1. A multi-channel capturing tracking-transferring method based on carrier and pseudo code joint estimation is characterized by comprising the following steps:

after signal capture is successful, determining sampling time;

acquiring carrier information and pseudo code information of all capturing channels at the sampling moment, and acquiring carrier information and pseudo code information of all tracking channels to obtain a capturing and tracking joint estimation parameter set;

carrying out joint difference estimation on carrier information and pseudo code information in the acquisition and tracking joint estimation parameter set to obtain a two-dimensional difference estimation result;

and performing self-adaptive matching from the capture channel to the tracking channel according to the two-dimensional difference estimation result.

2. The multi-channel acquisition tracking-to-tracking method according to claim 1, wherein the acquisition and tracking joint estimation parameter set comprises carrier doppler information and pseudo code phase information of an acquisition channel and carrier doppler information and pseudo code phase information of a tracking channel.

3. The multi-channel capturing-to-tracking method according to claim 1, wherein joint difference estimation is performed on carrier information and pseudo code information in the capturing-and-tracking joint estimation parameter set, and a two-dimensional difference estimation result is obtained according to a pseudo code phase comparison threshold and a carrier Doppler frequency offset comparison threshold.

4. The multi-channel acquisition tracking-conversion method as claimed in claim 3, wherein the pseudo code phase comparison threshold is i1 code phases, 3 ≦ i1 ≦ 10, and i1< Δ c, Δ c being at least the code phase difference between the channels.

5. The multi-channel acquisition-to-tracking method according to claim 4, wherein if the phase difference between the acquisition pseudo code phase and the tracking pseudo code phase does not exceed the pseudo code phase comparison threshold, the acquired signal and the tracked signal are classified as the same signal; otherwise, classifying the captured signal and the tracked signal as different paths of signals.

6. The multi-channel acquisition tracking-over-tracking method according to claim 3, wherein the pseudo-code phase comparison threshold is k carrier Doppler accuracies Δ cf.

7. The multi-channel acquisition tracking-to-tracking method according to claim 6, wherein if the frequency difference between the acquisition carrier Doppler and the tracking carrier Doppler does not exceed the pseudo code phase comparison threshold, the acquired signal and the tracking signal are classified as the same path of signal; otherwise, classifying the captured signal and the tracked signal as different paths of signals.

8. The multi-channel capturing-tracking method according to any one of claims 1 to 7, wherein the method for performing adaptive matching from the capturing channel to the tracking channel according to the two-dimensional difference estimation result comprises:

identifying an idle tracking channel in all tracking channels;

sending the identified capture channel parameters different from the tracking channel parameters into an idle tracking channel to start tracking;

when all channels capturing signals have entered the tracking state, the next round of capturing is started.

Background

In the prior art, as shown in fig. 1, when a measurement and control terminal receives multiple uplink signals at a time, because carrier doppler and pseudo code phase information acquired by the measurement and control terminal are not enough to distinguish which ground station signal is acquired, and which signal is acquired successfully and tracked, and which signal is not acquired successfully and is unknown, a channel requiring tracking in a multi-station signal overlapping area cannot enter a tracking state after being acquired successfully, and a signal which has been tracked is acquired successfully and set for tracking.

In addition, the tracking channel generally adopts preset fixed pseudo codes, and when a certain channel is successfully captured, the captured carrier Doppler and pseudo code phase are sent to a fixed known tracking channel preset with the same pseudo code for tracking. After the tracking is stable, the data bit stream information of the channel is analyzed through bit synchronization and frame synchronization, whether the current channel and other tracking channels repeatedly track the same target signal is identified through the analyzed special information such as the channel number of the current channel, if the target signal is the same, the channel is considered to be repeatedly captured, an unlocking recapture indication is sent, and the next round of capture tracking is started. The prior art can bring the problems of the increase of the acquisition time and the long-time occupation of the tracking channel.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method overcomes the defects of the prior art, provides a multi-channel capturing and tracking method based on carrier and pseudo code joint estimation, wherein a plurality of channels of direct spread spectrum system signals are input in the forward direction of a measurement and control terminal, and when the signals have the same frequency and the same code, the method can identify whether the captured signals and the signals of the tracking channel are repeated or not by utilizing the joint estimation difference value of the carrier and the pseudo code between the capturing channel and the tracking channel before the capturing and tracking, and eliminates the repeatedly captured signals, thereby avoiding the problems that an idle tracking channel is occupied for a long time, and the capturing time is prolonged because the repeatedly captured signals are eliminated by an information layer. The design is realized in FPGA, and the design adopts full digitalization design, so that the engineering is simple to realize and the application is wide.

The purpose of the invention is realized by the following technical scheme:

a multi-channel capturing tracking-transferring method based on carrier and pseudo code joint estimation comprises the following steps:

after signal capture is successful, determining sampling time;

acquiring carrier information and pseudo code information of all capturing channels at the sampling moment, and acquiring carrier information and pseudo code information of all tracking channels to obtain a capturing and tracking joint estimation parameter set;

carrying out joint difference estimation on carrier information and pseudo code information in the acquisition and tracking joint estimation parameter set to obtain a two-dimensional difference estimation result;

and performing self-adaptive matching from the capture channel to the tracking channel according to the two-dimensional difference estimation result.

Preferably, the acquisition and tracking joint estimation parameter set includes carrier doppler information and pseudo code phase information of the acquisition channel, and carrier doppler information and pseudo code phase information of the tracking channel.

In the multi-channel capturing-tracking method, preferably, the carrier information and the pseudo code information in the capturing and joint estimation parameter set are subjected to joint difference estimation, and a two-dimensional difference estimation result is obtained according to a pseudo code phase comparison threshold and a carrier Doppler frequency offset comparison threshold.

In the multi-channel acquisition tracking-conversion method, preferably, the pseudo code phase comparison threshold is i1 code phases, i1 is greater than or equal to 3 and less than or equal to 10, and i1 is less than Δ c, and Δ c is a code phase difference value between channels.

In the above multi-channel capturing-to-tracking method, preferably, if the phase difference between the captured pseudo code phase and the tracking pseudo code phase does not exceed the pseudo code phase comparison threshold, the captured signal and the tracked signal are classified as the same channel signal; otherwise, classifying the captured signal and the tracked signal as different paths of signals.

In the above multi-channel capturing-to-tracking method, preferably, the pseudo code phase comparison threshold is k carrier doppler accuracies Δ cf.

In the above multi-channel capturing-to-tracking method, preferably, if the frequency difference between the capturing carrier doppler and the tracking carrier doppler does not exceed the pseudo code phase comparison threshold, the captured signal and the tracked signal are classified as the same path of signal; otherwise, classifying the captured signal and the tracked signal as different paths of signals.

In the above method for multi-channel capture to tracking, preferably, the method for performing adaptive matching from the capture channel to the tracking channel according to the two-dimensional difference estimation result is as follows:

identifying an idle tracking channel in all tracking channels;

sending the identified capture channel parameters different from the tracking channel parameters into an idle tracking channel to start tracking;

when all channels capturing signals have entered the tracking state, the next round of capturing is started.

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

(1) in the prior art, a capture channel is successfully captured once, and capture parameters of the channel are set to a tracking channel preset with the same pseudo code. The invention adds a link of carrier and pseudo code joint estimation between the capturing channel and the tracking channel, changes the situation that only the capturing parameter of one capturing channel can be set to the fixed tracking channel at a time, and realizes a, channels which are repeatedly captured and enter the tracking can be eliminated; b. a single acquisition may adaptively assign the acquired plurality of channel tracking parameters to an idle tracking channel simultaneously.

(2) After the acquisition is successful, the accumulation register of the local reproduction pseudo code is used for generating acquisition and tracking parameter acquisition signals, so that the comparability problem under the pseudo code phase time-varying condition in the acquisition and tracking stage in a dynamic environment is solved;

(3) in the multi-channel tracking process, the algorithm of carrier Doppler and pseudo code phase joint difference estimation which is parallel among the capturing channels and serial among the tracking channels is adopted to estimate the difference of two-dimensional tracking parameters among the multiple channels, and a two-dimensional matrix vector records the estimation result, so that the system resources are saved to the maximum extent, and the difference estimation process is optimized;

(4) the invention samples the idle indication of the tracking channel, effectively identifies the idle tracking channel number, and adaptively matches the idle tracking channel number with the effectively captured channel in sequence according to the carrier and pseudo code joint estimation result, thereby changing the passive single tracking mode of the tracking channel in the traditional method.

Drawings

FIG. 1 is a processing flow of measurement and control terminal capture-to-tracking in the prior art;

FIG. 2 illustrates a processing method for capturing, transferring and tracking a measurement and control terminal according to the present invention;

FIG. 3 is a schematic diagram of tracking multi-dimensional parameter sampling instants;

FIG. 4 is a flow chart of a joint estimation with catch;

FIG. 5 is a schematic diagram of a joint estimation process;

FIG. 6 is a flow diagram of trace channel idle identification.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention discloses a multi-channel capturing to tracking method based on carrier and pseudo code joint estimation, which has the following basic ideas:

(1) generating a tracking parameter sampling signal by using the recovery time of the local pseudo code after successful acquisition;

(2) extracting carrier Doppler information and pseudo code phase information of each capturing channel and each tracking channel at the sampling moment, and forming a joint estimation parameter set by using each sampled channel parameter for carrying out differentiation identification with the capturing parameter set;

(3) performing joint difference estimation on the input tracking parameter set, comparing a difference result with a carrier difference threshold and a pseudo code difference threshold respectively, and storing a two-dimensional difference estimation result;

(4) the self-adaptive matching from the capture channel to the tracking channel is realized by using the joint estimation result and adopting a flow control method of two-dimensional parameter one-way traversal;

(5) calculating a pseudo code phase comparison threshold in joint estimation;

(6) and calculating a carrier Doppler frequency offset comparison threshold.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

The invention provides a multi-channel capturing and tracking method based on carrier and pseudo code joint estimation, which adds a carrier and pseudo code two-dimensional joint estimation design in the process of capturing and tracking so as to solve the problems that a tracking channel is occupied and the capturing time is too long when a same frequency and a same code are input in multiple channels, and realizes a block diagram shown in figure 2.

The multi-channel capturing tracking-transferring method based on carrier and pseudo code joint estimation comprises 4 steps: (1) the measurement and control terminal generates a tracking parameter sampling signal in real time; (2) collecting real-time carrier and pseudo code information of a currently captured and tracked multi-channel signal to form a tracking error control parameter set; (3) performing combined difference estimation on the input capture and tracking parameter set, comparing the difference estimation value with a threshold value, and storing a comparison result; (4) and the self-adaptive matching from the capture channel to the tracking channel is realized by using the result of the joint estimation and adopting a flow control method of multi-dimensional parameter one-way traversal.

1. Real-time generation of catch-and-follow parameter sampling signal by measurement and control terminal

Since in the implementation the acquisition and tracking are two independent parts and the pseudo-code phase of the tracking channel is changed in real time, a fixed time is found after the acquisition is completed, and the sampled pseudo-code phases of the acquisition and tracking are comparable. After the current channel is successfully captured, the high order of the pseudo code NCO is locally used as the query address of the local pseudo code, the address represents the phase of the currently captured pseudo code, the address is continuously effective before the current channel is captured, and the starting time of the address is used as the sampling time.

The generation step of tracking the multi-dimensional parameter sampling time in the steps is divided into the following steps: defining the length as 2^C1-an m-code sequence of 1; defining A pseudo code phase accumulation registers (a represents the number of channels) with N1 bit width, accumulatively storing the pseudo code phase in a register (a represents the number of channels) 0-1, generating the capturing pseudo code NCO corresponding to each channel (the local pseudo code NCO is generated and shown in figure 3), and if the frequency control precision of the local pseudo code is high, controlling the frequency of the local pseudo codeIn hertz, taking N1 as N0+ C1, wherein the N0 th bit output of the pseudo code accumulation register accum _ reg is a pseudo code phase clock, and the clock corresponds to the local pseudo code phase; ③ when the (0-C1-1) th bit of the pseudo code accumulation register accum _ reg is equal to a fixed constant value (the constant value is [0, C1-1 ]) under the driving of the system clock fs]The value in the range is taken, the generation time is aligned with the 0 th code phase output when the value is 0, the generation time is aligned with the C1-1 th code phase output when the value is C1-1), and the decision time pulse signal trackclk is output, the signal is a system clock width high level pulse signal, and the signal value is '0' at other times.

2. Acquiring real-time carrier and pseudo code information of a currently captured and tracked multi-channel signal to form a capture and tracking joint estimation parameter set; acquiring the acquisition parameters of the A acquisition channels and the tracking parameters of the A tracking channels at the acquisition time in the step;

when a trackclk pulse signal is in a high level, a register is used for latching A tracking channel carrier Doppler and pseudo code phase tracking locking identifiers (carrier locking identifiers are defined as carrier _ lock 0-carrier _ lock A-1, pseudo code locking identifiers are defined as code _ lock 0-code _ lock A-1, identifiers are '1' when locking and identifiers are '0' when unlocking), and A tracking channel carrier Doppler frequency control words and pseudo code phases are latched (tracking channel carrier Doppler frequency control words are defined as track _ freqword 0-track _ freqdA-1, and tracking channel pseudo code phase values are defined as track _ code phase 0-track _ code phase A-1).

3. Performing combined difference estimation on the input capture and tracking parameter set, and storing a difference estimation result;

in the step, the carrier Doppler value and the pseudo code phase value captured by the current channel are respectively differenced with the carrier Doppler value and the pseudo code phase value of each tracking channel, when the difference value is in an error range, the current captured channel is considered to enter a tracking state, and the capture parameters are discarded; if the difference value exceeds the error range, the currently captured channel and the tracking channel to be compared are considered to be two different channels; and after the comparison is finished, when the currently captured channel parameters are different from all the tracking channel parameters to be compared, reserving the carrier wave and pseudo code capturing parameters of the channel.

The implementation flow is shown in fig. 4, and the estimation process is shown in fig. 5, and the method is specifically implemented by the following steps: inputting carrier Doppler values track _ freqword 0-track _ freqwordA-1 to be compared of a tracking channel and a carrier Doppler value captured by a current channel to be differed to obtain a difference value delta freqword 0-delta freqwordA-1; inputting a pseudo code phase value track _ codephase 0-track _ codephase A-1 to be compared of a tracking channel and a pseudo code phase value captured by a current channel to obtain a pseudo code phase difference value delta codephase0

The implementation process is shown in fig. 4 and is specifically realized by the following steps: inputting carrier Doppler values track _ freqword 0-track _ freqwordA-1 to be compared of a tracking channel and a carrier Doppler value captured by a current channel to be differed to obtain a difference value delta freqword 0-delta freqwordA-1; inputting a pseudo code phase value track _ codephase 0-track _ codephase A-1 to be compared of a tracking channel and a pseudo code phase value captured by a current channel to obtain a pseudo code phase difference value delta codephase0

Δ codepheaseA-1; judging whether carrier locking identifiers carrier _ lock 0-carrier _ lock A-1 of tracking channels to be compared are locked, if the tracking channels are locked and the difference value delta freqword 0-delta freqwordA-1 is in the range of a threshold D, setting the carrier Doppler comparison identifiers cmp _ flag _ Ai of the current capture channel and the input tracking channel i (i is 0-A-1) to be '0' (indicating that the carrier Doppler is the same), and if the threshold is out of the range of D (D is a threshold value, the comparison identifiers cmp _ flag _ Ai are '1' (indicating that the carrier Doppler is different); judging whether tracking channel carrier locking identifiers code _ lock 0-code _ lock A-1 to be compared are locked or not, if the tracking channel carrier locking identifiers code _ lock 0-code _ lock A-1 to be compared are locked and the difference value delta codephase 0-delta codephase A-1 is in the range of a threshold E (E is a pseudo code phase estimation threshold and is explained in step 6), setting a pseudo code phase comparison identifier cmp _ flag _ Bi of a current capturing channel and an input tracking channel i (i is 0-A-1) to be equal to '0' (indicating that the pseudo code phases of the two are the same), and setting a comparison identifier cmp _ flag _ Bi to be equal to '1' (indicating that the pseudo code phases of the two are different) outside the range of the threshold E; judging whether the value of the current capture channel catch _ result is '1' ('1' indicates successful capture and '0' is unsuccessful), and if the value of catch _ result is '1', outputting a multidimensional parameter difference state identifier cmp _ flag ═ cmp _ flag _ Ai and cmp _ flag _ Bi (and the two are operated); if catch _ result is equal to '0', the output multi-dimensional parameter difference status flag cmp _ flag is equal to '1' (where a value of '1' for cmp _ flag indicates that the comparison result between the current capture channel and the input tracking channel multi-dimensional parameter value to be compared is not the same, and '0' indicates that the comparison result is the same). Since the number of captured channels is a, the number of tracked channels is a, each captured channel parameter is sequentially compared with a number of tracking channels, where a difference status flag register vector cmpresult _ reg 0-cmpresult _ reg a-1 is defined (the vector cmpresult _ reg has 0-a-1 bit), 0-a-1 parameter difference status flag quantities cmp _ flag of each capture channel are stored in 0-a-1 bit of the cmpresult _ regi, respectively (the 0bit represents the value of the capture channel 0 and the 0 th tracking channel parameter difference status flag p _ flag0, respectively, the 1bit represents the value of the capture channel 0 and the 1 st tracking channel parameter difference status flag cmp _ 1, respectively, … …, and so on).

4. Completing capture to tracking according to the comparison result;

in this step, according to the comparison result in step 3, firstly, an idle tracking channel is identified, and secondly, the identified capture channel parameters different from the parameters of each tracking channel are sequentially sent to the idle tracking channel to start tracking. If all captured channels have entered the tracking state, then the next round of capture is initiated.

(1) The idle channel identification process is shown in fig. 6, and the specific implementation is divided into the following steps: reading a capturing and tracking parameter difference state identification vector cmpresult _ region output in the step (3), wherein i represents a capturing channel number and takes a value of 0-A-1, and a defined variable j represents a tracking channel number and takes a value of 0-A-1; ② initializing j to 0; (iii) at this time, it is determined whether the value of j is greater than a-1, and if j > a-1, the tracking channel is output as the mark track _ channel (0) to track _ channel (a-1) indicating whether the tracking channel is free, and (j) 0 'indicates that the tracking channel is free, and (j) 1' indicates that the tracking channel is freeThe channel is occupied), and meanwhile, tracking channel numbers cmp _ num 0-cmp _ numA-1 which can be used by the capturing channel i are output, and the process is ended; if j is less than or equal to a-1, judging whether the value of the tracking channel locking identification loop _ flagj is equal to '1' ('1' indicates that the tracking channel is locked and '0' indicates that the tracking channel is not locked to be idle, wherein the loop _ flagj is carrier _ lockj and code _ lockj); if loop _ flag j is equal to '1', setting the value of track _ channel (j) to '1' to indicate that the tracking channel j is occupied, and entering the step 0; sixthly, if the loop _ flag is equal to '0', entering a step (b); adding 1 to the value of j, and proceeding to step III; initializing i to 0; ninthly, judging whether the value of i is greater than A-1; if r > A-1, go to step (c);if i is less than or equal to A-1, judging whether the value of the cmpresult _ region is equal to all zero (the values of the cmpresult _ region are all zero, which means that the parameters of the capture channel i are different from the parameters of the A tracking channels);if the values of cmpresult _ regions are all equal to zero, let track _ channel (j) be '0', cmpresult _ regions (j) be '1', cmp _ numi be j, and then proceed to step (c);if the values of cmpresult _ region are not all equal to zero, the value of i is incremented by 1 and step nini is performed.

(2) Setting acquisition parameters of an acquisition channel to a tracking channel

The tracking channel number cmp _ numi usable by the capture channel and the identification track _ channel (j) of whether the tracking channel is idle are obtained through the step 4- (1). Traversing the tracking state of each tracking channel from 0 to A-1, when the value of track _ channel (j) is '0', indicating that the tracking channel j is idle, and setting the capture parameter to the tracking channel to start tracking; when the value of track _ channel (j) is '1', it indicates that the tracking channel j is occupied, and a new round of acquisition is started without counting.

5. Calculating and using carrier Doppler decision threshold D in step 3

Suppose carrier Doppler intermediate frequency points of A channels of forward receiving channels of the measurement and control terminal are respectively f₀、f₀+Δf、f₀+2Δf、......、f₀+ (A-1) Δ f, carrier Doppler range is [ -f_d,+f_d]And Δ f is the difference in carrier doppler between each channel. Assume that the acquired carrier doppler accuracy is Δ cf.

The maximum Doppler frequency difference between the two channels is (A-1) Δ f +2f_dThe minimum Doppler frequency difference is delta f-2f_d. If the same signal is captured as being tracked, taking into account the error accuracy of + -k points captured (typically 0 ≦ k ≦ 5), then the threshold value D1 ∈ [ -k Δ cf, + k Δ cf]。

Combining the two situations, when the carrier Doppler frequency difference delta freqword 0-delta freqwordA-1 is in the range [ -k delta cf, + k delta cf ], the acquisition and tracking belong to the same path of signal; if the range of delta freqword 0-delta freqwordA-1 is outside the range of-k delta cf, + k delta cf ], then acquisition and tracking are considered to belong to different paths of signals.

6. Calculating and using pseudo code phase decision threshold E in step 3

Suppose the pseudo code initial phase among A channels of the forward receiving channel of the measurement and control terminal is C respectively₀、C₀+Δc、C₀+2Δc、......、C₀+ (A-1) Δ c, in generalAnd (6) taking the whole. Since the pseudo-code acquisition accuracy is typically 0.5 pseudo-code phases, here taking the error margin of i1 code phases (3 ≦ i1 ≦ 10, and Δ c > i1), if the acquired pseudo-code phase is the same as the one being tracked, E1 ∈ [ -i1, + i1]。

Combining the two situations, and when the phase difference value delta codephase 0-delta codephase A-1 of the acquisition pseudo code and the tracking pseudo code is in the range of [ -i1, + i1], the acquisition pseudo code and the tracking pseudo code belong to the same path of signal; if delta codephase 0-delta codephase A-1 is out of the range [ -i1, + i1], the acquisition and tracking are considered to belong to different paths of signals.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.