JP2979133B2 - Landing method and device by airborne radar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landing method and a landing apparatus that allow an aircraft to make a landing while judging an approach course by using a radar mounted on the aircraft.

[0002]

2. Description of the Related Art There are various methods for landing systems of aircraft that are to land at an airport. For example, IL
In S and MLS, for aircraft landing from the ground,
Guidance waves are emitted, and the approach course of the aircraft is set by the guidance waves. Therefore, the aircraft has landed on the runway according to the set approach course while receiving the guided radio waves.

[0003]

As described above, the aircraft lands along the approach course set by the guided radio waves from the ground, so that the set approach course is abnormally set for some reason. Even if this is done, there is no means on the aircraft side to detect this abnormality. Therefore, in such a landing system, the reliability of the entire system must depend on the ground surveillance system, and the aircraft must land with full confidence in the accuracy of the guided radio wave from the ground. There was a problem.

[0004]

According to the present invention, a pair of first reflectors C1 and C2 are separated from each other by a predetermined distance L1 in a direction orthogonal to a center line of the runway, and one of the runways of the runway is provided. The second reflectors E1 and E2 forming a pair are disposed parallel to and parallel to the center line of the runway at a predetermined distance L2 about an extension of the road end, and the first reflectors forming a pair C
1 and C2, are separated from each other by a predetermined distance L3 in a direction toward the other runway end facing the one runway end and in parallel with a direction along the center line of the runway.
The pair of third reflectors C3 and C4 are arranged in a direction from the pair of second reflectors E1 and E2 to the other runway end opposite to one runway end and on the runway. The first reflectors C1, C2 paired with the radar signals emitted by the aircraft approaching the runway are disposed in parallel with each other in the direction along the center line, and are spaced apart by a predetermined distance L4. The reflected signals are reflected by the reflectors C3 and C4, respectively, and the reflected signals are received on the aircraft side. From these received signals, the aircraft obtains its own azimuth information, and the pulse train of these received signals in the scanning angle direction is obtained. Are obtained, the antenna scanning angles corresponding to the peak values of the respective envelopes are obtained, and the average value of the two antenna scanning angles respectively corresponding to the paired first reflectors C1 and C2 is obtained. , And the third reflection that makes a pair The average value of the two antenna scan angles corresponding to C3 and C4 is obtained, and the magnitude relation between the two average values is compared. When both average values are equal, the azimuth approaching the aircraft to the runway is set to zero. And the radar signals emitted by the aircraft approaching the runway are reflected by the pair of second reflectors E1 and E2, respectively, and the reflected signals are received on the aircraft side. Information on the vertical approach angle of the own device is obtained. Further, the envelopes of the pulse trains in the scanning angle direction of the respective received signals are obtained, and the magnitude relation between the two envelopes is compared.
When the two envelopes match, the normal vertical approach angle of the aircraft is used. In the following, when simply referred to as the approach angle information and the approach angle, both indicate the approach angle information and the approach angle in the vertical direction with respect to the runway.

Further, according to the present invention, when the pulse width of the radar signal is W, the predetermined distance L2 between the pair of first reflectors C1 and C2 is parallel to the direction along the center line of the runway. At least (W / 4) around the extension of the runway edge
The first reflectors C1 and C2 forming a pair are provided at positions corresponding to a distance corresponding to μs.

The present invention also provides a radar mounted on an aircraft, which is spaced apart from the center line of the runway by a predetermined distance L1 in a direction perpendicular to the center line of the runway, and which is centered on an extension of the runway end in a direction along the center line. A pair of first reflectors C1 and C2 arranged at a predetermined distance L2 and a pair arranged at a predetermined distance L3 from the pair of first reflectors C1 and C2 in a direction along the center line. The second reflectors E1 and E
2, a pair of third reflectors C3 and C4 arranged at a predetermined distance L4 apart from the pair of second reflectors E1 and E2, and a radar signal emitted by an aircraft approaching the runway. , The pair of first and third pair of reflectors C1, C2 and C3, C4, respectively, are received on the aircraft side, and these received signals are signal processed to obtain azimuth information of the aircraft. And the signals reflected by the pair of second reflectors E1 and E2 are received by the aircraft, and the signals received are processed to calculate the approach angle information of the aircraft. The first pair
Reflectors C1, C2, third reflectors C3, C4 and second reflector
The reflected signals from the reflectors E1 and E2 are received on the aircraft side, and the received signals are time-processed and separated, and the received signals from the respective reflectors received on the aircraft side are separated. Envelope detecting means for respectively obtaining the envelopes of the pulse trains in the scanning angle direction, and the rising edges of the respective envelopes respectively corresponding to the first reflectors C1, C2 forming a pair and the third reflectors C3, C4 forming a pair. Antenna scanning angle calculating means for obtaining an antenna scanning angle corresponding to each peak value of the envelope from an antenna scanning angle corresponding to a half value of the peak value of the envelope with the falling edge, respectively;
The average value of the two antenna scan angles corresponding to each peak value of the envelope corresponding to the paired first reflector is obtained, and the respective peak values of the envelope corresponding to the paired third reflector are obtained. When the two average values are equal, the average value calculating means for obtaining the average value from the two antenna scanning angles corresponding to the above, the azimuth angle comparing means for comparing the magnitude relation between the two average values,
An azimuth angle calculating means for calculating the azimuth angle of the aircraft to be zero, and a magnitude relationship between two envelopes of the pulse train of the received signal respectively corresponding to the pair of second reflectors E1 and E2 obtained by the envelope detecting means. A signal processing device having an approach angle comparing means for comparing, an approach angle calculating means for calculating the approach angle to be zero as a normal approach angle of the aircraft when the two envelopes coincide, an azimuth angle of the aircraft; BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landing apparatus that displays an approach course of an aircraft determined from information and approach angle information and a display device that displays a position of the own aircraft so that the approach course of the own aircraft can be set on the aircraft side.

Further, in the present invention, the first and third reflectors C1, C2 and C3, C4 forming a pair each use a corner cube type reflector.

Further, in the present invention, each of the pair of second reflectors E1, E2 uses a corner reflector.

Further, according to the present invention, the pair of second reflectors E1, E2 are formed in a tapered shape symmetrical with respect to an orthogonal axis orthogonal to the corner axis of the reflectors E1, E2. It is.

Further, in the present invention, the tapered shape of the pair of second reflectors E1, E2 is a Taylor curve type.

Also, the present invention provides a radar signal having a pulse width of W
, The predetermined distance L2 between the pair of first reflectors C1 and C2 is a distance corresponding to at least (W / 4) μs about an extension of the runway end in a direction along the centerline of the runway. The present invention relates to a landing gear in which a pair of first reflectors C1 and C2 are installed at such positions as:

Further, according to the present invention, when the approach angle of an aircraft specified at each airport is α = 3 degrees, a second reflector disposed on the left side of the center line of the runway with respect to the approach direction of the aircraft. The plate E1 has its main axis serving as the central axis of the main lobe of the reflector E1 perpendicular to the runway surface (α-0.
5 °), installed in the direction opposite to the approach direction of the aircraft, and arranged on the right side of the center line of the runway, the second reflector E2 has a main axis serving as the central axis of the main lobe of the reflector E2. , Perpendicular to the runway surface (α + 0.5
The present invention relates to a landing gear that is inclined by an angle (degrees) and installed in a direction opposite to the approach direction of the aircraft.

[0013]

1 to 1 show an embodiment of the present invention.
3 will be described in detail. FIG. 1 shows an embodiment of the present invention.
Reflectors C3, C4 paired with the reflectors C1, C2 of FIG.
And a layout diagram showing the positional relationship between the pair of second reflectors E1 and E2, FIG. 2 is a configuration diagram showing an embodiment of the present invention, and FIG. 3 is a corner cube type used in the embodiment of the present invention. FIG. 3 is a perspective view of a main part of the reflection plates C1 to C4, showing corner axes A and B;
And the main axis P are shown. FIG. 4 shows an embodiment of the present invention, and is a perspective view of a main part of a corner type reflector E1, E2 formed in a tapered shape.
B and the main axis P are shown.

FIG. 5 is a reflection characteristic diagram of a plane including a corner axis AB and a main axis P of a normal corner-type reflector, and FIG.
Is the corner axis AB of the normal corner-type reflector shown in FIG.
FIG. 7 shows an embodiment of the present invention. FIG. 7 shows a reflection characteristic on a surface including a corner axis AB and a principal axis P of a tapered corner-type reflector. FIG. 8 is a reflection characteristic diagram on a plane perpendicular to the plane including the corner axis AB of the tapered corner-type reflector shown in FIG.

FIG. 9 shows an embodiment of the present invention. FIG. 9 is an exploded plan view of the reflector when the corner-type reflector is formed in a Taylor curve type. FIG. 10 shows the Taylor curve type reflector shown in FIG. FIG. 11 is a plan view showing an installation state, FIG. 11 is an explanatory diagram illustrating a state in which an approach course is set based on the installation position and reflection characteristics of a corner-type reflector, and FIG. 12 shows a case where the approach angle of the aircraft 1 is lower than the set angle. FIG. 13 is an example of a reception waveform diagram, and FIG. 13 is an explanatory diagram for explaining how to determine the antenna scanning angle corresponding to the peak value of the envelope H.

In FIG. 1, reference numeral 1 denotes an aircraft on which a radar 10 described later is mounted. 2 is runway, 3 is runway 2
Are a pair of first reflectors C1 and C2 for reflecting radar signals, and a third reflector C3 and a pair which will be described later.
Along with C4, it is for obtaining azimuth information of the aircraft 1 with respect to the runway 2 and is separated from the centerline 3 of the runway 2 by a predetermined distance L1 in a direction orthogonal to the centerline 3, that is, in a lateral direction of the centerline 3. The two runways 2 are arranged at a predetermined distance L2 apart from each other with a center on an extension line 5 of one runway end 4 parallel to a direction along the center line 3 of the runway 2.

Therefore, the predetermined distance L2, which is the distance difference between the reflectors C1 and C2, is such that the radar signals reflected from the left and right reflectors C1 and C2 can be separated and received. is necessary. Therefore, if the pulse width of the radar signal radiated from the radar 10 mounted on the aircraft 1 is W μs, the predetermined distance L2 is arranged at a distance at least equal to (W / 4) μs. I have.

In this embodiment, since a weather radar is used as the radar 10 mounted on the aircraft 1, the pulse width W of the radar signal is 1 μs (300 m in terms of transmission distance). is there. Therefore, the predetermined distance L2 is 75 m. That is, the distance difference (2 × L2) between the reflector C1 and the reflector C2 in the direction along the center line 3 is 1
It is set to 50 m.

In this embodiment, as shown in FIG. 3, a corner cube type reflector is used as each of the first reflectors C1 and C2. The reflection characteristic of the corner cube type reflector is such that when the aircraft 1 is located in front of the reflectors C1 and C2 and is within 45 degrees vertically, horizontally, and horizontally with respect to the front axis, the radar signal is totally reflected in the direction of the aircraft 1. You can do it.

Reference numerals E1 and E2 denote a pair of second reflectors for reflecting radar signals from the aircraft 1, for obtaining information on the approach angle of the aircraft 1. The pair of second reflectors E1 and E2 are separated from the center line 3 of the runway 2 by a predetermined distance L1 in a direction perpendicular to the centerline 3 of the runway 2, and the other runway end 4 is located opposite to the one runway end 4. ′, And are spaced apart from the first reflectors C1 and C2 by a predetermined distance L3 in parallel with the direction along the center line 3, and are located between the reflectors E1 and E2. Center line 3
Is 2 × L2. In the case of this embodiment, as shown in FIG. 4, the second reflectors E1 and E2 are both corner-shaped reflectors having the same structure and the same dimensions. Are formed in a tapered shape symmetrical with respect to orthogonal axes U and V orthogonal to the corner axis AB.

The corner-type reflectors used as the second reflectors E1 and E2 generally have a corner axis AB and an axis P (center axis of the main lobe) of the reflector E0 as shown in FIG. Are reflection characteristics having a very narrow reflection area (a narrow main lobe MR and side lobes SR are shown) with respect to the front of the reflection plate E0. On the other hand, as shown in FIG. 6, a plane perpendicular to the plane including the corner axis AB has a reflection characteristic having a reflection area of ± 45 degrees.

Then, the normal corner type reflection plate E0 is
It is formed by bending or laminating a rectangular plate at 90 degrees. In the case of such a reflector E0, as shown in FIG.
In addition to R, there is a side lobe SR of about -13 dB. Therefore, in the case of a moving object such as the aircraft 1, whether the received signal is due to the main lobe MR or the side lobe SR
It is not possible to discriminate between the side lobes SR as far as practically possible without any hindrance.

Therefore, in the present invention, as shown in FIGS. 4 and 7, the reflecting surface of the reflecting plate is symmetrical with respect to the orthogonal axis U and the orthogonal axis V (the direction of the main lobe MR) orthogonal to the corner axis AB. It is formed in a tapered shape. The size of the side lobe SR differs in the form of this tapered shape.

For example, each of the taper shapes is cos
^{In the case of the two} curves, the cos curve, and the triangular type, the magnitudes of the side lobes obtained from the general antenna theory are −32 dB, −23 dB, and −26.4 dB, respectively. The size of the SR can be set to an arbitrary size. Therefore, in the case of this embodiment, as shown in FIGS.
Is used. A Taylor-curve-type reflector that can be set to an arbitrary size is used.

C3 and C4 are paired third reflectors for reflecting radar signals. The other reflectors E1 and E2 separate the other runway end 4 from the other one. 'And the center line 3 of runway 2
Are arranged in parallel with each other at a predetermined distance L4. In the case of this embodiment, the predetermined distance L4 is 1
It is set to be about 000 m. The predetermined distance L4 is appropriately set to about 1000 m in consideration of the fact that the reflection plate is similarly installed for the approach of the aircraft 1 from the opposite direction of the runway 2. These values must be unified at each airport when this device is actually installed at each airport.

In FIG. 2, reference numeral 10 denotes a radar mounted on the aircraft 1. In this embodiment, a weather radar is used. Numeral 11 denotes a signal processing device, which receives a radar signal emitted from a transmitter 10a of the aircraft 1 entering the runway 2 with first and third reflectors C1, C2 and C3.
The reflected signals are respectively received by C4, and the reflected signals are received by the receiver 10b of the radar 10, and the signals are processed to calculate the azimuth information of the aircraft 1, and the second reflectors E1, E
2 is received, and signal processing is performed to calculate approach angle information of the aircraft 1. Reference numeral 12 denotes a display device, which displays the approach course of the aircraft 1 based on the azimuth and approach angle of the aircraft 1 obtained by the signal processing device 11, and also displays the position of the aircraft 1 with respect to the runway.

As shown in FIG. 2 and FIG. 13, the signal processing device 11 receives signals from a pair of first reflectors C1, C2, third reflectors C3, C4, and second reflectors E1, E2. Receiving signal separating means 13 for receiving the respective reflected signals on the aircraft 1 side, and time-processing and separating the received signals;
Envelope detecting means 14 for respectively obtaining the envelope of the pulse train in the antenna scanning angle direction of the signal received on the aircraft 1 side, and the rising and falling of each of the envelopes thus obtained. Antenna scanning angles θu1, θu2, θu3 corresponding to half the peak value
From θu4 and θd1, θd2, θd3, θd4, the antenna scanning angle θp corresponding to the peak value of the envelope H, respectively.
1, θp2, θp3, and θp4, respectively, and a pair of first reflectors C1, C
The average value .theta.a of the antenna scanning angles is obtained from the two antenna scanning angles .theta.p1 and .theta.p2 corresponding to the peak values of the envelope of the second envelope, and similarly, the peaks of the third reflectors C3 and C4 forming a pair. An average value calculating means 16 for obtaining an average value θb of the antenna scanning angles from the two antenna scanning angles θp3 and θp4 corresponding to the values is provided.

Further, an azimuth comparing means 17 for comparing the magnitude relation between the two average values θa and θb,
When a is larger than the average value θb, the aircraft 1 is located on the left side of the center line 3 of the runway 2, and when the average value θa is smaller than the average value θb, the aircraft 1 is located on the right side of the center line 3 of the runway 2. When the average value θa is equal to the average value θb, the azimuth angle calculating means 18 for calculating that the aircraft 1 is located on the center line 3 of the runway 2 and the second angle obtained by the envelope detecting means 14 are obtained. Envelope comparing means 1 for comparing the magnitude relationship between two envelopes of the pulse train of the received signal corresponding to the reflectors E1 and E2, respectively.
9 and when the envelope of the pulse train received from the reflector E1 is larger than the envelope of the pulse train received from the reflector E2, the aircraft 1 is determined to be lower than the normal approach angle, and the envelope of the pulse train received from the reflector E1 is When the envelope is smaller than the envelope of the pulse train received from the reflector E2, the aircraft 1 is higher than the normal approach angle, and when the two envelopes are equal in magnitude, the aircraft 1 is assumed to have the normal approach angle. Means 20.

Next, the specific shape of the tailor curve type reflector used in this embodiment as the second reflectors E1 and E2 will be described with reference to FIGS. When the half width of the reflected beam of the Taylor curve type reflector is set to 2 degrees, it is found from the usual antenna theory.
The length of the corner axis AB needs to be about 35 times the used wavelength.

Therefore, the radar 10 mounted on the aircraft 1 is a weather radar, and its wavelength is about 3 cm.
0 is 100 W (50 dBm), the length of the corner axis AB of the Taylor curved reflector is 35 × 3
= 105 cm is required.

The transmission power of the radar 10 is 50 dBm.
When the effective area of the reflector is 1.50 m ² ,
Normally, the receiver 10b of the radar 10 has a sufficient S / N because its receiving sensitivity is about -80 dB.

From these results, the second reflector E1,
As shown in FIGS. 9 and 10, the size of E2 is 1.05 m for the corner axes A and B, the length of the orthogonal axes U and V of the reflector is 2.8 m, and such a size. When the reflector is bent at a right angle and the reflector is assembled, the length is 2 m and the side lobe at that time is -40 dB, so that the level is lower than the noise of the receiver 10 b of the radar 10 and the approach course is erroneously recognized. I will not do it.

Next, a method of installing the second reflectors E1 and E2 for obtaining the approach angle α of the aircraft 1 will be described. First, assuming that the approach angle α of the aircraft 1 is 3 degrees, which is generally used worldwide, an installation method for obtaining the approach angle α of 3 degrees by the second reflectors E1 and E2 will be described. .

As shown in FIG. 11, the characteristic of the reflector E1 disposed on the left side of the runway 2 when viewed from the aircraft 1 approaching the airport is the central axis of the main lobe of the reflector E1. It is installed with the main axis P inclined 2.5 degrees backward, that is, in a direction perpendicular to the plane of the runway 2 by (α-0.5) degrees in the direction opposite to the approach direction of the aircraft 1. I have.
Accordingly, the main axis P1 of the second reflector E1, that is, the center of the main lobe MR1 is 2.5 degrees.

Similarly, the characteristic of the reflector E2 disposed on the right side of the runway 2 is that the principal axis P, which is the central axis of the main lobe of the reflector E2, is moved backward by 3.5 degrees. That is, it is installed in a state of being inclined in a direction perpendicular to the plane of the runway 2 by (α + 0.5) degrees in a direction opposite to the approach direction of the aircraft 1. Therefore, the main axis P of the second reflector E2
2, that is, the center of the main lobe MR2 is at 3.5 degrees. Therefore, the approach course of the aircraft 1 is
Intermediate line S of the main shafts of R1 and main lobe MR2
And the approach angle α = 3 degrees is obtained.

Next, the operation will be described with reference to FIGS. 1, 2, 12, and 13. FIG. A radar signal (transmission pulse T0) is radiated from a transmitter 10a of a radar 10 mounted on the aircraft 1 entering the runway 2. This radar signal is reflected by the first and third reflectors C1 to C4 and the second reflectors E1 and E2 arranged on both sides of the runway 2. Each of the reflected signals is received by the receiver 10b of the radar 10.

At this time, as shown in FIG. 12, when the radar 10 sweeps one time, each of the reflectors C1 to C4,
The time position is determined by the installation positions of E1 and E2, and received as corresponding pulse trains. The received signal composed of these pulse trains is input to the signal processing device 11 and subjected to signal processing as described below to obtain azimuth angle information and approach angle information.

First, the case where the azimuth information is obtained will be described. The time position of each received signal reflected from each of the reflectors C1 to C4, E1, and E2 and received by the receiver 10b of the radar 10 corresponds to each of the reflectors C1 to C4, E
Since the installation positions of E1 and E2 are determined, as shown in FIG. 12, the reflection signal from the reflection plate C1 is received at time T1. Similarly, the reflection signal from the reflection plate C2 is time T2, and the reflection signal from the reflection plate C3 is time T3.
4 is received at time T4. Thus, the time position of each received signal can be predicted in advance.

Therefore, the reflected signals from the reflecting plates C1 to C4 are first time-processed and separated by the received signal separating means 13, respectively. In this embodiment, since the pulse width W of the radar 10 is 1 μs, the following relationship exists between the reception times of the reflected signals. T2-T1 = T4-T3 = T6-T5 = 1 μs T3-T1 = T4-T2 = 2 μs T5-T3 = T6-T4 = (1000/300) × 2 μs

Here, the reflection plate C1 will be described as an example. Each pulse train separated as described above is shown in FIG.
As shown in (2), the envelope detecting means 14 obtains the envelope H of the pulse train with the change of the antenna scanning angle θ for the received pulse train received at the same distance. Next, in the antenna scanning angle calculation means 15, the antenna scanning angles θu1 and θd1 corresponding to the half value of the peak value of the envelope H at the rising and falling edges of the envelope H are obtained,
From these two antenna scanning angles θu1 and θd1, an antenna scanning angle θp1 corresponding to the peak value HP of the envelope H is obtained. Similarly, the antenna scanning angle θp of the reflector C2
2 is required.

Each of the reflectors C1 and C2 thus determined
When the antenna scanning angles .theta.p1 to .theta.p4 corresponding to the peak values of the envelopes C3 and C4 are obtained, the average value calculating means 16 calculates the peaks of the envelopes of the paired first reflectors C1 and C2. −antenna scanning angles θp1, θ corresponding to peak values
An average value θa of p2 (= [θp1 + θp2] / 2) is obtained, and similarly, each antenna scanning angle θp3 corresponding to the peak value of the envelope of the pair of third reflectors C3 and C4.
From θp4, the average value θb (= [θp3 + θp4] /
2) is required. The azimuth of the aircraft 1 with respect to the runway 2 is determined from the magnitude relationship between the average values θa and θb of the two antenna scanning angles.

That is, the average value θ of the two antenna scanning angles
The magnitudes of a and θb are compared by the azimuth angle comparison means 17, and the azimuth angle calculation means 18 calculates the azimuth of the aircraft 1 with respect to the runway 2.

That is, when both average values are equal, the aircraft 1 is located on the center line 3 of the runway 2 and the first reflectors C1, C2
Is smaller than the average value θb of the third reflectors C3 and C4, the aircraft 1 is located on the left side of the center line 3 of the runway 2, and the average value θa of the first reflectors C1 and C2. Is the third
Is larger than the average value θb of the reflectors C3 and C4, the aircraft 1 is located on the right side of the center line 3 of the runway 2. This state is displayed on the display device 12 as an image. Therefore, the pilot of the aircraft 1 is controlled manually or automatically by watching the display screen so that the two average values θa and θb are always equal.

Next, the case where the approach angle information is obtained will be described. The radar 1 is reflected from each of the reflection plates E1 and E2.
For each of the received signals received by the 0 receiver 10b, the envelope detecting means 14 calculates the envelope H of the pulse train with the change of the antenna scanning angle θ for the received pulse train received at the same distance in the same manner as described above. Can be

The envelopes of the reflectors E1 and E2 obtained in this way are compared with each other in the envelope comparison means 19, and the approach angle calculation means 20 calculates the approach angle of the aircraft 1 to the runway 2 by the approach angle calculation means 20. An angle is calculated.

Here, as shown in FIG. 11 and as described above, the half value characteristic of the reciprocation of the incident and reflection characteristics of the reflection plates E1 and E2 is as follows.
Since the approach angle α of the aircraft 1 is 3 degrees, the magnitudes of the envelopes of the radar reflected signals from the reflectors E1 and E2 are equal.

On the other hand, when the approach angle α of the aircraft 1 is lower than 3 degrees, the magnitude of the envelope of the reflected signal from the reflector E1 is larger than the magnitude of the envelope of the reflected signal from the reflector E2. growing. Conversely, when the approach angle α of the aircraft 1 is higher than 3 degrees, the envelope of the reflected signal from the reflector E2 becomes larger than the envelope of the reflected signal from the reflector E2. Therefore, on the aircraft 1 side, the aircraft may be controlled so that the magnitudes of the envelopes of the radar reflected signals from the reflectors E1 and E2 are equal.

The difference in the spatial attenuation of the reflected signal due to the difference in the distance at which the reflectors E1 and E2 are installed needs to be corrected when the aircraft 1 approaches the vicinity of the runway 2. Further, the distance from the aircraft 1 to the touchdown point on the runway 2 is measured by the ordinary distance measuring means. At this time, the position of the received pulse is a position corresponding to the half value of the rising portion of this pulse.

[0049]

According to the present invention, a pair of first reflectors C is provided.
1 and C2 are separated from each other by a predetermined distance L1 in a direction orthogonal to the center line of the runway and parallel to a direction along the center line of the runway with an extension of one end of the runway as a center. A pair of second reflectors E1 and E2 arranged at a distance L2 away from the pair of first reflectors C1 and C2 toward the other runway end facing one runway end. And arranged in parallel with the direction along the center line of the runway at a predetermined distance L3, and
And the second reflectors E1, E forming a pair.
2 and are separated from each other by a predetermined distance L4 in a direction toward the other runway end facing the one runway end and parallel to a direction along the center line of the runway, and enter the runway. Radar signal emitted by a flying aircraft
Reflectors C1, C2 and a third reflector C3 forming a pair
The aircraft receives the reflected signals at C4, receives the reflected signals on the aircraft side, obtains the azimuth information of the aircraft from these received signals, and generates the envelope of the pulse train in the scanning angle direction of each of these received signals. The antenna scanning angles corresponding to the peak values of the respective envelopes are determined, the average values of the two antenna scanning angles respectively corresponding to the paired first reflectors C1 and C2 are determined, and the paired antenna scanning angles are further determined. The average value of the two antenna scanning angles respectively corresponding to the third reflectors C3 and C4 is determined, and the magnitude relationship between the two average values is compared. When both average values are equal, the aircraft enters the runway. The azimuth is set to zero, and the radar signals emitted by the aircraft approaching the runway are reflected by the pair of second reflectors E1 and E2, respectively, and the reflected signals are received by the aircraft. Receiving From the signal, the aircraft obtains its own approach angle information, further obtains the envelope of the pulse train in the scanning angle direction of each of these received signals, compares the two envelopes, and compares the two envelopes. When the lines match, the aircraft's normal approach angle is used, so the information necessary for landing can be obtained using the radar normally mounted on the aircraft. And reliability is improved. In addition, the abnormality of the approach course due to the radio wave abnormality can be judged on the aircraft side, so that the reliability of the pilot for the landing system is improved. In addition, since the aircraft can grasp its position with respect to the runway, the landing course can be freely selected.

In addition, on the ground side, it is sufficient to simply install a reflector for reflecting radar radio waves at a predetermined location, which is very economical as a landing system and economical without the need for maintenance on the ground. It is.

Further, according to the present invention, when the approach angle of the aircraft specified at each airport is α = 3 degrees, the second position is located on the left side of the center line of the runway with respect to the approach direction of the aircraft. The reflection plate E1 has its main axis set to (α-0.
5 [deg.]) In the direction opposite to the approach direction of the aircraft, and the second reflector E2 disposed on the right side of the center line of the runway has a main axis of this reflector E2 of ([alpha] +0.5 [deg.]). Only the installation angle is set in the direction opposite to the approach direction of the aircraft, so that the approach angle of the aircraft can be arbitrarily selected according to the installation angle of the second reflectors E1 and E2.

Further, according to the present invention, a pair of second reflectors E1 and E2 each use a corner reflector and are symmetric with respect to an orthogonal axis perpendicular to the corner axis of the corner reflector. The second reflectors E1 and E2 forming a pair have a Taylor curve shape, so that side lobes can be suppressed and a side lobe of any size can be suppressed. The lobe can be set and the exact course can be set.

[Brief description of the drawings]

FIG. 1 is a layout diagram showing an embodiment of the present invention.

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

FIG. 3 is a perspective view of a corner cube type reflection plate.

FIG. 4 shows an embodiment of the present invention and is a perspective view of a corner-type reflector.

FIG. 5 is a view showing reflection characteristics of a surface including a corner axis of a conventional corner-type reflector.

FIG. 6 is a diagram showing reflection characteristics of a surface perpendicular to a corner axis of the reflector shown in FIG. 5;

FIG. 7 shows an embodiment of the present invention, and is a view showing reflection characteristics of a surface including a corner axis of a reflecting plate formed in a tapered shape.

FIG. 8 shows an embodiment of the present invention, and is a view showing reflection characteristics of a surface perpendicular to a corner axis of a reflecting plate formed in a tapered shape.

FIG. 9, showing an embodiment of the present invention, is a view showing a state where a Taylor curve type reflector is developed.

10 is a plan view showing the embodiment of the present invention and showing a state where the tailor curve type reflection plate shown in FIG. 9 is assembled.

FIG. 11 shows an embodiment of the present invention and is an explanatory diagram for setting an approach course of an aircraft.

FIG. 12 shows an embodiment of the present invention, and is a diagram illustrating a reception waveform when an approach angle of an aircraft is lower than a set approach angle.

FIG. 13 shows the embodiment of the present invention, and is an explanatory diagram for obtaining a peak value of an envelope of a received signal.

[Explanation of symbols]

 C1, C2 First reflecting plate forming a pair C3, C4 Third reflecting plate forming a pair E1, E2 Second reflecting plate forming a pair P Main axis H perpendicular to corner axes A, B of the reflecting plate H Envelope 1 Aircraft 2 Runway 3 Runway centerline 4 Runway edge 10 Radar 11 Signal processing device 12 Display device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B64F 1/18-1/20 B64D 45/04 G01S 13 / 60,13 / 91

Claims (9)

(57) [Claims] 1. A pair of first reflectors C1 and C2 are separated from each other by a predetermined distance L1 in a direction orthogonal to a center line of a runway, and a center of an extension of one runway end of the runway is centered. And a pair of second reflectors E1 and E2 are disposed in parallel with each other along the center line of the runway and at a predetermined distance L2 from each other, and
A predetermined distance L in a direction from the reflectors C1 and C2 to the other runway end opposite to the one runway end and parallel to a direction along the center line of the runway.
The third reflectors C3 and C4, which are arranged at a distance of 3 and are paired with each other,
In the direction from the reflectors E1, E2 to the other runway end facing the one runway end, and
A radar signal emitted by an aircraft approaching the runway is disposed in parallel with a direction along the center line of the runway and at a predetermined distance L4 apart from each other.
The signals are reflected by the pair of first reflectors C1, C2 and the pair of third reflectors C3, C4, respectively, and the reflected signals are received on the aircraft side. Obtains the azimuth information of its own device, further obtains the envelope of the pulse train in the scanning angle direction of each of these received signals, and obtains the antenna scanning angle corresponding to the peak value of each of the envelopes. The average value of the two antenna scanning angles respectively corresponding to the paired first reflectors C1 and C2 is obtained, and the average value of the two antenna scanning angles respectively corresponding to the paired third reflectors C3 and C4 is calculated. An average value is obtained, and the magnitude relationship between the two average values is compared. If the two average values are equal, the azimuth of approach of the aircraft to the runway is set to zero, and the aircraft launched into the runway fires at the azimuth angle. −
The reflected light is reflected by the pair of second reflectors E1 and E2, and the reflected signals are received on the aircraft side. From these received signals, the aircraft obtains vertical approach angle information of the aircraft itself, Further, the envelope of the pulse train in the scanning angle direction of each of these received signals is obtained, and the magnitude relationship between the two envelopes is compared. When the two envelopes match, the normal vertical direction of the aircraft is obtained. Landing method using an aircraft-borne radar. 2. When the pulse width of the radar signal is W, the predetermined distance L2 of the pair of first reflectors C1 and C2 is parallel to a direction along the center line of the runway. At least (W) about the extension of the one runway end.
4. The landing method using an aircraft-mounted radar according to claim 1, wherein said pair of first reflectors C1 and C2 are provided at positions corresponding to a distance corresponding to .mu.s. 3. A runway end of one of the runways, which is separated from a radar mounted on an aircraft by a predetermined distance L1 in a direction orthogonal to a centerline of the runway and parallel to a direction along the centerline. Of the pair of first reflectors C1 and C2 arranged at a predetermined distance L2 apart from each other about the extension of
Parallel to the direction from the pair of first reflectors C1 and C2 to the other runway end facing the one runway end and along the centerline of the runway. And a pair of second reflectors E1 and E2 arranged at a predetermined distance L3 apart from each other, and the other runway facing the one runway end from the pair of second reflectors E1 and E2. A pair of third reflectors C3, C4 arranged at a predetermined distance L4 apart from each other in a direction toward an end and in parallel with a direction along the center line of the runway, and enter the runway; The radar signals emitted by the aircraft are transmitted to the pair of first and third reflectors C1, C2.
And the signals reflected by C3 and C4 are received on the aircraft side, and the signals received are processed to calculate the azimuth information of the aircraft, and the pair of second reflectors E
1, the signals reflected by E2 are received on the aircraft side, and these received signals are signal-processed to calculate vertical approach angle information of the aircraft, and these received signals are time-processed and separated. Receiving signal separating means, an envelope detecting means for obtaining an envelope of a pulse train in the scanning angle direction of a signal received from each of the reflectors received by the aircraft, and a first reflector C1 forming the pair. , C2, and the pair of third reflectors C3, C4, respectively, from the antenna scanning angle corresponding to the half value of the peak value of the envelope of each of the rise and fall of each of the envelopes. Antenna scanning angle calculating means for respectively obtaining antenna scanning angles corresponding to the respective peak values of the line; and corresponding to the respective peak values of the envelope corresponding to the pair of first reflectors C1 and C2. One of the calculated average of these values from the antenna scan angle, the third reflector C3 forming the pair, C4
Average value calculating means for calculating an average value of the two antenna scanning angles corresponding to each peak value of the envelope corresponding to the average value; azimuth angle comparing means for comparing a magnitude relationship between the two average values; When the two average values are equal, the azimuth angle calculating means for calculating the azimuth angle of the aircraft to be zero and the reception means respectively corresponding to the pair of second reflectors E1, E2 obtained by the envelope detecting means. A vertical approach angle comparing means for comparing the magnitude relationship between two envelopes of the signal pulse train, and, when the two envelopes coincide, setting the approach angle to zero as a normal vertical approach angle of the aircraft. A signal processing device having an approach angle calculating means for calculating; and a display device for displaying an approach course of the aircraft determined from azimuth angle information and approach angle information of the aircraft and for displaying a position of the aircraft. Features Landing gear by airborne radar. 4. The pair of first and third reflectors C
4. The landing gear according to claim 3, wherein each of C1, C2, C3 and C4 uses a corner-cue reflector. 5. The pair of second reflectors E1, E2.
5. An aircraft mounted laser according to claim 3, wherein each of said lasers uses a corner type reflector.
Landing gear by da. 6. The pair of second reflectors E1, E2.
6. The landing by means of an aircraft-mounted radar according to claim 5, wherein said reflector is formed in a tapered shape symmetrical with respect to an orthogonal axis orthogonal to a corner axis of said reflectors E1, E2. apparatus. 7. The landing apparatus according to claim 6, wherein the tapered shape of the pair of second reflectors E1 and E2 is a taper curve type. . 8. When the pulse width of the radar signal is W, the predetermined distance L2 of the pair of first reflectors C1 and C2 is parallel to a direction along the center line of the runway. At least (W /
4) The pair of first reflectors C1 and C2 are installed at a position corresponding to a distance corresponding to μs, according to the radar mounted on an aircraft according to each of claims 3 to 7. Landing gear. 9. When the vertical approach angle of an aircraft defined at each airport is α = 3 degrees, the second aircraft disposed on the left side of the center line of the runway with respect to the approach direction of the aircraft. The reflecting plate E1 moves its main axis, which is the center axis of the main lobe of the reflecting plate E1, in the direction perpendicular to the runway surface by (α-
0.5 degrees), installed in the direction opposite to the approach direction of the aircraft, and the second reflector E2 disposed on the right side of the center line of the runway is located at the center of the main lobe of the reflector E2. The main axis, which is the axis, is perpendicular to the runway surface (α + 0.
The landing apparatus using an aircraft-mounted radar according to any one of claims 3 to 8, wherein the landing apparatus is tilted by 5 degrees) and installed in a direction opposite to the approach direction of the aircraft.