JPS6249278A - Ground range measuring radar - Google Patents

Abstract

PURPOSE:To form a null point for signal processing on a point to be ranged and improve a range measuring accuracy by changing the quantity of changeover of a main beam vertically changed over in accordance with a range measuring angle. CONSTITUTION:The beam data computing unit 10a of a signal processor 6 calculation based on a predetermine expression and two adders 12a. The beam directional angle of a main beam is corrected by the correcting angle computing unit 15 and the adders 12 so that the received signals of the main beam vertically changed over with respect to a range measuring angle are equal to one another in terms of the range measuring angle. Since beam directional angle data are controlled such that the received signals of the main beam vertically changed over are equal to one another in terms of synthetic signals agree with each other, that is, a null point is formed on a point being ranged, enabling an accurate range measurement to be performed by detecting the distance of the null point.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is installed in an aircraft, etc. This relates to improving the accuracy of ground ranging radar, which measures the distance to the ground.

[Conventional technology]

Figure 3 is a diagram showing the configuration blocks of a conventional ground ranging radar.
1i is a navigation sensor, (5) is a dive angle input section, (6) is a signal processor (3), and is a beam data calculation section in the Shingetsu processor (6), which switches all beam data.

It consists of addition, reduction', (12a), (12b), offset Nn departure, and distance measurement angle calculation I.

Conventional ground ranging radars are configured as described above. For example, the transmitting wave from the excitation/receiving (F< device (2) The waves are phased array antenna (1
1, it becomes a received wave, and is converted into a digital signal by an excitation/receiver (2). At this time, the beam controller (31) receives the beam directivity angle data from the beam data calculation unit Ql, and controls the main beam direction of the phased array antenna (1) by one step (41) (the main beam width is adjusted to the ranging angle). The signal processor (6) synthesizes these two received waves (difference [7 subtraction)].
By doing this, a null point is formed at the distance measurement point, and distance measurement is realized by detecting the distance of this null point.

In addition, the beam data calculation unit On in the signal processor (6) calculates phased data based on attitude angle data from the navigation sensor (4) and ranging dive angle data set by the operator etc. from the dive angle input unit (51). The beam directivity angle data θ+, θ−) of the array antenna (1) is calculated, and the beam controller (3)
Send to old-2.

Here, an example of the operation of the ground ranging radar is shown in Figure 4'5r.
I agree and add more. In Figure 4, α is the ground ranging radar, and e! +1 is aircraft, (c) is ground or sea surface, (c)
.

Main beam switched vertically of phased array antenna 0), (C) distance measurement axis, cat horizontal axis, (B)
These are the mechanical boresight axis of the phased ray antenna (1), (c) the dive angle for distance measurement, and (b) the angle for distance measurement.

In this case, the main beam (c) is switched up and down with respect to the ranging angle (1), which is the angle between the mechanical boresight axis (c) and the ranging axis field. f61
By combining (difference 1. subtraction), a null point in the distance measurement angle & J force direction is formed, and by detecting the distance of this null point, the distance measurement axis (
b) The ground or sea surface (c) Ground ranging radar c! I
It is possible to measure distances up to m.

[Problem that the invention attempts to solve]

As mentioned above, the conventional ground ranging radar calculates the distance by processing the signal of the receiving number 4 of the two main beams Q3 and Q4 which are switched upward and downward with respect to the ranging angle (2).

When the distance measurement angle (c) increases, two main beams (to)
.

Due to the shape difference of @, the composite signal 01) θ is
There is a difference between the null angle υ1 of B and the distance measurement angle ■ (Δφ2−−−・−θ
0・−一鵠 However, [7, θ0 ke distance measurement angle, θB1j distance measurement angle distance measurement v.

2.

main beam width. ) Occurrence 1-5 There was a problem in that the distance measurement accuracy was poor.

This invention was made to solve the above problems, and an object thereof is to obtain a ground ranging radar with good ranging accuracy.

[Failure to solve the problem]

In the ground ranging radar system according to the present invention, the switching amount of the main beam which is switched up and down with respect to the ranging angle is changed without regard to the ranging angle.

[Effect]

In this invention, since the control 11 is performed so that the receiving numbers 4 of the two main beams switched up and down have the same distance measurement angle 1, the distance measurement angle 0I2 null point angle (to) coincides with 1. Accurate distance measurement is possible.

〔Example〕

Fig. 1 is a block diagram showing an embodiment of the present invention. Items (1) to (51) in Fig. 1 are exactly the same as the above-mentioned conventional ground ranging radar. (6a) is a signal processor. can be,
The difference from the conventional method is that the beam data calculation unit (j08) calculates the correction amount tJ! Add 9 and add 1 (f2a) l, and add 7 to ii.

By this correction amount calculation QS and two additions (12a).

Main beam (c) switched downward to − at the distance measuring angle
.

The main beam (c), c! The beam direction angle of 4 is corrected.

Here, an example of correction amount calculation will be shown.

The distance measurement angle is θ0. If the main beam width at the distance measurement angle is θB, the correction value Δθ is sharp. (However, 17. The beam switching interval is θB and 1.

) In the ground ranging radar configured as above, the beam directivity angle data (θ+, θ
-) is controlled so that the null point angle (to) of the distance measurement angle and the composite signal 01 coincides with t, as shown in Figure 2, that is, a null point is formed at the distance measurement point, and the null point is Accurate distance measurement is possible by detecting the distance between points. .

By the way, in the above explanation, this invention was described as a method of switching the transmitting and receiving main beams upward and downward with respect to the ranging angle, but this invention It goes without saying that it can also be used by switching the main beam up or down with respect to the distance measurement angle and directing the other main beam to the distance measurement angle.

〔Effect of the invention〕

This invention ij As explained above, by a simple method of changing the switching amount of the main beam that switches up and down depending on the distance measurement angle, a null point for signal processing can be formed at the distance measurement point, and the distance measurement accuracy can be improved. This has the effect of improving.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing characteristics of the present invention, and FIG. 3d is a block diagram showing a conventional ground ranging radar. FIG. 4 is a diagram showing an example of the movement of a ground ranging radar, and FIG. 5 is a diagram showing the characteristics of a conventional ground ranging radar. J in the figure? And (1) is Phase Door】/Iyntenna. (2) Kei excitation/receiver, (31ij, beam controller,
(4) is a navigation sensor, (51 is a dive angle input section, (6
1, (6a) is the IH-number processor, (Ill (10a) is the beam data calculation unit, 01) is the beam data switch,
(12a) and (12b) are Calo arithmetic and subtraction. al is the offset f! 111-out, o4) calculates the ranging angle, o Kazu calculates the amount of correction, (a) shows the ground ranging radar, a
II is the aircraft, ff13 is the ground or sea surface, (c) @ is -L, the main beam below. (C) is distance measurement -1, rA is horizontal axis, @ke mechanical voise axis, @d distance measurement dive angle, device is distance measurement angle, (to) is null point angle, ((I) is composite The same reference numerals in each figure indicate the same or 11 corresponding parts.

Claims (1)

[Claims] A phased array antenna that forms an entrance and exit for transmitted waves and received waves into space, an excitation/receiver that forms a source of transmitted waves and converts received waves into digital signals, and a beam direction of the phased array antenna. and a beam controller that controls the shape, a navigation sensor that detects the attitude angle of the phased array antenna, a dive angle input unit that inputs the ranging dive angle, and a signal processor that mainly processes received digital signals. The signal processor has a distance measurement angle based on the attitude angle data from the navigation sensor and the distance measurement dive angle data from the dive angle input section (however, the distance measurement angle is determined by the phase door (This is the angle between the mechanical boresight axis of the ray antenna and the ranging axis.) Calculate the main beam of the phased array antenna with respect to the ranging angle by 0.3 to 0.6 times the main beam width. Beam data switching to switch up and down at regular intervals, offset amount calculation to switch the main beam up and down, and correction amount calculation to make the received signals of the main beam switched up and down equal at the measuring angle. What is claimed is: 1. A ground ranging radar characterized by comprising a beam data calculation section for performing