WO2020168462A1 - 一种卫星通信导航信号生成方法、装置及接收方法、装置 - Google Patents

一种卫星通信导航信号生成方法、装置及接收方法、装置 Download PDF

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WO2020168462A1
WO2020168462A1 PCT/CN2019/075458 CN2019075458W WO2020168462A1 WO 2020168462 A1 WO2020168462 A1 WO 2020168462A1 CN 2019075458 W CN2019075458 W CN 2019075458W WO 2020168462 A1 WO2020168462 A1 WO 2020168462A1
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signal
spreading code
data
modulation
pilot
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PCT/CN2019/075458
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English (en)
French (fr)
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康家方
王红星
刘传辉
陆发平
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中国人民解放军海军航空大学
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Priority to CN201980007696.1A priority Critical patent/CN111868545B/zh
Priority to PCT/CN2019/075458 priority patent/WO2020168462A1/zh
Publication of WO2020168462A1 publication Critical patent/WO2020168462A1/zh

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith

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  • the present invention relates to the technical field of satellite navigation parts, in particular to a method and device for generating satellite communication navigation signals and a method and device for receiving them.
  • the international research process of satellite navigation signal spread spectrum modulation can be roughly divided into three stages: The first stage is the BPSK period (before 2000). From the beginning of GPS in the 1970s, to around 2000, the navigation signal All use BPSK-R direct sequence spread spectrum modulation technology; the second stage is the BOC period (2000-2004), Betz proposed the concept of BOC modulation, which opened the prelude to the design of a new generation of satellite navigation signals, which is similar to BPSK-R. Compared with this, it improves the accuracy of pseudorange measurement from the signal system, and has better multipath suppression and anti-interference ability; the third stage is the MBOC period (2005 to present). In 2005, Betz and his team proposed BCS modulation.
  • pilot channel does not transmit data information, but is only used to transmit ranging positioning signals, while the data channel is used to transmit data information such as telegrams and short messages, which makes the integration time of the ranging signal much longer than spread spectrum modulation symbols
  • the duration of time improves the receiver's acquisition, tracking and ranging accuracy.
  • the technical problem to be solved by the present invention is to provide a satellite communication navigation signal generating method, device, and receiving method and device aiming at the deficiencies of the prior art.
  • a method for generating satellite communication and navigation signals includes:
  • pilot signal component spreading code modulate to generate the pilot component spread spectrum modulation signal S pilot (t);
  • the binary message or data information is modulated by the spreading code time shift position modulation method to generate the data component spread spectrum modulation signal S data (t).
  • the pilot component spread spectrum modulation signal S pilot (t) and the data component spread spectrum modulation signal S data (t) are modulated to the radio frequency to obtain two radio frequency components Signal, and then superimpose the two radio frequency signal components to obtain the radio frequency modulation signal S RF (t).
  • the spreading code time-shift position modulation can be further embodied.
  • the spreading code time shift position modulation method adopted by the data signal component is: a cyclic code shift keying modulation method.
  • the cyclic shift can generate N different spreading code time shift sequence sets
  • the spreading code time shift position modulation method used for the data signal component is: Among the N spreading code time shift sequence sets, select K spreading code time shift sequence sets to modulate log 2 K bits of message or data information, K ⁇ N.
  • the spreading code time shift position modulation method adopted by the data signal component is: spreading code time shift position modulation
  • first and second modulation methods are only two special cases of spreading code time-shifted position modulation methods, and do not limit the technical method.
  • the spreading code time-shifted position modulation of the present invention can be extended to other modifications, Changes, such modifications and changes are all within the spirit and teaching scope of the present invention.
  • a satellite communication and navigation signal receiving method includes:
  • the sequence value of the signal to be detected is compared, and the time corresponding to the maximum value is the position detection time. According to the mapping relationship between the binary data and the shift of the spreading code sequence in the modulation process, the binary message or data information is determined at the position detection time.
  • a satellite communication navigation signal generating device includes:
  • Spreading code generation module used to generate spreading codes for pilot signal components and spreading codes for data signal components
  • the pilot signal component modulation module is used to generate the pilot component spread spectrum modulation signal S pilot (t) according to the pilot signal component spread code;
  • the spreading code time-shifting position modulation module is used to modulate the binary message or data information by using the spreading code time-shifting position modulation method according to the data signal component spreading code to generate the data component spreading modulation signal S data (t ), the spreading code time-shift position modulation means: according to the difference of pre-modulated binary messages or data information, the data component spreading code sequence is shifted within the position symbol time interval T s , and the minimum shift time
  • the interval is 1 spreading code chip period T c
  • the up-conversion module is used to generate a carrier with a center frequency of f c and different phases, and modulate the pilot component spread spectrum modulation signal S pilot (t) and the data component spread spectrum modulation signal S data (t) to Radio frequency, two radio frequency component signals are obtained, and the two radio frequency signal components are superimposed to obtain a radio frequency modulation signal S RF (t).
  • the spreading code time shift position modulation module can be further embodied.
  • the spreading code time shift position modulation module is a spreading code cyclic shift keying modulation module.
  • the spreading code is cyclic
  • the shift keying modulation module adopts the cyclic code shift keying modulation method to modulate the binary message or data information.
  • the cyclic shift can generate N different spreading code time shift sequence sets, and the spreading code cyclic shift keying modulation module is specifically used for In the N spreading code time shift sequence sets, select K spreading code time shift sequence sets to modulate log 2 K bits of message or data information, K ⁇ N.
  • the spreading code time shift position modulation module is a spreading code time shift position modulation module.
  • a spreading code sequence of length N ⁇ T c the position symbol time interval T s > (N+1) ⁇ T c .
  • the first and second types of modulation modules mentioned above are only two special cases of spreading code time-shifted position modulation modules, and do not limit the technical solution.
  • the spreading code time-shifted position modulation module of the present invention can be extended to other modifications , Changes, such modifications and changes are within the spirit and teaching scope of the present invention.
  • a satellite communication navigation signal receiving device includes:
  • Spreading code local recurring code generation module used to generate the spreading code local recurring code of pilot signal component and data signal component
  • the down-conversion module generates a local carrier signal, and down-converts the radio frequency modulation signal S RF (t) received through the antenna to baseband to obtain a received baseband signal.
  • the local carrier signal includes a center frequency f c and a phase difference of 90° Two carriers;
  • the pilot signal capture and tracking module is used to capture and track the received baseband signal by using the local reproduction code of the spreading code of the pilot signal component, and extract the clock information of the pilot signal according to the result of the capture and tracking.
  • T s k ⁇ T pilot , which determines the time-shift modulation interval of each symbol data signal component;
  • the spreading code time shift position demodulation module is used to use the local reproducing code of the spreading code of the data signal component to perform correlation operations on the received baseband signal to obtain the correlated signal sequence to be detected, which is compared in the time shift modulation interval.
  • the detection signal sequence value, the time corresponding to the maximum value is the position detection time. According to the mapping relationship between the binary data and the shift of the spreading code sequence in the modulation process, the binary message or data information is determined by the position detection time.
  • FIG. 1 is a schematic flowchart of a method for generating satellite communication navigation signals according to an embodiment of the present invention
  • FIG. 2 is a signal flow chart of a method for generating satellite communication navigation signals according to an embodiment of the present invention
  • FIG. 3 is a schematic flowchart of a method for receiving a signal generated by the generating method shown in FIG. 1 according to an embodiment of the present invention
  • FIG. 4 is a signal flow chart of a method for receiving a signal generated by the generating method shown in FIG. 1 according to an embodiment of the present invention
  • FIG. 5 is a schematic diagram of a signal after correlation operation processing for receiving a signal generated by the generating method shown in FIG. 1 according to an embodiment of the present invention
  • FIG. 6 is a schematic structural diagram of an apparatus for generating satellite communication navigation signals according to an embodiment of the present invention.
  • FIG. 7 is a schematic structural diagram of an apparatus for receiving a signal generated by the generating apparatus shown in FIG. 6 according to an embodiment of the present invention
  • Fig. 8 is a curve diagram of the bit error rate obtained by the conventional BPSK modulation and the MPPM modulation of the present invention under the E b /N 0 standard in the prior art;
  • FIG. 9 is a graph of a bit error rate under the SNR standard obtained by the signal receiving method provided by an embodiment of the present invention.
  • FIG. 10 is a schematic diagram of a time-shift position modulation waveform of a spreading code in a signal generation method provided by an embodiment of the present invention.
  • FIG. 11 is a curve diagram of a bit error rate under the SNR standard obtained by the signal receiving method provided by an embodiment of the present invention.
  • Pulse position modulation is a way to load information using different positions where pulses appear, and it has a wide range of applications in the field of laser communication. From the perspective of power efficiency, pulse position modulation signals have lower average signal power. Compared with modulation methods such as BPSK, pulse position modulation has higher power efficiency.
  • Symbol grouping time-shift position spread spectrum modulation method uses the relative position of spread spectrum symbols to load information, which solves the problem of large duty cycle and low transmission spectrum efficiency of traditional multi-ary position modulation. It is an efficient in the field of spread spectrum Modulation method.
  • Satellite communication and navigation systems require precise synchronization, and the time positioning accuracy of the pilot channel signal by the receiver is more than 1% of the chip duration.
  • This precise clock synchronization provides a natural "ruler” for position modulation.
  • spread spectrum code position modulation and demodulation can be realized, which can further increase the power distribution ratio of pilot communication and data channels. It provides a solution for improving the accuracy of satellite navigation system and expanding user capacity.
  • the inventors of the present invention have discovered through research that the application of the above technical approach to the design of satellite navigation signals can greatly improve the overall performance index of the satellite navigation system. Specifically, the method and device for generating satellite communication navigation signals and the receiving method and device provided by the embodiments of the present invention will be described in detail below with reference to FIGS. 1-11.
  • a method 100 for generating satellite communication navigation signals as shown in FIG. 1 includes:
  • pilot signal component spreading code modulate to generate a pilot component spread spectrum modulation signal S pilot (t).
  • the binary message or data information is modulated by the spreading code time-shift position modulation method to generate the data component spreading modulation signal S data (t).
  • the time-shift interval of spread spectrum modulation is the time interval of position modulation
  • the minimum time-shift interval of time-shift position modulation is the duration of a single chip.
  • pilot signal S pilot (t) in Fig. 2 is modulated by the cos (f c t) carrier, but in fact, the pilot signal S pilot (t) can be further composed of two or It is composed of multiple signal components modulated by spreading codes. Two or more signal components can be modulated by two carriers, cos (f c t) and cos (f c t + ⁇ ).
  • the navigation signal generated in the embodiment of the present invention includes: pilot signal component and data signal component.
  • the data signal component modulates binary text or data information by spreading code time shift position modulation, instead of traditional BPSK or QPSK modulation. , Which greatly improves the power efficiency of the data signal component.
  • the spreading code time-shift position modulation method used by the data signal component may be: cyclic code shift Bit keying modulation method.
  • the cyclic shift can generate N different spreading code time shift sequence sets
  • the spreading code time shift position modulation method used for the data signal component is: Among the N spreading code time shift sequence sets, select K spreading code time shift sequence sets to modulate log 2 K bits of message or data information, K ⁇ N.
  • the spreading code time-shift position modulation method adopted by the data signal component may also be: spreading code time-shift position modulation.
  • a satellite communication navigation signal receiving method 200 receives signals generated by the generating method 100 of Embodiment 1.
  • the method 200 includes:
  • the binary message or data information is determined at the position detection time.
  • the received signal is first multiplied by the carrier, and then converted into a baseband signal by low-pass filtering; then, the spreading code is slidingly correlated with the received baseband signal to obtain a series of sliding correlation values, and then the magnitude of the correlation value And the position is judged to realize the demodulation of the data. Finally, the demodulated data is reorganized into the original data stream and output.
  • the appearance time of the original spread spectrum received signal is fixed, the signal after the correlation operation has a correlation peak at a fixed time, and the decision to restore the modulation data is based on the sign of the correlation peak; the correlation peak of the time-shifted position modulation signal is based on the modulation
  • the difference in data occurs at a certain moment in the time-shift interval, and the modulation data information is determined to be restored according to the position where it appears.
  • a satellite communication navigation signal receiving method provided in the above embodiment.
  • the method receives the signal generated by the generation method in Embodiment 1. After the correlation operation is processed, the demodulation detection of the received signal is transformed into a traditional pulse position modulation signal The demodulation detection.
  • a satellite communication navigation signal generating device 300 as shown in FIG. 6 includes: a spreading code generation module 310, a pilot signal component modulation module 320, a spreading code time shift position modulation module 330, and an up-conversion module 340. among them,
  • the spreading code generation module 310 is used to generate a pilot signal component spreading code and a data signal component spreading code.
  • the pilot signal component modulation module 320 is configured to generate the pilot component spread spectrum modulation signal S pilot (t) according to the pilot signal component spread code.
  • the spreading code time-shifting position modulation module 330 is used to modulate the binary message or data information in a way of spreading code time-shifting position modulation according to the data signal component spreading code to generate a data component spreading modulation signal S data (t ).
  • the up-conversion module 340 is used to generate a carrier wave with a center frequency of f c and different phases, and modulate the pilot component spread spectrum modulation signal S pilot (t) and the data component spread spectrum modulation signal S data (t) to radio frequency, Obtain two radio frequency component signals, and then superimpose the two radio frequency signal components to obtain a radio frequency modulation signal S RF (t).
  • the generating apparatus 300 may correspond to the execution subject of the generating method 100 according to the embodiment of the present invention, and the foregoing and other operations and/or functions of the generating apparatus 300 In order to implement the corresponding processes of the methods in FIG. 1 and FIG. 2 respectively, for the sake of brevity, details are not described herein again.
  • the spreading code time shift position modulation module 330 is a spreading code cyclic shift keying modulation module.
  • the cyclic shift keying modulation module adopts the cyclic code shift keying modulation method to modulate the binary message or data information.
  • the cyclic shift can generate N different spreading code time-shifting sequence sets, and the spreading code cyclic shift keying modulation module is specifically used in N In the spreading code time shift sequence set, select K spreading code time shift sequence sets to modulate log 2 K bits of message or data information, K ⁇ N.
  • the spreading code time-shifting position modulation module is a spreading code time-shifting position modulation module.
  • the position symbol time interval T s > (N+1) ⁇ T c .
  • a satellite communication navigation signal receiving device 400 shown in FIG. 7 receives signals generated by the generating device 300 described in Embodiment 3.
  • the receiving device 400 includes a spreading code local reproduction code generation module 410, a down-conversion module 420, a pilot signal acquisition and tracking module 430, and a spreading code time-shift position demodulation module 440. among them,
  • the spreading code local recurring code generating module 410 is used to generate the spreading code local recurring code of the pilot signal component and the data signal component.
  • the down-conversion module 420 generates a local carrier signal, and down-converts the radio frequency modulation signal S RF (t) received through the antenna to baseband to obtain a received baseband signal.
  • the local carrier signal includes two signals with a center frequency of f c and a phase difference of 90°. Carrier.
  • the pilot signal capture and tracking module 430 is used to capture and track the received baseband signal by using the local reproduction code of the spreading code of the pilot signal component, and extract the clock information of the pilot signal according to the result of the capture and tracking.
  • s k ⁇ T pilot , which determines the time-shift modulation interval of each symbol data signal component.
  • the spreading code time-shift position demodulation module 440 is used to use the local recurring code of the spreading code of the data signal component to perform correlation operations on the received baseband signal to obtain the correlated signal sequence to be detected, and compare the signal sequence to be detected in the time-shift modulation interval.
  • the detection signal sequence value, the time corresponding to the maximum value is the position detection time. According to the mapping relationship between the binary data and the shift of the spreading code sequence in the modulation process, the binary message or data information is determined by the position detection time.
  • the receiving device 400 may correspond to the execution subject of the receiving method 200 according to the embodiment of the present invention, and the foregoing and other operations and/or functions of the receiving device 400 In order to realize the corresponding processes of the methods in FIG. 3 and FIG. 4, for the sake of brevity, the details are not repeated here.
  • the received data signal component is correlated with the locally generated spreading code.
  • the correlation integral value is 1 (normalized When the received data signal component is not synchronized with the locally generated spreading code (synchronization error is greater than one chip interval), the correlation integral value approaches zero.
  • the demodulation detection process of the signal will become the demodulation detection of the multi-ary pulse position modulation (MPPM) signal.
  • MPPM pulse position modulation
  • bit error rate detected by the demodulation of the data signal component is the same as the bit error rate of the MPPM modulated signal.
  • the received signal signal-to-noise ratio SNR will be used as a standard to further explain the error performance of the data signal component.
  • bit error rate requirement of data is usually below 10-6 .
  • both are in a state of higher signal-to-noise ratio.
  • the bit error rate performance of PPM modulation Better than BPSK modulation.
  • the time-shift interval of the data signal component spreading code position modulation is 2 spreading modulation symbol time
  • the Q channel spreading code appears in the time interval
  • I channel pilot signal amplitude and Q channel signal The sum of squares of the amplitude is always 1 (the amplitude of the I channel is 1 during the time interval when the Q channel is zero), which ensures that the constant envelope value of the modulation signal is always 1, and the non-zero interval of the Q channel can be adjusted To adjust the pilot and data channel power ratio.
  • the PPM time-shift position modulation is designed. Take the time-shift interval of two spreading code periods as an example.
  • the Q-channel time-shifting spreading code sequence length is one spreading code sequence period, the number of movable positions is N+1, which is 10231; the maximum can be loaded
  • the spread spectrum modulation symbols of the data channel adopt BPSK modulation, and 2 bits of information are loaded in 2 spread spectrum code modulation cycles.
  • the method provided by the embodiment of the present invention increases the data transmission rate to the original value. 6.65 times.
  • the modulation order Since the modulation order has a direct relationship with the bit error rate, the increase of the modulation order has a logarithmic relationship with the increase of the information rate, and it will increase the complexity of the demodulation detection. It is better to use only 1024 positions and load 10bit information. Table 1 shows the comparison of the main technical parameters of the two methods.
  • the spreading code time shift position modulation scheme can reduce the spreading transmission rate before encoding from 1kb/ s is increased to 5kb/s (corresponding to the information rate after encoding is 1000b/s and 200b/s respectively), when the bit error rate is 10-6 , the required signal-to-noise ratio of the spreading code time-shift position modulation scheme is only 15.4 dB. Compared with the original modulation scheme, the error performance is 1.9dB worse.
  • the error rate curve is shown in Figure 11. However, only at the cost of a loss of 1.9dB of signal-to-noise ratio, in exchange for a 5 times increase in transmission rate, is of great theoretical significance and application value.
  • the PPM modulation scheme can greatly increase the transmission rate of the message data.
  • the data volume of the satellite navigation system message is small, and the update time is not high, but it is required for tracking, capturing and positioning.
  • Higher precision is required, that is, a higher pilot and data channel power ratio is required.
  • the spreading code time-shift position modulation is introduced into the data signal component. Compared with the traditional BPSK modulation method, this modulation method has higher power efficiency and can more efficiently use the limited transmission power to complete the message or data. transmission.
  • the direct effects of this include:
  • the information transmission rate of the data component signal can be greatly increased.
  • the transmission of text information can be completed more quickly; on the other hand, on the basis of the transmission of text information, additional information such as short messages, disaster broadcasts, and early warnings can be transmitted to broaden the application areas of satellite navigation systems.
  • the power ratio of the pilot signal component and the data signal component can be further increased, thereby improving the acquisition and tracking performance and positioning accuracy of the satellite navigation system receiving end.
  • the power ratio of the pilot signal component and the data signal component can be increased by 10:1, compared with the signals with power ratios of 1:1 and 3:1 currently used, and the acquisition and tracking of the receiver The performance is improved by 2.60 and 0.84dB respectively.
  • the transmission rate of the data signal component and the power ratio of the pilot signal component and the data signal component can be improved at the same time.
  • the satellite navigation signal design provided by the present invention does not change the pilot signal components.
  • the reception processing process of the pilot signal components is the same as that of the prior art.
  • the traditional receiver can still capture and track the pilot signal components provided by the present invention. Frequency signal.
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are merely illustrative, for example, the division of units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or integrated. To another system, or some features can be ignored, or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may also be electrical, mechanical or other forms of connection.
  • the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments of the present invention.
  • each embodiment of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of the present invention is essentially or a part that contributes to the existing technology, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium It includes several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods in the various embodiments of the present invention.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program code .

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Abstract

一种基于扩频码时移位置调制的卫星通信导航信号生成方法,包括:生成导频信号分量扩频码和数据信号分量扩频码(110);根据导频信号分量扩频码,调制生成导频分量扩频调制信号S pilot(t)(120);根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t)(130);采用中心频率为f c、相位不相同的载波,将导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)(140)。还涉及一种卫星通信导航信号接收方法、生成装置、接收装置。

Description

一种卫星通信导航信号生成方法、装置及接收方法、装置 技术领域
本发明涉及卫星导航件技术领域,尤其涉及一种卫星通信导航信号生成方法、装置及接收方法、装置。
背景技术
国际上对卫星导航信号扩频调制方式的研究历程可以大致分为三个阶段:第一阶段是BPSK时期(2000年之前),从20世纪70年代GPS始建开始,到2000年左右,导航信号都采用BPSK-R直接序列扩频调制技术;第二阶段是BOC时期(2000-2004年),Betz提出了BOC调制的概念,拉开了新一代卫星导航信号设计的序幕,与BPSK-R相比,从信号体制上提高了伪距测量的精度,并具有更好的多径抑制和抗干扰能力;第三阶段是MBOC时期(2005年至今),2005年Betz和他的团队又提出BCS调制的概念,并衍生出了Crazy BPSK、复合BCS(Composite BCS,CBCS)、交替BCS(Alternative BCS,ABCS)、复合BOC(Composite BOC,CBOC)、时分复用BOC(TMBOC)、正交复用BOC(QMBOC)等扩频调制技术,这些技术方案使得卫星导航扩频调制的灵活性进一步提高。
当前,在第三阶段演进的基础上,为兼顾捕获、跟踪精度和电文数据的传输,在GPS、伽利略、北斗等卫星导航***中,普遍采用了导频通道与电文数据通道分离的传输方式,其中导频通道不传输数据信息,仅用于传输测距定位信号,数据通道则用于 传输电文、短报文等数据信息,这使得测距信号的积分时间可以远远大于扩频调制码元的持续时间,提高了接收机的捕获、跟踪与测距精度。
现有的技术体制下,增大导频信号与电文数据信号的功率比,虽可进一步提升接收机的性能,但意味着电文数据传输速率或可靠性的降低。
探索新体制卫星通信导航信号设计,充分利用受限的星上发射功率,在不降低电文数据信号的传输速率和可靠性的前提下,进一步增大导频信号与数据信号的功率比,进而提高接收机捕获跟踪性能、定位精度等技术性能指标,是当前卫星导航信号设计面临的一项技术难题,也是卫星导航***发展进步的关键。
发明内容
本发明所要解决的技术问题是针对现有技术的不足,提供一种卫星通信导航信号生成方法、装置及接收方法、装置。
本发明解决上述技术问题的技术方案如下:一种卫星通信导航信号生成方法,包括:
生成导频信号分量扩频码和数据信号分量扩频码;
根据导频信号分量扩频码,调制生成导频分量扩频调制信号S pilot(t);
根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t),所述扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为:T s=k×T pilot,k>0;
采用中心频率为f c、相位不相同的载波,将所述的导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
在上述技术方案的基础上,所述的扩频码时移位置调制可进一步具体化。
第一:
对于数据信号分量中长度为N的扩频码序列,T s=N×T c,数据信号分量采用的扩频码时移位置调制方法是:循环码移位键控调制方法。
进一步地,对于数据信号分量中长度为N的扩频码序列,循环移位可产生N个不同的扩频码时移序列集合,数据信号分量采用的扩频码时移位置调制方法是:在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
第二:
数据信号分量采用的扩频码时移位置调制方法是:扩频码时间移位位置调制;
所述扩频码时间移位位置调制指的是:对于长度为N×T c的扩频码序列,位置码元时间区间Ts>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间T s内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特的电文或数据信息。
上述第一、第二种调制方法仅为扩频码时移位置调制方法的两种特例,并不是对本技术方法进行限制,本发明所述的扩频码时移位置调制可延伸为其他修改、变化,这样的修改、变化都在本发明的精神和教导范围内。
本发明解决上述技术问题的另一种技术方案如下:一种卫星 通信导航信号接收方法,包括:
生成导频信号分量和数据信号分量的扩频码本地复现码;
通过天线接收射频调制信号S RF(t),利用中心频率为f c、相位相差90°的两个载波,将所述射频调制信号S RF(t)下变频到基带,得到接收基带信号;
利用导频信号分量的扩频码本地复现码,对所述接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot确定每一码元数据信号分量的时移调制区间;
利用数据信号分量的扩频码本地复现码,对所述接收基带信号进行相关运算,得到相关后的待检测信号序列;
比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
本发明解决上述技术问题的另一种技术方案如下:一种卫星通信导航信号生成装置,包括:
扩频码产生模块,用于生成导频信号分量扩频码和数据信号分量扩频码;
导频信号分量调制模块,用于根据导频信号分量扩频码,生成导频分量扩频调制信号S pilot(t);
扩频码时移位置调制模块,用于根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t),所述扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为: T s=k×T pilot,k>0;
上变频模块,用于生成中心频率为f c、相位不相同的载波,并将所述的导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
在上述技术方案的基础上,所述的扩频码时移位置调制模块可进一步具体化。
第一:
所述扩频码时移位置调制模块为扩频码循环移位键控调制模块,对于数据信号分量中长度为N的扩频码序列,T s=N×T c,所述扩频码循环移位键控调制模块,采用循环码移位键控调制方法对二进制的电文或数据信息进行调制。
进一步地,对于数据信号分量中长度为N的扩频码序列,循环移位可产生N个不同的扩频码时移序列集合,所述扩频码循环移位键控调制模块,具体用于在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
第二:
所述扩频码时移位置调制模块为扩频码时移位置调制模块,对于长度为N×T c的扩频码序列,位置码元时间区间T s>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间Ts内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特的电文或数据信息。
上述第一、第二种调制模块仅为扩频码时移位置调制模块的两种特例,并不是对本技术方案进行限制,本发明所述的扩频码时移位置调制模块可延伸为其他修改、变化,这样的修改、变化 都在本发明的精神和教导范围内。
本发明解决上述技术问题的另一种技术方案如下:一种卫星通信导航信号接收装置,包括:
扩频码本地复现码产生模块,用于生成导频信号分量和数据信号分量的扩频码本地复现码;
下变频模块,生成本地载波信号,将通过天线接收到的射频调制信号S RF(t)下变频到基带,得到接收基带信号,所述本地载波信号包括中心频率为f c、相位相差90°的两个载波;
导频信号捕获跟踪模块,用于利用导频信号分量的扩频码本地复现码,对所述接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot,确定每一码元数据信号分量的时移调制区间;
扩频码时移位置解调模块,用于利用数据信号分量的扩频码本地复现码,对接收基带信号进行相关运算,得到相关后的待检测信号序列,在时移调制区间内比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
本发明附加的方面及其的优点将在下面的描述中部分给出,部分将从下面的描述中变得明显,或通过本发明实践了解到。
附图说明
为了更清楚地说明本发明实施例的技术方案,下面将对本发明实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面所描述的附图仅仅是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以 根据这些附图获得其他的附图。
图1为本发明实施例提供一种卫星通信导航信号生成方法的示意性流程图;
图2为本发明实施例提供一种卫星通信导航信号生成方法的信号流程图;
图3为本发明实施例提供一种接收附图1所示的生成方法生成的信号的方法的示意性流程图;
图4为本发明实施例提供的一种接收附图1所示的生成方法生成的信号的方法的信号流程图;
图5为本发明实施例提供的一种接收附图1所示的生成方法生成的信号的相关运算处理后的信号示意图
图6为本发明实施例提供的一种卫星通信导航信号生成装置的示意性结构图;
图7为本发明实施例提供的一种接收图6所示的生成装置产生的信号的装置的示意性结构图;
图8为现有技术中在E b/N 0标准下得到传统BPSK调制和本发明MPPM调制的误码率曲线图;
图9为本发明实施例提供的信号接收方法得到接收信噪比SNR标准下的误码率曲线图;
图10为本发明实施例提供的信号生成方法中扩频码时移位置调制波形示意图;
图11为本发明实施例提供的信号接收方法得到接收信噪比SNR标准下的误码率曲线图。
具体实施方式
下面将结合本发明实施例中的附图,对本发明实施例中的技 术方案进行清楚、完整地描述,显然,所描述的实施例是本发明的一部分实施例,而不是全部实施例。基于本发明中的实施例,本领域普通技术人员在没有做出创造性劳动的前提下所获得的所有其他实施例,都应属于本发明保护的范围。
脉冲位置调制是一种利用脉冲出现的不同位置来加载信息的方式,其在激光通信领域有广泛的应用。从功率效率的角度来讲,脉冲位置调制信号具有更低的平均信号功率,相对于BPSK等调制方式,脉冲位置调制的功率效率更高。码元分组时移位置扩频调制方法利用扩频码元的相对位置加载信息,解决了传统多进制位置调制占空比大,传输频谱效率低的问题,是扩频领域中的一种高效调制方法。
卫星通信导航***要求精确的同步,接收机对导频通道信号的时间定位精度达1%码片时长量级以上。这一精确时钟同步为位置调制提供了一个天然的“标尺”,利用这一精确的时间标尺可以实现扩频码位置调制和解调,进而可进一步增大导频通信与数据通道的功率分配比,为提高卫星导航***精度、扩大用户容量提供了一种解决方案。
本发明的发明人经过研究发现,将上述技术途径应用于卫星导航信号设计,可以大幅提升卫星导航***的综合性能指标。具体的,下文中结合附图1-11对本发明实施例提供的一种卫星通信导航信号生成方法、装置及接收方法、装置进行详细的描述。
实施例1
如图1所示的一种卫星通信导航信号生成方法100,包括:
110、生成导频信号分量扩频码和数据信号分量扩频码。
120、根据导频信号分量扩频码,调制生成导频分量扩频调制信 号S pilot(t)。
130、根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t)。
其中,扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为:T s=k×T pilot,k>0。
140、采用中心频率为f c、相位不相同的载波,将导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
具体的,在该实施例中,还可以参见附图2所示的信号流程图。图2中,扩频调制时移区间为位置调制的时间区间,时移位置调制的最小时移间隙为单个码片时长。时移位置调制之后与数据通道扩频码相乘得到扩频码时移位置调制信号;然后再与导频通道扩频调制信号一并由载波完成上变频调制,得到调制信号S RF(t)。
需要说明的是:附图2中的导频信号S pilot(t)由cos(f ct)载波进行调制只是一种示例,实际上,导频信号S pilot(t)可进一步由两个或多个经扩频码调制后的信号分量组成,两个或多个信号分量可由cos(f ct)和cos(f ct+θ)两个载波进行调制。
本发明实施例中生成的导航信号包括:导频信号分量和数据信号分量,数据信号分量采用扩频码时移位置调制的方式调制二进制的电文或数据信息,代替了传统的BPSK或QPSK调制方式,大大提高了数据信号分量的功率效率。
可选地,在步骤130中,对于数据信号分量中长度为N的扩频码序列,T s=N×T c,数据信号分量采用的扩频码时移位置调制方法可以是:循环码移位键控调制方法。
进一步地,对于数据信号分量中长度为N的扩频码序列,循环移位可产生N个不同的扩频码时移序列集合,数据信号分量采用的扩频码时移位置调制方法是:在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
可选地,在步骤130中,数据信号分量采用的扩频码时移位置调制方法还可以是:扩频码时间移位位置调制。
扩频码时间移位位置调制指的是:对于长度为N×T c的扩频码序列,位置码元时间区间T s>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间T s内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特的电文或数据信息。
实施例2
如图3所示的一种卫星通信导航信号接收方法200,接收实施例1的生成方法100生成的信号,方法200包括:
210、生成导频信号分量和数据信号分量的扩频码本地复现码。
220、通过天线接收射频调制信号S RF(t),利用中心频率为f c、相位相差90°的两个载波,将射频调制信号S RF(t)下变频到基带,得到接收基带信号。
230、利用导频信号分量的扩频码本地复现码,对接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot确定每一码元数据信号分量的时移调制区间。
240、利用数据信号分量的扩频码本地复现码,对接收基带信号进行相关运算,得到相关后的待检测信号序列。
250、比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
具体的,在该实施例中,还可以参见附图4所示的信号流程图和附图5所示的相关运算处理后的信号示意图。
图4中,接收信号首先与载波相乘,再经低通滤波转变为基带信号;然后,将扩频码与接收基带信号做滑动相关,得到一系列的滑动相关值,再对相关值的幅度和位置进行判决,从而实现数据的解调,最后,解调数据重组为原始的数据流形式输出。
为进一步说明调制方案及其与原扩频调制***的区别,以2个扩频码周期为时移区间、1个码片周期为时移时隙为示意。数据信号分量中,传统扩频调制方式的相关接收信号、及扩频码时移位置调制的相关接收信号如图5所示。图5中,原扩频接收信号的出现时间是固定的,相关运算后的信号在固定时刻出现相关峰,根据相关峰的正负,判决恢复调制数据;时移位置调制信号的相关峰根据调制数据的不同,出现在时移区间内的某一时刻,根据其出现的位置时刻判决恢复调制数据信息。
上述实施例中提供的一种卫星通信导航信号接收方法,该方法接收的是实施例1中的生成方法生成的信号,相关运算处理后,使得接收信号的解调检测转化成为传统脉冲位置调制信号的解调检测。
本领域技术人员应该熟知,上述相关运算或滑动相关可通过快速傅里叶算法来实现,以有效降低计算的复杂度,因此,基于快速傅里叶算法的处理方法也在本发明的保护范畴之中。
实施例3
如图6所示的一种卫星通信导航信号生成装置300,包括:扩频 码产生模块310、导频信号分量调制模块320、扩频码时移位置调制模块330和上变频模块340。其中,
扩频码产生模块310用于生成导频信号分量扩频码和数据信号分量扩频码。导频信号分量调制模块320用于根据导频信号分量扩频码,生成导频分量扩频调制信号S pilot(t)。
扩频码时移位置调制模块330用于根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t)。其中,扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为:T s=k×T pilot,k>0。
上变频模块340用于生成中心频率为f c、相位不相同的载波,并将的导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
应理解,在本发明实施例中,根据本发明实施例的生成装置300,可对应于根据本发明实施例的生成方法100的执行主体,并且该生成装置300的上述和其它操作和/或功能分别为了实现图1和图2中的各个方法的相应流程,为了简洁,在此不再赘述。
可选地,扩频码时移位置调制模块330为扩频码循环移位键控调制模块,对于数据信号分量中长度为N的扩频码序列,T s=N×T c,扩频码循环移位键控调制模块,采用循环码移位键控调制方法对二进制的电文或数据信息进行调制。
进一步地,对于数据信号分量中长度为N的扩频码序列,循环 移位可产生N个不同的扩频码时移序列集合,扩频码循环移位键控调制模块具体用于在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
可选地,扩频码时移位置调制模块为扩频码时移位置调制模块,对于长度为N×T c的扩频码序列,位置码元时间区间T s>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间Ts内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特的电文或数据信息。
实施例4
如图7所示的一种卫星通信导航信号接收装置400,接收实施例3所述的生成装置300产生的信号。接收装置400包括:扩频码本地复现码产生模块410、下变频模块420、导频信号捕获跟踪模块430和扩频码时移位置解调模块440。其中,
扩频码本地复现码产生模块410用于生成导频信号分量和数据信号分量的扩频码本地复现码。下变频模块420生成本地载波信号,将通过天线接收到的射频调制信号S RF(t)下变频到基带,得到接收基带信号,本地载波信号包括中心频率为f c、相位相差90°的两个载波。
导频信号捕获跟踪模块430用于利用导频信号分量的扩频码本地复现码,对接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot,确定每一码元数据信号分量的时移调制区间。
扩频码时移位置解调模块440用于利用数据信号分量的扩频码本地复现码,对接收基带信号进行相关运算,得到相关后的待检测信号序列,在时移调制区间内比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位 的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
应理解,在本发明实施例中,根据本发明实施例的接收装置400,可对应于根据本发明实施例的接收方法200的执行主体,并且该接收装置400的上述和其它操作和/或功能分别为了实现图3和图4中的各个方法的相应流程,为了简洁,在此不再赘述。
为了进一步说明本发明技术方案的优势,下面将给出本发明实施例所提供方法的一些技术性能指标结果。
第一、数据信号分量解调误码率
由于扩频码具有很好的自相关特性,接收的数据信号分量与本地产生的扩频码进行相关运算,当数据信号分量与本地产生的扩频码同步时,相关积分值为1(归一化),当接收的数据信号分量与本地产生的扩频码不同步时(同步误差大于一个码片间隔),相关积分值趋近于零。
相关运算之后,信号的解调检测过程将变成多进制脉冲位置调制(MPPM)信号的解调检测,只需比较多个相关运算值,得到最大值所对应位置,参照调制时的“二进制数据”到“扩频码时移位置”映射规则,进行“扩频码时移位置”到“二进制数据”的映射,即可得到二进制的解调数据。
由信号的接收处理过程可见,数据信号分量解调检测的误码率与MPPM调制信号的误码率相同。
为了更直观的展现本发明的误码性能优势,下面将结合附图,在高斯白噪声信道条件下,分别以比特信噪比(E b/N 0)和接收信号信噪比(SNR)为标准,对本发明提供的方法和现行的BPSK调制方式的性能进行比较。
1、E b/N 0标准
得到传统BPSK调制和MPPM调制的误码率曲线图如图8所示。从图8中可以看出,2PPM调制的误码性能比BPSK差3dB,在信噪比较高时,高进制PPM调制的误码性能优于BPSK调制,进制数越高,误码性能越好。在误码率为10 -6时,1024PPM调制所需的信噪比比BPSK调制低约5.2dB,展现了PPM调制的技术体制优势。
然而,在卫星导航***中,我们通常考虑总体接收信号(导频信号与数据信号的叠加)的信噪比与误码率之间的关系。下面将以接收信号信噪比SNR为标准,对数据信号分量的误码性能进行进一步说明。
2、接收信号信噪比(SNR)标准
假设导频通信与电文数据通道的功率比为3:1,通过合理的设计,可以确保PPM扩频调制码元的能量为单个BPSK数据通道码元符号能量的4倍,由此可以得到接收信噪比SNR标准下的误码率曲线图如图9所示。
从图9中可以看出,在SNR标准下,PPM调制的阶数越高,误码率越差,但误码率并不随阶数的升高而急剧增大;对比BPSK调制,在低信噪比情况下,多进制PPM调制的误码性能较差,在高性噪比情况下,多进制PPM调制的误码性能优于BPSK调制,当误码率为10 -6时,1024PPM调制的所需的信噪比比BPSK调制低约1.1dB。
实际传输中,数据的误码率要求通常在10 -6量级以下,这种情况下,无论BPSK调制还是PPM调制,都处于较高信噪比的状态,此时PPM调制的误码率性能优于BPSK调制。
第二、对比实验
扩频码时移位置调制中,一种基带导频和数据通道扩频信号示意如图10所示。
在图10中,数据信号分量扩频码位置调制的时移区间为2个扩频调制码元时间,Q通道扩频码出现的时间区间内,I通道导频信号的幅值与Q通道信号幅值的平方和恒为1(Q通道为零的时间区间内,I通道的幅值为1),由此可确保调制信号恒包络值恒为1,并可通过调整Q通道非零区间上的幅值来调节导频与数据通道功率比。
需要说明的是,图10中的2个扩频码元周期只是示意性的,实际时移区间可根据需要增大或减小。
根据本发明实施例的调制***设计方案,参照北斗B2a调制信号(导频与数据通道的信号功率比为1:1,扩频码长度N=10230),设计PPM时移位置调制。以两个扩频码周期的时移区间为例,当Q通道时移扩频码序列长度为一个扩频码序列周期时,可移动的位置数为N+1,也就是10231;最多可可加载的比特信息为log 2(10231)=13.3bit。在B2a信号调制方案中,数据通道扩频调制码元均采用BPSK调制的方式,2个扩频码调制周期内加载2bit信息,本本发明实施例提供的方法的使数据传输速率提升到达原来的达6.65倍。
由于调制阶数与误码率有直接关系,调制阶数的增大与信息速率的提升呈对数关系,且会带来解调检测复杂度的增大,不妨仅采用1024个位置,加载10bit信息。两种方式下的主要技术参数对比如表1所示。
表1信号体制参量对比
调制方式 1024PPM QPSK
导频数据通道功率比 1:1 1:1
比特速率(5位编码前) 5kb/s 1kb/s
信息速率(5位编码后) 1000bit/s 200bit/s
信噪比(误码率为10 -6) 15.4dB 13.5dB
由上表可以看出,对比两种调制方案,在扩频码、导频与数据通道功率比相同的条件下,扩频码时移位置调制方案可将编码前的扩频传输速率由1kb/s提高到5kb/s(对应编码后信息速率分别为1000b/s和200b/s),在误码率为10 -6时,扩频码时移位置调制方案所需的信噪比仅为15.4dB,与原调制方案相比较,误码性能差1.9dB,误码率曲线如图11所示。但是,仅以1.9dB的信噪比损失为代价,换取5倍的传输速率提升,是有很大的理论意义和应用价值的。
从对比中可以看出,PPM的调制方案可大幅提高电文数据的传输速率,在实际应用中,卫星导航***电文的数据量较小,且对更新时间的要求不高,而对跟踪捕获和定位精度要求更高,也就是要求更高的导频与数据通道的功率比。
本领域普通技术人员可以认识到,卫星通信导航信号中的各种技术指标是可以互换的,降低数据信号分量的传输速率可以换取更低的数据信号分量发射功率,从而在总功率不变的前提下,提升导频信号分量的发射功率,进而提升卫星导航接收机的捕获跟踪性能和定位精度。
总的来说,对于本发明的技术方案,相对于现有技术而言,具有如下有益效果:
1、在数据信号分量中引入了扩频码时移位置调制,相对于传统的BPSK调制方式,这种调制方式具有更高的功率效率,可以更高效的使用有限的发射功率完成电文或数据的传输。由此带来的直接效果包括:
①在不改变导频信号分量与数据信号分量功率比的前提下,可大幅提高数据分量信号的信息传输速率。一方面,可以更快速地完成电文信息的传输;另一方面,可以在传输电文信息的基础上,额外传输 短报文、灾害广播、预警等信息,拓宽卫星导航***应用领域。
②在不增大数据分量信号信息传输速率的前提下,可以进一步加大导频信号分量与数据信号分量的功率比,进而提升卫星导航***接收端的捕获跟踪性能和定位精度。就本发明所提供的技术方案,可将导频信号分量与数据信号分量的功率比提高的10:1,对比现在使用的功率比为1:1和3:1的信号,接收机的捕获跟踪性能分别提升2.60、0.84dB。
③可同时提高数据信号分量的传输速率和导频信号分量与数据信号分量的功率比。
2、可与原***实现兼容性过渡。本发明提供的卫星导航信号设计并未对导频信号分量进行改变,导频信号分量的接收处理过程与现有技术的接收处理过程相同,传统的接收机仍能捕获跟踪到本发明提供的导频信号。
本领域普通技术人员可以意识到,结合本文中所公开的实施例描述的各示例的单元及算法步骤,能够以电子硬件、计算机软件或者二者的结合来实现,为了清楚地说明硬件和软件的可互换性,在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行,取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能,但是这种实现不应认为超出本发明的范围。
在本申请所提供的几个实施例中,应该理解到,所揭露的***、装置和方法,可以通过其它的方式实现。例如,以上所描述的装置实施例仅仅是示意性的,例如,单元的划分,仅仅为一种逻辑功能划分,实际实现时可以有另外的划分方式,例如多个单元或组件可以结合或者可以集成到另一个***,或一些特征可以忽略,或不执行。另外, 所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口、装置或单元的间接耦合或通信连接,也可以是电的,机械的或其它的形式连接。
作为分离部件说明的单元可以是或者也可以不是物理上分开的,作为单元显示的部件可以是或者也可以不是物理单元,即可以位于一个地方,或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本发明实施例方案的目的。
另外,在本发明各个实施例中的各功能单元可以集成在一个处理单元中,也可以是各个单元单独物理存在,也可以是两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现,也可以采用软件功能单元的形式实现。
集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时,可以存储在一个计算机可读取存储介质中。基于这样的理解,本发明的技术方案本质上或者说对现有技术做出贡献的部分,或者该技术方案的全部或部分可以以软件产品的形式体现出来,该计算机软件产品存储在一个存储介质中,包括若干指令用以使得一台计算机设备(可以是个人计算机,服务器,或者网络设备等)执行本发明各个实施例方法的全部或部分步骤。而前述的存储介质包括:U盘、移动硬盘、只读存储器(ROM,Read-Only Memory)、随机存取存储器(RAM,Random Access Memory)、磁碟或者光盘等各种可以存储程序代码的介质。
以上,仅为本发明的具体实施方式,但本发明的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本发明揭露的技术范围内,可轻易想到各种等效的修改或替换,这些修改或替换都应涵盖在本发明的保护范围之内。因此,本发明的保护范围应以权利要求的保护范 围为准。

Claims (10)

  1. 一种卫星通信导航信号生成方法,包括:
    生成导频信号分量扩频码和数据信号分量扩频码;
    根据导频信号分量扩频码,调制生成导频分量扩频调制信号S pilot(t);
    根据数据信号分量扩频码,采用扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t),所述扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为:T s=k×T pilot,k>0;
    采用中心频率为f c、相位不相同的载波,将所述导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
  2. 如权利要求1所述的卫星通信导航信号生成方法,其特征在于,对于数据信号分量中长度为N的扩频码序列,T s=N×T c,数据信号分量采用的扩频码时移位置调制方法是:循环码移位键控调制方法。
  3. 如权利要求2所述的卫星通信导航信号生成方法,其特征在于,对于数据信号分量中长度为N的扩频码序列,循环移位可产生N个不同的扩频码时移序列集合,数据信号分量采用的扩频码时移位置调制方法是:在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
  4. 如权利要求1所述的卫星通信导航信号生成方法,其特征在于,数据信号分量采用的扩频码时移位置调制方法是:扩频码时间移 位位置调制;
    所述扩频码时间移位位置调制指的是:对于长度为N×T c的扩频码序列,位置码元时间区间T s>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间T s内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特的电文或数据信息。
  5. 一种卫星通信导航信号接收方法,接收如权利要求1-4中任一项所述的生成方法生成的信号,包括:
    生成导频信号分量和数据信号分量的扩频码本地复现码;
    通过天线接收射频调制信号S RF(t),利用中心频率为f c、相位相差90°的两个载波,将所述射频调制信号S RF(t)下变频到基带,得到接收基带信号;
    利用导频信号分量的扩频码本地复现码,对所述接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot确定每一码元数据信号分量的时移调制区间;
    利用数据信号分量的扩频码本地复现码,对所述接收基带信号进行相关运算,得到相关后的待检测信号序列;
    比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
  6. 一种卫星通信导航信号生成装置,包括:
    扩频码产生模块,用于生成导频信号分量扩频码和数据信号分量扩频码;
    导频信号分量调制模块,用于根据导频信号分量扩频码,生成导频分量扩频调制信号S pilot(t);
    扩频码时移位置调制模块,用于根据数据信号分量扩频码,采用 扩频码时移位置调制的方式对二进制的电文或数据信息进行调制,生成数据分量扩频调制信号S data(t),所述扩频码时移位置调制是指:根据预调制二进制的电文或数据信息的不同,数据分量扩频码序列在位置码元时间区间T s内进行移位,移位的最小时间间隔为1个扩频码码片周期T c,T s与导频信号分量的扩频码周期T pilot的对应关系为:T s=k×T pilot,k>0;
    上变频模块,用于生成中心频率为f c、相位不相同的载波,并将所述导频分量扩频调制信号S pilot(t)和数据分量扩频调制信号S data(t)调制到射频,得到两路射频分量信号,再将两路射频信号分量叠加,得到射频调制信号S RF(t)。
  7. 如权利要求6所述的卫星通信导航信号生成装置,其特征在于,所述扩频码时移位置调制模块为扩频码循环移位键控调制模块,对于数据信号分量中长度为N的扩频码序列,T s=N×T c,所述扩频码循环移位键控调制模块,采用循环码移位键控调制方法对二进制的电文或数据信息进行调制。
  8. 如权利要求7所述的卫星通信导航信号生成装置,其特征在于,对于数据信号分量中长度为N的扩频码序列,循环移位可产生N个不同的扩频码时移序列集合,所述扩频码循环移位键控调制模块,具体用于在N个扩频码时移序列集合中,选取K个扩频码时移序列集调制log 2K比特的电文或数据信息,K≤N。
  9. 如权利要求6所述的卫星通信导航信号生成装置,其特征在于,所述扩频码时移位置调制模块为扩频码时移位置调制模块,对于长度为N×T c的扩频码序列,位置码元时间区间T s>(N+1)×T c,根据预调制二进制的电文或数据信息的不同,扩频码序列在时间区间Ts内直接移位,共包含M=T s/T c-N+1个不同位置,调制log 2M比特 的电文或数据信息。
  10. 一种卫星通信导航信号接收装置,接收如权利要求6-9中任一项所述生成装置产生的信号,包括:
    扩频码本地复现码产生模块,用于生成导频信号分量和数据信号分量的扩频码本地复现码;
    下变频模块,生成本地载波信号,将通过天线接收到的射频调制信号S RF(t)下变频到基带,得到接收基带信号,所述本地载波信号包括中心频率为f c、相位相差90°的两个载波;
    导频信号捕获跟踪模块,用于利用导频信号分量的扩频码本地复现码,对所述接收基带信号进行捕获和跟踪,根据捕获跟踪的结果,提取导频信号的时钟信息,根据关系式T s=k×T pilot,确定每一码元数据信号分量的时移调制区间;
    扩频码时移位置解调模块,用于利用数据信号分量的扩频码本地复现码,对接收基带信号进行相关运算,得到相关后的待检测信号序列,在时移调制区间内比较待检测信号序列值,取最大值对应的时刻为位置检测时刻,根据调制过程中二进制数据与扩频码序列移位的映射关系,由位置检测时刻判决得到二进制的电文或数据信息。
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