CN112865816A - Multi-target ranging method and system based on inquiry response system - Google Patents

Abstract

The invention has proposed a multi-target range finding method and its system based on inquiry response system, receive the radio frequency signal through the receiver of the inquiry response system at first, and mix the radio frequency signal into the intermediate frequency signal and send AD module to carry on AD sampling; sending the sampled signals to an FPGA module of an inquiry response system to be converted into I, Q baseband signals; then judging a useful signal through a threshold so as to generate a correlation peak, and carrying out digital signal processing on the useful signal to obtain real amplitude data and phase data; utilizing an inquiry and response time sequence frame of an inquiry response system, starting counting when the inquiry response system inquires, namely, transmits signals, and synchronously sending out a correlation peak, counting data, amplitude data and phase difference data to an information processing terminal when counting once; and finally, calculating by combining the time sequence specified by the information processing terminal with the correlation peak, the counting data, the amplitude data and the phase difference data to obtain the distance of multiple targets.

Description

Multi-target ranging method and system based on inquiry response system

Technical Field

The invention belongs to the field of communication, and particularly relates to a multi-target ranging method and a multi-target ranging system based on an inquiry response system.

Background

The conventional multi-target ranging method of the current inquiry response system comprises the following steps: firstly, decoding a PN code (spread spectrum code) through digital down conversion, comparing a local code with the received PN code bit by bit, adding 1 to the counter when the local code and the received PN code are the same, comparing the same number of the local code and the received PN code with a threshold after one PN code period is continued, outputting a synchronous mark signal if the local code and the received PN code are more than the threshold, otherwise delaying the PN code by one code element through a control circuit, resetting the counter, simultaneously recording the number of the code elements delayed by the PN code by another counter, and outputting a synchronous mark signal A; the intermediate frequency digital processed signal is compared with the phase discrimination of a local PN code clock signal to output an advanced or lagging pulse signal, the input pulse of the frequency divider is controlled to be added or subtracted according to the advanced or lagging pulse of the phase discrimination circuit, the local phase code is adjusted to output a synchronous mark signal B, the transmission delay can be calculated according to the synchronous mark signals A and B, and the target distance is obtained.

The prior art has complex steps, large error of a measuring result, long time consumption and ineffective control of precision error and time.

Disclosure of Invention

The present invention addresses the above-mentioned shortcomings of the prior art, and provides a multi-target ranging method based on an inquiry response system and a system thereof, in the scheme of the invention, the interrogator, the responder and the FPGA module which are carried by the inquiry response system are adopted, and combines the self inquiry and response time sequence frame of the inquiry and response system, and utilizes the pseudo code distance measurement to realize the multi-target distance measurement, compared with the prior art, the method has simpler and more convenient operation, higher precision and less time consumption, and is based on the fixed time sequence of the inquiry and response time sequence frame, under the condition of faster and more uniform data processing, the real-time performance of the data processing is ensured, complex decoding related period operation is not required, a modulation signal is not required to carry a ranging code and target information, and additional ranging equipment is not required, the fast and accurate multi-target ranging can be realized, and the ranging precision error and time are effectively controlled.

The specific implementation content of the invention is as follows:

the invention provides a multi-target ranging method based on an inquiry response system, which carries out multi-target ranging based on the inquiry response system and comprises the following steps:

s1, receiving a radio frequency signal through a receiver of an inquiry response system, mixing the radio frequency signal into an intermediate frequency signal, and sending the intermediate frequency signal to an AD (analog-to-digital) module for AD sampling;

s2, after AD sampling, sending a signal obtained by sampling to an FPGA module of the inquiry response system to convert the signal into an I, Q baseband signal;

s3, despreading the obtained I, Q baseband signal, judging a useful signal through a threshold to generate a correlation peak, and carrying out digital signal processing on the useful signal to obtain real amplitude data and phase data; the method comprises the steps that an inquiry and response time sequence frame of an inquiry response system is utilized, counting is started when the inquiry response system inquires, namely signals are transmitted, when the inquiry response system responds, namely I, Q baseband signals are received and despread to obtain correlation peaks, the counter of the inquiry and response time sequence frame is utilized for counting once, and the correlation peaks, counting data, amplitude data and phase difference data are synchronously sent to an information processing terminal when the counting is performed once;

and S4, calculating by combining the time sequence specified by the information processing terminal with the correlation peak, the counting data, the amplitude data and the phase difference data to obtain the distance of multiple targets.

In order to better implement the present invention, further, when the query response system in step S3 despreads the obtained I, Q baseband signal, the local code and the spreading code sequence identical to the transmitting end are used to despread the baseband signal, and the modulated signal of the correlation peak is resolved into a useful signal through threshold judgment, and a pulse output is synchronously generated, and the correlation peak, the count data, the amplitude data, and the phase difference data are synchronously output on the upper edge of the pulse output; and when the system responds, the first correlation peak is solved, a value is added on the counter, and the counter counts once in the process of solving a correlation peak, and is cleared when the inquiry response system is converted into an inquiry.

In order to better implement the present invention, further, in step S4, the signal obtained after despreading the same target under test includes three modulated signals, and the three modulated signals are divided into two types: the first modulation signal and the second modulation signal in the three modulation signals are modulation signals with a spreading code of DS1, and the third modulation signal is a modulation signal with a spreading code of DS 2; for each target, three correlation peaks are obtained after despreading.

In order to better implement the present invention, after a plurality of targets are despread, three continuous correlation peaks with the same time interval and fixed time interval are determined as the correlation peak of the same target, and the plurality of targets are distinguished.

In order to better realize the invention, the correlation peaks of a plurality of targets are further screened by utilizing the amplitude and the phase difference, three continuous correlation peaks corresponding to each target are judged, and the plurality of targets are distinguished.

In order to better realize the invention, further, after a plurality of targets are despread, three continuous correlation peaks with the same time interval and fixed are judged as the correlation peak of the same target; and simultaneously screening the correlation peaks of the multiple targets by combining the amplitude and the phase difference, judging three continuous correlation peaks corresponding to each target, and distinguishing the multiple targets.

In order to better implement the method, after a plurality of targets are distinguished, the distance of each target is calculated by using the counting values of three starting related peaks of the same target.

In order to better implement the present invention, further, the step s2. specifically includes:

s2.1, sending the signals subjected to AD sampling to an FPGA module for I, Q down-conversion processing to obtain I, Q baseband signals;

and S2.2, performing low-pass filtering and extraction on the I, Q baseband signal subjected to the down-conversion treatment.

The invention also provides an inquiry response system which is used for multi-target ranging and comprises a multi-channel transmitter, an inquiry machine, a responder, a multi-channel receiver, a power supply and a final control processing mainboard;

the multi-channel transmitter is sequentially connected with the interrogator, the responder, the multi-channel receiver, the power supply and the final control processing mainboard.

In order to better implement the invention, further, the power supply and terminal control processing mainboard comprises an AD module, an FPGA module and an information processing terminal;

the FPFA module comprises a down-conversion unit and a de-spread demodulation unit; the down-conversion unit comprises an IQ down-conversion unit, an I path low-pass filtering extraction unit and a Q path low-pass filtering extraction unit; the interface demodulation unit comprises a BPSK correlator and an MSK correlator;

the input end of the AD module is connected with the multi-channel transmitter, and the output end of the AD module is connected with the IQ down-conversion unit;

the IQ down-conversion unit is respectively connected with the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit;

the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit are respectively connected with the BPSK correlator and the MSK correlator;

and the output ends of the BPSK correlator and the MSK correlator are connected with an information processing terminal.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the invention only needs to process data in the FPGA module of the receiving end and synchronously sends out related peak, counter data, amplitude and phase difference, and the information processing terminal is sleeved into a simple calculation formula to calculate according to the corresponding time sequence, so that the distance information of different targets can be obtained. And compared with the prior art, the process is more simplified.

Drawings

FIG. 1 is a schematic flow chart of the present invention;

FIG. 2 is a timing diagram illustrating an implementation of the present invention;

FIG. 3 is a schematic view of the processing flow of the FPGA module of the present invention;

fig. 4 is a block diagram of a receiving segment for responding by the interrogation response system of the present invention.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and therefore should not be considered as a limitation to the scope of protection. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1:

the embodiment provides a multi-target ranging method based on an inquiry response system, which performs multi-target ranging based on the inquiry response system, as shown in fig. 1, and includes the following steps:

s1, receiving a radio frequency signal through a receiver of an inquiry response system, mixing the radio frequency signal into an intermediate frequency signal, and sending the intermediate frequency signal to an AD (analog-to-digital) module for AD sampling;

s2, after AD sampling, sending a signal obtained by sampling to an FPGA module of the inquiry response system to convert the signal into an I, Q baseband signal;

s3, despreading the obtained I, Q baseband signal, judging a useful signal through a threshold to generate a correlation peak, and carrying out digital signal processing on the useful signal to obtain real amplitude data and phase data; the method comprises the steps that an inquiry and response time sequence frame of an inquiry response system is utilized, counting is started when the inquiry response system inquires, namely signals are transmitted, when the inquiry response system responds, namely I, Q baseband signals are received and despread to obtain correlation peaks, the counter of the inquiry and response time sequence frame is utilized for counting once, and the correlation peaks, counting data, amplitude data and phase difference data are synchronously sent to an information processing terminal when the counting is performed once;

and S4, calculating by combining the time sequence specified by the information processing terminal with the correlation peak, the counting data, the amplitude data and the phase difference data to obtain the distance of multiple targets.

The working principle is as follows: compared with the conventional multi-target distance measurement method, the novel multi-target distance measurement method based on the inquiry response system has the following characteristics:

1. almost all inquiry and response systems have fixed transmission and reception frameworks to limit the time sequence, and the method can adapt to most inquiry and response systems under fixed conditions;

2. by using a pseudo code demodulation technology, the correctness of demodulation related peaks and data is ensured, and no false target appears;

3. the counter is started by utilizing the inherent transmitting and receiving frames of the system, the related peak generated during despreading the pseudo code triggers one-time counting, the data of the counter, the demodulated amplitude and phase difference data are synchronously sent to the distance calculation module at the lower edge of the related peak while the related peak is output, the real-time performance of the data is ensured, the complex decoding related cycle operation is not required, the distance measurement code and the target information are not required to be carried in the modulation signal, and the redundant distance measurement equipment is not required;

4. and calculating and judging the correlation peak, the counter data, the amplitude and the phase difference to obtain the distance of one or more targets so as to achieve multi-target ranging.

Example 2:

in this embodiment, on the basis of the above embodiment 1, in order to better implement the present invention, as shown in fig. 2, when the query response system in step S3 despreads the obtained I, Q baseband signal, the local code and the spreading code sequence identical to the spreading code sequence at the transmitting end are used to despread the baseband signal, and by threshold judgment, the modulated signal of the correlation peak is resolved into a useful signal, and a pulse output is synchronously generated, and the correlation peak, the count data, the amplitude data, and the phase difference data are synchronously output at the upper edge of the pulse output; and when the system responds, the first correlation peak is solved, a value is added on the counter, and the counter counts once in the process of solving a correlation peak, and is cleared when the inquiry response system is converted into an inquiry.

Further, in step S4, the despread signal obtained for the same target under test includes three modulated signals, and the three modulated signals are divided into two types: the first modulation signal and the second modulation signal in the three modulation signals are modulation signals with a spreading code of DS1, and the third modulation signal is a modulation signal with a spreading code of DS 2; for each target, three correlation peaks are obtained after despreading.

Furthermore, after a plurality of targets are despread, three continuous correlation peaks with the same time interval and fixed time interval are judged as the correlation peak of the same target, and the targets are distinguished.

Further, the amplitude and the phase difference are utilized to screen the correlation peaks of the multiple targets, three continuous correlation peaks corresponding to each target are judged, and the multiple targets are distinguished.

Further, after a plurality of targets are distinguished, the distance of each target is calculated by using the counting value of three starting correlation peaks of the same target.

The working principle is as follows: de-spreading the obtained I, Q baseband signal, namely de-correlating and de-spreading a spread spectrum code sequence with the same local code as the transmitting end, judging the useful signal by a threshold, generating a correlation peak, and carrying out digital signal processing correlation operation on the useful signal to obtain real amplitude data and phase data; as shown in fig. 2, the interrogation system interrogates according to a certain sequence, starts counting at the time of the transmitting stage (interrogation, low level), the signal of each target in the signal received by the responding section comprises two different DS codes, three sections of modulated signals are totally, the first and second sections of modulated signals have spreading codes of DS1, the third section of modulated signals have spreading codes of DS2, the interval between the modulated signals is fixed according to the sequence, when the responding stage (receiving, high level) is converted to the first correlation peak, a value is counted, the counter is not cleared, and when the counter is converted to the first correlation peak, the number is counted once, until the frame is reset again when the frame is converted to the transmitting (low level);

when the relevant peak is solved, the signal is considered to be effective, a pulse output is synchronously generated, and the counter value, the solved amplitude value and the phase difference at the moment are synchronously output on the pulse upper edge;

in the embodiment of the present application, the principle of calculating the multi-target distance is as follows: 1. because a certain inquiry response system inquires and responds according to a specified time sequence, the intervals among the solved 3 correlation peaks are the same, and whether the 3 correlation peaks belong to the same target or not can be preliminarily judged by utilizing the fixed interval; 2. the modulation signal comprises two different spreading codes (DS codes), the first and second sections of modulation signal spreading codes are DS1, the third section of modulation signal spreading code is DS2, and DS2 is certainly behind DS1, and whether 3 related peaks belong to the same target or not can be further judged according to the previous interval; 3. by utilizing the amplitude value and the phase difference which are simultaneously solved when each correlation peak is generated, the amplitude value and the phase difference which are solved by 3 correlation peaks of the same target are consistent, otherwise, the amplitude value and the phase difference which are solved by different targets reaching a receiver are inconsistent, even if the intervals of the correlation peaks solved by a plurality of targets are very close, and by utilizing the characteristic, whether the 3 correlation peaks belong to the same target can be accurately judged again; 4. under the condition that different targets are distinguished, the values of 3 correlation peak counters of the same target are calculated, namely the speed of electromagnetic waves propagating in air is S, the counting clock of the FPGA is X (unit MHz), the counting values are N1, N2 and N3, then the time from transmitting to receiving N1 can be regarded as T1= (1/X) × N1 (unit us), N2 and N3 are sequentially calculated, then the target distance L1= S × T1, and similarly, L2, L3 and 3 distances are calculated to carry out error estimation, if the accurate distance value is required, the time for processing signals by the FPGA module is considered, namely the distance of one target can be obtained, and the correlation peak counting values of multiple targets are repeatedly calculated, so that the distances of multiple targets can be obtained.

Other parts of this embodiment are the same as those of embodiment 1, and thus are not described again.

Example 3:

in this embodiment, on the basis of any one of the above embodiments 1-2, as shown in fig. 3, in order to better implement the present invention, further, the step s2. specifically operate as follows:

s2.1, sending the signals subjected to AD sampling to an FPGA module for I, Q down-conversion processing to obtain I, Q baseband signals;

and S2.2, performing low-pass filtering and extraction on the I, Q baseband signal subjected to the down-conversion treatment.

The working principle is as follows:

other parts of this embodiment are the same as any of embodiments 1-2 described above, and thus are not described again.

Example 4:

the embodiment also provides an inquiry response system, which is used for multi-target ranging, as shown in fig. 3 and 4, the inquiry response system comprises a multi-channel transmitter, an inquiry machine, a transponder, a multi-channel receiver, a power supply and a final control processing mainboard;

the multi-channel transmitter is sequentially connected with the interrogator, the responder, the multi-channel receiver, the power supply and the final control processing mainboard.

Furthermore, the power supply and terminal control processing mainboard comprises an AD module, an FPGA module and an information processing terminal;

the FPFA module comprises a down-conversion unit and a de-spread demodulation unit; the down-conversion unit comprises an IQ down-conversion unit, an I path low-pass filtering extraction unit and a Q path low-pass filtering extraction unit; the interface demodulation unit comprises a BPSK correlator and an MSK correlator;

the input end of the AD module is connected with the multi-channel transmitter, and the output end of the AD module is connected with the IQ down-conversion unit;

the IQ down-conversion unit is respectively connected with the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit;

the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit are respectively connected with the BPSK correlator and the MSK correlator;

and the output ends of the BPSK correlator and the MSK correlator are connected with an information processing terminal.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.

Claims (10)

1. A multi-target ranging method based on an inquiry response system is characterized in that a plurality of target ranging are carried out based on the inquiry response system, and the method comprises the following steps:

s1, receiving a radio frequency signal through a receiver of an inquiry response system, mixing the radio frequency signal into an intermediate frequency signal, and sending the intermediate frequency signal to an AD (analog-to-digital) module for AD sampling;

s2, after AD sampling, sending a signal obtained by sampling to an FPGA module of the inquiry response system to convert the signal into an I, Q baseband signal;

s3, despreading the obtained I, Q baseband signal, judging a useful signal through a threshold to generate a correlation peak, and carrying out digital signal processing on the useful signal to obtain real amplitude data and phase data; the method comprises the steps that an inquiry and response time sequence frame of an inquiry response system is utilized, counting is started when the inquiry response system inquires, namely signals are transmitted, when the inquiry response system responds, namely I, Q baseband signals are received and despread to obtain correlation peaks, the counter of the inquiry and response time sequence frame is utilized for counting once, and the correlation peaks, counting data, amplitude data and phase difference data are synchronously sent to an information processing terminal when the counting is performed once;

and S4, calculating by combining the time sequence specified by the information processing terminal with the correlation peak, the counting data, the amplitude data and the phase difference data to obtain the distance of multiple targets.

2. The multi-target ranging method according to claim 1, wherein the query response system despreads the obtained I, Q baseband signal in step S3, despreads the baseband signal by using a local code and a spreading code sequence identical to that of the transmitting end, determines a modulation signal of the correlation peak as a useful signal by a threshold, synchronously generates a pulse output, and synchronously outputs the correlation peak, the count data, the amplitude data, and the phase difference data at an upper edge of the pulse output; and when the system responds, the first correlation peak is solved, a value is added on the counter, and the counter counts once in the process of solving a correlation peak, and is cleared when the inquiry response system is converted into an inquiry.

3. The multi-target ranging method based on the query response system as claimed in claim 2, wherein the signals obtained by despreading the same object to be measured in step S4 include three modulated signals, and the three modulated signals are divided into two types: the first modulation signal and the second modulation signal in the three modulation signals are modulation signals with a spreading code of DS1, and the third modulation signal is a modulation signal with a spreading code of DS 2; for each target, three correlation peaks are obtained after despreading.

4. The multi-target ranging method based on the query response system as claimed in claim 3, wherein after the de-spreading of the plurality of targets, three consecutive correlation peaks with the same time interval and fixed time interval are determined as the correlation peak of the same target, and the plurality of targets are distinguished.

5. The multi-target ranging method based on the inquiry response system as claimed in claim 3, wherein the correlation peaks of the plurality of targets are screened by using the amplitude and the phase difference, three continuous correlation peaks corresponding to each target are determined, and the plurality of targets are distinguished.

6. The multi-target ranging method based on the interrogation response system as claimed in claim 3, wherein after a plurality of targets are de-spread, three consecutive correlation peaks having the same time interval and being fixed are determined as the correlation peaks of the same target; and simultaneously screening the correlation peaks of the multiple targets by combining the amplitude and the phase difference, judging three continuous correlation peaks corresponding to each target, and distinguishing the multiple targets.

7. A multi-target ranging method based on an inquiry response system as claimed in claim 4, 5 or 6 wherein after a plurality of targets are distinguished, the distance of each target is calculated by using the counting value of three related peaks of the same target.

8. The multi-target ranging method based on the query response system as claimed in claim 1, wherein the step s2. is specifically operated as follows:

s2.1, sending the signals subjected to AD sampling to an FPGA module for I, Q down-conversion processing to obtain I, Q baseband signals;

and S2.2, performing low-pass filtering and extraction on the I, Q baseband signal subjected to the down-conversion treatment.

9. An inquiry response system is used for multi-target distance measurement and is characterized by comprising a multi-channel transmitter, an inquiry machine, a response machine, a multi-channel receiver, a power supply and a final control processing mainboard;

the multi-channel transmitter is sequentially connected with the interrogator, the responder, the multi-channel receiver, the power supply and the final control processing mainboard.

10. The inquiry and response system of claim 9, wherein said power supply and terminal control processing board comprises an AD module, an FPGA module, and an information processing terminal;

the FPFA module comprises a down-conversion unit and a de-spread demodulation unit; the down-conversion unit comprises an IQ down-conversion unit, an I path low-pass filtering extraction unit and a Q path low-pass filtering extraction unit; the interface demodulation unit comprises a BPSK correlator and an MSK correlator;

the input end of the AD module is connected with the multi-channel transmitter, and the output end of the AD module is connected with the IQ down-conversion unit;

the IQ down-conversion unit is respectively connected with the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit;

the I path low-pass filtering extraction unit and the Q path low-pass filtering extraction unit are respectively connected with the BPSK correlator and the MSK correlator;

and the output ends of the BPSK correlator and the MSK correlator are connected with an information processing terminal.

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