Radar sensor architecture and radar sensor

Abstract

The present invention discloses a radar sensor architecture and a radar sensor, wherein the radar sensor architecture includes: a first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first noise cancellation module. The first leakage interference cancellation module is connected between the input ends of the first amplification module and the second amplification module, and is used to detect the second input signal in the radio frequency domain (RF) to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the output ends of the first amplification module and the intermediate frequency module, and is used to detect the third input signal in the intermediate frequency domain (IF) to suppress the leakage interference signal. The present invention introduces a leakage interference cancellation module to offset the leakage interference signal leaked to the receiving channel, so as to improve the signal-to-noise ratio of the radar sensor, thereby improving the sensitivity of the receiver.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a radar sensor architecture and a radar sensor. Background Art

[0002] Radar sensors have been widely used in the field of vehicle-mounted autonomous driving, and will have broad application prospects in the fields of smart home, smart health care, smart security, industrial detection, etc. The electromagnetic wave signal emitted by the radar sensor is reflected back by the target and received by the receiving antenna of the radar sensor. By demodulating the amplitude and phase information of the target echo signal, the target's existence, distance, direction, speed and other characteristic information can be detected. In the actual radar sensor circuit and system, whether the transmitting and receiving antennas are shared or separated, the transmitting signal of the transmitting channel will leak to the receiving channel, causing the transmitter to saturate and reduce the receiver signal-to-noise ratio and sensitivity. For radar sensors with shared transmitting and receiving antennas, a circulator is generally used to provide 20dB of transmitting and receiving isolation, and due to the non-ideal matching characteristics of the antenna port, part of the transmitting signal will be reflected back to the receiving channel; for radar sensors with separate transmitting and receiving antennas, the isolation between the transmitting antenna and the receiving antenna is limited by the distance between the two, and part of the transmitting signal of the transmitting antenna will be directly reflected to the receiving antenna through the background debris at a very close distance.

[0003] Therefore, the existing radar sensor has the problem of transmission signal coupling leakage to the receiving channel. This leakage signal not only contains the transmission carrier signal, but also carries part of the transmitter noise. The leaked transmitter noise will reduce the signal-to-noise ratio of the receiving channel, resulting in reduced sensitivity of the receiver.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a radar sensor architecture and a radar sensor to solve the problem that the existing radar sensor has a transmitting signal coupled and leaked to the receiving channel, reducing the signal-to-noise ratio of the receiving channel and causing a decrease in the sensitivity of the receiver.

[0006] The technical solution of the present invention is as follows:

[0007] A radar sensor architecture includes: a first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first leakage interference cancellation module; wherein,

[0008] The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transmission antenna;

[0009] The receiving antenna receives the echo signal of the transmitting signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and inputs it into the analog-to-digital conversion module;

[0010] The first leakage interference cancellation module is connected between the input ends of the first amplification module and the second amplification module, and is used to detect the second input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the first amplification module and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal.

[0011] According to a further configuration of the present invention, the first leakage interference cancellation module includes: a first amplitude detection unit, a first control unit and a first amplitude and phase adjustable unit; wherein,

[0012] One end of the first amplitude detection unit is connected to the second amplification module, and the other end of the first amplitude detection unit is connected to the first control unit, for performing amplitude detection on the second input signal and inputting the detection result to the first control unit;

[0013] The first control unit is connected to the amplitude detection unit and the first amplitude and phase adjustable unit respectively, and is used to output a first control signal and a second control signal to the first amplitude and phase adjustable unit according to the detection result fed back by the first amplitude detection unit;

[0014] The first amplitude and phase adjustable unit is respectively connected to the output end of the first amplification module, the first control unit and the input end of the second amplification module, and is used to access the transmission signal and adjust the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal;

[0015] When the detection power of the second input signal at the carrier frequency of the transmitted signal is minimum, the leakage interference signal is suppressed; wherein the input signal of the second amplification module is the echo signal plus the leakage interference signal minus the first output signal.

[0016] According to a further configuration of the present invention, the first leakage interference cancellation module includes: a first amplitude detection unit, a first control unit and a first amplitude and phase adjustable unit; wherein,

[0017] One end of the first amplitude detection unit is connected to the output end of the intermediate frequency module, and the other end of the first amplitude detection unit is connected to the first control unit, for detecting the amplitude of the third input signal and feeding back the detection result to the first control unit;

[0018] The first control unit is connected to the first amplitude detection unit and the first amplitude and phase adjustable unit respectively, and is used to output a first control signal and a second control signal to the first amplitude and phase adjustable unit according to the detection result fed back by the first amplitude detection unit;

[0019] The first amplitude and phase adjustable unit is respectively connected to the output end of the first amplification module, the first control unit and the input end of the second amplification module, and is used to access the transmission signal and adjust the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal.

[0020] A further configuration of the present invention also includes: a second leakage interference cancellation module; the second leakage interference cancellation module is connected between the second frequency source and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal.

[0021] According to a further configuration of the present invention, the second leakage interference cancellation module includes: a second amplitude detection unit, a second control unit and a second amplitude and phase adjustable unit; wherein,

[0022] One end of the second amplitude detection unit is connected to the output end of the intermediate frequency module, and the other end of the second amplitude detection unit is connected to the second control unit, for detecting the amplitude of the third input signal and feeding back the detection result to the second control unit;

[0023] The second control unit is connected to the second amplitude detection unit and the second amplitude and phase adjustable unit respectively, and is used to output a third control signal and a fourth control signal to the second amplitude and phase adjustable unit according to the detection result fed back by the second amplitude detection unit;

[0024] The second amplitude and phase adjustable unit is connected to the output end of the second frequency source and the input end of the intermediate frequency module respectively, and is used to receive the first input signal and adjust the amplitude and phase of the first input signal to obtain a second output signal that can cancel the leakage interference signal;

[0025] When the detection power of the third input signal at the intermediate frequency carrier frequency is minimum, the leakage interference signal is suppressed; wherein the input signal of the intermediate frequency module is the intermediate frequency signal plus the leakage interference signal minus the second output signal.

[0026] A further configuration of the present invention further includes: a crystal oscillator, which is connected to the first frequency source and the second frequency source respectively, and is used to provide an oscillation frequency for the first frequency source and the second frequency source.

[0027] According to a further configuration of the present invention, the intermediate frequency module comprises: an intermediate frequency amplifier and an intermediate frequency filter; wherein,

[0028] The input end of the intermediate frequency amplifier is connected to the second mixer, and the output end of the intermediate frequency amplifier is connected to the input end of the intermediate frequency filter, so as to amplify the intermediate frequency signal;

[0029] The output end of the intermediate frequency filter is connected to the analog-to-digital conversion module, and is used to output a third input signal to the analog-to-digital conversion module after filtering the intermediate frequency signal.

[0030] According to a further configuration of the present invention, the second amplification module includes a low noise amplifier, an input end of the low noise amplifier is connected to the receiving antenna, and an output end of the low noise amplifier is connected to the second mixer for amplifying the echo signal.

[0031] A radar sensor architecture includes: a first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first leakage interference cancellation module; wherein,

[0032] The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transmission antenna;

[0033] The receiving antenna receives the echo signal of the transmitting signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and inputs it into the analog-to-digital conversion module;

[0034] The first leakage interference cancellation module is connected between the second frequency source and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the second frequency source and the output end of the first amplification module, and is used to detect the second input signal to suppress the leakage interference signal.

[0035] A radar sensor architecture includes: a first frequency source, a second frequency source, a first mixer, a first amplification module, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a first leakage interference cancellation module, a circulator, and a transceiver antenna; wherein:

[0036] The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transceiver antenna;

[0037] The transceiver antenna receives the echo signal of the transmission signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and inputs it into the analog-to-digital conversion module;

[0038] The first leakage interference cancellation module is connected between the input ends of the first amplification module and the second amplification module, and is used to detect the second input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the first amplification module and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal.

[0039] A radar sensor comprises the radar sensor architecture as described above.

[0040] The present invention provides a radar sensor architecture and a radar sensor, wherein the radar sensor architecture includes: a first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first leakage interference cancellation module. Among them, the first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transmitting antenna; the receiving antenna receives the echo signal of the transmission signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer mixes the second input local oscillator signal provided by the first frequency source with the second input signal to obtain an intermediate frequency signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and input it into the analog-to-digital conversion module; the first leakage interference cancellation module is connected between the input ends of the first amplification module and the second amplification module, and is used to detect the second input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the first amplification module and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal. The present invention introduces a first leakage interference cancellation module between the first amplification module and the second amplification module (radio frequency domain) or the intermediate frequency module (intermediate frequency domain) to offset the leakage interference signal leaked to the receiving channel, so as to improve the signal-to-noise ratio of the radar sensor and further improve the sensitivity of the receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0042] Figure 1 The principle of the radar sensor architecture in one embodiment of the present invention is Figure 1 .

[0043] Figure 2 The principle of the radar sensor architecture in one embodiment of the present invention is Figure 2 .

[0044] Figure 3 The principle of the radar sensor architecture in one embodiment of the present invention is Figure 3 .

[0045] Figure 4The principle of the radar sensor architecture in one embodiment of the present invention is Figure 4 .

[0046] Figure 5 It is a schematic diagram of a radar sensor in an embodiment of the present invention in which a first frequency source and a second frequency source share a crystal oscillator.

[0047] Figure 6 It is a schematic diagram of a radar sensor transmitting antenna and a receiving antenna shared by one embodiment of the present invention.

[0048] The marks in the accompanying drawings are: 1. first frequency source; 2. second frequency source; 3. first mixer; 4. first amplification module; 5. transmitting antenna; 6. second amplification module; 7. second mixer; 8. intermediate frequency module; 81. intermediate frequency amplifier; 82. intermediate frequency filter; 9. analog-to-digital conversion module; 10. receiving antenna; 11. first leakage interference cancellation module; 111. first amplitude detection unit; 112. first control unit; 113. first amplitude and phase adjustable unit; 12. second leakage interference cancellation module; 121. second amplitude detection unit; 122. second control unit; 123. second amplitude and phase adjustable unit; 13. crystal oscillator; 14. circulator; 15. transmitting and receiving antenna; 16. DSP chip. DETAILED DESCRIPTION

[0049] The present invention provides a radar sensor architecture and a radar sensor. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] In the embodiments and the scope of the patent application, unless the text specifically defines the article, "a", "an", "the" and "the" may also include plural forms. If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0051] It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intermediate elements. In addition, the "connection" or "coupling" used herein can include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0052] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0053] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0054] The inventors have found that in traditional continuous wave radar sensors, the radar detection range is generally increased by increasing the transmit power, but increasing the transmit power will also increase the transmit signal leaking into the receiving channel, which may exceed the dynamic range of the receiving channel. The noise carried by the leaked signal will also deteriorate the signal-to-noise ratio of the receiving channel and reduce the receiver sensitivity. In the future, radar sensors will need to have low power consumption and weak target signal detection capabilities, such as weak vital signs such as breathing, heartbeat, blood pressure in the field of smart health and weak vibration signals in industrial detection, which will put higher requirements on the dynamic range and sensitivity of radar sensors.

[0055] In view of the above technical problems, the present invention provides a radar sensor architecture, which introduces a leakage interference cancellation module between the transmitter and the receiver to offset the leakage interference signal, thereby not only improving the dynamic range of the radar sensor, but also improving the sensitivity.

[0056] Please also see Figures 1 to 6 , the present invention provides a preferred embodiment of a radar sensor architecture.

[0057] like Figure 1 and Figure 2As shown, a radar sensor architecture provided by the present invention includes: a first frequency source 1, a second frequency source 2, a first mixer 3, a first amplification module 4, a transmitting antenna 5, a second amplification module 6, a second mixer 7, an intermediate frequency module 8, an analog-to-digital conversion module 9, a receiving antenna 10 and a first leakage interference cancellation module 11. Among them, the first input local oscillator signal output by the first frequency source 1 and the first input signal output by the second frequency source 2 are mixed by the first mixer 3 and amplified by the first amplification module 4 to obtain a transmission signal, and the transmission signal enters the free space through the transmitting antenna 5; the receiving antenna 10 receives the echo signal of the transmission signal and obtains a second input signal after amplification by the second amplification module 6 and inputs it into the second mixer 7; the second mixer 7 mixes the second input local oscillator signal provided by the first frequency source 1 with the second input signal to obtain an intermediate frequency signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module 8 to obtain a third input signal and input it into the analog-to-digital conversion module 9; the first leakage interference cancellation module 11 is connected between the input ends of the first amplification module 4 and the second amplification module 6, and is used to detect the second input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module is connected between the first amplification module 4 and the output end of the intermediate frequency module 8, and is used to detect the third input signal to suppress the leakage interference signal.

[0058] Specifically, the first frequency source 1, the second frequency source 2, the first mixer 3, the first amplification module 4, and the transmitting antenna 5 constitute a transmitter, and the first frequency source 1, the second amplification module 6, the second mixer 7, the intermediate frequency module 8, the analog-to-digital conversion module 9, the receiving antenna and the first leakage interference cancellation module 11 constitute a receiver, and the receiver and the transmitter share the first frequency source 1.

[0059] like Figure 1 As shown, when the first leakage interference cancellation module 11 is connected between the input ends of the first amplification module 4 and the second amplification module 6, the first frequency source 1 provides the first input local oscillation signal LO for the first mixer 3. Tx (t), whose amplitude is V LO , frequency is f LO , the phase noise is φ LO (t). The second frequency source 2 provides the first input signal IF to the first mixer 3. Tx (t), whose amplitude is V IF , frequency is f IF , the phase noise is φ IF (t), and then after being mixed and amplified by the first mixer 3, a transmit signal Tx(t) is obtained, whose amplitude is V TX , frequency is f TX, the phase noise is φ Tx (t). Wherein, the first input local oscillator signal LO Tx (t), the first input signal IF Tx (t), the transmitted signal Tx(t) is expressed by the following expression:

[0060] LO Tx (t) = V LO cos[2πf LO t+φ LO (t)];

[0061] IF Tx (t) = V IF cos[2πf IF t+φ IF (t)];

[0062] Tx(t)=V TX cos[2πf Tx t+φ Tx (t)],f Tx =f LO +f IF ,φ Tx (t) = φ LO (t)+φ IF (t).

[0063] After the transmission signal Tx(t) enters the free space through the transmission antenna, the transmission signal Tx(t) will be reflected after encountering the detection target and received by the receiving antenna 10, thereby entering the receiver. The echo signal received by the receiving antenna 10 in the receiver is Rx(t), and the first frequency source 1 provides the second input local oscillator signal LO for the second mixer 7. Rx (t), and the first input local oscillator signal LO Tx (t) and the second input local oscillator signal LO Rx (t) is the coherent local oscillator signal, i.e. LO Tx (t) = LO Rx (t), thus, when the second mixer 7 performs mixing, the coherent noise characteristics are offset, thereby suppressing the noise and improving the signal-to-noise ratio.

[0064] Assuming that the static distance of the detection target from the radar sensor is d0, and the displacement caused by the vibration / motion of the detection target itself is d(t), the model of the echo signal Rx(t) received by the receiving antenna 10 can be described as:

[0065]

[0066] Among them, the amplitude of the received echo signal is V RX, c is the propagation speed of electromagnetic waves in free space.

[0067] In addition to the echo signal Rx(t) of the detected target, due to the transmission-reception leakage and the reflection of the background objects near the radar sensor, there is also a leakage interference signal Ri(t) at the receiving front end of the radar sensor. Ri(t) can be equivalent to the delayed signal of Tx(t):

[0068] Ri(t)=V Ri cos[2πf Tx (ti)+φ Tx (ti)];

[0069] Where i is the equivalent delay time from transmission to reception of the leakage interference signal, and the amplitude of the leakage interference signal is V Ri .

[0070] Usually, the leakage interference signal Ri(t) is 20-30 dB larger than the echo signal Rx(t), so it is very easy to cause the second amplification module 6 located at the receiving front end to saturate, limiting the dynamic range of the radar sensor front end.

[0071] By introducing the first noise cancellation module 11 in the radio frequency (RF) domain, wherein the input of the first leakage interference cancellation module 11 is a transmission signal, the transmission signal outputs a first output signal Rxc(t) after passing through the first leakage interference cancellation module 11:

[0072] Rxc(i)=kTx(t-τ)=kV Tx cos[2πf Tx t-2πf Tx τ+φ Tx (t-tτ)];

[0073] The amplitude and phase of the transmit signal Rxc(t) relative to the first output signal Rxc(t) can be controlled by the first leakage interference cancellation module 11. Then the second input signal Ry(t) input to the second mixer 7 is expressed as:

[0074] Ry(t)=G LNA [Rx(t)+Ri(t)-Rxc(t)];

[0075] Among them, G LNA is the gain of the second amplification module. From the above formula, it can be seen that the first output signal Rxc(t) output by the first leakage interference cancellation module 11 can offset the leakage interference signal Ri(t), that is, it can suppress the leakage interference signal Ri(t) transmitted to the receiver.

[0076] The echo signal after noise cancellation is amplified by the first amplification module 4 to obtain a second input signal Ry(t) and a second input local oscillator signal LO Rx (t) After mixing by the second mixer 7, an intermediate frequency signal IF is obtained. RX1 (t):

[0077] IFR X1 (t) = LPF {Ry(t)LO Rx (t)};

[0078] The intermediate frequency signal IF RX1 (t) After passing through the intermediate frequency module 8, a third input signal IF is obtained. RX (t), continue to enter the analog-to-digital conversion module 9 and convert it into a digital signal for subsequent radar signal processing, that is, give it to the subsequent DSP chip 16 for processing.

[0079] It can be seen that the present invention introduces the first leakage interference cancellation module 11 in the radio frequency (RF) domain. The first output signal output by the first leakage interference cancellation module 11 can offset the leakage interference signal, that is, it can suppress the noise interference signal transmitted to the receiver, so that the second amplification module 6 will not be saturated due to the presence of the leakage interference signal. This can not only improve the dynamic range of the RF front end, but also reduce the leakage interference signal, thereby improving the signal-to-noise ratio, and further improving the sensitivity of the receiver.

[0080] It should be noted that the first leakage interference cancellation module 11 is connected between the first amplification module 4 and the output end of the intermediate frequency module 8 to RX (t) The principle of detecting to suppress the leakage interference signal is similar to that the first leakage interference cancellation module 11 is connected between the input ends of the first amplification module 4 and the second amplification module 6 .

[0081] In other embodiments, the radar sensor architecture can also be configured to include: a first frequency source 1, a second frequency source 2, a first mixer 3, a first amplification module 4, a transmitting antenna 5, a second amplification module 6, a second mixer 7, an intermediate frequency module 8, an analog-to-digital conversion module 9, a receiving antenna 10 and a first leakage interference cancellation module 11. Among them, the first input local oscillator signal output by the first frequency source 1 and the first input signal output by the second frequency source 2 are mixed by the first mixer 3 and amplified by the first amplification module 4 to obtain a transmission signal, and the transmission signal enters the free space through the transmitting antenna 5; the receiving antenna 10 receives the echo signal of the transmission signal and obtains a second input signal after amplification by the second amplification module 6 and inputs it into the second mixer 7; the second mixer 7 mixes the second input local oscillator signal provided by the first frequency source 1 with the second input signal to obtain an intermediate frequency signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module 8 to obtain a third input signal and input it into the analog-to-digital conversion module 9; the first leakage interference cancellation module 11 is connected between the output end of the second frequency source 2 and the intermediate frequency module 8, and is used to detect the third input signal to suppress the leakage interference signal; or, the first leakage interference cancellation module 11 is connected between the second frequency source 2 and the output end of the first amplification module 4, and is used to detect the second input signal to suppress the leakage interference signal. Different from the first leakage interference cancellation module 11 being arranged between the first amplification module 4 and the second amplification module 6 or between the first amplification module 4 and the output end of the intermediate frequency module 8, in the present embodiment, the first leakage interference amplification module 11 is located between the second frequency source 2 and the output end of the intermediate frequency module 8 or between the second frequency source 2 and the output end of the first amplification module 4 to suppress the leakage interference signal in the intermediate frequency domain.

[0082] like Figure 1As shown, in a further implementation of an embodiment, the first leakage interference cancellation module 11 includes: a first amplitude detection unit 111, a first control unit 112 and a first amplitude and phase adjustable unit 113. Among them, one end of the first amplitude detection unit 111 is connected to the second amplification module 6, and the other end of the first amplitude detection unit 111 is connected to the first control unit 112, for performing amplitude detection on the second input signal and inputting the detection result to the first control unit 112; the first control unit 112 is respectively connected to the first amplitude detection unit 111 and the first amplitude and phase adjustable unit 113, for outputting a first control signal and a second control signal to the first amplitude and phase adjustable unit 113 according to the detection result fed back by the first amplitude detection unit 111; the first amplitude and phase adjustable unit 113 is respectively connected to the output end of the first amplification module 4, the first control unit 112 and the input end of the second amplification module 6, for accessing the transmission signal and adjusting the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal.

[0083] Specifically, the first amplitude and phase adjustable unit 113 includes an adjustable attenuator for adjusting the amplitude and an adjustable phase shifter for adjusting the phase. The first amplitude detection unit 111 detects the second input signal (i.e., point P) at the output end of the second amplification module 6, and inputs the detection result to the first control unit 112 for detection and judgment, and then the first control unit 112 outputs two control signals to adjust the adjustable attenuator and the adjustable phase shifter, thereby adjusting the amplitude and phase of the connected transmission signal, so that the first output signal output by the first amplitude and phase adjustable unit 113 can be canceled with the received leakage interference signal, wherein the input signal of the second amplification module 6 is the echo signal plus the leakage interference signal minus the first output signal. The present invention realizes the suppression of leakage interference signals through the above-mentioned detection, control and adjustment process cycle, wherein when the detection power of the second input signal at the carrier frequency of the transmission signal is the smallest, the leakage interference signal is suppressed.

[0084] In another embodiment, that is, when the first leakage interference cancellation module 11 is connected between the first amplification module 4 and the output end of the intermediate frequency module 8, the first leakage interference cancellation module 11 includes: a first amplitude detection unit 111, a first control unit 112 and a first amplitude and phase adjustable unit 113. Among them, one end of the first amplitude detection unit 111 is connected to the output end of the intermediate frequency module 8, and the other end of the first amplitude detection unit 111 is connected to the first control unit 112, which is used to detect the amplitude of the third input signal and feed back the detection result to the first control unit 112; the first control unit 112 is respectively connected to the first amplitude detection unit 111 and the first amplitude and phase adjustable unit 113, which is used to output the first control signal and the second control signal to the first amplitude and phase adjustable unit 113 according to the detection result fed back by the first amplitude detection unit 111; the first amplitude and phase adjustable unit 113 is respectively connected to the output end of the first amplification module 4, the first control unit 112 and the input end of the second amplification module 6, which is used to access the transmission signal and adjust the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal.

[0085] In this embodiment, compared with the first leakage interference cancellation module 11 connected between the input ends of the first amplification module 4 and the second amplification module 6, both of which complete the detection and judgment cancellation in the RF domain, the difference is that this embodiment completes the detection and judgment in the intermediate frequency domain, and completes the noise cancellation in the RF domain. That is to say, the present invention can complete the cancellation and detection and judgment in the RF domain, or complete the cancellation in the RF domain and complete the detection and judgment in the intermediate frequency domain, or complete the detection and judgment in the RF domain and complete the cancellation in the intermediate frequency domain.

[0086] In a further implementation of an embodiment, Figure 4 As shown, the radar sensor architecture also includes: a second leakage interference cancellation module 12; the second leakage interference cancellation module 12 is connected between the second frequency source 2 and the output end of the intermediate frequency module 8, and is used to detect the third input signal to suppress the leakage interference signal.

[0087] Specifically, based on the first leakage interference cancellation module 11 being set in the radio frequency domain of the radar sensor, this embodiment further sets a second leakage interference cancellation module 12 in the intermediate frequency domain, which can further reduce the leakage noise of the radar sensor and improve the signal-to-noise ratio of the front end of the radar sensor.

[0088] Further, the second leakage interference cancellation module 12 includes: a second amplitude detection unit 121, a second control unit 122 and a second amplitude and phase adjustable unit 123. Among them, one end of the second amplitude detection unit 121 is connected to the output end of the intermediate frequency module 8, and the other end of the second amplitude detection unit 121 is connected to the second control unit 122, which is used to detect the amplitude of the third input signal and feed back the detection result to the second control unit 122; the second control unit 122 is respectively connected to the second amplitude detection unit 122 and the second amplitude and phase adjustable unit 123, which is used to output the third control signal and the fourth control signal to the second amplitude and phase adjustable unit 123 according to the detection result fed back by the second amplitude detection unit 122; the second amplitude and phase adjustable unit 123 is respectively connected to the output end of the second frequency source 2 and the input end of the intermediate frequency module 8, which is used to access the first input signal and adjust the amplitude and phase of the first input signal to obtain a second output signal that can cancel the leakage interference signal.

[0089] Specifically, the second amplitude detection unit 121 detects the intermediate frequency signal at the intermediate frequency carrier at the Q point. fIF The signal power at the frequency, and the detection result is sent to the second control unit 122, the second control unit 122 makes a determination according to the detection result and generates two control signals to control the amplitude and phase of the second amplitude and phase adjustable unit 123 respectively, so that the input first input signal IF Tx (t) After passing through the second amplitude and phase adjustable unit 123, the intermediate frequency signal IF RX1 (t) at the intermediate frequency carrier frequency f IF The input signal of the intermediate frequency module 8 is the intermediate frequency signal IF RX1 (t) plus the leakage interference signal Ri(t) minus the second output signal IFc(t). The present invention performs a detection-control-adjustment process cycle through the second leakage interference cancellation module 12, and further suppresses the radar sensor's transmit-receive leakage signal through adaptive cancellation in the intermediate frequency domain, which can further improve the sensor's signal-to-noise ratio. Wherein, when the detection power of the third input signal at the intermediate frequency carrier frequency is the minimum, the leakage interference signal is suppressed.

[0090] In some embodiments, Figure 5 As shown, the radar sensor also includes: a crystal oscillator 13, which is connected to the first frequency source 1 and the second frequency source 2 respectively. The first frequency source 1 and the second frequency source 2 share a crystal oscillator, and the crystal oscillator provides an oscillation frequency for the first frequency source 1 and the second frequency source 2.

[0091] In some embodiments, the second amplification module 6 includes a low noise amplifier, an input end of the low noise amplifier is connected to the receiving antenna 10, and an output end of the low noise amplifier is connected to the second mixer 7 for amplifying the echo signal.

[0092] In a further implementation of an embodiment, Figure 1 As shown, the intermediate frequency module 8 includes: an intermediate frequency amplifier 81 and an intermediate frequency filter 82. The input end of the intermediate frequency amplifier 81 is connected to the second mixer 7, and the output end of the intermediate frequency amplifier 81 is connected to the input end of the intermediate frequency filter 82, for amplifying the intermediate frequency signal; the output end of the intermediate frequency filter 82 is connected to the analog-to-digital conversion module 9, for filtering the intermediate frequency signal and then outputting a third input signal to the analog-to-digital conversion module 9.

[0093] Specifically, the intermediate frequency filter 82 is a high-pass filter. It can be known from the classical radar equation that the size of the echo signal of the detected target body is inversely proportional to the fourth power of the distance between the target and the radar sensor. Therefore, the closer the target, the stronger the radar echo, and the farther the target, the weaker the radar echo. Echo signals of different distances enter the receiver at the same time and finally enter the analog-to-digital conversion module 9. Due to the imbalance of signal amplitude, it is easy to cause saturation quantization noise of the analog-to-digital conversion module 9. The present invention introduces a high-pass filter in the intermediate frequency domain, uses the rising edge transmission characteristics of the high-pass filter to realize spatial filtering, completes the equalization processing of the echo signal, compensates the amplitude of the echo signal at different distances, and realizes the high dynamic range of the digital-to-analog conversion module. In addition, the invention adopts a low intermediate frequency structure, and the intermediate frequency signal of the demodulated received signal is a low intermediate frequency frequency, which can avoid the influence of the flicker noise of the intermediate frequency circuit.

[0094] In some embodiments, Figure 6 As shown, the radar sensor can also realize signal transmission and reception by installing the transceiver antenna 15 on the circulator 14.

[0095] In some embodiments, the present invention further provides a radar sensor, which may be a continuous wave (CW) radar sensor or a frequency modulated continuous wave (FMCW) radar sensor, and includes the radar sensor architecture as described above. Specific details are as described in a radar sensor architecture, which will not be repeated here.

[0096] In summary, the radar sensor architecture and radar sensor provided by the present invention have the following beneficial effects:

[0097] In the radio frequency (RF) domain, a first leakage interference cancellation module is introduced to output a signal with adjustable amplitude and phase to cancel the transmission-reception interference, improve the dynamic range of the sensor RF front-end circuit, and reduce leakage noise;

[0098] In the intermediate frequency (IF) domain, the amplitude and phase adjustable signal output by the second leakage interference cancellation module is introduced to offset the transmission-reception interference, further reduce the leakage noise at the sensor transmitter, and improve the signal-to-noise ratio of the sensor front end;

[0099] The sensor adopts a low intermediate frequency architecture based on a dual frequency source. The intermediate frequency signal of the demodulated received signal is a low intermediate frequency signal, which can avoid the influence of flicker noise of the intermediate frequency circuit.

[0100] The rising edge of the high-pass filter in the intermediate frequency module is used to achieve amplitude balance of the intermediate frequency signal to be sampled, compensate for the amplitude of the echo signal at different distances, and maximize the sampling dynamic range of the analog-to-digital conversion module of the radar sensor.

[0101] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A radar sensor architecture, It is characterized in that include: A first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first leakage interference cancellation module; wherein, The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transmission antenna; The receiving antenna receives the echo signal of the transmitting signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and inputs it into the analog-to-digital conversion module; the first input local oscillator signal and the second input local oscillator signal are coherent local oscillator signals; The first leakage interference cancellation module is respectively connected to the output end of the first amplification module, the output end of the second amplification module and the input end of the second amplification module, and is used to detect the second input signal to suppress the leakage interference signal; the first leakage interference cancellation module includes: a first amplitude detection unit, a first control unit and a first amplitude and phase adjustable unit; wherein, One end of the first amplitude detection unit is connected to the output end of the second amplification module, and the other end of the first amplitude detection unit is connected to the first control unit, for performing amplitude detection on the second input signal and inputting the detection result to the first control unit; The first control unit is connected to the amplitude detection unit and the first amplitude and phase adjustable unit respectively, and is used to output a first control signal and a second control signal to the first amplitude and phase adjustable unit according to the detection result fed back by the first amplitude detection unit; The first amplitude and phase adjustable unit is respectively connected to the output end of the first amplification module, the first control unit and the input end of the second amplification module, and is used to access the transmission signal and adjust the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal; When the detection power of the second input signal at the carrier frequency of the transmitted signal is minimum, the leakage interference signal is suppressed; wherein the input signal of the second amplification module is the echo signal plus the leakage interference signal minus the first output signal.

2. The radar sensor architecture according to claim 1, It is characterized in that Also includes: A second leakage interference cancellation module; The second leakage interference cancellation module is connected between the output end of the second frequency source and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal.

3. The radar sensor architecture according to claim 2, It is characterized in that The second leakage interference cancellation module includes: a second amplitude detection unit, a second control unit and a second amplitude and phase adjustable unit; wherein, One end of the second amplitude detection unit is connected to the output end of the intermediate frequency module, and the other end of the second amplitude detection unit is connected to the second control unit, for detecting the amplitude of the third input signal and feeding back the detection result to the second control unit; The second control unit is connected to the second amplitude detection unit and the second amplitude and phase adjustable unit respectively, and is used to output a third control signal and a fourth control signal to the second amplitude and phase adjustable unit according to the detection result fed back by the second amplitude detection unit; The second amplitude and phase adjustable unit is connected to the output end of the second frequency source and the input end of the intermediate frequency module respectively, and is used to receive the first input signal and adjust the amplitude and phase of the first input signal to obtain a second output signal that can cancel the leakage interference signal; When the detection power of the third input signal at the intermediate frequency carrier frequency is minimum, the leakage interference signal is suppressed; wherein the input signal of the intermediate frequency module is the intermediate frequency signal plus the leakage interference signal minus the second output signal.

4. The radar sensor architecture according to claim 1, It is characterized in that Also includes: A crystal oscillator, the crystal oscillator is connected to the first frequency source and the second frequency source respectively, and is used to provide an oscillation frequency for the first frequency source and the second frequency source.

5. The radar sensor architecture according to claim 1, It is characterized in that The intermediate frequency module includes: an intermediate frequency amplifier and an intermediate frequency filter; wherein, The input end of the intermediate frequency amplifier is connected to the second mixer, and the output end of the intermediate frequency amplifier is connected to the input end of the intermediate frequency filter, so as to amplify the intermediate frequency signal; The output end of the intermediate frequency filter is connected to the analog-to-digital conversion module, and is used to output a third input signal to the analog-to-digital conversion module after filtering the intermediate frequency signal; The second amplification module includes a low noise amplifier, an input end of the low noise amplifier is connected to the receiving antenna, and an output end of the low noise amplifier is connected to the second mixer, for amplifying the echo signal.

6. A radar sensor architecture, It is characterized in that include: A first frequency source, a second frequency source, a first mixer, a first amplification module, a transmitting antenna, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a receiving antenna and a first leakage interference cancellation module; wherein, The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transmission antenna; The receiving antenna receives the echo signal of the transmitting signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and inputs it into the analog-to-digital conversion module; the first input local oscillator signal and the second input local oscillator signal are coherent local oscillator signals; The first leakage interference cancellation module is respectively connected to the output end of the second frequency source, the input end of the intermediate frequency module and the output end of the intermediate frequency module, and the first leakage interference cancellation module is connected between the second frequency source and the output end of the intermediate frequency module, and is used to detect the third input signal to suppress the leakage interference signal; the first leakage interference cancellation module includes: a first amplitude detection unit, a first control unit and a first amplitude and phase adjustable unit; wherein, One end of the first amplitude detection unit is connected to the output end of the intermediate frequency module, and the other end of the first amplitude detection unit is connected to the first control unit, for performing amplitude detection on the third input signal and inputting the detection result to the first control unit; The first control unit is connected to the amplitude detection unit and the first amplitude and phase adjustable unit respectively, and is used to output a first control signal and a second control signal to the first amplitude and phase adjustable unit according to the detection result fed back by the first amplitude detection unit; The first amplitude and phase adjustable unit is respectively connected to the output end of the second frequency source, the first control unit and the input end of the intermediate frequency module, and is used to access the first input signal and adjust the amplitude and phase of the first input signal according to the first control signal and the second control signal to obtain a second output signal that can cancel the leakage interference signal.

7. A radar sensor architecture, It is characterized in that include: A first frequency source, a second frequency source, a first mixer, a first amplification module, a second amplification module, a second mixer, an intermediate frequency module, an analog-to-digital conversion module, a first leakage interference cancellation module, a circulator, and a transceiver antenna; wherein, The first input local oscillator signal output by the first frequency source and the first input signal output by the second frequency source are mixed by the first mixer and amplified by the first amplification module to obtain a transmission signal, and the transmission signal enters the free space through the transceiver antenna; The transceiver antenna receives the echo signal of the transmission signal and obtains a second input signal after amplification by the second amplification module and inputs it into the second mixer; the second mixer obtains an intermediate frequency signal after mixing the second input local oscillator signal provided by the first frequency source with the second input signal; the intermediate frequency signal is amplified and filtered by the intermediate frequency module to obtain a third input signal and input it into the analog-to-digital conversion module; the first input local oscillator signal and the second input local oscillator signal are coherent local oscillator signals; The first leakage interference cancellation module is respectively connected to the output end of the first amplification module, the output end of the second amplification module and the input end of the second amplification module, and is used to detect the second input signal to suppress the leakage interference signal; The first leakage interference cancellation module includes: a first amplitude detection unit, a first control unit and a first amplitude and phase adjustable unit; wherein, One end of the first amplitude detection unit is connected to the output end of the second amplification module, and the other end of the first amplitude detection unit is connected to the first control unit, for performing amplitude detection on the second input signal and inputting the detection result to the first control unit; The first control unit is connected to the amplitude detection unit and the first amplitude and phase adjustable unit respectively, and is used to output a first control signal and a second control signal to the first amplitude and phase adjustable unit according to the detection result fed back by the first amplitude detection unit; The first amplitude and phase adjustable unit is respectively connected to the output end of the first amplification module, the first control unit and the input end of the second amplification module, and is used to access the transmission signal and adjust the amplitude and phase of the transmission signal according to the first control signal and the second control signal to obtain a first output signal that can cancel the leakage interference signal.

8. A radar sensor, It is characterized in that The invention comprises a radar sensor architecture as claimed in any one of claims 1 to 5.

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