JPS60381A - Measuring device of wave speed and wavelength by radar - Google Patents

Abstract

PURPOSE:To improve the reliability of the titled device by processing a signal received every rotation of an antenna on the basis of one-dimensional Fourier transformation and measuring the relative wave transmitting speed to a radar and the wavelength on the basis of the processed signal. CONSTITUTION:A signal received from a radar antenna 1 is inputted to a high speed Fourier converter 7 through a logarithmic straight type receiving circuit 2, a gate setter 4, a gain characteristic correcting circyit 5, and an A/D converter 6 and converted into an one-dimensional space spectral signal repeated to a distance. The space spectral signal is guided to a wavelength calculating circuit 10 through a main wavelength spectral extracting circuit 8 to calculate the wavelength of the wave. On the other hand, the output of the main wavelength spectral extracting circuit 8 is stored in a main wavelength spectral storing circuit 9. A phase difference detecting circuit 11 compares the phase of the stored spectral signal with that of the spectral signal obtained at the succeeding rotation of the antenna and a wave speed calculating circuit 12 calculates the transmission speed of the wave.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring device for measuring wave propagation speed and e-length by Fourier transform of reflected signals from waves in radar image processing.

Conventional devices of this type cover a wide range where reflected waves from waves can be seen on the radar screen.

After performing A-D conversion of video signals, recording, conversion from polar coordinates or radar images to rectangular coordinates, etc.

It is measured by calculating two-dimensional Fourier transform, correlation coefficient of two-dimensional signals, etc., and the time required for the side legs is long.

Despite using a high-speed computer equipped with a large amount of memory elements, it is possible to determine the propagation speed of waves by signal analysis of images for each rotation of the antenna. It was difficult to increase the liquid length.

Based on the above-mentioned facts, the present invention is based on the fact that, even in general radar, if the direction is limited to the propagation direction of the waves on the screen with respect to the signal reflected from the regular head of waves in stormy weather, Focusing on the fact that one-dimensional Fourier transform is possible, we will study the relative propagation speed and wavelength of waves relative to radar.

It is intended to measure L-1 temporally by signal analysis for each antenna rotation. means for processing the received signal into a spatial spectrum signal through the Takao-Rier transform; means for extracting the spatial spectrum with the largest amplitude from this signal to calculate the wavelength of the waves; The present invention is a wave speed and wavelength measuring device using radar, comprising means for detecting a phase difference and calculating a wave propagation speed.

In the following, one embodiment of the device of the present invention will be explained with reference to the drawings.In the figures, 1 is a radar antenna, 2 is a log-linear characteristic receiving circuit, 3 is a radar indicator, and 4 is an automatic method or manual method. This is a gate setting device that extracts signals from the general direction of wave propagation and the distance range where sea surface reflection exists (hereinafter simply referred to as distance) using a method. A gate circuit is set.

The received signal that has passed through the gate circuit set by the gate setter 4 is passed through the gain characteristic correction circuit 5 in the next stage so that the amplitude becomes constant y with respect to the distance.
An analog-to-digital converter 6 converts the signal into a digital signal. Next, this signal is Fourier-transformed by a fast Fourier transformer 7 to obtain a one-dimensional spatial spectrum signal that is repeated with respect to distance. 8 is a dominant wavelength spectrum extracting circuit for extracting a spatial spectrum having the largest amplitude component from this spatial spectrum signal. The output vector signal from this circuit 8 is led to a wave wavelength calculation circuit 10, where the wave wavelength is calculated. On the other hand, the dregs vector signal output by the circuit 8 is the main liquid length spectrum 1. It is also led to circuit 9 and stored in circuit N.

The main wavelength spectral phase difference detection circuit 1 compares the phase of this spectrum signal with the spectrum signal during the next antenna rotation.
This will be done in 1. From the value of the phase difference comparatively detected by this circuit 11, the speed calculation circuit 12 calculates the speed per rotation of the antenna, and from that value, the speed per second and the speed per hour are calculated. These speed values and the wave wavelength value calculated by the wave wavelength calculation circuit 1o are displayed on the wavelength/wave speed display 13.

As described in detail above, the present invention processes the received signal for each rotation of the antenna using one-dimensional fast Fourier transform in the propagation direction of waves on the radar and the distance range where sea surface reflection exists, and based on this processed signal. Since this device instantaneously measures the wave propagation speed and wavelength relative to the radar, the structure can be simpler than conventional devices.

Moreover, it has the outstanding effect of being able to obtain highly reliable wave information very easily and in a short time through signal analysis for images of each rotation of the antenna.

[Brief explanation of the drawing]

FIG. 1 is a prono diagram showing an embodiment of the device of the present invention. 1. Radar antenna, 2. Log-linear characteristic receiving circuit, 3. Radar indicator, 4. Gate setting device. 5... Gain characteristic correction circuit, 6... A-D converter, 7
...Fast Fourier transformer, 8. Dominant wavelength spectrum extraction circuit, 9. Dominant wavelength spectrum storage circuit. 10. Wave wavelength calculation circuit, 11. Main wavelength spectrum phase difference detection circuit, 12. Wave speed calculation circuit, 13. Wavelength/wave speed indicator. Patent applicant Japan Radio Co., Ltd.

Claims (1)

[Claims] Means for processing the received signal for each rotation of the antenna, which is extracted from the wave propagation direction by the radar and the distance where the sea surface reflection exists, into a spatial spectrum signal through fast Fourier transform, and extracting the spatial spectrum with the largest amplitude from this signal. A method for detecting wave velocity and flame emission by a radar, comprising means for calculating the wavelength of e-waves, and means for detecting the phase difference of the spatial spectrum for each rotation of the antenna to calculate the wave propagation velocity. measuring device.