Double-engine multi-beam tracking method applied to Beidou communication baseband chip

Abstract

The invention belongs to the technical field of Beidou communication receiver baseband chips, and particularly relates to a double-engine multi-beam tracking method applied to a Beidou communication baseband chip, and the method comprises the steps: a Beidou receiver receives a satellite signal and carries out the preprocessing of the satellite signal, and obtains a Beidou satellite intermediate frequency signal; converting the intermediate frequency signal into a digital signal through an analog-to-digital conversion module, and dividing the digital signal into 21 parallel beam channels; and the capture engine performs time-frequency two-dimensional search on the digital signals of the 21 beam channels to respectively obtain carrier phases and the like of the first beam to the twenty-first beam. Through a master-slave engine cooperative working mechanism, a dynamic parameter compensation strategy and a sensor fusion technology, the method aims to effectively reduce hardware overhead, remarkably improve robustness and positioning accuracy of multi-beam tracking at the same time so as to meet requirements of low-power-consumption terminal equipment, and enhance positioning performance in a complex environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of Beidou communication receiver baseband chips, and particularly relates to a dual-engine multi-beam tracking method applied to Beidou communication baseband chips. Background Art

[0002] In the design architecture of Beidou receiver baseband chips, as Figure 2 shown, the analog-to-digital conversion module is closely connected to the acquisition engine, and the acquisition engine is further connected to 21 independent tracking channel engines. These tracking channel engines are each docked with 21 beam local carrier generators to achieve precise tracking of the carrier phase and Doppler frequency shift of all Beidou satellite beams. However, there are obvious deficiencies in the traditional solution: Each tracking channel engine is equipped with complex components such as a carrier numerically controlled oscillator and a loop filter inside. This not only makes the 21 parallel tracking channels occupy a large amount of FPGA logic resources, but also leads to a significant increase in chip area and power consumption, making it difficult to meet the requirements of low-power terminal devices; More critically, each tracking channel works independently, lacking necessary parameter correlation modeling. When the Doppler frequency shift undergoes a sudden change (for example, in a high-speed motion scenario), this independence easily leads to tracking loss of lock, and then the signal needs to be reacquired, which poses a threat to the continuity of positioning. In addition, the existing solutions fail to fully exploit and utilize the time-varying correlation of the carrier phase difference and Doppler frequency shift between beams, which not only causes unnecessary repeated calculations, but also may lead to the accumulation of errors. Especially in a complex electromagnetic environment, this accumulated error is more likely to be amplified, thus having an adverse impact on the positioning accuracy. Summary of the Invention

[0003] (I) Technical Problems to be Solved In order to overcome the technical problems existing in the design of existing Beidou receiver baseband chips, such as large consumption of hardware resources, poor adaptability to dynamic environments, computational redundancy, and susceptibility of positioning accuracy to complex electromagnetic environments, the present invention provides a dual-engine multi-beam tracking method applied to Beidou communication baseband chips. The method aims to effectively reduce the hardware overhead through a master-slave engine collaborative working mechanism, a dynamic parameter compensation strategy, and sensor fusion technology, while significantly enhancing the robustness and positioning accuracy of multi-beam tracking to meet the requirements of low-power terminal devices and enhance the positioning performance in complex environments.

[0004] (II) Technical Solutions The present invention is realized through the following technical solutions: The present invention provides a dual-engine multi-beam tracking method applied to a Beidou communication baseband chip. The method is based on dual-engine multi-beam tracking, and the dual-engine multi-beam tracking includes a Beidou receiver, a radio frequency front-end module connected to the Beidou receiver, an analog-to-digital conversion module connected to the radio frequency front-end module, a capture engine connected to the analog-to-digital conversion module, a first tracking channel engine connected to the capture engine, a second tracking channel engine connected to a signal selector, a signal selector connected to the capture engine, a beam setter connected to the second tracking channel engine, a difference calculation unit connected to the second tracking channel engine and the signal selector, a difference updater connected to the difference calculation unit, a gyroscope connected to the difference updater, a first beam local carrier generator connected to the first tracking channel engine, and second beam local carrier generators, third beam local carrier generators, fourth beam local carrier generators, fifth beam local carrier generators, sixth beam local carrier generators, seventh beam local carrier generators, eighth beam local carrier generators, ninth beam local carrier generators, tenth beam local carrier generators, eleventh beam local carrier generators, twelfth beam local carrier generators, thirteenth beam local carrier generators, fourteenth beam local carrier generators, fifteenth beam local carrier generators, sixteenth beam local carrier generators, seventeenth beam local carrier generators, eighteenth beam local carrier generators, nineteenth beam local carrier generators, twentieth beam local carrier generators, and twenty-first beam local carrier generators respectively connected to the second tracking channel engine; The method includes: 1. The Beidou receiver receives satellite signals and performs preprocessing to obtain Beidou satellite intermediate frequency signals f m , generally taking a value of 15.75 MHz; the preprocessing is: using the radio frequency front-end module to receive satellite signals and perform down-conversion and filtering processing, and outputting Beidou satellite intermediate frequency signals; 2. The intermediate frequency signals are converted into digital signals through the analog-to-digital conversion module and divided into 21 parallel beam channels; 3. The capture engine performs time-frequency two-dimensional search on the digital signals of the 21 beam channels, and respectively obtains the carrier phases and Doppler frequencies of the first beam to the twenty-first beam (the first beam to the twenty-first beam cover the first beam, the second beam, the third beam, the fourth beam, the fifth beam, the sixth beam, the seventh beam, the eighth beam, the ninth beam, the tenth beam, the eleventh beam, the twelfth beam, the thirteenth beam, the fourteenth beam, the fifteenth beam, the sixteenth beam, the seventeenth beam, the eighteenth beam, the nineteenth beam, the twentieth beam, and the twenty-first beam); k= 1, 2,......, 21; (4) The first tracking channel engine locks on to the carrier phase of the first beam and the Doppler frequency , and generates a corresponding local carrier signal through the first beam local carrier generator; (5) The signal selector selects the input mode according to the power-on state of the Beidou receiver, specifically including: If it is the first power-on, the carrier phases of the first beam to the twenty-first beam captured in step (3) and the Doppler frequency are directly input to the second tracking channel engine; If it is not the first power-on, the carrier phase difference output by the difference calculation unit and are input to the second tracking channel engine; (6) The beam setter controls the second tracking channel engine to sequentially track the carrier phases of the second beam to the twenty-first beam and the Doppler frequency ; (7) The difference calculation unit calculates the carrier phase differences between the first beam and the second beam to the twenty-first beam and the Doppler frequency differences ; (8) According to the characteristic that the geostationary orbit satellite is stationary relative to the Earth reference system, the relative motion between the satellite receiver and the satellite is equivalent to the motion of the satellite receiver relative to the Earth reference rate. Therefore, the Doppler change caused by the relative motion between the satellite receiver and the satellite can be measured and predicted by a gyroscope. The gyroscope is used to calculate the motion state of the satellite receiver and output the real-time acceleration that changes with time a ( t ), and Doppler prediction is performed for the beams that are not being calculated by the tracking channel engine; That is, the difference updater updates the Doppler frequencies of the second beam to the twenty-first beam according to the real-time acceleration output by the gyroscope a ( t ), and the formula is: ; where, is the center frequency of the satellite signal, generally taking the value of 2491.75 MHz, c is the speed of light, generally taking the value of 299792458 m / s, and t is time; (9) Input the updated carrier phase and the Doppler frequency to the second beam local carrier generator to the twenty-first beam local carrier generator to generate corresponding local carrier signals to achieve real-time tracking of the first to twenty-first beams.

[0005] Preferably, the signal output by the first beam local carrier generator is: , where is the intermediate frequency signal frequency of the Beidou satellite in step (i), and t is time.

[0006] Preferably, the signals output by the second beam local carrier generator to the twenty-first beam local carrier generator (the second beam local carrier generator to the twenty-first beam local carrier generator include the second beam local carrier generator, the third beam local carrier generator, the fourth beam local carrier generator, the fifth beam local carrier generator, the sixth beam local carrier generator, the seventh beam local carrier generator, the eighth beam local carrier generator, the ninth beam local carrier generator, the tenth beam local carrier generator, the eleventh beam local carrier generator, the twelfth beam local carrier generator, the thirteenth beam local carrier generator, the fourteenth beam local carrier generator, the fifteenth beam local carrier generator, the sixteenth beam local carrier generator, the seventeenth beam local carrier generator, the eighteenth beam local carrier generator, the nineteenth beam local carrier generator, the twentieth beam local carrier generator, the twenty-first beam local carrier generator) are: .

[0007] (III) Advantageous Effects Through the master-slave engine collaborative working mechanism, dynamic parameter compensation strategy, and sensor fusion technology, the present invention aims to effectively reduce the hardware overhead, while significantly improving the robustness and positioning accuracy of multi-beam tracking, so as to meet the requirements of low-power terminal devices and enhance the positioning performance in complex environments. Description of the Drawings

[0008] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present invention will become more apparent: Figure 1 is the system block diagram of the present invention.

[0009] Figure 2 is the system block diagram of the prior art. Detailed Embodiments

[0010] In order to overcome the defects that traditional Beidou baseband chips need to be configured with 21 independent tracking channel engines, and each engine includes modules such as a carrier numerically controlled oscillator (NCO) and a loop filter, resulting in high hardware complexity and high power consumption. Therefore, the present invention proposes a dual-engine multi-beam tracking method applied to Beidou communication baseband chips. Through a dual-engine architecture (the main engine locks the main beam, and the slave engine dynamically polls the remaining beams), the number of hardware channels is reduced from 21 to 2 core engines, significantly reducing the FPGA logic resource occupancy rate (about 60% reduction), while reducing the chip area and power consumption, and adapting to the low-power scenario requirements of Internet of Things terminals, etc.; The specific implementation above is as follows: The method is implemented based on dual-engine multi-beam tracking. The dual-engine multi-beam tracking includes a Beidou receiver, a radio frequency front-end module connected to the Beidou receiver, an analog-to-digital conversion module connected to the radio frequency front-end module, a capture engine connected to the analog-to-digital conversion module, a first tracking channel engine connected to the capture engine, a second tracking channel engine connected to a signal selector, a signal selector connected to the capture engine, a beam setter connected to the second tracking channel engine, a difference calculation unit connected to the second tracking channel engine and the signal selector, a difference updater connected to the difference calculation unit, a gyroscope connected to the difference updater, a first beam local carrier generator connected to the first tracking channel engine, and second beam local carrier generators, third beam local carrier generators, fourth beam local carrier generators, fifth beam local carrier generators, sixth beam local carrier generators, seventh beam local carrier generators, eighth beam local carrier generators, ninth beam local carrier generators, tenth beam local carrier generators, eleventh beam local carrier generators, twelfth beam local carrier generators, thirteenth beam local carrier generators, fourteenth beam local carrier generators, fifteenth beam local carrier generators, sixteenth beam local carrier generators, seventeenth beam local carrier generators, eighteenth beam local carrier generators, nineteenth beam local carrier generators, twentieth beam local carrier generators, and twenty-first beam local carrier generators respectively connected to the second tracking channel engine (refer to Figure 1 shown); In the traditional scheme, when the Doppler frequency shift suddenly changes (such as high-speed movement), it is easy to lose lock due to the independent operation of the channels and needs to re-capture the signal, resulting in positioning interruption. Therefore, the present invention introduces the fusion technology of a difference calculation unit and a gyroscope sensor. By calculating the carrier phase difference and Doppler frequency difference between the main beam and the remaining beams in real time a ( t ) and combining the acceleration output by the gyroscope to dynamically update the prediction model ( ), thereby realizing the Doppler frequency shift pre-compensation of non-tracking beams, effectively avoiding the lock loss problem, and improving the continuous positioning ability in high-speed scenarios; In addition, the traditional method requires 21 engines to independently solve the signals of the same satellite group, resulting in repeated calculations (such as Doppler prediction and loop filtering) and error accumulation. Through the master-slave engine cooperation mechanism of the present invention, the master engine (the first tracking channel engine) continuously locks the first beam and generates a reference local carrier signal. The slave engine (the second tracking channel engine) dynamically generates local carrier signals for the remaining beams based on the difference calculation results. The present invention eliminates redundant calculations through parameter correlation modeling, and at the same time uses gyroscope data to suppress the Doppler frequency shift error caused by movement, improving the positioning accuracy (the measured error is reduced by about 30%); In addition, the number of traditional hardware channels is fixed at 21, and resources cannot be allocated as needed. The invention controls the slave engine to track the second to the twenty-first beams in a polling manner through a beam setter, supports dynamic adjustment of the tracking priority (for example, preferentially tracking satellites with high elevation angles), and can be adapted to newly added satellites or frequency points in the future (such as the B3 frequency band) through software configuration, reducing the hardware upgrade cost; The above specific embodiments are as follows: The method includes: (1) The Beidou receiver receives satellite signals and performs preprocessing to obtain Beidou satellite intermediate frequency signals f m , generally taking a value of 15.75 MHz; the preprocessing is: using the radio frequency front-end module to receive satellite signals and perform down-conversion and filtering processing, and outputting Beidou satellite intermediate frequency signals; (2) Converting the intermediate frequency signal into a digital signal through an analog-to-digital conversion module and dividing it into 21 parallel beam channels; (3) The acquisition engine performs time-frequency two-dimensional searches on the digital signals of the 21 beam channels, and respectively obtains the carrier phases and Doppler frequencies of the first beam to the twenty-first beam (the first beam to the twenty-first beam cover the first beam, the second beam, the third beam, the fourth beam, the fifth beam, the sixth beam, the seventh beam, the eighth beam, the ninth beam, the tenth beam, the eleventh beam, the twelfth beam, the thirteenth beam, the fourteenth beam, the fifteenth beam, the sixteenth beam, the seventeenth beam, the eighteenth beam, the nineteenth beam, the twentieth beam, the twenty-first beam); where k = 1, 2,......, 21; (4) The first tracking channel engine locks and tracks the carrier phase and Doppler frequency of the first beam, and generates a corresponding local carrier signal through the first beam local carrier generator; the first tracking channel engine is set as the master engine, and fixedly locks the carrier phase and Doppler frequency of the first beam, generating a reference signal as the reference source for all beam tracking; The second tracking channel engine is set as a slave engine, and receives the original parameters at the first power-on or the difference parameters at non-first power-on through a signal selector. Combining with the polling instructions of the beam setter, local carrier signals of the remaining 20 beams are generated in sequence. Additionally, a dynamic switching logic is set. That is, at the first power-on, the slave engine directly uses the carrier phase and Doppler frequency output by the acquisition engine; At non-first power-on, based on the carrier phase difference and Doppler frequency difference to update the parameters, reducing the real-time computation amount. Specifically, they are steps (five) and (six) as follows: (Five) The signal selector selects the input mode according to the power-on state of the Beidou receiver, specifically including: If it is the first power-on, the carrier phase and Doppler frequency of the first beam to the twenty-first beam captured in step (three) are directly input to the second tracking channel engine; If it is non-first power-on, the carrier phase difference output by the difference calculation unit and are input to the second tracking channel engine; Six) The beam setter controls the second tracking channel engine to sequentially track the carrier phase and Doppler frequency of the second beam to the twenty-first beam in a polling manner; Seven) The difference calculation unit calculates the carrier phase differences between the first beam and the second beam to the twenty-first beam (reflecting the phase offset between adjacent beams, used to eliminate common errors such as ionospheric delay) and Doppler frequency differences; Eight) According to the characteristic that the geostationary orbit satellite is stationary relative to the Earth reference system, the relative motion between the satellite receiver and the satellite is equivalent to the motion of the satellite receiver relative to the Earth reference rate. Therefore, the Doppler change caused by the relative motion between the satellite receiver and the satellite can be measured and predicted using a gyroscope. The gyroscope is used to calculate the motion state of the satellite receiver and outputs the real-time acceleration a ( t ) that changes with time, and performs Doppler prediction for the beams not being calculated by the tracking channel engine; That is, the difference updater updates the Doppler frequencies of the second beam to the twenty-first beam according to the real-time acceleration a ( t ) output by the gyroscope through a formula (through the acceleration a ( t)Integrate to predict the Doppler shift caused by the movement of the receiver and achieve dynamic frequency offset compensation. Additionally, the acceleration a ( t ) is incorporated into the Doppler prediction model to solve the limitation of traditional solutions that rely on the parameters of satellite signals themselves and ignore local dynamic changes). The formula is as follows: ; where is the center frequency of the satellite signal, generally taking the value of 2491.75 MHz, c is the speed of light, generally taking the value of 299792458 m / s, and t is time; The above setting is a closed-loop update mechanism. The difference updater adjusts in real time according to the gyroscope data to ensure that the local carrier signal generated by the engine remains synchronized with the satellite signal and avoid tracking loss due to sudden movement; (IX) Input the updated carrier phase and Doppler frequency into the local carrier generators of the second beam to the twenty-first beam to generate corresponding local carrier signals to achieve real-time tracking of the first to twenty-first beams; Among them, the signal output by the local carrier generator of the first beam is: , where is the intermediate frequency signal frequency of the Beidou satellite in step (I), and t is time; Among them, the signals output by the local carrier generators of the second beam to the twenty-first beam (the local carrier generators of the second beam to the twenty-first beam include the local carrier generator of the second beam, the local carrier generator of the third beam, the local carrier generator of the fourth beam, the local carrier generator of the fifth beam, the local carrier generator of the sixth beam, the local carrier generator of the seventh beam, the local carrier generator of the eighth beam, the local carrier generator of the ninth beam, the local carrier generator of the tenth beam, the local carrier generator of the eleventh beam, the local carrier generator of the twelfth beam, the local carrier generator of the thirteenth beam, the local carrier generator of the fourteenth beam, the local carrier generator of the fifteenth beam, the local carrier generator of the sixteenth beam, the local carrier generator of the seventeenth beam, the local carrier generator of the eighteenth beam, the local carrier generator of the nineteenth beam, the local carrier generator of the twentieth beam, and the local carrier generator of the twenty-first beam) are: .

[0011] The comparison table of the present invention (dual-engine) and the traditional solution (21-channel) is as follows:

[0012] The present invention realizes the reuse of hardware resources through a dual-engine architecture, enhances the tracking robustness through differential dynamic compensation, and enhances the dynamic adaptability through sensor fusion, providing new innovations for the efficient and low-power design of Beidou baseband chips.

Claims

1. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip, the method comprising: (1) A Beidou receiver receives satellite signals and performs preprocessing to obtain Beidou satellite intermediate frequency signals; (2) The intermediate frequency signals are converted into digital signals through an analog-to-digital conversion module and divided into 21 parallel beam channels; (3) The capture engine performs a two-dimensional time-frequency search on the digital signals of 21 beam channels, and obtains the carrier phases of the first beam to the twenty-first beam respectively and Doppler frequencies ; where k = 1, 2,...,..., 21; It is characterized in that: the following steps are further included; (4) The first tracking channel engine locks to track the carrier phase of the first beam and the Doppler frequency , and generates a corresponding local carrier signal through the first beam local carrier generator; (5) A signal selector selects an input mode according to the power-on state of the Beidou receiver, specifically including; If it is the first power-on, the carrier phases of the first beam to the twenty-first beam captured in step (III) and the Doppler frequencies are directly input to the second tracking channel engine; If it is not the first power-on, the carrier phase difference output by the difference calculation unit and are input to the second tracking channel engine; (6) The beam setter controls the second tracking channel engine to sequentially track the carrier phases of the second beam to the twenty-first beam in a polling manner and the Doppler frequencies ; (7) The difference calculation unit calculates the carrier phase differences between the first beam and the second beam to the twenty-first beam and the Doppler frequency differences ; (8) The difference updater updates the Doppler frequencies of the second beam to the twenty-first beam according to the real-time acceleration output by the gyroscope a ( t ) by using the formula: ; wherein, is the center frequency of the satellite signal, c is the speed of light, and t is the time; (9) Input the updated carrier phase and Doppler frequency into the second beam local carrier generator to the twenty-first beam local carrier generator, and generate corresponding local carrier signals to achieve real-time tracking of the first to twenty-first beams.

2. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip according to claim 1, characterized in that: The signal output by the first beam local carrier generator is: , where is the intermediate frequency signal frequency of the Beidou satellite in step (i), and t is time.

3. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip according to claim 1, characterized in that: The signals output by the second beam local carrier generator to the twenty-first beam local carrier generator are as follows: .

4. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip according to claim 1, characterized in that: The Beidou receiver is further connected with a radio frequency front-end module for receiving satellite signals and performing down-conversion and filtering processing, and outputting Beidou satellite intermediate frequency signals.

5. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip according to claim 1, characterized in that: In the said step (VIII), f 0 = 2491.75 MHz.

6. The dual-engine multi-beam tracking method applied to the Beidou communication baseband chip according to claim 1, wherein: In the step (VIII), c = 299792458 m / s.

7. A dual-engine multi-beam tracking method applied to a Beidou communication baseband chip according to claim 2 or 3, characterized in that: f m = 15.75 MHz.

Images