JP4025328B2 - Bistatic active processing equipment - Google Patents

Description

  The present invention relates to a bistatic active process and apparatus that uses a transmitting array and a receiving array that exist at different positions, and in particular performs a target position localization using an RDT transmission method.

  In the conventional bistatic processing method, an ODT (Omni Directional Transmission) transmission method that transmits signals in all directions at once around the transmission array is used. The target is detected by comparing the received signal and the position is localized 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.

To simplify the formulation in the description of the position localized method in bistatic processing method using the conventional ODT transmission scheme, it is on the X-axis transmitting array and the receiving array, described as the of both arrays intermediate is the origin However, it is possible to convert easily by appropriately selecting the coordinate axes in other cases. At the interval L between the transmission array center S and the reception array center R, the transmission signal transmitted in all directions by ODT transmission at the time Ts is reflected after reaching the target T (x, y), and the time Tr Is assumed to be received in the direction θr. The position of the target T exists on an ellipse with a propagation distance c (Tr-Ts) determined from the propagation speed c of the signal focusing on the transmission array center S and the reception array center R and the propagation time Tr-Ts. . By obtaining the intersection of this ellipse and the reception azimuth line, the target position is localized and becomes as follows.

Japanese Patent Laid-Open No. 9-26474

However, in ODT transmission becomes weak transmission signal output per one direction for transmitting signals in all directions at once from the transmitter, it is difficult to make long distance detection. On the other hand, in the case of RDT transmission in which signals are sequentially transmitted from a transmitter one direction at a time, a transmission signal output per direction is stronger than ODT transmission in principle as long as it has the same output power. Is excellent. However, when RDT transmission is used, it is difficult to determine which transmission signal the received signal is for, and thus the position of the target cannot be localized by bistatic processing.

Explaining the problem with reference to Figure 2 below. FIG. 2 is a diagram showing a problem of bistatic processing when RDT transmission is used. It is assumed that the transmission signal output from the transmitter is reflected on the target to generate a reflected signal and is received at the receiver at time Tr and azimuth θr. In the case of RDT transmission, since the transmission beam is rotated with time, even when the transmission signal transmitted to the azimuth θs at time Ts is reflected back from the target T, it is transmitted to the azimuth θg at time Tg. Even when the transmission signal is reflected back from the target G, it is received in the receiving direction θr. That is, there is a possibility that a target corresponding to a plurality of transmission beams of the azimuth θg and the azimuth θs exists on the azimuth line of the reception azimuth θr, and the transmission beams cannot be distinguished. Thus, in the RDT transmission method, there is a possibility of reflection by a plurality of transmission beams even in one reception direction. For this reason, there has been a problem that if the transmission beam cannot be specified, it is difficult to target the position.

RDT (Rotational Directional Transmission) transmitter that transmits signals according to a predetermined transmission order, a receiver that is located at a different location from the transmitter and that receives signals transmitted from the transmitter, and a transmitter reference A transmission reference of the transmitter having a first input terminal to which the azimuth is input, a second input terminal to which the position information of the transmitter is input, and a third input terminal to which the position information of the receiver is input A relative angle detecting means for detecting a relative angle with respect to the direction of the center of the receiver viewed from the direction, and a fourth input terminal for inputting a transmission setting direction set in advance to the transmitter reference direction in the transmitter, Based on the relative angle detected by the relative angle detection means, the right side of the transmitter reference azimuth is the right side of the transmitter reference azimuth with respect to the receiver center azimuth. Towards the heart of the vessel A transmission start azimuth determining means for outputting a left transmission start azimuth that is an azimuth away from the position, a right transmission order determining means for determining a right transmission order based on a right transmission start azimuth output from the transmission start azimuth determining means, Left-side transmission order determining means for determining the left-side transmission order based on the left-side transmission start direction output from the transmission-start-direction determining means, and transmitting from the transmitter determined by the right-side transmission order determining means and the left-side transmission order determining means The signal is transmitted in a direction away from the direction close to the receiver.

  According to the first specific example of the present invention, the transmission order is determined and transmitted so as to transmit the transmission beam in a direction sequentially away from the direction of the reception array using the transmission array reference direction and the transmission / reception array position information. Thus, an RDT transmission method suitable for the bistatic processing method is realized, and the reception position-reception time characteristics for each transmission beam are separated without crossing, and the target position localization can be achieved.

  According to the second specific example of the present invention, in the bistatic active processing method in which the receiver array is arranged behind the transmitter array, in addition to the effect of the first specific example, the right region indicates the transmission order of the transmission beams, It is only necessary to rotate the transmission from the right rear to the right front and rotate the transmission order of the transmission beam from the left rear to the left front. There is an effect that the processing is simple and can be easily realized without the need for modification.

<< Specific Example 1 >>
FIG. 3 is a functional block diagram of the bistatic processing apparatus according to the first embodiment of the present invention.

The transmission array reference direction input terminal 1 to which the transmission array reference direction is input, the transmission array position input terminal 2 to which the transmission array position information is input, and the reception array position input terminal 3 to which the reception array position information is input are the array relative angle. Connect to the calculation means 4. A transmission setting azimuth input terminal 5 to which a transmission azimuth (to be referred to as a transmission setting azimuth hereinafter) set in advance in the transmission array (relative to the transmission array reference azimuth) is input is connected to the transmission start azimuth determining means 6.

  The array relative angle calculation means 4 to which the transmission array reference azimuth, the transmission array position, and the reception array position are input is connected to the transmission start azimuth determination means 6, and the transmission start azimuth determination means 6 is the right transmission order determination means 7-1. And to the left transmission order determining means 7-2. The right transmission order determination means 7-1 and the left transmission order determination means 7-2 are connected to the transmission array 8.

Next, the operation of this bistatic transmission device will be described. The transmission array reference direction information input from the transmission array reference direction input terminal 1, 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 center of the receiving array as seen from 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 determination means 6. The transmission start azimuth determining means 6 selects an angle that is closest to the array relative angle and sandwiches the array relative angle from the transmission setting azimuths, and sets the right transmission start azimuth to the right transmission order determining means 7-1 and the left transmission start azimuth to the left The data is sent to the transmission order determination means 7-2.

A method for determining the transmission start direction will be described with reference to FIG. FIG. 6 is an explanatory diagram of a transmission start direction and order in the bistatic processing device of the first specific example, and a to j are transmission setting directions. Assume that the receiving array is located behind the transmitting array and the relative angle between the transmitting array and the receiving array is the direction R. Among the transmission setting directions, the directions closest to R 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 reception array is located in front of the transmission array and the array relative angle is F, c is 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. If the distance between the centers of the transmission / reception array is L, the signal propagation speed is c, the transmission beam azimuth is θ _si , and the reception beam azimuth θ _r , a reflector exists on the center azimuth line of the beam transmitted at the transmission time ti. When it is assumed that the reception time tr of the reflected wave from the reflector is as follows.

Here, consider a case in which the transmission order of the transmission beams is transmitted in a direction (A direction shown in FIG. 1) that sequentially approaches from the direction outside the reception array. FIG. 4 is a plot of a reception azimuth-reception time curve when a beam is transmitted in a direction approaching sequentially from the outside of the reception array. This plots the reception azimuth-reception time curve for the half-plane with Y as the parameter, with the transmission beam azimuth θsi as a parameter. D point ● represents the reception time and reception direction of the reflected signal from the target. In the case of FIG. 4, a reflected signal by a transmission beam transmitted in the past at a short distance may be received earlier than a reflected signal by a transmission beam transmitted thereafter. In this case, it is difficult to specify the transmission beam corresponding to the point D. Therefore, since the propagation time from transmission to reception is not determined, target position localization is impossible.

Next, consider a case in which the transmission order of the transmission beams is transmitted in a direction (B direction shown in FIG. 1) that is sequentially separated from the direction of the receiving array. FIG. 5 is a plot of a reception azimuth-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 the reception azimuth-reception time curve for the half-plane with Y as the parameter, with the transmission beam azimuth θsi as a parameter. D point ● represents the reception time and reception direction of the reflected signal from the target. As can be seen from FIG. 5, since the reflected signals can be received in the order of transmission of the transmission beams, it is possible to separate the transmission azimuth and reception time characteristics for each transmission beam and specify the transmission beam. In this way, by transmitting the transmission order of the transmission beams of RDT transmission in a direction (B direction and C direction shown in FIG. 1) sequentially away from the direction of the receiving array side, the transmission beam can be specified and the target Location localization is possible.

  Next, when the determination results of the right and left transmission start directions are respectively input to the right transmission order determining means 7-1 and the left transmission order determining means 7-2, the right transmission order determining means 7-1 and the left transmission order determining means 7-1 The transmission order determining means 7-2 determines the transmission order of the beams so that the transmission beams are transmitted sequentially away from the array relative angle direction, and outputs 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, and the left transmission order is f, g, h, i, j. When the array relative angle is F, 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 beams.

  In the above example, the transmission is performed separately for the right side and the left side, but it is also possible to transmit the right side and the left side alternately. Assuming that the array relative angle is R in FIG. 6, the right side e, the left side f, and the following are alternately 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 opened, the transmission beam can be identified more easily.

  As described above, according to the present invention, the transmission order is determined and transmitted so as to transmit the transmission beam in a direction sequentially away from the direction of the reception array using the transmission array reference direction and the transmission / reception array position information. Thus, an RDT transmission method suitable for the bistatic processing method is realized, and the reception position-reception time characteristics for each transmission beam are separated without crossing, and the target position localization can be achieved.

<< Specific Example 2 >>
FIG. 7 is an explanatory diagram of the transmission start direction and order in the bistatic processing device of the second embodiment of the present invention.

  In the bistatic active processor that tows the receiver array behind the ship where the transmitter array is installed, the transmission order of the transmit beams in the RDT transmission is changed so that the starboard side beam rotates from the right rear to the right front, The beam on the port side is rotated from the left rear to the left front. In the case of the transmission beam configuration shown in FIG. 7, the right transmission order is e, d, c, b, a, and the left transmission order is f, g, h, i, j.

  The operation is the same as in the first specific example. However, since the relative angle between the transmission array and the reception array is always constant, the transmission order can be obtained in advance.

  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 effect of the first example, the right region indicates the transmission order of the transmission beams. Rotate from the right rear to the right front, and the left region may be transmitted by rotating the transmission order of the transmission beams from the left rear to the left front. There is an effect that the processing is simplified and can be realized easily without the need to change.

It is explanatory drawing of the position location method in the bistatic processing method using the conventional ODT transmission system. It is a figure showing the problem of the bistatic process at the time of using RDT transmission. It is a functional block diagram of the bistatic processing apparatus of the specific example 1 of this invention. It is a plot figure of the reception azimuth | reception time curve when a beam is transmitted to the direction which approaches sequentially from the outside of a receiving array. It is a plot figure of a reception azimuth-reception time curve when a beam is transmitted in a direction sequentially away from the direction on the receiving array side. It is explanatory drawing of the transmission start azimuth | direction and transmission order in the bistatic processing apparatus of the specific example 1 of this invention.

Explanation of symbols

1: Position input terminal 2: Transmission array position input terminal 3: Reception array position input terminal 3
4: Array relative angle calculation means 4
5: Transmission setting direction input terminal 5
6: Transmission start direction determining means 6
7-1: Right transmission order determination means 7-1
7-2: Left side transmission order determination means 7-2
8: Transmitting array

Claims (1)

A transmitter that transmits a signal according to a predetermined transmission order by RDT (Rotational Directional Transmission) transmission method;
A receiver that is located at a different location from the transmitter and that receives a signal transmitted from the transmitter;
A first input terminal to which the reference direction of the transmitter is input; a second input terminal to which position information of the transmitter is input; and a third input terminal to which position information of the receiver is input. A relative angle detecting means for detecting a relative angle with respect to the orientation of the receiver center as seen from the transmission reference orientation of the transmitter;
A fourth input terminal configured to input a transmission setting azimuth set in advance relative to the transmitter reference azimuth to the transmitter, and based on a relative angle detected by the relative angle detection unit, Right-side transmission start azimuth that is a direction away from the receiver center azimuth on the right side of the transmitter reference azimuth, and left- side transmission start that is a direction away from the receiver center azimuth on the left side of the transmitter reference azimuth A transmission start direction determining means for outputting the direction;
A right transmission order determination means for determining a right transmission order based on the right transmission start direction output from the transmission start direction determination means;
Left-side transmission order determining means for determining a left-side transmission order based on the left-side transmission start direction output from the transmission start azimuth determining means;
The transmission order of signals transmitted from the transmitter determined by the right transmission order determination means and the left transmission order determination means includes:
A bistatic active processing device, wherein transmission is performed in a direction sequentially away from a direction close to the receiver.

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