CN105445765B - A kind of pseudo range measurement method of Beidou navigation satellite system hybrid constellation - Google Patents

Abstract

The present invention discloses a method for measuring the pseudo-range of the mixed constellation of the Beidou navigation satellite system, which is aimed at the difference in rate between the D2 navigation message broadcast by the Beidou navigation satellite system earth GEO satellite and the D1 navigation message broadcast by the non-GEO satellite, resulting in a synchronization header of the subframe. The interval is different, and the pseudo-range cannot be synchronously output at the whole second of Beidou time. Using the idea of fuzzy control, the pseudo-range transmission time of the IGSO satellite is used as the benchmark, and the fuzzy control rules are set to correct and estimate the pseudo-range output of the GEO satellite. Realize pseudo-range synchronization output and receiver positioning and timing.

Description

A Pseudorange Measurement Method of Beidou Navigation Satellite System Mixed Constellation

technical field

The invention relates to a pseudo-range measurement method, in particular to a pseudo-range measurement method of a Beidou navigation satellite system mixed constellation, and belongs to the technical field of satellite navigation.

Background technique

The Beidou Navigation Satellite System, referred to as the Beidou system, or BDS in English, is a global satellite navigation system built in China that integrates basic navigation services and differential integrity services. ), 3 inclined synchronous orbit satellites (IGSO) and 27 medium-high orbit satellites (MEO). 160°E; MEO satellite orbit altitude is 21,528 kilometers, orbital inclination angle is 55°; IGSO satellite orbital altitude is 35,786 kilometers, orbital inclination angle is 55°.

At the end of 2012, the regional navigation system consisting of 5 GEO satellites, 5 IGSO satellites and 4 MEO satellites began to provide positioning and timing services to China and its surrounding areas. Smart driving tests, disaster relief and mitigation, mobile phone navigation, car navigation and many other fields have produced extensive economic and social benefits. On March 30, 2015, the first new generation of Beidou navigation satellite was successfully launched. The successful launch of this satellite marked the start of the Beidou satellite navigation system from regional operation to global expansion. The new generation of Beidou satellites will carry out hydrogen atomic clocks, Inter-satellite links, new navigation signal system and other test and verification work will take the lead in providing basic services to countries along the “Belt and Road” in 2018; in 2020, global service capabilities will be formed and a world-class global satellite navigation system will be built.

Beidou IGSO satellites and MEO satellites broadcast D1 navigation messages, and D1 navigation messages consist of superframes, main frames and subframes. Each superframe is 36000 bits, lasts 12 minutes, each superframe is composed of 24 main frames; each main frame is 1500 bits, lasts 30 seconds, each main frame is composed of 5 subframes; each subframe is 300 bit, which lasts 6 seconds, and each subframe consists of 10 words; each word is 30 bits, which lasts 0.6 seconds. Beidou GEO broadcasts D2 navigation message, and D2 navigation message consists of superframe, main frame and subframe. Each superframe is 180,000 bits and lasts 6 minutes. Each superframe is composed of 120 main frames; each main frame is 1500 bits and lasts 3 seconds. Each main frame is composed of 5 subframes; each subframe is 300 bit, which lasts 0.6 seconds, and each subframe consists of 10 words; each word is 30 bits, which lasts 0.06 seconds.

Compared with D1 navigation message and D2 navigation message, the rising edge of the subframe header of D1 navigation message is aligned with the whole second of Beidou time, and the two subframe headers are separated by 6 seconds; the speed of D2 navigation message is 10 times that of D1 navigation message, adjacent The interval between two subframe headers is 0.6 seconds. The second time corresponding to the second count in a week refers to the moment corresponding to the first pulse rising edge of the synchronization header of the current main frame 1, which means that the rising edge of the subframe header does not All aligned to the full second of Beidou time. The layout of this mixed constellation and the broadcast of different navigation messages add complexity to the pseudorange measurement and receiver clock correction in the real-time receiver. The traditional pseudorange latched whole second signal aligned with the system time is no longer directly Be applicable. The solution at the hardware level includes increasing the frequency of the pseudo-range latch signal, using two sets of pseudo-range latch signals, etc., which increases the pressure and complexity of hardware operation.

The Beidou GEO satellite is fixed in the geosynchronous orbit above the equator. The IGSO and GEO orbits are at the same height. Theoretical analysis and experimental verification of the effective coverage of Beidou IGSO and GEO show that although the pseudo-range propagation time changes in real time due to satellite movement and receiver movement, using IGSO with a similar azimuth to GEO as the benchmark, the pseudo-range propagation time of the two The time difference will not exceed 10ms, which also lays the foundation for the application of fuzzy control.

The fuzzy control system is a computer digital control system based on fuzzy collection, fuzzy language variables and fuzzy logic reasoning. Fuzzy control belongs to the category of nonlinear control and intelligent control. The fuzzy controller summarizes experience and experimental results into several Rules, reasoning according to rules, and quickly complete operations. Selecting the appropriate fuzzy model and formulating appropriate rules can obtain more ideal output results. Its principles can be divided into four processes: fuzzification, fuzzy rules, fuzzy reasoning and defuzzification.

Contents of the invention

The technical problem to be solved by the present invention is to provide a pseudo-range measurement method for the mixed constellation of the Beidou navigation system in view of the deficiency of the background technology, which solves the asynchronous pseudo-range output caused by the difference in the navigation messages broadcast by the Beidou GEO satellite and the non-GEO satellite The problem is to realize the synchronous output of pseudo-range, receiver positioning and receiver clock error correction.

A pseudo-range measurement method for a Beidou navigation satellite system hybrid constellation, specifically comprising the following steps:

Step 1, power on and reset the receiver, and randomly generate a pseudo-range latch signal TIC with adjustable rising edge position inside the receiver;

Step 2, generate the local ranging code and carrier, capture the satellite signal, and the successfully captured signal enters the tracking channel;

Step 3, respectively performing bit synchronization and subframe synchronization on GEO satellites, IGSO satellites, and MEO satellites;

Step 4. After each channel realizes subframe synchronization, it switches to the pseudorange output and ephemeris demodulation mode, and then calculates the initial pseudorange propagation time, satellite position and pseudorange correction parameters. Among them, IGSO satellite and MEO satellite channels realize bit synchronization After that, trigger the frame synchronization full-second pulse signal to realize the pseudo-range output at the whole second of Beidou time;

Step 5, select the pseudo-range propagation time of an IGSO satellite calculated in step 4 as the reference t _{ρ,IGSO_r} , and correct the pseudo-range transmission time t _ρ,GEO of the GEO satellite;

Step 6: Use fuzzy control rules to correct the pseudorange propagation time of the GEO satellite channel, and obtain the pseudorange propagation time t _{ρ,GEO_cor} synchronous with IGSO;

Step 7. Obtain the initial pseudorange ρ according to the propagation time of the pseudorange, and use the carrier phase to smooth the pseudorange:

Among them, ρ _{s, k} is the pseudo-range smoothed at the current moment, φ _k is the carrier phase at the current moment, ρ _{s, k-1} is the pseudo-range smoothed at the previous moment, and φ _k-1 is the carrier phase at the previous moment , ρ _k is the unsmoothed pseudorange at the current moment, and M is the smoothing time constant;

Step 8, calculate the clock error of the receiver by performing receiver positioning, and calculate the control quantity of the pseudo-range latch signal, and then correct the position of the pseudo-range latch signal. The specific calculation formula is as follows:

N _TIC,k ＝N _TIC,k-1 +(Δδ _{u -Δt TIC_frame} )*f _c /c

In the above formula, Δδ _u is the clock error residual obtained by receiver positioning, Δt _{TIC_frame} is the fixed delay of channel frame synchronization, N _TIC,k is the control amount of TIC at the current moment, N _TIC,k-1 is the TIC at the previous moment The control amount of , f _c is the sampling frequency of TIC;

Step 9, after the receiver achieves a positioning, correct the TIC pulse to align with the whole second of Beidou time.

As a further preferred solution of the pseudo-range measurement method of the Beidou navigation satellite system hybrid constellation of the present invention, in step 4, the subframe header is corrected to the full-second position by means of soft calculation, so as to realize the pseudo-range synchronous output of all satellites.

As a further preferred solution of the pseudo-range measurement method of the mixed constellation of the Beidou navigation satellite system of the present invention, in step 4, under the premise of not changing the period of the pseudo-range latch signal, the three types of Beidou satellites are realized by using software correction methods, namely Pseudorange synchronous output under two speed navigation messages.

As a further preferred solution of the method for measuring the pseudorange of the mixed constellation of the Beidou navigation satellite system of the present invention, in step 5, the pseudorange propagation time of an IGSO closest to the equator is selected as a reference, and the pseudorange propagation time of GEO is corrected.

As a further preferred solution of the pseudo-range measurement method of the Beidou navigation satellite system hybrid constellation of the present invention, in step 7, the GEO pseudo-range propagation time is corrected by using a fuzzy control method.

As a further preferred solution of the method for measuring the pseudorange of the mixed constellation of the Beidou navigation satellite system of the present invention, in step 9, the propagation time of the pseudorange of the GEO satellite and the IGSO satellite is corrected using a simplified fuzzy control rule.

Compared with the prior art, the present invention has beneficial effects reflected in:

No changes are made to the traditional pseudo-range latch signal, and the pseudo-range propagation time output by the channel is corrected at the software level. Taking advantage of the fact that the IGSO satellite and the GEO satellite have the same orbit height and the pseudo-range transmission time has little difference, the fuzzy control idea is adopted. Realize pseudo-range synchronous output and receiver positioning under three Beidou satellites and two navigation message modes. The invention has clear purpose, simple technology, easy realization, strong engineering application value, is suitable for Beidou navigation receiver, and has reference value for other satellite navigation systems using mixed constellations or different navigation messages.

Description of drawings

Fig. 1 is a flowchart of the realization of the functions of the present invention;

Fig. 2 is the principle block diagram of fuzzy control of the present invention;

Fig. 3 is fuzzy control input quantity membership function curve of the present invention;

Fig. 4 is fuzzy control output quantity membership function curve of the present invention;

Fig. 5 is when t _{ρ, GEO} > t _{ρ, IGSO_r} , a schematic diagram of the position of the subframe header and the pseudorange latch signal before positioning;

Fig. 6 is a schematic diagram of the position of the subframe header and the pseudorange latch signal before positioning when t _{ρ, GEO} = t _{ρ, IGSO_r} ;

Fig. 7 is when t _{ρ, GEO} <t _{ρ, IGSO_r} , a schematic diagram of the position of the subframe header and the pseudorange latch signal before positioning;

Fig. 8 is a schematic diagram of positions of the subframe header, the pseudorange latch signal, and the IGSO frame synchronization whole second signal after positioning;

Fig. 9 is a schematic diagram of the position of the subframe header, the pseudorange latch signal, and the IGSO frame synchronization second signal after positioning when the frame deframing fails.

detailed description

Below in conjunction with accompanying drawing, the technical scheme of invention is described in detail:

As shown in Figure 1, a pseudo-range measurement method for the mixed constellation of the Beidou navigation satellite system specifically includes the following steps:

Step 1, power on and reset the receiver, and randomly generate a pseudo-range latch signal TIC with adjustable rising edge position inside the receiver;

Step 2, generate the local ranging code and carrier, capture the satellite signal, and the successfully captured signal enters the tracking channel;

Step 3, respectively performing bit synchronization and subframe synchronization on GEO satellites, IGSO satellites, and MEO satellites;

Step 4. After each channel realizes subframe synchronization, it switches to the pseudorange output and ephemeris demodulation mode, and then calculates the initial pseudorange propagation time, satellite position and pseudorange correction parameters. Among them, IGSO satellite and MEO satellite channels realize bit synchronization After that, trigger the frame synchronization full-second pulse signal to realize the pseudo-range output at the whole second of Beidou time;

Step 4.1, after the IGSO satellite and MEO satellite channels realize the subframe synchronization, trigger the frame synchronization full-second pulse signal, the frame synchronization full-second pulse signal period is 1s, and the rising edge lags behind the subframe header by 1ms, which is convenient for detecting the next subframe header Update the position of the frame-synchronized full-second pulse when it arrives. The function of the frame-synchronized full-second pulse is to realize the pseudo-range output with a frequency of 1Hz;

Step 4.2, after each channel realizes the subframe synchronization, it is transferred to the pseudorange output and ephemeris demodulation mode, and the detection of the subframe header or frame synchronization whole second pulse triggers the high code clock counter to count and the latch to latch, and the counter The frequency is, the counter is cleared at the beginning of the frame, counting to the rising edge of TIC, and the value of the counter is synchronously placed in the latch;

Step 4.3, each channel reads the frame synchronization count value, and calculates the channel pseudo-range propagation time, and the calculation formula is t _ρ =1-N _c /f _c ;

Step 5, select the pseudo-range propagation time of an IGSO satellite calculated in step 4 as the reference t _{ρ,IGSO_r} , and correct the pseudo-range transmission time t _ρ,GEO of the GEO satellite;

Step 6: Use fuzzy control rules to correct the pseudorange propagation time of the GEO satellite channel, and obtain the pseudorange propagation time t _{ρ,GEO_cor} synchronous with IGSO;

Step 7. Obtain the initial pseudorange ρ according to the propagation time of the pseudorange, and use the carrier phase to smooth the pseudorange:

Among them, ρ _{s, k} is the pseudo-range smoothed at the current moment, φ _k is the carrier phase at the current moment, ρ _{s, k-1} is the pseudo-range smoothed at the previous moment, and φ _k-1 is the carrier phase at the previous moment , ρ _k is the unsmoothed pseudorange at the current moment, and M is the smoothing time constant;

Step 8, calculate the clock error of the receiver by performing receiver positioning, and then calculate the control quantity of the pseudo-range latch signal, and then correct the position of the pseudo-range latch signal. The specific calculation formula is as follows:

N _TIC,k ＝N _TIC,k-1 +(Δδ _{u -Δt TIC_frame} )*f _c /c

In the above formula, Δδ _u is the clock error residual obtained by receiver positioning, Δt _{TIC_frame} is the fixed delay of channel frame synchronization, N _TIC,k is the control amount of TIC at the current moment, N _TIC,k-1 is the TIC at the previous moment The control amount of , f _c is the sampling frequency of TIC;

Step 9, after the receiver achieves a positioning, the TIC pulse is corrected to align with the whole second of Beidou time.

Among them, in step 4, for the problem that the period of a GEO subframe is 0.6 seconds, which cannot be fully aligned with the whole second of Beidou time, the subframe header is corrected to the position of the whole second through soft calculation, so as to realize all Satellite pseudorange synchronization output.

Under the premise of not changing the period of the pseudo-range latching signal, the method of software correction is adopted to realize the synchronous output of pseudo-range for three types of Beidou satellites, that is, two-speed navigation messages.

Taking advantage of the fact that IGSO satellites and GEO satellites are at the same orbital height, the pseudo-range propagation time of an IGSO closest to the equator is selected as a reference, and the pseudo-range propagation time of GEO is corrected.

In view of the different positions of the pseudo-range latch signal TIC, GEO satellite sub-frame header, and IGSO satellite sub-frame header before positioning, the fuzzy control method is used to correct the GEO pseudo-range propagation time.

Aiming at the fact that the pseudo-range propagation time of GEO satellite and IGSO satellite has only three possible situations after the receiver is positioned, a simplified fuzzy control rule is used to correct it.

The overall flow chart of this method is shown in Figure 2, for Beidou intermediate frequency signals respectively. The above process needs to complete the following tasks:

1. The Beidou navigation receiver needs to have the baseband signal processing function and the loop tracking and positioning solution function to realize the technical solution. Baseband signal processing functions include carrier NCO generation, code NCO generation, complex phase rotation digital down conversion, local Beidou spread spectrum code generation, correlator, time base signal generation, observation data measurement, frame synchronization signal generation and navigation message demodulation, etc. The function of loop tracking and positioning calculation mainly completes the prediction of Beidou visible stars, Doppler prediction, the initialization of each channel of Beidou, the reading and storage of the leading, real-time and lagging related values of each channel, the carrier tracking loop and code tracking loop Loop control, reading of observation data at the time of pseudorange latching, carrier phase assisted pseudorange smoothing processing, tracking Doppler filtering processing, reading of subframe data and analysis of navigation messages, real-time storage of satellite ephemeris and almanac, Functions such as Beidou positioning calculation and speed calculation, Beidou timing loop control and serial port protocol framing and unframing.

2. Construct fuzzy controller.

Construct one-dimensional fuzzy control rules. Assuming that the difference between the pseudo-range propagation time of the GEO latched by the pseudo-range latch signal and the reference IGSO satellite is Δt _{ρ, after GEO-IGSO_r is} fuzzified, it is E, and its fuzzy subset is {N, ZO, PS, PM, PB, PX }, representing negative, zero, positive small, positive middle, positive large, and positive, respectively. The fuzzy subset of the control quantity (that is, the correction quantity) U is {NX, NB, NM, NS, ZO, P}, respectively representing negative pole, negative large, negative medium, negative small, zero, positive, and the discrete domain is {- 0.8, -0.6, -0.4, -0.2, 0, 0.6}, the output is a discrete precise value. The fuzzy identification rule is "If Athens B", and the fuzzy relation R can be written as: R=A×B

Written as a fuzzy inference sentence:

if E ＝N then U ＝P

if E = ZO then U = ZO

if E = PS then U = NS

if E = PM then U = NM

if E = PB then U = NB

if E = PX then U = NX

The membership function curves of the input and output are shown in Figure 3 and Figure 4 respectively.

For the fuzzy control rule to modify the GEO pseudo-range transmission time, according to the two modes of the receiver before positioning and after positioning, the GEO pseudo-range transmission time is greater than, equal to, and less than the reference IGSO pseudo-range transmission time. The main difference between the two modes is whether the pseudo-range latch signal TIC has been aligned with the whole second of Beidou time. It should be noted that all the following fuzzy control rules are not contradictory to each other, and the set of fuzzy control rules is applicable to all situations.

2.1 Before the receiver is positioned, the position of the rising edge of the TIC is random, and the GEO pseudorange transmission time is longer than the reference IGSO. As shown in Figure 5, there are three situations as shown in Table 1:

Table 1

Condition (a) (b) (c) E. ZO PB N u ZO NB P

The horizontal arrow in the figure is the time flow, the vertical arrow is the relative position of the subframe head and the rising edge of the pseudo-range latch signal, the highest dotted arrow is the pseudo-range latch signal, the cycle is 1s, k-1 time is before, k time At the end, the difference between the two is 1s; the higher solid arrow is the IGSO subframe header, with a period of 6s, and the lowest solid arrow is the GEO subframe header, with a period of 0.6s; N _c1 and N _c2 are respectively pseudorange latched Pseudorange counts for IGSO satellites and GEO satellites for which signals are latched.

Situation (a) The two subframe headers latched by the pseudo-range latch signal are synchronous subframe headers, the input quantity is applicable to the fuzzy rule ZO, the output quantity is applicable to ZO, and there is no need to modify t _ρ,GEO ; The GEO subframe header is ahead of the IGSO subframe header by one GEO subframe period, the input quantity is applicable to the fuzzy rule PB, the output quantity is applicable to NB, t _{ρ, GEO} minus 6s; case (c) the latched IGSO subframe header is more than GEO The subframe header is ahead of a GEO subframe period, the input quantity is applicable to the fuzzy rule N, and the output quantity is applicable to P, t _{ρ, GEO} plus 6s.

2.2 Before the receiver is positioned, the position of the rising edge of the TIC is random, and the transmission time of the GEO pseudorange is exactly equal to the reference IGSO. As shown in Figure 6, there are two cases as shown in Table 2:

Table 2

Condition (a) (b) E. ZO PB u ZO NB

Situation (a) The two subframe headers latched by the pseudo-range latch signal are synchronous subframe headers, the input quantity is applicable to the fuzzy rule ZO, the output quantity is applicable to ZO, and there is no need to modify t _ρ,GEO ; The GEO subframe header is one GEO subframe period ahead of the IGSO subframe header, the input quantity is applicable to the fuzzy rule PB, and the output quantity is applicable to NB, t _{ρ, GEO} minus 6s.

2.3 Before the receiver is positioned, the position of the rising edge of the TIC is random, and the GEO pseudorange transmission time is shorter than the reference IGSO. As shown in Figure 7, there are two cases as shown in Table 3:

table 3

Condition (a) (b) E. ZO PB u ZO NB

Situation (a) The two subframe headers latched by the pseudo-range latch signal are synchronous subframe headers, the input quantity is applicable to the fuzzy rule ZO, the output quantity is applicable to ZO, and there is no need to modify t _ρ,GEO ; The GEO subframe header is one GEO subframe period ahead of the IGSO subframe header, the input quantity is applicable to the fuzzy rule PB, and the output quantity is applicable to NB, t _{ρ, GEO} minus 6s.

2.4 After the receiver is positioned, the TIC position is corrected by the clock difference, and the position of the rising edge is aligned with the whole second of Beidou time. As shown in Figure 8: IGSO frame synchronization full second pulse trigger, pseudorange latch signal, IGSO subframe header, GEO subframe header, and the position of IGSO frame synchronization full second pulse are basically fixed.

Table 4

E. PM PB PX u N M NB NX

As shown in Table 4, there are only three positional relationships between the latched GEO subframe header and the IGSO subframe header. The GEO subframe header is ahead of the IGSO subframe header. And PX, output corresponding to NM, NB and NX, t _{ρ, GEO} corresponding minus 0.4s, 0.6s, 0.8s. The shorter vertical dotted line in the figure is the IGSO frame synchronization full-second signal with a period of 1s, which is 1ms later than the IGSO subframe header.

2.5 Before and after receiver positioning, weak signal and strong interference lead to possible deframing failure of GEO satellites. As shown in Figure 9, if the two subframe headers shown in the figure fail to deframe, the pseudorange latch signal actually latches the pseudorange count value of the last GEO subframe header, and the fuzzy control rule can also be used Make corrections, output the correct pseudorange, and improve the robustness of the receiver, as shown in Table 5:

table 5

E. ZO P.S. u ZO NS

3. The least square method realizes receiver positioning and clock error correction.

The least square method is used to locate the receiver to obtain the clock difference, and the clock difference parameters are returned to correct the TIC, so that the TIC is aligned with the Beidou time (BDT) whole second. The algorithm is as follows:

The pseudorange equation is

ρ _cj ＝[(x _j -x _u ) ² +(y _j -y _u ) ² +(z _j -z _u ) ² ] ^1/2 +δt _u +v _j (1)

Where ρ _cj is the pseudorange from satellite j to the user, (x _u , y _u , z _u ) and (x _j , y _j , z _j ) represent the position coordinates of the user and the satellite in the ECEF coordinate system respectively, and δt _u is The equivalent distance error generated by the user clock error, v _j is the corrected pseudo-range error, and the number of observation satellites is n. The receiver position and clock deviation are written in the form of receiver position coordinates, receiver clock deviation and correction amount.

in, Δx _u , Δy _u , Δz _u , Δδt _u are the corresponding corrections.

For the pseudorange observation equation in Carry out Taylor series expansion at , ignoring the higher-order terms to get:

The constant term of the positioning equation is:

The observation vector from receiver to satellite j is:

Among them, R _j is the distance from satellite j to the receiver position, so the pseudorange residual can be expressed as:

In the above formula, there are 4 unknown quantities Δx _u , Δy _u , Δz _u , Δδt _u , which can be solved by using 4 satellites for distance measurement. Because the position of the receiver is used in the equation, an iterative method must be adopted For calculation, the receiver position can be selected arbitrarily. When the calculated receiver position is close to the real position, the number of iterations is small. When the difference between the values of Δx _u , Δy _u , Δz _u , and δt _u calculated twice in a row is very small, The iteration can be stopped, and _ρj is the pseudorange after a series of corrections to the actual measured pseudorange.

Written in the form of a matrix for the above formula, there are:

Δρ=H*Δx (7)

in:

When the number of satellites participating in the calculation is as large as 4, the least square method can be used for calculation, and the calculation result is:

Δx＝(H ^T H) ^-1 H ^T Δρ (8)

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, some improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the present invention. scope of protection.

Claims (5)

1. A method for measuring pseudoranges of a Beidou navigation satellite system hybrid constellation, characterized in that: specifically comprise the steps: Step 1, power on and reset the receiver, and randomly generate a pseudo-range latch signal TIC with adjustable rising edge position inside the receiver; Step 2, generate the local ranging code and carrier, capture the satellite signal, and the successfully captured signal enters the tracking channel; Step 3, respectively performing bit synchronization and subframe synchronization on GEO satellites, IGSO satellites, and MEO satellites; Step 4. After each channel realizes subframe synchronization, it switches to the pseudorange output and ephemeris demodulation mode, and then calculates the initial pseudorange propagation time, satellite position and pseudorange correction parameters. Among them, IGSO satellite and MEO satellite channels realize bit synchronization After that, trigger the frame synchronization full-second pulse signal to realize the pseudo-range output at the whole second of Beidou time; Step 5, select the pseudo-range propagation time of an IGSO satellite calculated in step 4 as the reference t _{ρ,IGSO_r} , and correct the pseudo-range transmission time t _ρ,GEO of the GEO satellite; Step 6: Use fuzzy control rules to correct the pseudorange propagation time of the GEO satellite channel, and obtain the pseudorange propagation time t _{ρ,GEO_cor} synchronous with IGSO; Step 7. Obtain the initial pseudorange ρ according to the propagation time of the pseudorange, and use the carrier phase to smooth the pseudorange: <mrow><msub><mi>&amp;rho;</mi><mrow><mi>s</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>=</mo><mfrac><mn>1</mn><mi>M</mi></mfrac><msub><mi>&amp;rho;</mi><mi>k</mi></msub><mo>+</mo><mfrac><mrow><mi>M</mi><mo>-</mo><mn>1</mn></mrow><mi>M</mi></mfrac><mo>&amp;lsqb;</mo><msub><mi>&amp;rho;</mi><mrow><mi>s</mi><mo>,</mo><mi>k</mi><mo>-</mo><mn>1</mn></mrow></msub><mo>+</mo><mi>&amp;lambda;</mi><mrow><mo>(</mo><msub><mi>&amp;phi;</mi><mi>k</mi></msub><mo>-</mo><msub><mi>&amp;phi;</mi><mrow><mi>k</mi><mo>-</mo><mn>1</mn></mrow></msub><mo>)</mo></mrow><mo>&amp;rsqb;</mo></mrow> Among them, ρ _{s, k} is the pseudo-range smoothed at the current moment, φ _k is the carrier phase at the current moment, ρ _{s, k-1} is the pseudo-range smoothed at the previous moment, and φ _k-1 is the carrier phase at the previous moment , ρ _k is the unsmoothed pseudorange at the current moment, and M is the smoothing time constant; Step 8, calculate the clock error of the receiver by performing receiver positioning, and calculate the control quantity of the pseudo-range latch signal, and then correct the position of the pseudo-range latch signal. The specific calculation formula is as follows: N _TIC,k ＝N _TIC,k-1 +(Δδ _{u -Δt TIC_frame} )*f _c /c <mrow><msub><mi>N</mi><mrow><mi>T</mi><mi>I</mi><mi>C</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>=</mo><mfenced open = "{" close = ""><mtable><mtr><mtd><mrow><msub><mi>N</mi><mrow><mi>T</mi><mi>I</mi><mi>C</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>+</mo><msub><mi>f</mi><mi>c</mi></msub></mrow></mtd><mtd><mrow><msub><mi>N</mi><mrow><mi>T</mi><mi>I</mi><mi>C</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>&lt;</mo><mn>0</mn></mrow></mtd></mtr><mtr><mtd><mrow><msub><mi>N</mi><mrow><mi>T</mi><mi>I</mi><mi>C</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>-</mo><msub><mi>f</mi><mi>c</mi></msub></mrow></mtd><mtd><mrow><msub><mi>N</mi><mrow><mi>T</mi><mi>I</mi><mi>C</mi><mo>,</mo><mi>k</mi></mrow></msub><mo>&gt;</mo><msub><mi>f</mi><mi>c</mi></msub></mrow></mtd></mtr></mtable></mfenced></mrow> In the above formula, Δδ _u is the clock error residual obtained by receiver positioning, Δt _{TIC_frame} is the fixed delay of channel frame synchronization, N _TIC,k is the control amount of TIC at the current moment, N _TIC,k-1 is the TIC at the previous moment The control amount of , f _c is the sampling frequency of TIC; Step 9, after the receiver achieves a positioning, correct the TIC pulse to align with the whole second of Beidou time. 2. The pseudo-range measurement method of the Beidou navigation satellite system mixed constellation according to claim 1, characterized in that: in step 4, the subframe header is corrected to the position of the whole second by means of soft calculation, so as to realize the position of all satellites The pseudorange synchronization output of . 3. The pseudo-range measurement method of the Beidou navigation satellite system mixed constellation according to claim 1, characterized in that: in step 4, under the premise of not changing the period of the pseudo-range latch signal, the method of software correction is used to realize Beidou Three types of satellites, that is, pseudo-range synchronous output under two speed navigation messages. 4. the Beidou navigation satellite system mixed constellation pseudo-range measurement method according to claim 1 is characterized in that: in step 5, the pseudo-range propagation time of an IGSO closest to the equator is selected as a reference, and the pseudo-range of GEO The propagation time is corrected. 5. The Beidou navigation satellite system mixed constellation pseudo-range measurement method according to claim 1, characterized in that: in step 9, the pseudo-range propagation time of GEO satellites and IGSO satellites is corrected using simplified fuzzy control rules.