JPH05240935A - Monopulse angle measuring instrument - Google Patents

Abstract

PURPOSE:To discriminate the quadrant of an input having a wide dynamic range by inputting an I- and Q-video signals at every sum and difference receiving signals and calculating the amplitude value of the video signals by using approximate values. CONSTITUTION:A receiver 2 detects phases of sum and difference receiving signals from a monopulse antenna 1 after amplification and outputs I-video signals and Q-video signals which are the orthogonal phase detecting components of the I-video signals. After the I- and Q-video signals are A/D-converted 3, absolute values found by means of absolute value calculators 101 and 102 are inputted to weighting computing elements 103-107 in a pair of (A, B) and the maximum value of A¦I¦+B¦Q¦ is selected by comparing and selecting 111-114 the calculated results of the elements 103-107. By outputting the process and results of the selection to an amplitude ratio calculator 150 and quadrant discriminator 140 from compared/discriminated result outputting devices 121-124, the phase angle formed by the I- and Q-video signals (for example, one angle obtained when 360 deg. is divided into twenty parts) is discriminated and the quadrant (whether on the left side or right side or a beam nose) is discriminated from the discriminated results of phase angles of the sum and difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for tracking a wireless antenna. Used for monopulse measurement method. In particular, the present invention relates to a determining means for determining the right and left from the beam nose in monopulse angle measurement using the sum and difference antenna patterns.

[0002]

2. Description of the Related Art Conventionally, in a monopulse angle measuring means using a sum and difference antenna pattern of this kind, as shown in FIG. 2, a monopulse antenna 1 is used to determine the right and left of the beam nose (hereinafter referred to as quadrant). Receiving device for amplifying and phase-detecting each reception signal corresponding to each reception signal of sum and difference and outputting a video signal (I video signal) and a quadrature phase detection component signal (Q video signal) of the I video signal 2, an analog / digital converter 3 for converting the I and Q video signals into digital signals, and digital I and Q from the analog / digital converter 3.
A combiner 201 that calculates the amplitude value of the received signal with the video signal as an input, a phase angle calculator 202 that calculates the phase angle formed by the I and Q video signals, and a phase angle with the sum and difference phase angles as inputs. It has a quadrant determiner 203 for calculating the difference and determining the quadrant, and an amplitude ratio calculator 204 for calculating the amplitude ratio of the sum difference by inputting the amplitude values of the sum and the difference, respectively. Here, the phase angle calculator 202 uses tan ⁻¹ (Q /
Although I) needs to be calculated, it is necessary to use function approximation to calculate tan ⁻¹ , which is difficult to realize in an application that requires real-time processing such as radar signal processing. For the calculation of the normal tan ^-1 for this, table look-up circuit is used to refer a table in advance by calculating the value already tan ^-1. Further, as shown in FIG. 3, the quadrant is determined by the sum reception signal 301 and the difference reception signal 3
Utilizing the fact that the phase of 02 becomes opposite phase with the beam nose of the sum beam as a boundary, when the phase difference is almost zero (when the sum difference is in phase), it is judged as the right side of the beam nose, and the phase difference is almost 1
When it is 80 ° (in the case of the sum difference difference opposite phase), it is determined to be the left side of the beam nose.

[0003]

A quadrant decision circuit using such a conventional table look-up circuit has an analog circuit which requires a wide dynamic range like a radar using a Doppler filter in recent years. The number of digital bits after digital conversion increases, which makes the table large and difficult to realize. For example, when the number of digital bits after analog-to-digital conversion is 12 bits (this is the standard value for radar using a Doppler filter), the number of tables is 2 ²⁴ = 16 × 10 ⁶ . In addition, analog
When the Doppler filter processing is performed after the digital conversion, the number of bits is increased by 2 to 3 bits due to the processing, and the number of tables is 2 ³⁰ = 1 × 10 ⁹ , which is almost impossible to realize. For this purpose, there is a method of calculating the Q / I in advance and then referring to the table.
The division of / I is required, and there is a drawback that the circuit configuration becomes complicated.

The present invention eliminates such drawbacks, and an object of the present invention is to provide a monopulse angle measuring device capable of quadrant determination even for an input having a wide dynamic range.

[0005]

According to the present invention, a system is provided corresponding to each of a sum reception signal and a difference reception signal which are reception signals given from a monopulse antenna system, and each system provides a phase of the reception signal. A receiver for detecting and generating an I video signal and a Q video signal which is a quadrature phase detection component signal of the I video signal, and an I video signal and a Q video signal generated by the receiver, respectively converted to digital signals. A quadrant determiner that includes an analog-digital converter and performs quadrant determination based on the signals provided from the two systems, and the amplitude value of the sum reception signal and the amplitude of the difference reception signal based on the signals provided from the two systems. In a monopulse angle measuring device equipped with an amplitude ratio calculator for calculating an amplitude ratio with a value, each of the above-mentioned systems uses the analog-to-digital converter. An absolute value calculator that calculates the absolute value of each signal by inputting the I video signal and the Q video signal converted into the digital signal, and a weighting coefficient of a different value for each of the absolute values calculated by this absolute value calculator Multiply by
A plurality of weighting calculators for adding the products and a comparison selection by a tournament for the calculation results of the plurality of weighting calculators to select the maximum value of the calculation results and the comparison selection given to the amplitude ratio calculator. And I video signal and Q
It is characterized by further comprising: a determination unit that determines which one of a plurality of ranges obtained by dividing the 360 ° phase angle with the video signal.

Here, the judging means generates a signal indicating the weighting calculator selected by each of the comparison selectors in the process of comparison processing, and gives the signal to the quadrant judger, the comparison judgment result output device and the absolute judgment device. It is preferable to include a code judging device for judging the sign of the I video signal and the sign of the Q video signal given to the value calculator and giving the judgment result to the quadrant judger.

[0007]

The I-video signal and the Q-video signal are input for each of the sum received signal and the difference received signal, and the amplitude value thereof is calculated by the approximate expression A | I | + B | Q |, and for each separated phase angle range. A | I | and B | Q | are weighted, the weighting results are compared with each other, the larger one is selected, and a signal indicating which (A, B) pair is selected in this process is generated. This signal and I video signal and Q
Quadrant determination is performed based on the determination result of the code of the video signal.
That is, since the approximate calculation in the I / Q combination is used, the table required for the quadrant determination using the table lookup circuit is not required, and thus a circuit that can handle an input having a wide dynamic range can be realized.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of this embodiment. In this embodiment, as shown in FIG. 1, a received signal corresponding to each received signal of the sum and difference from the monopulse antenna 1 is amplified and phase-detected to detect a video signal (I video signal) and an I video signal. A receiving device 2 for outputting a quadrature phase detection component signal (Q video signal) of the signal, an analog / digital converter 3 for converting each of the I and Q video signals into a digital signal, and a digital signal from the analog / digital converter 3. Absolute value calculators 101 and 102 for calculating the absolute value of each of the I and Q video signals by using the I and Q video signals as inputs, and (1, 1) as a set of (A, B).
/ 8) (7/8, 1/2) (1/2, 7/8) (1 /
8, 1) Weighting calculators 103 to 107 that perform weighting of (45/64, 45/64) on the outputs of the absolute value calculators 101 and 102, and the output of the weighting calculator 103 and the output of the weighting calculator 104. And a larger one, a comparison selector 112 that compares the output of the weighting calculator 105 and the output of the weighting calculator 106 and outputs the larger one, and a weighting calculator 107.
Of the comparison selector 113 and the output of the comparison selector 111 and outputs the larger one, and the comparison selector 114 which compares the output of the comparison selector 112 and the output of the comparison selector 113 and outputs the larger one. And the comparison determination result output devices 121 to 124 that output which (A, B) pair is selected by the comparison selectors 111 to 114, and the absolute value calculators 101 and 1
Inputs the code determiners 131 and 132 that determine the signs of the I and Q video signals that are the inputs of 02, and the outputs of the comparison and determination result output devices 121 to 124 for the sum and difference and the outputs of the code determiners 131 and 132. A quadrant determiner 140 for performing the quadrant determination and an amplitude ratio calculator 150 for calculating the amplitude ratio of the sum and the difference with the output of the comparison selector 114, which is the amplitude value of each of the sum and the difference, as an input.

In this embodiment, as shown in FIG. 1, a system is provided corresponding to each of a sum reception signal and a difference reception signal which are reception signals given from a monopulse antenna system,
Each system includes a receiving apparatus 2 that phase-detects a received signal to generate an I video signal and a Q video signal that is a quadrature phase detection component signal of the I video signal, and the receiving apparatus 2
Analog-to-digital converter 3 for converting each of the I video signal and the Q video signal generated in
And a quadrant determiner 140 that performs quadrant determination based on signals provided from the two systems, and an amplitude of a sum received signal amplitude value and a difference received signal amplitude value based on the signals provided from the two systems. An amplitude ratio calculator 150 for calculating a ratio, and as a feature of the present invention, each of the above systems is an I-video signal and a Q-video signal converted into digital signals by the analog-digital converter 3. To the absolute value calculator 101 and 102 for calculating the absolute value of each signal, and multiplying the absolute values calculated by the absolute value calculators 101 and 102 by weighting coefficients of different values, and adding the products Of the plurality of weighting calculators 103 to 107 and the calculation results of the plurality of weighting calculators by a tournament to obtain the maximum of the calculation results. Select, the amplitude ratio calculator 150
To the quadrant discriminator 140. The comparator / selectors 111-114 and the comparator / selectors 111-114 each generate a signal indicating the weighting calculator selected in the comparison process.
To the quadrant discriminator 140. The discriminant determination result output devices 121 to 124 and the I video signal code and the Q video signal code given to the absolute value calculators 101 and 102 are respectively determined, and the determination results are sent to the quadrant discriminator 140. It provides the code judging devices 131 and 132.

Next, the operation of this embodiment will be described. Each set of (A, B) above sequentially gives the maximum value as the phase angle changes, and (1, 1/8) is (0 ° -18.4).
°), (7/8, 1/2) is (18.4 ° to 40.2)
°), (45/64, 45/64) is (40.2 ° ~ 4
9.8 °), (1/2, 7/8) is (49.8 ° -7)
1.6 °), (1/8, 1) is (71.6 ° to 90 °)
, Which is the coefficient that gives the maximum value of the approximate expression A | I | + B | Q | output. (Note that regarding the value of the amplitude value by this approximate expression, the utility model / quadrature signal synthesizer (56-
047995). ) Therefore, by combining the outputs of the comparison determination result output devices 121 to 124 and the output of the code determination devices 131 and 132, I and Q
It is possible to determine the phase angle formed by the video signal (correctly, one of 360 degrees divided into 20), and the difference between the sum and the difference is determined based on the phase angle determination result of the sum and the difference. If is less than or equal to a predetermined value, the sum-difference in-phase is set, and if more than a predetermined value, the sum-difference in-phase is set, and the quadrant determination is performed.

[0011]

As described above, the present invention provides I / Q.
Since an approximate calculation in synthesis is used, the circuit is simplified, and quadrant judgment can be realized even when the input dynamic range is wide.

[Brief description of drawings]

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

FIG. 2 is a block configuration diagram showing a configuration of a conventional example.

FIG. 3 is a diagram showing a phase relationship between sum and difference received signals.

[Explanation of symbols]

 1 Monopulse Antenna 2 Receiver 3 Analog / Digital Converter 101, 102 Absolute Value Calculator 103-107 Weighting Calculator 111-114 Comparison Selector 121-124 Comparison Judgment Result Outputter 131, 132 Code Judgmenter 140 Quadrant Judgmenter 150 Amplitude ratio calculator 201 Combiner 202 Phase angle calculator 203 Quadrant determiner 204 Amplitude ratio calculator

Claims (2)

[Claims] 1. A system is provided corresponding to each of a sum reception signal and a difference reception signal which are reception signals given from a monopulse antenna system, and each system performs phase detection of the reception signal and an I video signal and this I signal. A receiver for generating a Q video signal which is a quadrature phase detection component signal of the I video signal, and an analog / digital converter for converting the I video signal and the Q video signal generated by the receiver into digital signals, respectively. , A quadrant determiner for making a quadrant decision based on the signals given from the two systems, and an amplitude ratio between the amplitude value of the sum received signal and the amplitude value of the difference received signal based on the signals given from the two systems In a monopulse angle measuring device equipped with an amplitude ratio calculator, each of the above systems is converted into a digital signal by the analog / digital converter. An absolute value calculator that calculates the absolute value of each signal by inputting the I video signal and the Q video signal, and each of the absolute values calculated by this absolute value calculator is multiplied by a weighting coefficient of a different value, and the product is calculated. A plurality of weighting calculators to be added, and a comparison selector for performing a comparison process by a tournament on the calculation results of the plurality of weighting calculators to select the maximum value of the calculation results and giving it to the amplitude ratio calculator. A monopulse angle measuring device comprising: a determination unit that determines which of a plurality of ranges obtained by dividing 360 degrees the phase angle formed by the I video signal and the Q video signal belongs to. 2. The determination means generates a signal indicating a weighting calculator selected by each of the comparison selectors in the process of comparison processing, and outputs the signal to the quadrant determiner, the comparison determination result output device, and the absolute value. 2. The monopulse angle measuring device according to claim 1, further comprising a code judging device for judging the sign of the I video signal and the sign of the Q video signal given to the calculator and giving the judgment result to the quadrant judger.