CN109782233B - Radar working method and system based on Fourier transform - Google Patents
Radar working method and system based on Fourier transform Download PDFInfo
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- CN109782233B CN109782233B CN201910071009.4A CN201910071009A CN109782233B CN 109782233 B CN109782233 B CN 109782233B CN 201910071009 A CN201910071009 A CN 201910071009A CN 109782233 B CN109782233 B CN 109782233B
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Abstract
The application provides a radar working method and system based on Fourier transform, wherein the method comprises the following steps: transmitting electromagnetic waves to a target in a square wave mode with a duty ratio of 50%, and receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as those of the transmitting unit; performing frequency sweeping from low to high within the frequency sweeping range of the square wave to obtain the mean value of radar detection signals under different square wave frequencies; and carrying out Fourier transform on the frequency domain data containing the scanning frequency and the signal mean value to obtain time domain information. The technical scheme has the advantages of strong detection capability, small transmitting power and low signal-to-noise ratio, and can detect a plurality of signals.
Description
Technical Field
The application relates to the field of target detection, in particular to a radar working method and system based on Fourier transform.
Background
Radar is a technology for obtaining target information by radiating an electromagnetic wave to a target and receiving an echo thereof. The distance, speed, reflection area and the like of the target can be calculated through the information such as the transmitting and receiving time difference, frequency difference and echo signal intensity of the electromagnetic waves. Radars have been widely used in military, defense, traffic, weather and other fields.
The radar may be of various types, such as pulse radar, pulse doppler radar, continuous wave radar, frequency modulated continuous wave radar, pulse compression radar, and the like. The radar has wide application and can simultaneously measure the distance and the speed of a target, and is a pulse Doppler radar and a frequency modulation continuous wave radar. The measurement accuracy of the pulse Doppler radar depends on the pulse width, the narrower the pulse is, the higher the accuracy is, but the transmitting power of the radar is required to be very high under the condition of the narrow pulse; the frequency modulation continuous wave radar has the characteristic of low power, but is difficult to detect multiple targets.
Disclosure of Invention
In order to solve one of the problems, the application provides a radar working method and system based on Fourier transform.
According to a first aspect of the embodiments of the present application, there is provided a radar operating method based on fourier transform, the method including the steps of:
transmitting electromagnetic waves to a target in a square wave mode with a duty ratio of 50%, and receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as those of the transmitting unit;
performing frequency sweeping from low to high within the frequency sweeping range of the square wave to obtain the mean value of radar detection signals under different square wave frequencies;
and carrying out Fourier transform on the frequency domain data containing the scanning frequency and the signal mean value to obtain time domain information.
According to a second aspect of the embodiments of the present application, there is provided a radar operating system based on fourier transform, the system including:
a transmitting unit which transmits electromagnetic waves to a target in a square wave pattern with a 50% duty ratio;
the receiving unit is used for receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as the transmitting unit;
the transmitting unit and the receiving unit sweep frequency from low to high within the frequency sweep range of the square wave to obtain the mean value of the radar detection signals under different square wave frequencies;
and the signal processing equipment is used for carrying out Fourier transform on the frequency domain data containing the scanning frequency and the signal mean value to obtain time domain information and calculating target information according to the time domain information.
This application technical scheme advantage lies in:
1) has stronger detection capability. The signal transmitting and receiving duty ratio of the scheme is 50%, so that the total duty ratio is 25% and is far higher than that of a pulse Doppler radar (the signal transmitting and receiving duty ratio is usually less than 1%). Therefore, the method greatly improves the signal utilization rate of the radar and enhances the detection capability.
2) With less transmit power. This scheme can make signal utilization promote to can make the transmitted power of radar reduce, also make the radar signal be difficult to the interception simultaneously.
3) With a higher signal-to-noise ratio. This scheme can make signal utilization promote, and then can improve the SNR of radar, makes the radar have better interference killing feature.
4) Has multi-target detection capability. Although the frequency modulation continuous wave radar has small power, the frequency modulation continuous wave radar is difficult to cope with the task of multiple targets, and the radar working method based on the Fourier transform has good effect on the detection of the multiple targets and can easily distinguish the targets with different distances and speeds.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 shows a schematic diagram of a radar working system based on fourier transform according to the scheme;
fig. 2 shows a schematic diagram of the radar working method based on the fourier transform according to the scheme.
Detailed Description
In order to make the technical solutions and advantages of the embodiments of the present application more apparent, the following further detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings makes it clear that the described embodiments are only a part of the embodiments of the present application, and are not exhaustive of all embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
The core idea of the scheme is that the signal transmitting duty ratio and the signal receiving duty ratio are both 50%, the total duty ratio is 25%, and then the target is analyzed and calculated based on Fourier transform, so that the performance of the radar is optimized.
As shown in fig. 1, the present solution discloses a radar operating system based on fourier transform, the system including: a transmitting unit, a receiving unit and a signal processing device; the transmitting unit transmits electromagnetic waves to a target in a square wave mode with a 50% duty ratio; the receiving unit receives the electromagnetic wave reflected by the target in a square wave mode with the same frequency and phase as the transmitting unit; the transmitting unit and the receiving unit sweep frequency from low to high within the frequency sweep range of the square wave to obtain the mean value of the radar detection signals under different square wave frequencies; and the signal processing equipment is used for carrying out Fourier transform on the frequency domain data containing the scanning frequency and the signal mean value to obtain time domain information and calculating target information according to the time domain information.
In this scheme, the transmitting unit includes: the transmitting unit transmits square waves in a discontinuous mode; in order to cooperate with the transmitting unit, the receiving unit also receives square waves in a discontinuous manner, so as to achieve synchronization and accuracy of transmission and reception. Preferably, in this scheme, the transmitting unit includes: a transmitter and a transmitting antenna connected to the transmitter; the receiving unit includes: a receiver and a receiving antenna connected to the receiver.
In the scheme, in order to facilitate the query and reading of the data by a user, the system is provided with a display device for displaying the processing result. The display device is electrically connected with the signal processing device.
As shown in fig. 2, the present solution further provides a radar operating method based on fourier transform, and the method includes the steps of:
transmitting electromagnetic waves to a target in a square wave mode with a duty ratio of 50%, and receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as those of the transmitting unit;
performing frequency sweeping from low to high within the frequency sweeping range of the square wave to obtain the mean value of radar detection signals under different square wave frequencies;
when the scanning process is finished, obtaining a group of data corresponding to the square wave frequency and the signal mean value, wherein the group of data is a frequency domain signal; performing Fourier transform on the frequency domain signal to obtain a time domain signal of the radar, and judging target information according to the time domain signal; the velocity information of the target needs to be calculated according to Doppler law through the frequency difference of the transmitted and received electromagnetic wave signals.
The present solution is further illustrated by the following examples.
The embodiment provides a radar working system and method based on Fourier transform, as shown in FIG. 1. The system comprises: a transmitter, a transmitting antenna, a receiver, a receiving antenna, a signal processing device and a display device. When the radar works, the transmitter transmits electromagnetic waves to a target through the transmitting antenna in a square wave mode with a duty ratio of 50%, and meanwhile, the receiver receives the electromagnetic waves through the receiving antenna in a square wave mode with the same frequency and the same phase. The frequency of the square wave is scanned from low to high, and at each scanning frequency, the transmitting and receiving process lasts for a period of time, and the average value of the intensity of the received electromagnetic wave signal in the period of time is recorded. When the scanning process is finished, obtaining a group of data corresponding to the square wave frequency and the signal mean value, wherein the group of data is a frequency domain signal; performing Fourier transform on the frequency domain signal to obtain a time domain signal of the radar, and judging target information according to the time domain signal; the velocity information of the target needs to be calculated according to Doppler law through the frequency difference of the transmitted and received electromagnetic wave signals.
In this embodiment, the frequency sweep range of the square wave is set to be F0～FnThe sweep interval is Δ F and the duration at each sweep frequency is T. Then at the beginning of the scan, the transmitter and receiver are at F0For transmitting and receiving electromagnetic waves at frequencies, i.e. the transmitter and receiver being turned on synchronously
Time, synchronous closing
Time, cycle sequentially. After a duration T, the mean value S of the received signal strength over the time T is recorded0(ii) a Then the next scanning frequency F is carried out0+ Δ F, the procedure is the same as the previous time until the frequency is FnAnd ending the frequency sweep.
After the frequency sweeping process, a series of data corresponding to the scanning frequency F and the signal mean value S is obtained, and the series of data is called frequency domain data. After the data is subjected to Fourier transform, a series of data corresponding to the flight time and the signal intensity of the electromagnetic wave is obtained, and the data is called time domain data. From the time domain information, information such as the distance to the target and the reflection area can be calculated.
In the frequency sweeping process, the frequency of the electromagnetic wave transmitted by the transmitter is set to be f0The frequency of the electromagnetic wave received by the receiver being f0+fdThen we can depend on the frequency difference fdAnd calculating the speed information of the target according to the Doppler law.
In conclusion, the radar working system and the method have the advantages of strong detection capability, small transmitting power and low signal-to-noise ratio, and can detect a plurality of radar objects.
The present application is described in terms of flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (3)
1. A radar working method based on Fourier transform is characterized by comprising the following steps:
transmitting electromagnetic waves to a target in a square wave mode with a duty ratio of 50%, and receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as those of the transmitting unit;
the frequency sweep is carried out from low to high in the frequency sweep range of the square wave, wherein the frequency sweep range of the square wave is F0～FnA sweep interval of Δ F, a duration of T at each sweep frequency,
transmit and receive sync on
Time, synchronous closing
Time, cycle by cycle;
duration T, recording the mean value S of the intensity of the received signal over time T0；
For the next scanning frequency F0+ Δ F, the procedure is the same as the previous time until the frequency is FnAfter the frequency sweep is finished, obtaining the mean value of the radar detection signals under different square wave frequencies;
carrying out Fourier transform on frequency domain data containing scanning frequency and signal mean value to obtain time domain information;
calculating the distance and the reflection area of the target according to the time domain information;
frequency f of the transmitted electromagnetic wave0And frequency f of received electromagnetic wave0+fdAccording to the frequency difference fdAnd doppler law, calculating velocity information of the target.
2. A fourier transform-based radar operating system, comprising:
the transmitting unit transmits electromagnetic waves to a target in a square wave mode with 50% duty ratio, and the sweep range of the square wave is F0～FnThe scan interval is Δ F; the duration at each scanning frequency is T;
the receiving unit is used for receiving the electromagnetic waves reflected by the target in a square wave mode with the same frequency and phase as the transmitting unit;
wherein the transmitting unit transmits square waves in an intermittent manner; and/or the receiving unit receives square waves in a discontinuous mode;
a transmitter and a transmitting antenna connected to the transmitter; and/or, the receiving unit comprises: receiver and receiving antenna connected with receiver
The transmitting unit and the receiving unit sweep frequency from low to high within the frequency sweep range of the square wave to obtain the mean value of the radar detection signals under different square wave frequencies;
and the signal processing equipment is used for carrying out Fourier transform on the frequency domain data containing the scanning frequency and the signal mean value to obtain time domain information and calculating target information according to the time domain information.
3. The radar operating system of claim 2, further comprising: and the display device is used for displaying the processing result.
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