CN114553260B - High-precision measurement system for DS/FH spread spectrum signal carrier frequency - Google Patents
High-precision measurement system for DS/FH spread spectrum signal carrier frequency Download PDFInfo
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- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
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- H04B1/713—Spread spectrum techniques using frequency hopping
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Abstract
The invention discloses a high-precision measurement system of DS/FH spread spectrum signal carrier frequency, which comprises: the device comprises a spread hopping pattern module, a despreading and debounce module, a sampling buffer module, a two-dimensional slotting module, a compensation correction module, an integral accumulation module, a peak value searching module and a frequency resolving module; the despreading and frequency-hopping module performs pseudo code despreading and frequency-hopping on the received signal according to the real-time direct-spread pseudo code and the frequency-hopping frequency; the two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search subslots according to the carrier Doppler frequency shift and the carrier Doppler change rate range in the captured information; the compensation correction module carries out carrier frequency compensation correction on the sampling data read by the sampling buffer module in reverse order according to the frequency hopping frequency output by the spread hopping pattern module and the subslot information output by the two-dimensional slotting module; and the frequency calculating module calculates carrier Doppler frequency shift and carrier Doppler change rate of the received signal at the output moment by adopting a time correction technology according to the integral peak subslot information.
Description
Technical Field
The invention belongs to the field of wireless communication, and relates to a high-precision measurement system for DS/FH spread spectrum signal carrier frequency.
Background
The spread spectrum communication technology has been widely used in military and civil communication systems because of its advantages of good confidentiality, strong anti-interference capability and high spectrum efficiency, and the spread spectrum communication uses a spreading code to modulate baseband information at a transmitting end, and then uses the same spreading code to despread at a receiving end to recover original baseband information.
Spread spectrum communication can be classified into Direct Sequence (DS) spreading, frequency Hopping (Frequency Hopping, FH) spreading, time Hopping (TH) and other single system spreading techniques according to the spreading method, and hybrid spreading obtained by combining the above methods. DS spread spectrum has the advantages of good communication concealment and good multipath interference resistance, but has the advantages of limited processing gain, strict requirement on synchronization, poor far and near effects, good far and near characteristics, very wide communication bandwidth and capability of avoiding single-frequency interference, but has the advantages of complex fast time hopping equipment and poor concealment in slow time hopping, and the DS/FH spread spectrum technology increases the frequency hopping working mode on the basis of DS spread spectrum, integrates the advantages of DS spread spectrum and FH spread spectrum, has the advantages of good DS spread spectrum concealment and the capability of FH spread spectrum on interference avoidance numbers, overcomes the far and near effects of a DS spread spectrum system, breaks through the bottleneck of a single spread spectrum mode, and therefore, the DS/FH spread spectrum technology occupies important positions in the military field and has important significance in the civil communication field.
In complex environments such as high dynamic state, low signal-to-noise ratio, strong interference and the like, the bandwidth of a high-precision signal tracking loop is extremely narrow, to realize reliable tracking of spread spectrum communication, further accurate measurement of the carrier frequency of a received signal is required on the basis of signal acquisition in advance, the purpose of accurate measurement of the carrier frequency is to make the difference between the carrier frequency of a local signal and the carrier frequency of the received signal smaller, so that the carrier loop can quickly and reliably perform frequency synchronization, and if the error between the local signal and the received signal exceeds the traction range of the tracking loop, the tracking loop cannot normally lock.
The traditional measurement method generally adopts fast Fourier transform (Fast Fourier Transform, FFT) to directly measure the frequency of the sampling data of the received signal, is simple, easy to realize engineering and wide in application, but cannot overcome the influence of different carrier Doppler at different frequency hopping points, only realizes rough measurement of carrier Doppler frequency shift, does not measure carrier Doppler change rate, cannot correct frequency shift caused by target high-speed maneuver, processing time delay and the like, has poor frequency measurement precision, cannot adapt to the performance requirement of an actual receiving system, and therefore, how to accurately, quickly and effectively measure the carrier frequency of DS/FH spread spectrum signals becomes a key core technology to be solved urgently for DS/FH spread spectrum communication systems.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a high-precision measuring system for the carrier frequency of a DS/FH spread spectrum signal, which can rapidly, effectively and accurately measure the carrier frequency of the DS/FH spread spectrum signal under the scene of high dynamic and low signal-to-noise ratio and provide high-precision carrier Doppler frequency shift and carrier Doppler change rate measurement values for subsequent signal processing.
The aim of the invention is achieved by the following technical scheme:
a high accuracy measurement system of DS/FH spread spectrum signal carrier frequency, the measurement system comprising: the device comprises a spread hopping pattern module, a despreading and debounce module, a sampling buffer module, a two-dimensional slotting module, a compensation correction module, an integral accumulation module, a peak value searching module and a frequency resolving module;
the spread spectrum pattern module combines the direct spread spectrum pseudo code and the frequency hopping pattern according to the capturing information to generate the direct spread spectrum pseudo code and the frequency hopping frequency in real time;
the despreading and despreading module performs pseudo code despreading and frequency despreading on the received signal according to the direct-spread pseudo code and the frequency hopping frequency generated in real time;
the sampling buffer module carries out filtering sampling and data buffer on the correction data output by the despreading and skipping module;
the two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search sub-slots according to the carrier Doppler frequency shift and the carrier Doppler change rate range in the captured information;
the compensation correction module carries out carrier frequency compensation correction on the sampling data read by the sampling buffer module in reverse order according to the frequency hopping frequency output by the spread hopping pattern module and the subslot information output by the two-dimensional slotting module;
the integral accumulation module is used for obtaining integral accumulation data by adopting a coherent integration method and a noncoherent integration method for the compensation data output by the compensation correction module;
the peak value searching module adopts a comparison searching method to the integral accumulation data of all sub-slots to obtain sub-slot information of integral peak values;
and the frequency calculating module adopts a time correction method according to the integral peak subslot information to calculate and obtain the carrier Doppler frequency shift and the carrier Doppler change rate of the received signal at the output moment.
According to a preferred embodiment, the spread-spectrum pattern module is configured to generate a spread-spectrum code phase, a frequency-hopping code phase, and a carrier Doppler frequency shift f based on the acquisition information acq Combining the direct-spread pseudo code and the frequency hopping pattern to generate the direct-spread pseudo code C in real time ds And frequency of hopping hopp 。
According to a preferred embodiment, the despreading and despreading module outputs a frequency hopping frequency f according to the spreading and despreading pattern module hopp And an operating clock frequency f sys Using a calculation formula CW hopp ＝f hopp /f sys ×2 32 Data conversion is carried out to obtain a frequency hopping frequency control word CW hopp For CW hopp Accumulating to obtain inquiry address, mapping address, looking up table to generate frequency hopping frequency f hopp Is a local carrier of (a); direct-spread pseudo code C output by receiving signal and spread-spectrum pattern module ds Performing exclusive-or operation, and then performing exclusive-or operation on the result and the frequency hopping frequency f hopp And (3) carrying out complex multiplication operation on the local carrier wave to finish the spread spectrum correction of the received signal.
According to a preferred embodiment, the sampling buffer module is configured to sample the signal according to the signal sampling frequency f samp Using a calculation formula CW samp ＝f samp /f sys ×2 32 And performing data conversion, generating clear pulse by using a direct digital frequency synthesizer DDS, continuously accumulating the correction data output by the despreading and debounce module by using an accumulator, outputting an accumulated value when the clear pulse is effective, integrating and clearing the data input into the accumulator, circularly performing the process, finishing filtering sampling processing on the correction data output by the despreading and debounce module, storing the sampling data in a data buffer module in positive sequence, and when the number of the sampling data reaches N multiplied by M, N is the number of coherent integration points, M is the number of incoherent integration times, starting a data processing state, and reading the sampling data from the data buffer module in reverse sequence.
According to a preferred embodiment, the two-dimensional slotting module is based on the captured informationIs of carrier Doppler shift f acq Adopting a calculation formula v acq ＝f acq ×c/f RF Data conversion is carried out to obtain an initial movement velocity v acq Wherein c is the propagation speed of light in vacuum, f RF Is a radio frequency;
dividing the movement speed into 2L v +1 motion speed search value, motion speed search round l v ∈(0,1,…,2L v ) Motion speed search step v step From the minimum movement velocity v acq -L v ×v step Sequentially searching to the maximum movement velocity v acq +L v ×v step ；
Dividing acceleration into L according to carrier Doppler change rate range a +1 acceleration search values, acceleration search run l a ∈(0,1,…,L a ) Acceleration search step a step ＝(a max -a min )/L a From the minimum acceleration a min Sequentially searching to the maximum acceleration a max ；
2L v +1 motion velocity search value sums L a +1 acceleration search values together form (2L v +1)×(L a +1) two-dimensional search sub-slots, search for a motion velocity search value v in the sub-slots comp V is acq +(l v -L v )×v step Search value of acceleration a comp Is a as min +l a ×a step 。
According to a preferred embodiment, the compensation correction module searches for the value v based on the motion speed of the search sub-slot in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K dopl ＝v comp /c×(f RF +f hopp )×(2 32 /f samp ) Data conversion is carried out to obtain a carrier Doppler frequency shift control word K dopl At the same time, searching value a according to acceleration of searching subslots in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K rate ＝a comp /c×(f RF +f hopp )×(2 32 /f samp ) 2 Data conversion is carried out to obtain a carrier Doppler change rate control word K rate The method comprises the steps of carrying out a first treatment on the surface of the Control word K for Doppler shift of carrier wave dopl Performing one-time accumulation to obtain inquiry address, generating a local carrier wave with carrier wave Doppler frequency shift through address mapping and table lookup, and simultaneously controlling a carrier wave Doppler change rate control word K rate Performing accumulation twice to obtain a query address, and generating a local carrier wave with the carrier wave Doppler change rate through address mapping and table lookup; and finally, carrying out complex multiplication operation on the local carrier generated by the two paths to obtain a local composite carrier, and carrying out complex multiplication operation on the sampling data read in reverse order from the sampling buffer module and the local composite carrier to finish frequency compensation of carrier Doppler frequency shift and carrier Doppler change rate.
According to a preferred embodiment, the integral accumulation module obtains integral accumulation data by adopting an N-point coherent integration method and an M-time incoherent integration method on the frequency compensation data output by the compensation correction module; the peak value searching module adopts a comparison searching method to the integral accumulation data of all the searching sub-slots to obtain the motion velocity v of the sub-slot where the integral peak value is located vpp And acceleration a vpp 。
According to a preferred embodiment, the frequency calculation module calculates the frequency of the motion v based on the motion v output by the peak search module vpp And acceleration a vpp Combined with the sample data processing time t calcu Correcting and obtaining the carrier Doppler frequency shift f of the received signal at the current moment by adopting a time correction technology dopl Is [ -v vpp +a vpp ×t calcu ]/c×(f RF +f hopp ) Carrier Doppler change rate f rate Is a as vpp /c×(f RF +f hopp )。
The foregoing inventive concepts and various further alternatives thereof may be freely combined to form multiple concepts, all of which are contemplated and claimed herein. Various combinations will be apparent to those skilled in the art from a review of the present disclosure, and are not intended to be exhaustive or all of the present disclosure.
Compared with the traditional DS/FH spread spectrum signal carrier frequency measuring method, the method has the following beneficial effects:
adapting to high dynamic scenes. The two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search subslots to compensate and correct the carrier frequency, realizes the dual measurement of the carrier Doppler frequency shift and the carrier Doppler change rate of the received signal, and can adapt to the performance requirement of a high-dynamic scene compared with the traditional capturing method.
The frequency measurement accuracy is high. The two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search sub-slots to carry out compensation correction of the carrier frequency, overcomes the influence of different carrier Doppler of different frequency hopping points, combines a time correction technology, and further improves the measurement precision of the carrier frequency compared with the traditional measurement method.
The real-time processing performance is good. The invention adopts the high-frequency clock to rapidly process the sampling data read by the sampling buffer module in reverse order, so that the related operation quantity is reduced, a plurality of integral accumulation modules can be adopted for parallel processing, the data processing time is greatly shortened, and compared with the traditional measuring method, the capturing speed is obviously improved.
Drawings
FIG. 1 is a schematic diagram of the working principle of the high-precision measuring system of the carrier frequency of the DS/FH spread spectrum signal of the present invention;
fig. 2 is a schematic diagram of the working principle of the despreading and debounce module according to the present invention;
FIG. 3 is a schematic diagram of the working principle of the sample buffer module of the present invention;
fig. 4 is a schematic diagram of the working principle of the compensation correction module of the present invention.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.
It should be noted that, for the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments.
The invention discloses a high-precision measurement system of DS/FH spread spectrum signal carrier frequency, which comprises: the device comprises a spread spectrum jump pattern module, a despreading and debounce module, a sampling buffer module, a two-dimensional slotting module, a compensation correction module, an integral accumulation module, a peak value searching module and a frequency resolving module.
The principle of operation of the measuring system of the present invention is shown with reference to fig. 1. Specifically:
preferably, the spread spectrum hopping pattern module generates the direct spread spectrum pseudo code and the frequency hopping frequency in real time according to the capturing information by combining the direct spread spectrum pseudo code and the frequency hopping pattern.
Further, the spread-spectrum hopping pattern module is used for obtaining the direct-spread code phase, the frequency hopping code phase and the carrier Doppler frequency shift f in the captured information acq Combining the direct-spread pseudo code and the frequency hopping pattern to generate the direct-spread pseudo code C in real time ds And frequency of hopping hopp 。
Preferably, the despreading and despreading module performs pseudo code despreading and frequency despreading on the received signal according to a direct-spread pseudo code and a frequency hopping frequency generated in real time.
Further, referring to fig. 2, the despreading and despreading module outputs a frequency f according to the spreading and despreading pattern module hopp And an operating clock frequency f sys Using a calculation formula CW hopp ＝f hopp /f sys ×2 32 Data conversion is carried out to obtain a frequency hopping frequency control word CW hopp For CW hopp Accumulating to obtain inquiry address, mapping address, looking up table to generate frequency hopping frequency f hopp Is a local carrier of (a); direct-spread pseudo code C output by receiving signal and spread-spectrum pattern module ds Performing exclusive-or operation, and then performing exclusive-or operation on the result and the frequency hopping frequency f hopp Performs complex multiplication operation on the local carrier of (2)And the received signal completes the jump correction.
Preferably, the sampling buffer module performs filtering sampling and data buffering on the correction data output by the despreading and despreading module.
Further, reference is made to fig. 3. The sampling buffer module samples the frequency f according to the signal samp Using a calculation formula CW samp ＝f samp /f sys ×2 32 Performing data conversion, generating clear pulse by using a direct digital frequency synthesizer (DDS), then continuously accumulating the correction data output by the despreading and debounce module by using an accumulator, outputting an accumulated value when the clear pulse is effective, integrating and clearing the data input into the accumulator, circularly performing the process, finishing filtering and sampling processing on the correction data output by the despreading and debounce module, storing the sampling data in a data buffer module in positive sequence, and when the number of the sampling data reaches N multiplied by M, N is the number of coherent integration points, M is the number of incoherent integration times, starting a data processing state, and reading the sampling data from the data buffer module in reverse sequence.
Preferably, the two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search sub-slots according to the carrier Doppler frequency shift and the carrier Doppler change rate range in the captured information.
Further, the two-dimensional slotting module performs Doppler frequency shift f according to the carrier wave in the captured information acq Adopting a calculation formula v acq ＝f acq ×c/f RF Data conversion is carried out to obtain an initial movement velocity v acq Wherein c is the propagation speed of light in vacuum, f RF Is a radio frequency; dividing the movement speed into 2L v +1 motion speed search value, motion speed search round l v ∈(0,1,…,2L v ) Motion speed search step v step From the minimum movement velocity v acq -L v ×v step Sequentially searching to the maximum movement velocity v acq +L v ×v step The method comprises the steps of carrying out a first treatment on the surface of the Dividing acceleration into L according to carrier Doppler change rate range a +1 acceleration search values, acceleration search run l a ∈(0,1,…,L a ) Acceleration search step a step ＝(a max -a min )/L a From the minimum acceleration a min Sequentially searching to the maximum acceleration a max ；2L v +1 motion velocity search value sums L a +1 acceleration search values together form (2L v +1)×(L a +1) two-dimensional search sub-slots, search for a motion velocity search value v in the sub-slots comp V is acq +(l v -L v )×v step Search value of acceleration a comp Is a as min +l a ×a step 。
Preferably, the compensation correction module performs compensation correction of carrier frequency on the sampling data read by the sampling buffer module in reverse order according to the frequency hopping frequency output by the spread hopping pattern module and the subslot information output by the two-dimensional slotting module.
Further, reference is made to fig. 4. The compensation correction module searches the value v according to the motion speed of the sub-slot searched in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K dopl ＝v comp /c×(f RF +f hopp )×(2 32 /f samp ) Data conversion is carried out to obtain a carrier Doppler frequency shift control word K dopl At the same time, searching value a according to acceleration of searching subslots in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K rate ＝a comp /c×(f RF +f hopp )×(2 32 /f samp ) 2 Data conversion is carried out to obtain a carrier Doppler change rate control word K rate The method comprises the steps of carrying out a first treatment on the surface of the Control word K for Doppler shift of carrier wave dopl Performing one-time accumulation to obtain inquiry address, generating a local carrier wave with carrier wave Doppler frequency shift through address mapping and table lookup, and simultaneously controlling a carrier wave Doppler change rate control word K rate Performing accumulation twice to obtain a query address, and generating a local carrier wave with the carrier wave Doppler change rate through address mapping and table lookup; finally, carrying out complex multiplication operation on the local carrier generated by two paths to obtain a local composite carrier, and carrying out complex multiplication operation on the sampling data read in reverse order from the sampling buffer module and the local composite carrier to finish carrier Doppler frequency shift and carrier Doppler changeFrequency compensation of the chemical conversion rate.
Preferably, the integral accumulation module adopts a coherent integration method and a noncoherent integration method for the compensation data output by the compensation correction module to obtain integral accumulation data, and the peak value search module adopts a comparison search method for the integral accumulation data of all sub-slots to obtain sub-slot information of an integral peak value.
Further, the integral accumulation module adopts N-point coherent integration and M-time incoherent integration methods for the frequency compensation data output by the compensation correction module to obtain integral accumulation data; the peak value searching module adopts a comparison searching method to the integral accumulation data of all the searching sub-slots to obtain the motion velocity v of the sub-slot where the integral peak value is located vpp And acceleration a vpp 。
Preferably, the frequency calculating module calculates the carrier Doppler frequency shift and the carrier Doppler change rate of the received signal at the output moment by adopting a time correction method according to the integral peak subslot information.
Further, the frequency calculation module calculates the motion velocity v according to the peak value search module vpp And acceleration a vpp Combined with the sample data processing time t calcu Correcting and obtaining the carrier Doppler frequency shift f of the received signal at the current moment by adopting a time correction technology dopl Is [ -v vpp +a vpp ×t calcu ]/c×(f RF +f hopp ) Carrier Doppler change rate f rate Is a as vpp /c×(f RF +f hopp )。
Examples
Taking DS/FH spread spectrum signal transmitted by a satellite as an example, the working frequency f RF 22.0GHz, direct spread code rate R ds R ds 10.0Mcps, direct spread code period L ds 2500, frequency hopping rate R fh Frequency hopping interval f is 20kHop/s fh Modulating the information rate R for 40kHz b At 4.0kbps, the carrier Doppler shift range is + -900.0 kHz, and the carrier Doppler rate of change range is + -7.5 kHz/s.
The spread-spectrum pattern module is used for obtaining the direct spread code phase, the frequency-hopping code phase and the carrier Doppler frequency shift f in the captured information acq Real worldGenerating direct-amplification pseudo code C ds And frequency of hopping hopp 。
The despreading and debounce module performs despreading and debounce according to the real-time direct-spread pseudo code C ds And frequency of hopping hopp The received signal is subject to pseudo code despreading and frequency despreading.
Signal sampling frequency f of sampling buffer module samp The received signal is filtered and sampled to obtain sampling data at 100kHz, when the number of the sampling data reaches NxM to be 100 x 16, the data processing state is started, and the two-dimensional slotting module carries out Doppler frequency shift f according to the carrier wave in the captured information acq Obtaining the initial movement velocity v acq Dividing the motion speed into 101 motion speed search values, and searching the motion speed by a step v step At 1.0m/s from the minimum motion velocity v acq -50 sequential search to maximum movement velocity v acq +50, dividing acceleration into 201 acceleration search values according to the carrier Doppler change rate range, and searching acceleration for step a step At 1.0m/s from minimum acceleration of-100.0 m/s 2 Sequentially searching to the maximum acceleration of +100.0m/s 2 The 101 motion velocity search values and the 201 acceleration search values together constitute 101×201 two-dimensional search sub-slots.
And the compensation and correction module carries out compensation and correction of carrier frequency on the sampling data read by the sampling buffer module in reverse order according to the frequency hopping frequency output by the spread hopping pattern module and the subslot information output by the two-dimensional slotting module.
And the integral accumulation module acquires integral accumulation data by adopting an N-point coherent integration method and an M-time incoherent integration method on the frequency compensation data output by the compensation correction module.
The peak value searching module adopts a comparison searching method to the integral accumulation data of all the searching sub-slots to obtain the motion velocity v of the sub-slot where the integral peak value is located vpp And acceleration a vpp 。
The frequency resolving module outputs the motion velocity v according to the peak value searching module vpp And acceleration a vpp Combined with the sample data processing time t calcu Correcting and obtaining the carrier Doppler frequency shift f of the received signal at the current moment by adopting a time correction technology dopl Multiple carrierRate of change of puller f rate 。
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
1. A high accuracy measurement system for DS/FH spread spectrum signal carrier frequency, the measurement system comprising: the device comprises a spread hopping pattern module, a despreading and debounce module, a sampling buffer module, a two-dimensional slotting module, a compensation correction module, an integral accumulation module, a peak value searching module and a frequency resolving module;
the spread spectrum pattern module combines the direct spread spectrum pseudo code and the frequency hopping pattern according to the capturing information to generate the direct spread spectrum pseudo code and the frequency hopping frequency in real time; the despreading and despreading module performs pseudo code despreading and frequency despreading on the received signal according to the direct-spread pseudo code and the frequency hopping frequency generated in real time; the sampling buffer module carries out filtering sampling and data buffer on the correction data output by the despreading and skipping module;
the two-dimensional slotting module divides the motion speed and the acceleration into a plurality of two-dimensional search sub-slots according to the carrier Doppler frequency shift and the carrier Doppler change rate range in the captured information;
the compensation correction module carries out carrier frequency compensation correction on the sampling data read by the sampling buffer module in reverse order according to the frequency hopping frequency output by the spread hopping pattern module and the subslot information output by the two-dimensional slotting module;
the integral accumulation module is used for obtaining integral accumulation data by adopting a coherent integration method and a noncoherent integration method for the compensation data output by the compensation correction module;
the peak value searching module adopts a comparison searching method to the integral accumulation data of all sub-slots to obtain sub-slot information of integral peak values;
the frequency calculating module adopts a time correction method according to the integral peak subslot information to calculate and obtain the carrier Doppler frequency shift and the carrier Doppler change rate of the received signal at the output moment;
the spread-spectrum pattern module is used for capturing information according to the informationDirect-spread code phase, frequency-hopping code phase and carrier doppler frequency shift f acq Combining the direct-spread pseudo code and the frequency hopping pattern to generate the direct-spread pseudo code C in real time ds And frequency of hopping hopp 。
2. The high-precision measurement system of DS/FH spread spectrum signal carrier frequency as claimed in claim 1, wherein the despreading and debounce module is based on the frequency hopping frequency f output by the spread spectrum pattern module hopp And an operating clock frequency f sys Using a calculation formula CW hopp ＝f hopp /f sys ×2 32 Data conversion is carried out to obtain a frequency hopping frequency control word CW hopp For CW hopp Accumulating to obtain inquiry address, mapping address, looking up table to generate frequency hopping frequency f hopp Is a local carrier of (a);
direct-spread pseudo code C output by receiving signal and spread-spectrum pattern module ds Performing exclusive-or operation, and then performing exclusive-or operation on the result and the frequency hopping frequency f hopp And (3) carrying out complex multiplication operation on the local carrier wave to finish the spread spectrum correction of the received signal.
3. The high-precision measurement system of DS/FH spread spectrum signal carrier frequency as claimed in claim 2, wherein the sampling buffer module is based on the signal sampling frequency f samp Using a calculation formula CW samp ＝f samp /f sys ×2 32 And performing data conversion, generating clear pulse by using a direct digital frequency synthesizer DDS, continuously accumulating the correction data output by the despreading and debounce module by using an accumulator, outputting an accumulated value when the clear pulse is effective, integrating and clearing the data input into the accumulator, circularly performing the process, finishing filtering sampling processing on the correction data output by the despreading and debounce module, storing the sampling data in a data buffer module in positive sequence, and when the number of the sampling data reaches N multiplied by M, N is the number of coherent integration points, M is the number of incoherent integration times, starting a data processing state, and reading the sampling data from the data buffer module in reverse sequence.
4. The DS/FH spread spectrum signal carrier of claim 3The high-precision wave frequency measuring system is characterized in that the two-dimensional slotting module carries out Doppler frequency shift f according to the carrier wave in the captured information acq Adopting a calculation formula v acq ＝f acq ×c/f RF Data conversion is carried out to obtain an initial movement velocity v acq Wherein c is the propagation speed of light in vacuum, f RF Is a radio frequency;
dividing the movement speed into 2L v +1 motion speed search value, motion speed search round l v ∈(0,1,…,2L v ) Motion speed search step v step From the minimum movement velocity v acq -L v ×v step Sequentially searching to the maximum movement velocity v acq +L v ×v step ；
Dividing acceleration into L according to carrier Doppler change rate range a +1 acceleration search values, acceleration search run l a ∈(0,1,…,L a ) Acceleration search step a step ＝(a max -a min )/L a From the minimum acceleration a min Sequentially searching to the maximum acceleration a max ；
2L v +1 motion velocity search value sums L a +1 acceleration search values together form (2L v +1)×(L a +1) two-dimensional search sub-slots, search for a motion velocity search value v in the sub-slots comp V is acq +(l v -L v )×v step Search value of acceleration a comp Is a as min +l a ×a step 。
5. The high accuracy measurement system of DS/FH spread spectrum signal carrier frequency as claimed in claim 4, wherein the compensation correction module searches for value v according to the motion velocity of the sub-slot searched in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K dopl ＝v comp /c×(f RF +f hopp )×(2 32 /f samp ) Data conversion is carried out to obtain a carrier Doppler frequency shift control word K dopl ，
At the same time, searching value a is searched according to the acceleration of the sub-slot in the two-dimensional slotting module comp And the frequency hopping frequency f output by the frequency hopping pattern module hopp Adopting a calculation formula K rate ＝a comp /c×(f RF +f hopp )×(2 32 /f samp ) 2 Data conversion is carried out to obtain a carrier Doppler change rate control word K rate ；
Control word K for Doppler shift of carrier wave dopl Performing one-time accumulation to obtain inquiry address, generating a local carrier wave with carrier wave Doppler frequency shift through address mapping and table lookup, and simultaneously controlling a carrier wave Doppler change rate control word K rate Performing accumulation twice to obtain a query address, and generating a local carrier wave with the carrier wave Doppler change rate through address mapping and table lookup;
and finally, carrying out complex multiplication operation on the local carrier generated by the two paths to obtain a local composite carrier, and carrying out complex multiplication operation on the sampling data read in reverse order from the sampling buffer module and the local composite carrier to finish frequency compensation of carrier Doppler frequency shift and carrier Doppler change rate.
6. The high-precision measurement system of DS/FH spread spectrum signal carrier frequency as claimed in claim 5, wherein the integration accumulation module uses N-point coherent integration and M-time incoherent integration methods to obtain integration accumulation data for the frequency compensation data output by the compensation correction module;
the peak value searching module adopts a comparison searching method to the integral accumulation data of all the searching sub-slots to obtain the motion velocity v of the sub-slot where the integral peak value is located vpp And acceleration a vpp 。
7. The high-precision measurement system of DS/FH spread spectrum signal carrier frequency as claimed in claim 6, wherein the frequency resolving module is based on the motion velocity v output by the peak searching module vpp And acceleration a vpp Combined with the sample data processing time t calcu Correcting and obtaining the carrier Doppler frequency shift f of the received signal at the current moment by adopting a time correction technology dopl Is [ -v vpp +a vpp ×t calcu ]/c×(f RF +f hopp ) Carrier Doppler change rate f rate Is a as vpp /c×(f RF +f hopp )。
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