JPH0324488A - Signal processor for radar - Google Patents

Abstract

PURPOSE:To enable direct evaluation of performance of a digital filter by inputting a test signal from a test signal generation circuit into a digital filter to display an output thereof on a performance display monitor. CONSTITUTION:A test signal from a test signal generation circuit 51 is inputted into a digital filter 201 before the operation of a radar apparatus and an output of the filter 201 is displayed on a performance display monitor 52 to evaluate performance such as a degree of vanishing clutters of the filter 201 singly for the apparatus. While the apparatus is in operation, the test signal is mixed with a receiving video signal 12 within a dead time of the radar in a mixing circuit 53 and inputted into the filter 201 to be added to evaluation by the test signal during the operation of the apparatus thereby performing an evaluation directly by a real data.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention suppresses clutter from a received video signal of a radar by forming a pattern for moving clutter such as weather clutter detected from the received video signal. This paper relates to a radar signal processing device equipped with a digital filter that performs (Prior Art) FIG. 2 shows a general ellipse of a radar device.

In FIG. 2, the output transmission signal of a transmitter 1 is radiated from an antenna 3 via a circulator 2. The reflected waves of this radiated radio wave from the target etc. are the same antenna 3.
The signal is received by the circulator 2 and input to the receiver 4 via the circulator 2. From the receiver 4, a video amplified received video signal 2 is outputted to a signal processing device 20, which is the object of the present invention. Then, in the signal processing device 20, the received video signal 1
2, performs signal processing such as clutter suppression and interference removal, outputs the processed video signal 13 to the data processing device 6, and converts the processed video signal 13 into an analog signal l4 to a PPI indicator, etc. Output to the display device 7, etc. is performed. The data processing device 6 performs processing such as tracking on the processed video signal 13, and outputs a digital signal 15, which is symbol data, to the display device 76. Incidentally, clutter suppression in such radar equipment was initially performed using techniques such as MTI processing that utilizes the difference in Doppler frequency between the target and clutter, and LOG/CFAR processing that utilizes the statistical properties of clutter amplitude. Ta. The former MTI process is a process performed to suppress fixed clutter such as ground clutter, and is a type of band pass filter. With the advancement of digital technology, this MTT processing device developed into a digital MTI processing device, and then further developed into a digital MTI processing device.
As a result of the discovery that filters can effectively function to suppress not only fixed clutter but also moving clutter such as weather clutter, a device equipped with a digital filter, ie, a signal processing device 20, was developed. This signal processing device 20 basically includes a digital filter 201, a clutter detection circuit 202, a weight calculation circuit 203, and a D/A converter 204, as shown in FIG. 3, for example. The operation of this device is roughly as follows. First, assuming several patterns of clutter offline,
S/C (Si
gnal to clut. ter Ratio) is calculated in advance, and the calculated weight is stored in an internal memory provided in the weight calculation circuit 203. Then, online, the clutter detection circuit 202
detects moving clutter such as weather clutter from the received video signal 12, the weight calculation circuit 203 calculates the frequency characteristics of the detected moving clutter by a statistical method, compares the obtained pattern with the assumed clutter pattern, The optimal weight for the detected clutter is extracted from the internal memory and applied to the digital filter 20.
Output to 1. As a result, the digital filter 201 performs clutter suppression on the clutter present in the received video signal 12 by forming a pattern null. (Problems to be Solved by the Invention) The conventional radar signal processing device described above does not have an evaluation function for determining whether the optimal weight has been selected for the detected clutter, and the performance of the digital filter is For display devices such as radar PPI indicators,
There was a problem in that it was necessary to evaluate whether the target detection was successful by displaying the signal-processed video. The present invention has been made in view of these conventional problems, and its purpose is to provide a radar signal processing device that can directly evaluate the performance of a digital filter. (Means for Solving the Problems) In order to achieve the above object, a radar signal processing device of the present invention has the following configuration. That is, the radar signal processing device of the present invention performs radar signal processing including a digital filter that performs clutter suppression from a received video signal of the radar by forming a pattern with respect to moving clutter detected from the received video signal of the radar. In the device;
A test signal generation circuit that generates a test signal for evaluating the characteristics of the digital filter; and a performance display monitor that receives the output of the digital filter and displays the characteristics of the filter. It is. (Function) Next, the function of the radar signal processing device of the present invention configured as described above will be explained. By inputting a test signal to the digital filter and displaying its output on a performance display monitor, it is possible to directly evaluate the performance of the digital filter, such as the degree of clutter cancellation. That is, according to the present invention, since it is possible to perform an evaluation test as a single device, it is possible to form an appropriate signal processing device in advance and incorporate it into the radar device, thereby making the evaluation of the entire radar device more appropriate and improving its performance. This can make it easier. (Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 shows a radar signal processing device according to an embodiment of the present invention. As shown in FIG. 2, a test signal generation circuit 51 and a performance display monitor 52 are provided, and the test signal is inputted together with the received video signal 12 to a digital filter 201 via a mixing circuit 53.
2, the output of the digital filter 201 is directly input. With this arrangement, the test signal generated by the test signal generation circuit 51 can be processed before the signal processing device is installed in the radar device, or after the signal processing device is installed in the radar device and before the radar device is operated. By operating the digital filter 201 and displaying the results on the performance display monitor 52, the performance of the digital filter, such as the degree of clutter elimination, can be evaluated using the signal processing device alone. Also, when the radar equipment is in operation, radar dead and
By mixing the test signal and the received video signal 12 in the mixing circuit 53 and inputting the mixed signal to the digital filter 201 within the time period, it becomes possible to perform evaluation using actual data in addition to evaluation using the test signal during operation. ing. That is, the clutter detection circuit 202 to which the received video signal l2 is input statistically processes the frequency characteristics of the moving clutter, and based on this, the weight calculation circuit 203 determines the optimal weighting coefficient (weight) of the digital signal. It also becomes possible to evaluate the frequency characteristics of the filter 201. It goes without saying that by inputting the test signal generated by the test signal generation circuit 51 to the digital filter 201, the frequency characteristics of the digital filter can be directly displayed on the display device 7. (Effects of the Invention) As explained above, according to the radar signal processing device of the present invention, evaluation tests can be performed as a single device, so that an appropriate signal processing device can be formed in advance and incorporated into the radar device. This has the effect of making it easier to evaluate the overall radar equipment and improve its performance.

[Brief explanation of drawings]

Claims (1)

[Claims] In a radar signal processing device comprising a digital filter that performs clutter suppression from a received video signal by forming a pattern with respect to moving clutter detected from the received video signal of the radar; for evaluating characteristics of the digital filter. A radar signal processing device comprising: a test signal generating circuit that generates a test signal; and a performance display monitor that receives the output of the digital filter and displays the characteristics of the filter.