JP2000028707A - Bi-static active processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain position localization by a bi-static processing using an RDT (rotary direction transition) system. SOLUTION: A position input terminal 1, transmission array position input terminal 2, and reception array position input terminal 3 are connected with an array relative angle calculating means 4. A transmission setting azimuth input terminal 5 is connected with a transmission starting azimuth deciding means 6. The array relative angle calculating means 4 is connected with the transmission starting azimuth deciding means 6, and the transmission starting azimuth deciding means 6 is connected with a right side transmission sequence deciding means 7-1 and a left side transmission sequence deciding means 7-2. The right side transmission sequence deciding means 7-1 and the left side transmission sequence deciding means 7-2 are connected with a transmission array 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a transmitting array and a receiving array located at different positions from each other.
The present invention relates to a bistatic active process and an apparatus for performing a target location limitation using a transmission method.

[0002]

2. Description of the Related Art In a conventional bistatic processing method,
By using the ODT (Omni Directional Transmission) transmission method that transmits signals in all directions at once with the transmission array as the center, the reflected signal from the target is received by the receiving array, and the transmitted signal and the received signal are compared. The target is detected, and the position is limited based on the time difference between the transmission time and the reception time of the reflected signal from the target, and the reception direction of the reflected signal.

FIG. 1 is an explanatory diagram of a position limiting method in a conventional bistatic processing method using the ODT transmission method. For the sake of simplicity, the description will be made assuming that the transmission array and the reception array are on the X-axis, and that the origin is located between the two arrays. In other cases, however, by appropriately selecting the coordinate axes, It can be easily converted. In FIG. 1, when the distance between the center S of the transmitting array and the center R of the receiving array is L, O
It is assumed that the transmission signal transmitted in all directions by the DT transmission is reflected after reaching the target T (x, y), and is received at the time Tr in the direction θr. The position of the target T exists on an ellipse having a constant propagation distance c (Tr-Ts) obtained from the propagation speed c and the propagation time Tr-Ts of the signal with the transmission array center S and the reception array center R as focal points. (However,
Let c be the signal propagation speed). By finding the intersection of this ellipse and the receiving azimuth line, the position of the target is limited and becomes as follows.

[0004]

(Equation 1)

[0005]

SUMMARY OF THE INVENTION However, ODT
In transmission, since the signal is transmitted from the transmitter in all directions at once, the transmission signal output per direction becomes weak,
It was difficult to detect long distances. On the other hand, in the case of RDT transmission in which a signal is sequentially transmitted from the transmitter in one direction at a time, if the output power is the same, the ODT is theoretically possible.
Since the transmission signal output per direction is stronger than the transmission, it is excellent for long distance detection. However, when RDT transmission is used, it is difficult to determine which transmission signal the received signal corresponds to, so that the position of the target cannot be limited by the bistatic process.

The problem will be described below with reference to FIG. Third
The figure shows a problem of bistatic processing when RDT transmission is used. It is assumed that a transmission signal output from a transmitter is reflected on a target to generate a reflected signal, and the receiver receives the signal at a time Tr and an azimuth θr. RDT
In the case of transmission, since the transmission beam is rotated with time, even when the transmission signal transmitted to the azimuth θs at time Ts returns from the target T and returns, the transmission transmitted to the azimuth θg at time Tg When the signal is reflected back from the target G, it is also received in the reception direction θr. That is, on the azimuth line of the reception azimuth θr, there is a possibility that there is a target corresponding to a plurality of transmission beams in the azimuth θg and the azimuth θs, and the transmission beams cannot be distinguished. As described above, in the RDT transmission method, there is a possibility that a single reception direction may be reflected by a plurality of transmission beams. For this reason, there is a problem that it is difficult to limit the position of the target unless the transmission beam can be specified.

[0007]

[Means for Solving the Problems] RDT (Rotatary Direction)
al Transmission) a transmitter that transmits a signal by a transmission method, and a receiver that is located at a different position from the transmitter and receives a signal transmitted from the transmitter, and the transmitter transmits the signal in a predetermined transmission order. Send.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 <Configuration> FIG. 3 is a functional block diagram of a bistatic processing apparatus according to Embodiment 1 of the present invention.

A position input terminal 1 for inputting a transmission array reference direction, a transmission array position input terminal 2 for inputting transmission array position information, and a reception array position input terminal 3 for inputting reception array position information are array relative angles. Calculation means 4
Connect to A transmission setting azimuth input terminal 5 to which a transmission azimuth (hereinafter referred to as a transmission setting azimuth) preset in the transmission array (relative to the transmission array reference azimuth) is input is connected to a transmission start azimuth determining means 6.

Array relative angle calculation means for inputting the transmission array reference direction, the transmission array position, and the reception array position
4 is connected to the transmission start direction determination means 6, and the transmission start direction determination means 6 is connected to the right transmission order determination means 7-1 and the left transmission order determination means 7-2. The right transmission order determining means 7-1 and the left transmission order determining means 7-2 are connected to the transmission array 8.

<Operation> Next, the operation of the bistatic transmission device will be described. The transmission array reference direction information input from the transmission array reference direction input terminal 1 and the transmission array position information input from the transmission array position input terminal 2 and the reception array position information input from the reception array position input terminal 3 are array-relative. It is sent to the angle calculation means 4. The array relative angle calculation means 4 calculates the relative angle of the transmission / reception array center with respect to the transmission array reference azimuth, and sends the result to the transmission start azimuth determination means 6.

The transmission setting direction input from the transmission setting direction input terminal 5 is sent to the transmission start direction determining means 6. The transmission start direction determining means 6 selects an angle closest to the array relative angle and sandwiches the array relative angle from among the transmission setting directions, sets the right transmission start direction to the right transmission order determining means 7-1, and sets the left transmission start direction to the left. It is sent to the transmission order determining means 7-2.

A method of determining the transmission start direction will be described with reference to FIG. FIG. 6 is an explanatory diagram of a transmission start direction and an order in the bistatic processing device of the first embodiment.
a to j are transmission setting directions. Suppose now that the receiving array is located behind the transmitting array and the relative angle between the transmitting array and the receiving array is azimuth R. The orientations closest to R among the transmission setting orientations are e and f. At this time, the direction e away from R on the right side of the transmission array reference direction is selected as the right transmission start direction, and the direction f away from R on the left side of the transmission array reference direction is selected as the left transmission start direction. When the receiving array is located in front of the transmitting array and the array relative angle is F, c is similarly selected as the right transmission start direction and b is selected as the left transmission start direction.

The reason for determining the transmission start direction as described above will be described below. Now, assuming that the distance between the centers of the transmitting and receiving arrays is L, the signal propagation speed is c, the transmitting beam direction is θ _si , and the receiving beam direction is θ _r , a reflector exists on the center direction line of the beam transmitted at the transmission time ti. Assuming that the reflection has been performed, the reception time tr of the reflected wave from the reflector is as follows.

[0015]

(Equation 2)

Here, a case is considered in which the transmission order of the transmission beams is transmitted in the direction (A direction shown in FIG. 1) approaching sequentially from a direction outside the receiving array. FIG. 4 is a plot of a direction receiving direction-receiving time curve when a beam is transmitted from a direction outside the receiving array to a direction approaching sequentially. This is a plot of a reception azimuth-reception time curve for a positive half surface with the transmission beam azimuth θ _si as a parameter. Point D represents the reception time and reception direction of the reflected signal from the target. In the case of FIG. 4, there may be a case where a reflection signal by a transmission beam transmitted in the past at a short distance is received earlier than a reflection signal by a transmission beam transmitted thereafter. In this case, it is difficult to specify the transmission beam corresponding to the point D, so that the propagation time from transmission to reception is not determined, so that the target position limitation is impossible.

Next, consider a case where the transmission order of the transmission beams is transmitted in a direction (direction B shown in FIG. 1) that is sequentially separated from the direction of the receiving array. FIG. 5 is a plot of a direction reception direction-reception time curve when a beam is transmitted in a direction sequentially away from the direction of the receiving array. This is a plot of a reception azimuth-reception time curve for a positive half surface with the transmission beam azimuth θ _si as a parameter. D point ●
The reception time and the reception direction of the reflected signal from the target are shown. From FIG. 5, it can be seen that since the reflected signals can be received in the transmission order of the transmission beams, it is possible to separate the transmission beams without intersecting the reception azimuth-reception time characteristics and to specify the transmission beam. In this way, by transmitting the transmission order of the transmission beam of the RDT transmission in a direction (B direction and C direction shown in FIG. 1) sequentially away from the direction on the receiving array side, the transmission beam can be specified and the target beam can be specified. Location limitation becomes possible.

Next, when the determination results of the right and left transmission start orientations are input to the right transmission order determination means 7-1 and the left transmission order determination means 7-2, respectively, the right transmission order determination means 7- 1 and the left-side transmission order determining means 7-2 determine the transmission order of the beams so as to transmit the transmission beams sequentially in a direction away from the direction of the array relative angle, and output the result to the transmission array 8.

For example, assuming that the array relative angle is R in FIG. 6, the right transmission order is e, d, c, b, a.
The transmission order on the left side is f, g, h, i, j. Also, if the array relative angle is F
In the case of, the right transmission order is c, d, e, f, g, and the left transmission order is b, a, j, i, h. When the transmission order is input to the transmission array 3, the transmission array performs transmission according to the transmission order of the transmission beam.

In the above example, the transmission is performed separately for the right side and the left side, but the transmission may be performed alternately for the right side and the left side. Assuming that the array relative angle is R in FIG. 6, the right side e, the left side f, and thereafter, d, g, c, h,
b, i, a, j. In this case, since the time interval of the reception azimuth-reception time characteristic for each transmission beam is widened, the transmission beam can be specified more easily.

<Effect> As described above, according to the present invention, the transmission order is determined by using the transmission array reference direction and the transmission / reception array position information so that the transmission beam is transmitted in a direction sequentially away from the direction of the reception array. Therefore, the RDT transmission method suitable for the bistatic processing method is realized, and the transmission direction and the reception time characteristics of each transmission beam are separated without crossing each other, and the target position can be limited.

<< Embodiment 2 >><Structure> FIG. 7 is an explanatory diagram of the transmission start direction and the order in the bistatic processing apparatus of Embodiment 2 of the present invention.

In a bistatic active processing apparatus in which a receiver array is towed behind a ship on which a transmitter array is installed, the transmission order of transmission beams in RDT transmission is determined by the order of the beams on the starboard side from the right rear to the right front. The beam on the port side is rotated from the rear left to the front left. In the case of the transmission beam configuration shown in FIG. 7, the transmission order on the right side is e, d, c, b, a
And the transmission order on the left side is f, g, h, i, j.

<Operation> As in the first embodiment, since the relative angle between the transmission array and the reception array is always constant, the transmission order can be determined in advance.

<Effects> As described above, according to the present invention,
In the bistatic active processing method in which the receiver array is arranged behind the transmitter array, in addition to the effects of the first embodiment, the right region rotates the transmission order of the transmission beam from the right rear to the right front, In the left area, the transmission order of the transmission beams may be rotated from the rear left to the front left, and transmission is performed. Therefore, it is not necessary to change the transmission order of the transmission beams according to the position and orientation of the transmission / reception array, and processing is simplified. There is an effect that it can be easily realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a position localization method in a conventional bistatic processing method using an ODT transmission method.

FIG. 2 is a diagram illustrating a problem of bistatic processing when RDT transmission is used.

FIG. 3 is a functional block diagram of a bistatic processing device according to a first embodiment of the present invention.

FIG. 4 is a plot of a direction reception direction-reception time curve when a beam is transmitted in a direction sequentially approaching from a direction outside the reception array.

FIG. 5 is a plot of a direction reception direction-reception time curve when a beam is transmitted in a direction sequentially away from the side of the reception array.

FIG. 6 is an explanatory diagram of a transmission start direction and a transmission order in the bistatic processing device according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of a transmission start direction and a transmission order in the bistatic processing device of Example 2 of the present invention.

[Explanation of symbols]

 1: Position input terminal 2: Transmission array position input terminal 3: Receive array position input terminal 3: 4: Array relative angle calculation means 45: Transmission setting direction input terminal 56: Transmission start direction determination means 6 7-1: Right side transmission Order determining means 7-1 7-2: Left transmitting order determining means 7-2 8: Transmission array

Claims (3)

[Claims] [Claim 1] RDT (Rotatary Directional Transmissio)
n) a transmitter that transmits a signal by a transmission method, and a receiver that is located at a different position from the transmitter and receives a signal transmitted from the transmitter, the transmitter according to a predetermined transmission order. A bistatic active processing device for transmitting a signal. 2. A relative angle detecting means for detecting a relative angle between the receiver and the transmitter, and a transmission order of a signal transmitted from the transmitter is determined based on the relative angle detected by the relative angle detecting means. The bistatic active processing device according to claim 1, further comprising: a transmission order determining unit that performs transmission, and wherein the transmitter transmits signals in accordance with the transmission order determined by the transmission order determining unit. 3. The transmission order of the signal transmitted from the transmitter determined by the transmission order determination means is such that the signal is transmitted in a direction away from a direction closer to the receiver of the transmitter. A bistatic active processing device according to claim 1.