated elevation angle from the amplitude extrapolation section 15 are inputted into an elevation angle calculation section 17 to determine an elevation angle which is inputted into a height measuring calculation section 18. The height measuring calculation section 18 calculates the altitude H by R sin phi with the distance R inputted from the radar 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar height measurement device for a height measurement radar that performs two-beam amplitude comparison.

Generally, a height measuring radar measures the altitude of a target using a number of beams having different elevation angles. Conventionally, this height-measuring radar obtains altitude information by comparing the amplitudes of two adjacent beams, but if there is a target between the two beams, it is possible to measure the height of that target. The problem was that there was a large error in height measurement of targets flying outside the two-beam range.

The purpose of the present invention is to solve the above-mentioned drawbacks by performing height measurement by extrapolation even for targets flying outside the 2 beams of the height measurement radar, and to improve the flight altitude of low-altitude flights. To provide a radar height measuring device capable of accurately measuring heights.K
be.

The radar height measurement device of the present invention includes an amplitude comparing means for comparing radar target signal levels received by two antenna beams having different elevation angles and selecting a beam having a higher signal level; difference calculation means for calculating the difference in signal level between the two beams; and when the output level difference of this difference calculation is larger than the signal level difference of each beam at the peak angle of one of the beams measured in advance, a correction angle proportional to this level difference is calculated. an extrapolation calculation means for performing extrapolation calculations; an elevation angle of the radar target is calculated from the correction angle calculated by the extrapolation calculation means and the angle on the side of the larger signal level selected by the amplitude means; and radar distance information is obtained. and altitude calculation means for inputting and calculating the altitude of the radar target.

FIG. 1 shows an operational principle of height measurement in the case of pencil beam scanning according to an embodiment of the present invention.

This figure shows a state in which an aerial radar [1] with a pencil beam of a height measuring radar captures an eye 192 with beams 3 and 4. Let the received intensity amplitude value and elevation angle value of one beam 3 be AL, φLJ=, respectively, and the received intensity amplitude value and elevation angle value of this beam and the adjacent beam 4 be AL+I, respectively.
Assign φL+1. First, compare the amplitude values (ALAt, ++) of each beam 3 and 4 from this height measurement radar,
As a result of the comparison, a central beam (3) with a large amplitude is determined. If the difference between these beam amplitude values exceeds the predetermined maximum amplitude difference (Mu person Accurate altitude values can be obtained.

FIG. 2 is a basic configuration diagram of an embodiment of the present invention.

First, the amplitude value (AL, -AL
+1) is input to the amplitude comparator 11, and as a result of this comparison, the center beam (3) with the larger amplitude is input to the data section 1.
6, and this data section 16 outputs the elevation angle value of the center beam to the elevation angle calculation section 17.

Next, the comparator 11 calculates the amplitude values AL of the two beams.

AL+1 is supplied to the amplitude subtracter 12, and a difference calculation (AL-
AL+1) and its absolute value l AL-AL+11
is input to the amplitude comparator 13. In addition, from the data section 16 into which measured values have been input in advance, the difference AMAX value between the amplitude of the other O beam and 1.: when one beam has the maximum amplitude is supplied to the amplitude comparison 1s) 13, and the subtracter 12 A comparison is made with the manually generated amplitude difference IAL-AL+11.

Next, in this comparator 13, %AMAX≧AL-A
In the case of L+1, the amplitude value IAL− is sent to the amplitude interpolation processing unit 14.
Supply AL++l and calculate the interpolated elevation angle (φσ) (φ
σ−K・l AL −AL+1 Matadashi K is constant Wk)
. Also, in the comparator 13, AMAX<AL AL+1
In this case, the amplitude value I AL -AI is sent to the amplitude extrapolation processing unit 15.
, +1 l and calculate its extrapolated elevation angle (φσ) (
φσ=to−IAL−Ar,++l).

The elevation angle φL φL+1 from the data section 16 + the interpolated elevation angle φσ from the amplitude interpolation processing section 14 or the extrapolated elevation angle φσ from the amplitude extrapolation processing section 15 are input to the elevation calculation section 17 and output. This height measurement calculation unit 18 inputs the distance R from the radar 10,
Calculate the altitude H using Rgtnφ.

Note that the data control unit 19 uses the clock from the radar 10 to form timings for performing control to sequentially perform processing in each of these circuits.

Further, in this embodiment, the extrapolation angle calculation is performed using a constant ratio measurement &(K), and this is because a logarithmic amplifier is used in the radar receiving device.

As described above, the present invention has the effect of preventing a height measurement error of a height measurement radar device to a target outside the adjacent two beams by comparing the two beam amplitudes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the operating principle of the present invention, and FIG. 2 is a block diagram showing an embodiment of the present invention. In the diagram, 1... antenna, 2... target, 3, 4...
...beam, 10° ... height measurement radar, 11
．． 13...Par° amplitude comparator, 12...Amplitude subtractor, 14...Amplitude interpolation processing unit, 15...
...Amplitude extrapolation processing section, 16... Data section, 17
. . . Elevation angle calculation section, 18 . . . Height measurement calculation section, 19 . . . Data control section.

Claims (1)

[Claims] amplitude comparison means for comparing radar target signal levels received by two antenna beams with different elevation angles and selecting the beam with the larger signal level; and an amplitude comparison means for calculating the difference in signal level between the two beams. calculation means; and extrapolation calculation means for extrapolating a correction angle proportional to this level difference when the output level difference of this difference calculation is larger than the signal level difference of each beam at the peak angle of one of the beams measured in advance. , the elevation angle of the radar target is calculated from the correction angle calculated by the extrapolation calculation means and the angle of the larger signal level selected by the amplitude comparison means, the radar distance information is inputted, and the altitude of the radar target is calculated. A radar height measurement device including an altitude calculation means for calculating.