Wideband Time-Domain Monopulse Measurement Method Based on Normalized Euclidean Distance

Abstract

The present invention provides a broadband time-domain monopulse measurement method based on the normalized Euclidean distance, which relates to a monopulse radar measurement method. This method uses a broadband monopulse antenna to transmit a broadband pulse signal and receive the broadband pulse signal reflected by the target to be measured; the signal received by the sum port of the broadband monopulse antenna is used as the reference signal, and the normalized Euclidean distance directivity coefficient of the received signals of the azimuth difference port and the elevation difference port to the reference signal is calculated; the broadband monopulse antenna is rotated, and when the normalized Euclidean distance directivity coefficient reaches the minimum value, the azimuth and elevation information of the target to be measured is obtained, and the target distance is obtained based on the transmission delay. This method has low complexity and high accuracy. As the bandwidth is broadened, the accuracy is improved without increasing the complexity, and at the same time, it has the ability to counter narrowband electromagnetic stealth and interference.

Description

Technical Field

[0001] The present invention relates to a broadband time-domain monopulse measurement method based on normalized Euclidean distance, belonging to the technical field of radar measurement. Background Art

[0002] Monopulse measurement is a widely used radar measurement method. By transmitting and receiving monopulse signals, the position information of the target can be given. How to improve the measurement accuracy is an important issue in monopulse measurement. In the existing monopulse measurement methods, the transmitted and received signals are mostly narrow-band signals. Signals with a narrow spectrum are easily interfered with or evaded by stealth targets in actual target detection, and at the same time, it also limits the space for improving the measurement accuracy. With the progress of technology, the bandwidth of the system is gradually increasing, and more and more systems based on broadband pulses have emerged. The method of using broadband pulse signals to achieve monopulse measurement is of great significance for improving the monopulse measurement accuracy, combating narrow-band electromagnetic interference or stealth.

[0003] However, due to the wide bandwidth and the complexity of the spectral components, the frequency-domain analysis of broadband pulses is rather cumbersome. This makes the complexity of broadband pulse signal processing increase sharply, and then makes it difficult to design and apply a monopulse measurement system based on broadband pulses. Therefore, how to design a monopulse measurement method for broadband pulses that can combat narrow-band electromagnetic stealth and interference, has a low signal processing algorithm complexity, and high measurement accuracy is an important issue in this field. Summary of the Invention

[0004] Technical Problem: The present invention provides a broadband time-domain monopulse measurement method based on normalized Euclidean distance to reduce the complexity of the signal processing algorithm, improve the measurement accuracy, and combat narrow-band electromagnetic stealth and interference.

[0005] Technical Solution: A broadband time-domain monopulse measurement method based on normalized Euclidean distance of the present invention uses a broadband monopulse antenna. The broadband monopulse antenna has a sum port, an azimuth difference port, and an elevation difference port; the broadband monopulse antenna transmits a broadband pulse signal A(t); the broadband pulse signal A(t) reaches the target to be measured and is reflected, and after a delay τ, it is received by the broadband monopulse antenna. The sum port receives the signal r0(t), the azimuth difference port receives the signal s α (t), and the elevation difference port receives the signal s β (t); the measurement steps are as follows:

[0006] Step 1: Calculate the azimuth normalized Euclidean distance directivity coefficient M according to the following formula α :

[0007]

[0008]

[0009]

[0010] M α = 1 - d ar

[0011] Step 2: Calculate the pitch normalized Euclidean distance directivity coefficient M according to the following formula β :

[0012]

[0013]

[0014]

[0015] M β = 1 - d βr

[0016] Step 3: Rotate the wideband monopulse antenna in the azimuth direction to find the azimuth angle with the minimum absolute value of M, and this azimuth angle is the azimuth angle α where the measured target is located; rotate the wideband monopulse antenna in the pitch direction to find the pitch angle with the minimum absolute value of M α and this pitch angle is the pitch angle β where the measured target is located. β

[0017] Step 4: Calculate the distance D from the wideband monopulse antenna to the measured target according to the following formula, where c is the speed of light in vacuum;

[0018] D = cτ / 2

[0019] The electrical axis direction of the wideband monopulse antenna does not change within the working frequency band, and the electrical axis direction is consistent with the beam direction of the sum beam and the zero-point direction of the difference beam.

[0020] The pulse amplitude ratio S represents the energy difference between pulse signals, the waveform fidelity ρ represents the waveform change degree between pulse signals, the normalized Euclidean distance d is a binary function with S and ρ as variables, which can reflect the energy and waveform changes of the pulse signals received by the antenna; the pulse energy change information in the time domain corresponds to the amplitude information in the frequency domain, the pulse waveform change information in the time domain corresponds to the phase information in the frequency domain, and the normalized Euclidean distance synthesizes the pulse energy change information and the pulse waveform change information, and simply utilizes the spectrum information within the wide frequency band.

[0021] This wideband time-domain monopulse method uses a directivity pattern based on the normalized Euclidean distance, rather than the frequency-domain directivity pattern used in the usual monopulse measurement method. Since the time-domain method is used, the calculation amount does not increase when the bandwidth increases, and at the same time the pulse width decreases, improving the measurement accuracy.

[0022] ​Advantageous effects: The advantageous effects of the present invention are as follows:

[0023] (1) A broadband time-domain monopulse measurement method based on the normalized Euclidean distance can simply process broadband pulse signals, and the working bandwidth can be increased without increasing the computational complexity.

[0024] (2) A broadband time-domain monopulse measurement method based on the normalized Euclidean distance uses pulse signals in the time domain, fully utilizes the spectral information within the frequency band, and has high measurement accuracy.

[0025] (3) A broadband time-domain monopulse measurement method based on the normalized Euclidean distance has no increase in computational amount when the bandwidth increases, and at the same time the pulse width decreases, improving the measurement accuracy.

[0026] (4) A broadband time-domain monopulse measurement method based on the normalized Euclidean distance has an ultra-wide working frequency band and has the ability to counter narrowband electromagnetic stealth and interference. Description of the drawings

[0027] Figure 1 is a schematic diagram of the measurement scenario of the present invention.

[0028] In the figure: The broadband monopulse antenna 1 transmits broadband pulse signals and receives broadband pulse signals reflected by the target under test 2; the broadband monopulse antenna 1 has a sum port 11, an azimuth difference port 12, and an elevation difference port 13. Detailed implementation manners

[0029] The following further describes the detailed implementation manners of the present invention in conjunction with the drawings and embodiments.

[0030] In Figure 1 , the broadband monopulse antenna 1 transmits broadband pulse signals and receives broadband pulse signals reflected by the target under test 2; the broadband monopulse antenna 1 has a sum port 11, an azimuth difference port 12, and an elevation difference port 13; the electrical axis direction of the broadband monopulse antenna 1 does not change within the working frequency band, and the electrical axis direction is consistent with the beam pointing of the sum beam and the zero-point pointing of the difference beam.

[0031] The specific steps of this embodiment include:

[0032] Step 1: The broadband monopulse antenna 1 transmits and receives signals:

[0033] The broadband monopulse antenna 1 transmits a broadband pulse signal A(t); the broadband pulse signal reaches the target under test 2 and is reflected, and after a delay τ, it is received by the broadband monopulse antenna 1. The sum port 11 receives the signal r0(t), the azimuth difference port 12 receives the signal s α (t), and the elevation difference port 13 receives the signal sβ (t);

[0034] Step 2: Calculation and processing of received signals:

[0035] Calculate the normalized Euclidean distance directivity coefficient M of r0(t) and the received signal s α (t): α :

[0036]

[0037]

[0038]

[0039] M α = 1 - d ar ;

[0040] Calculate the normalized Euclidean distance between r0(t) and the received signal s β (t):

[0041]

[0042]

[0043]

[0044] M β = 1 - d βr ;

[0045] Step 3: Measure the position of the measured target 2:

[0046] The broadband monopulse antenna 1 rotates in the azimuth direction to find the azimuth angle α pointed by the electrical axis of the broadband monopulse antenna 1 when M α is the minimum; the broadband monopulse antenna 1 rotates in the elevation direction to find the elevation angle β pointed by the electrical axis of the broadband monopulse antenna 1 when M β is the minimum;

[0047] Calculate the distance D of the measured target 2 by the following formula, where c is the speed of light in vacuum;

[0048] D = cτ / 2

[0049] At this time, the azimuth angle of the measured target 2 is α, the elevation angle is β, and the distance is D.

[0050] According to the above, the present invention can be realized.

Claims

1. A broadband time-domain monopulse measurement method based on the normalized Euclidean distance, characterized in that: This method uses a broadband monopulse antenna (1), which has a sum port (11), an azimuth difference port (12), and an elevation difference port (13); the broadband monopulse antenna (1) transmits a broadband pulse signal A(t); the broadband pulse signal A(t) reaches the target under test (2) and is reflected, and after a delay τ, it is received by the broadband monopulse antenna (1). The sum port (11) receives the signal r0(t), the azimuth difference port (12) receives the signal s α (t), and the elevation difference port (13) receives the signal s β (t); the measurement steps are as follows: Step 1: Calculate the azimuth-normalized Euclidean distance directivity coefficient M α , M α The calculation formula of is as follows: M α = 1 - d αr Among them, ρ αr represents the waveform change degree between the pulse signal s α (t) and r0(t), and S αr represents the pulse amplitude ratio between the pulse signal s α (t) and r0(t); d αr is a binary function with S αr and ρ αr as variables, reflecting the changes in both the energy and waveform of the pulse signal received by the antenna; Step 2: Calculate the pitch normalized Euclidean distance directivity coefficient M β , M β The calculation formula of is as follows: M β = 1 - d βr Among them, ρ βr represents the waveform change degree between the pulse signal s β (t) and r0(t), and S βr represents the pulse amplitude ratio between the pulse signal s β (t) and r0(t); d βr is a binary function with S βr and ρ βr as variables, reflecting the changes in both the energy and waveform of the pulse signal received by the antenna; Step 3: The broadband monopulse antenna (1) rotates in the azimuth direction to find M α The azimuth angle with the smallest absolute value. This azimuth angle is the azimuth angle α of the position where the target under test (2) is located; the broadband monopulse antenna (1) rotates in the elevation direction to find M β The elevation angle with the smallest absolute value. This elevation angle is the elevation angle β of the position where the target under test (2) is located; Step 4: Calculate the distance D from the broadband monopulse antenna (1) to the target under test (2) using the following formula, where c is the speed of light in vacuum; D = cτ / 2 At this time, the position azimuth angle of the target under test (2) is α, the elevation angle is β, and the distance is D.

2. The broadband time-domain monopulse measurement method based on the normalized Euclidean distance according to claim 1, characterized in that: The electrical axis of the broadband monopulse antenna (1) does not change within the working frequency band, and the electrical axis points coincide with the beam direction of the sum beam and the zero point direction of the difference beam.

Images