CN111600602A - Phase discriminator and radar system using same - Google Patents

Abstract

The invention provides a phase discriminator and a radar system using the same, wherein the phase discriminator comprises a pilot signal, a receiving signal, a sampling unit, an exclusive-OR gate unit and an accumulator, the sampling unit samples the pilot signal and the receiving signal, the exclusive-OR gate unit processes the sampled data and then outputs a binary code stream, and the binary code stream is further processed by the accumulator to obtain the phase difference between the pilot signal and the receiving signal. The phase discriminator and the radar system thereof have simple hardware structure, do not need to use an ADC (analog-to-digital converter), reduce the design and popularization cost, improve the dynamic range of a radar receiver and improve the competitiveness of products.

Description

A phase detector and radar system using the same

technical field

The invention belongs to the field of radar application, and more particularly relates to a method for dynamic positioning of radar.

Background technique

In the civil and military fields, radar systems are often used for positioning. At present, there are mainly FMCW (Frequency Modulated Continuous Wave, frequency modulated continuous wave), point-frequency radar, OFDM radar and other design schemes for positioning with radar systems.

The US invention patent US10436890 with the application date of May 6, 2015 discloses a positioning method based on FMCW. The scheme adopts the time-division multiplexing method of MIMO radar, and the received echo frequency and the transmitted frequency change are both the law of triangular waves. , using the two-dimensional Fourier transform to calculate the target distance with a small time difference.

The US patent for invention US10557933, filed on March 9, 2017, discloses a radar positioning method. The solution mainly uses a Doppler correction phase rotation control unit to determine the frequency components used for correction of Doppler based on the moving speed of the moving object. The Doppler correction of the phase rotation amount, and then realize the positioning of moving objects such as vehicles.

The system design of the above two schemes is relatively complicated, the cost of popularization and application is high, the scope of popularization and application is limited, and the dynamic receiving range of the radar is limited.

Therefore, it is necessary to develop a new type of radar positioning implementation method to simplify the system design, reduce the complexity and cost, and improve the dynamic receiving range of the radar.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned shortcomings of the prior art, the present invention proposes an implementation method of a frequency conversion positioning radar based on a single-bit comparator.

In the first aspect, the present invention proposes a phase detector, including a pilot signal, a received signal, a sampling unit, an XOR gate unit and an accumulator, the sampling unit samples the pilot signal and the received signal, and the XOR gate unit After processing the sampled data, a binary code stream is output, and the binary code stream is further processed by the accumulator to obtain the phase difference between the pilot signal and the received signal.

Further, the frequencies of the pilot signal and the received signal are adjustable.

Further, the XOR gate unit uses a 1-bit comparator to convert the analog signal into a logic code stream, and thereby discriminate the phase.

Further, the XOR gate unit performs serial or parallel processing on the binary code stream.

Further, the XOR gate unit may also use logic components.

Further, the accumulator can also be any one of an integrator or a programmable logic device.

Further, the sampling unit performs single-bit sampling on the pilot signal and the received signal.

Further, the binary code stream is propagated through optical fiber or conducted by electrical signal. During optical fiber propagation, the transceiver part and the digital processing part of the system can be distributed in different geographical locations to form a distributed system.

In the second aspect, the present invention proposes a radar system, including a phase detector, a sampling unit, an exclusive OR gate unit and an accumulator, the sampling unit samples the pilot signal and the received signal, and the exclusive OR gate unit samples the sampled data After processing, the binary code stream is output, and the binary code stream is further processed by the accumulator to obtain the phase difference between the pilot signal and the received signal.

Further, the frequencies of the pilot signal and the received signal are adjustable.

Further, the XOR gate unit uses a 1-bit comparator to convert the analog signal into a logic code stream, and thereby discriminate the phase.

Further, the XOR gate unit performs serial or parallel processing on the binary code stream.

Further, the XOR gate unit may also use logic components.

Further, the accumulator can also be any one of an integrator or a programmable logic device.

Further, the sampling unit performs single-bit sampling on the pilot signal and the received signal.

Further, the binary code stream is propagated through optical fiber or conducted by electrical signal. During optical fiber propagation, the transceiver part and the digital processing part of the system can be distributed in different geographical locations to form a distributed system.

Further, the radar system further includes a transmitter and a receiver, and the transmitter and receiver can be directly up-converted or multi-stage up-converted.

Using the phase detector and the radar system of the present invention, the hardware structure is simple, and ADC (Analog-to-Digital Converter, analog-to-digital converter) is not required, so the cost is reduced and the dynamic range of the radar receiver is improved.

Description of drawings

Fig. 1: The structure diagram of the positioning radar system of the present invention.

Figure 2: Schematic diagram of data sampling of the present invention.

Figure 3: Schematic diagram of the composition of the phase detector of the present invention.

Detailed ways

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Although the present invention will be described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that these embodiments do not limit the invention to these embodiments. For example, on the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

Please refer to the structure diagram of the positioning radar system of the present invention. )composition.

The frequency conversion is continuously generated by the pilot CW (Continuous Wave, continuous wave) transmitter 101 to generate a CW pilot signal Spilot, and the CW pilot signal Spilot is up-converted to a millimeter wave frequency band, such as 28GHz or 70GHz, through the transmitter 102, and is transmitted by the antenna. The transmitted waveform bounces off the target 103, and the echo signal is received by the receiver 104 and down-converted back to the CW frequency. The received signal Srec and the CW pilot signal Spilot of the receiver are signals of the same frequency, but the phase offset corresponds to the delay time of the target. Differently, the system determines the distance of the target by detecting the time difference of the echo signals. In the case where the transceiving signal is only a sine wave of a specific frequency, the time delay is converted into a phase difference. The detection of the phase difference can be completed by the phase detector 105. By adjusting the frequency of the input signal, the phase detection accuracy of the phase detector 105 can be precisely adjusted correspondingly, and further used to accurately determine the target distance. The transmitter 102 and the receiver 104 in FIG. 1 can be directly up-converted or multi-stage up-converted. During the target 103 detection process, the system can use discretely transformed different pilot frequencies to locate the target.

Please refer to the data sampling schematic diagram of the present invention in FIG. 2, the circular black solid point in the figure is the sampling point, in the present invention, the phase detector 105 uses the optical fiber photoelectric converter to directly compare the sine wave input signal with the 0V point, and then outputs 1 and 0 secondary optical signals, where 1 represents the input voltage is greater than 0V, 0 represents the input voltage is less than 0V, since the comparison is only performed at fixed time intervals, such as commercial photoelectric converters using 10Gbps bandwidth, the comparison sampling point is set to Fixed intervals of 100ps, so a 1GHz sine wave is ten times oversampled and converted to a binary sequence of 1111100000, when the phase error or delay is less than 100ps, the binary sequence indistinguishable is usually difficult to detect.

In this system, the phase detector 105 samples the received signal Srec and the CW pilot signal Spilot of the same frequency with the same clock rate and converts them into two sets of binary code streams, and distinguishes and discriminates small phase differences through the binary code streams.

For example, when the input waveform and sampling time are integer multiples, the 1G signal is sampled by 10G, and a balanced binary code stream of 5 consecutive 1s and 5 consecutive 0s will appear fixed. When the input signal is 0.99G, it is also sampled by 10G. In every 1000 binary code streams, there will be nine unbalanced code streams of 1111100000 and one 1111110000. By analyzing the position of this single unbalanced code 1111110000 pattern in the overall code stream, detailed phase information can be given.

In this system, by setting the frequency of the frequency conversion continuous piloted CW (Continuous Wave, continuous wave) transmission source and the sampling frequency of non-integer multiples, a periodic unbalanced binary code stream is introduced, and the secondary signal generated by the transmitted signal and the received signal is compared. The system code stream can further identify the phase difference between the two and achieve the purpose of radar positioning.

Please refer to the schematic diagram of the composition of the phase detector of the present invention in FIG. 3 , the received signal Srec and the CW pilot signal Spilot are signals of the same frequency, the above two signals are sampled by a single bit, and converted into two sets of binary signals at the fs sampling rate of the sampling unit 301 Code stream, the binary code stream can be propagated through optical fiber or conducted by electrical signal to XOR gate unit 302 for operation. During optical fiber propagation, the transceiver part and digital processing part of the system can be distributed in different geographical locations to form a distributed system. The XOR gate unit 302 can process the input code stream in series or in parallel, different bits of the code stream lead to 1 output, and the same bit leads to 0 output, the XOR gate unit 302 uses a 1bit comparator to convert the analog signal into a logic code stream, And thus discriminate the phase, the output of the XOR gate unit 302 enters the accumulator 303, and accumulates the result of the XOR gate unit 302 within a certain period of time, and the result value of the accumulator 303 corresponds to the phase difference of the two input signals. The accumulator 303 at can also be replaced with either an integrator or a programmable logic device, and the output of the accumulator 303 is further used by other circuits.

The XOR gate unit 302 here can also be replaced by logic components or a combination of logic components that can realize the same function, and is not limited to the XOR gate.

Claims (17)

1. a phase detector, comprises pilot signal, received signal, sampling unit, it is characterized in that, also comprise XOR gate unit and accumulator, sampling unit samples pilot signal and received signal, XOR gate unit is to After the sampled data is processed, a binary code stream is output, and the binary code stream is further processed by the accumulator to obtain the phase difference between the pilot signal and the received signal. 2. The phase detector according to claim 1, wherein the frequencies of the pilot signal and the received signal are adjustable. 3 . The phase detector according to claim 1 , wherein the XOR gate unit converts the analog signal into a logic code stream by using a 1-bit comparator, and thus discriminates the phase. 4 . 4. The phase detector according to claim 1, wherein the XOR gate unit performs serial or parallel processing on the binary code stream. 5 . The phase detector according to claim 1 , wherein the XOR gate unit can also use logic components. 6 . 6. The phase detector according to claim 1, wherein the accumulator can also be any one of an integrator or a programmable logic device. 7. The phase detector according to claim 1, wherein the sampling unit performs single-bit sampling on the pilot signal and the received signal. 8. phase detector as claimed in claim 1 is characterized in that, described binary code stream is propagated through optical fiber or electrical signal conduction, when optical fiber is propagated, the transceiver part and digital processing part of the system can be distributed in different Geographical locations form distributed systems. 9. A radar system, comprising a phase detector, is characterized in that, also comprising a sampling unit, an XOR gate unit and an accumulator, the sampling unit samples the pilot signal and the received signal, and the XOR gate unit samples the sampled data. After processing, the binary code stream is output, and the binary code stream is further processed by the accumulator to obtain the phase difference between the pilot signal and the received signal. 10. The radar system according to claim 9, wherein the frequencies of the pilot signal and the received signal are adjustable. 11. The radar system according to claim 9, wherein the XOR gate unit converts the analog signal into a logic code stream by using a 1-bit comparator, and thereby discriminates the phase. 12. The radar system according to claim 9, wherein the XOR gate unit performs serial or parallel processing on the binary code stream. 13. The radar system according to claim 9, wherein the XOR gate unit can also use logic components. 14. The radar system according to claim 9, wherein the accumulator can also be any one of an integrator or a programmable logic device. 15. The radar system according to claim 9, wherein the sampling unit performs single-bit sampling on the pilot signal and the received signal. 16. The radar system according to claim 9, characterized in that, the binary code stream is propagated through optical fiber or conducted by electrical signal, and during optical fiber propagation, the transceiver part and the digital processing part of the system can be distributed in different geographical locations. Locations form a distributed system. 17. The radar system according to claim 9, further comprising a transmitter and a receiver, and the transmitter and receiver can be directly up-converted or multi-stage up-converted.

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