CN110703279B - Satellite navigation signal generation method based on chip-level pulse time hopping - Google Patents

Abstract

Translated fromChinese

本发明涉及一种基于码片级脉冲跳时的卫星导航信号生成方法，包括基带扩频调制；信号伪码发生器生成信号伪码，进行码片赋形后，与编码后的电文调制在一起，得到基带扩频信号；码片跳时调制；跳频伪码发生器生成跳频伪码序列，控制码片选通脉冲发生器，生成码片选通脉冲，与所述基带扩频信号进行码片跳时调制，得到码片跳时信号；射频调制；载波发生器生成射频载波，与所述码片跳时信号进行射频调制，生成射频信号，经放大、滤波后，完成基于码片级脉冲跳时的卫星导航信号的生成，通过天线播发给用户。本发明实现抗干扰能力的提升，同时保持与现有卫星导航信号体制的兼容性，并支持基于载波相位测量的高精度应用。

The invention relates to a method for generating satellite navigation signals based on chip-level pulse time hopping, which includes baseband spread spectrum modulation; a signal pseudo-code generator generates a signal pseudo-code, which is modulated with the encoded message after chip shaping. , obtain baseband spread spectrum signal; chip time hopping modulation; frequency hopping pseudo code generator to generate frequency hopping pseudo code sequence, control chip gating pulse generator, generate chip gating pulse, and carry out with the baseband spread spectrum signal Chip time hopping modulation to obtain chip time hopping signal; radio frequency modulation; the carrier generator generates a radio frequency carrier, and performs radio frequency modulation with the chip time hopping signal to generate a radio frequency signal, which is amplified and filtered to complete the chip-level based signal. The generation of satellite navigation signals with pulse skipping is broadcast to users through the antenna. The invention realizes the improvement of anti-interference ability, maintains compatibility with the existing satellite navigation signal system, and supports high-precision applications based on carrier phase measurement.

Description

Satellite navigation signal generation method based on chip-level pulse time hopping

Technical Field

The invention belongs to the field of satellite navigation, and particularly relates to a satellite navigation signal generation method based on chip-level pulse time hopping.

Background

Current satellite navigation signals are susceptible to interference and shadowing, primarily because the average transmit power of the signal is limited because the navigation satellite is a power limited system. The satellite navigation signal mainly adopts a continuous broadcast signal modulated by direct sequence spread spectrum, and the ground level of the satellite navigation signal is low, generally about-160 dBW. Moreover, the frequency and modulation mode of the satellite navigation signal are public, and are particularly easily affected by matching spectrum interference.

In order to improve the anti-interference capability of signals, the most effective and direct method is to increase the transmission power of the signals, and therefore, in the process of GPS modernization, a spot beam power enhancement mode is designed for M code signals, and the power of an area can be enhanced by more than 20 dB. The other method is to adopt an anti-interference signal system, such as a direct sequence spread spectrum frequency hopping signal or a direct sequence spread spectrum time hopping signal, and to improve the anti-interference capability by separating the anti-interference signal from the interference signal in a time domain or a frequency domain.

In the aspect of anti-interference signal system, the radio navigation system of spread spectrum and frequency hopping system (patent number: CN 200910072086.8) provides a radio navigation system of hopping spread spectrum system, the navigation message is directly spread spectrum modulated and frequency hopping modulated in the spread spectrum and frequency hopping modulation module, and then is transmitted from the antenna through the high pass filter and the power amplifier. The patent "a burst navigation signal system and receiving method" (patent number: CN 201019114075.1) relates to a burst satellite navigation beacon broadcasted by a direct-transmitting satellite navigation system or a repeater satellite navigation system satellite, or a gap satellite navigation signal. The patent "a navigation signal generation method of time division system" (patent number: CN 201810245853.X) discloses a navigation signal generation method of time division system, which realizes two-way transmission between satellites by way of time division multiplexing and improves the utilization rate of frequency band. The document 'navigation satellite anti-interference technology based on mixed spread spectrum' combines the DS/TH mixed spread spectrum technology with the existing navigation satellite, after the navigation signal is subjected to DS code spread spectrum, each code piece after direct spread is divided into a plurality of time slots, and the time slots are selected according to a time hopping sequence to transmit the navigation signal.

It can be seen that the above patent adopts a hybrid spread spectrum scheme including direct sequence spread spectrum (DS/FH) and direct sequence spread spectrum (DS/TH) signals in order to improve the interference resistance of the navigation signals. The center frequency of the direct spread spectrum frequency hopping signal jumps along with time, the frequency hopping code controls the frequency at which the signal is broadcast, and the frequency and the interference signal are separated, so that the anti-interference capability is improved. However, the direct sequence spread spectrum frequency hopping has two disadvantages, firstly, the frequency hopping system signal is incompatible with the existing satellite navigation signal, and secondly, the high-precision measurement of the carrier phase of the frequency modulation signal has certain problems. The traditional direct sequence spread time hopping signal is incompatible with the current satellite navigation signal and can not be directly received by the existing receiving method. When a chip is divided into a plurality of time slots, the power spectrum of the signal is changed, and the bandwidth of the signal is increased.

Disclosure of Invention

The invention aims to: the method overcomes the defects of the prior art, and provides a chip-level pulse time hopping-based satellite navigation signal generation method under the conditions that the power of a satellite platform is limited and the average power of a transmitted signal is given, so that the improvement of the anti-interference capability is realized, the compatibility with the conventional satellite navigation signal system is kept, and the high-precision application based on carrier phase measurement is supported.

The technical solution of the invention is as follows:

a satellite navigation signal generation method based on chip-level pulse time hopping comprises the following steps:

(1) baseband spread spectrum modulation; a signal pseudo code generator generates a signal pseudo code, and after chip shaping, the signal pseudo code and the coded text are modulated together to obtain a baseband spread spectrum signal;

(2) chip time hopping modulation; the frequency hopping pseudo code generator generates a frequency hopping pseudo code sequence, controls the chip gating pulse generator to generate chip gating pulses, and performs chip time hopping modulation with the baseband spread spectrum signal to obtain a chip time hopping signal;

(3) radio frequency modulation; and the carrier wave generator generates a radio frequency carrier wave, performs radio frequency modulation on the radio frequency carrier wave and the chip time hopping signal to generate a radio frequency signal, completes generation of a satellite navigation signal based on chip-level pulse time hopping after amplification and filtering, and broadcasts the satellite navigation signal to a user through an antenna.

Further, the baseband spread spectrum modulation is specifically obtained by the following method:

(1.1) generating a signal pseudo code; pseudo code sequence generated by signal pseudo code generatorColumn is { c_l}，c_l∈{1,-1}，l＝0,1,2,…；

(1.2) shaping a chip waveform; carrying out chip waveform shaping on the pseudo code sequence to obtain a pseudo code waveform:

in the formula (I), the compound is shown in the specification,

is a chip waveform, T_c＝1/R_cIs chip width, R_cIs the code rate, t is the time variable;

(1.3) baseband spread spectrum modulation; modulating the text d (t) and the pseudo code waveform C (t) to obtain a baseband spread spectrum modulation signal s_b(t) ═ d (t) · c (t), text d (t) ∈ {1, -1 }.

Further, the step (1.2) performs chip waveform shaping on the pseudo code sequence, specifically:

in the satellite navigation signal, a rectangular chip waveform or a binary offset carrier waveform is adopted;

for a rectangular chip waveform, there are:

the binary offset carrier waveform is a sinusoidal BOC chip waveform, for which

In the formula (f)_sSubcarrier frequency modulated for BOC, 2f_s/R_cAre integers.

Further, the chip time hopping modulation in step (2) specifically includes:

(2.1) spread spectrum modulating signal s of base band_b(T) in time domain by chip width T_cThe grouping is carried out in such a way that,dividing every N chips into a group, and marking as 0,1,2, …, N-1, wherein only one chip in every N chips is gated, and the power of the N chips is concentrated on one chip; wherein N is an integer greater than 1 and represents the number of chips contained in each packet;

(2.2) the time hopping pseudo code generator generates a time hopping pseudo code sequence c_TH,lMapped by time hopping pseudo code sequence, corresponding to every NT_cTime, in the ith chip packet, a number L belonging to {0,1,2, …, N-1} is output_iControlling the chip strobe generator to generate the chip strobe p_pulse(t)；

(2.3) at time T ∈ [ i.N.T ]_c,(i+1)·N·T_c) The pseudo-random number generated by the time-hopping pseudo-code generator is L_i(ii) a Where i denotes the ith packet, the chip strobe p generated by the chip strobe generator_pulse(t) is:

(2.4) spreading the baseband spread Signal s_b(t) and chip strobe p_pulse(t) multiplying to realize chip time-hopping modulation to obtain a chip time-hopping signal s_TH(t)：

s_TH(t)＝s_b(t)·p_pulse(t)。

Further, the time hopping pseudo code sequence mapping in step (2.2) is implemented by the following method:

(2.2.1) time hopping pseudo code sequence { cTH, l }, cTH_,lE {1,0}, l ═ 0,1,2, …, and is converted from serial to parallel

The way of the road is that the road is,

meaning rounding up, i.e. mapping an integer L every M chips_iThe ith group has corresponding M binary code sequences of { c }_1,i}、{c_2,i}、…、{c_M,i}。

(2.2.2) the decoder translates the M binary chip values corresponding to the ith packet to a value belonging to {0,1,2, …,2 }^MDecimal number of-1 }, i.e.

(2.2.3) adding L_M,iModulo N to obtain the number L belonging to {0,1,2, …, N-1}_iI.e. L_i＝L_M,i mod N。

Further, the radio frequency modulation in the step (3) is realized by the following method:

(3.1) the carrier generator generates a radio frequency carrier cos (2 π f)_RFt)；f_RFIs the radio frequency carrier frequency, t is the time variable;

(3.2) chip time-hopping signal s_TH(t) multiplied by the radio frequency carrier, having s_TH,RF(t)＝s_TH(t)·cos(2πf_RFt)；

s_TH,RFAnd (t) after being amplified by the pulse amplifier and filtered by the filter, the signal is broadcasted to the user through the antenna.

Further, the present invention also provides a satellite navigation signal generating system, including:

a baseband spread spectrum modulation module: generating a signal pseudo code by a signal pseudo code generator, carrying out chip shaping, and modulating the signal pseudo code and a coded text together to obtain a baseband spread spectrum signal;

chip time hopping modulation module: generating a frequency hopping pseudo code sequence through a frequency hopping pseudo code generator, controlling a chip gating pulse generator to generate a chip gating pulse, and performing chip time hopping modulation on the chip gating pulse and a baseband spread spectrum signal generated by a baseband spread spectrum modulation module to obtain a chip time hopping signal;

the radio frequency modulation module: and generating a radio frequency carrier wave by a carrier wave generator, carrying out radio frequency modulation on the radio frequency carrier wave and the chip time hopping signal to generate a radio frequency signal, amplifying and filtering the radio frequency signal to finish the generation of the satellite navigation signal based on the chip-level pulse time hopping, and broadcasting the satellite navigation signal to a user through an antenna.

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

the invention discloses a satellite navigation signal based on chip-level pulse time hopping and a generation method thereof, which realize the improvement of the anti-interference capability on the premise of certain average transmitting power, compared with the prior method, the method disclosed by the invention has the following advantages:

(1) the current anti-interference navigation signal system usually adopts a mixed spread spectrum mode and is incompatible with the current satellite navigation signal receiving mode; the satellite navigation signal based on chip-level pulse time hopping provided by the invention is completely compatible with the existing satellite navigation signal system, and can be received by using the existing receiving method.

(2) In the existing direct sequence spread time hopping signal system, a chip is divided into a plurality of time slots, and through time slot hopping, a signal is only broadcast in one time slot each time, so that the power spectrum of the signal is changed, and the bandwidth of the signal is increased. The invention adopts the mode of chip gating pulse to change the position of gating one chip in each group of N chips, thereby realizing the effect of equivalent chip time hopping without changing the frequency spectrum of signals.

(3) The invention realizes the conversion of continuous signals with low average power into random pulse position quasi-continuous signals with high instantaneous power when realizing chip-level pulse skipping at the chip level. Specifically, the power of N chips is concentrated on one chip, and the carrier phase is continuous for one code period processing, so that high-precision application based on carrier phase measurement can be supported. For users with time-hopping code sequences, the anti-interference capability can be improved by 10lg (N) dB. The improvement of the anti-interference capability can be flexibly adjusted by changing the value of N.

Drawings

FIG. 1 is a schematic diagram of a satellite navigation signal based on chip-level pulse time hopping according to the present disclosure;

FIG. 2 is a pseudo code sequence mapping method for time hopping

FIG. 3 is a diagram of chip-level pulse time-hopping signal generation

FIG. 4 shows the baseband waveform of a chip-hopping signal

FIG. 5 is a power spectrum of a chip-hopping signal

Fig. 6 is a correlation function of a chip-hopping signal.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

The average power of the transmitted signal is constant, in order to improve the anti-interference capability of the signal, the invention adopts a chip-level pulse time hopping scheme, namely, a spread spectrum code sequence is grouped according to chips, each group of N chips has only one chip to gate, the position of the gated chip is determined by a gating pulse, and the gating pulse can be generated by a time hopping code and is pseudo-random. In the scheme of the invention, the power of N original chips is concentrated on one chip, and for a user without a time hopping code, a traditional navigation signal receiving and processing method can be adopted, so that the invention is compatible with the existing satellite navigation signal; for the users with the time hopping codes, after matched receiving can be carried out, the signal power is improved by N times, and the anti-interference capability is improved by 10lg (N) dB.

In order to achieve the above object, the present invention discloses a method for generating a satellite navigation signal based on chip-level pulse time hopping, and the specific flow is shown in fig. 1.

Step 1, base band spread spectrum modulation. The signal pseudo code generator generates a signal pseudo code, carries out chip shaping and then modulates the signal pseudo code and the coded text together to obtain a baseband spread spectrum signal. The message d (t) is epsilon {1, -1}, t is a time variable, and the message symbol rate is R_sSymbol width of T_s＝1/R_s(ii) a Code rate of R_cChip width of T_c＝1/R_c。

The baseband spread spectrum modulation is obtained by the following method:

1) and generating a signal pseudo code. The pseudo code sequence generated by the signal pseudo code generator is { c_lThe l-th chip c_l∈{1,-1}，l＝0,1,2,…；

2) And shaping a chip waveform. Carrying out chip waveform shaping on the code sequence to obtain a pseudo code waveform:

in the formula (I), the compound is shown in the specification,

for the chip waveform, in the satellite navigation signal, a rectangular chip waveform or a Binary Offset Carrier (BOC) waveform may be used. For a rectangular chip waveform, there are:

for a sinusoidal BOC chip waveform, there are

In the formula (f)_sSubcarrier frequency modulated for BOC, 2f_s/R_cAre integers.

3) And (4) baseband spread spectrum modulation. Modulating the text d (t) and the pseudo code waveform C (t) to obtain a baseband spread spectrum modulation signal s_b(t)：

s_b(t)＝d(t)·C(t)

Andstep 2, chip time hopping modulation. The frequency hopping pseudo code generator generates a frequency hopping pseudo code sequence, controls the chip gating pulse generator to generate chip gating pulses, and performs chip time hopping modulation with the baseband spread spectrum signal to obtain a chip time hopping signal.

The chip time hopping modulation is obtained by the following method:

(1) will s_b(T) in time domain by chip width T_cGrouping is carried out, N chips are divided into a group, which is marked as 0,1,2, … and N-1, only one chip in every N chips is gated, and the power of the N chips is concentrated on one chip, wherein N is an integer greater than 1 and represents the number of chips contained in each group.

(2) The time-hopping pseudo-code generator generates a time-hopping pseudo-code sequence c_TH,lMapped by time hopping pseudo code sequence, corresponding to every NT_cTime, in the ith chip packet, output one belongs to{0,1,2, …, N-1} number L_iControlling the chip strobe generator to generate the chip strobe p_pulse(t)。

The time hopping pseudo code sequence mapping can be obtained by the following method:

(2.1) time hopping pseudo code sequence { c_TH,l}，c_TH,lE {1,0}, l ═ 0,1,2, …, and is converted from serial to parallel

The way of the road is that the road is,

meaning rounding up, i.e. mapping an integer L every M chips_i. In the ith group, the corresponding M-path binary code sequence is { c_1,i}、{c_2,i}、…、{c_M,i}，

(2.2) the decoder translates the M binary chip values corresponding to the ith packet to a value belonging to {0,1,2, …,2 }^MDecimal number of-1 }, i.e.

(2.3) mixing L_M,iModulo N to obtain the number L belonging to {0,1,2, …, N-1}_iI.e. by

L_i＝L_M,i mod N

(3) At time T ∈ [ i.N.T_c,(i+1)·N·T_c) The pseudo-random number generated by the time-hopping pseudo-code generator is L_i. i denotes the ith packet, the chip strobe p generated by the chip strobe generator_pulse(t) is:

(4) spreading the baseband signal s_b(t) and chip strobe p_pulse(t) multiplying to realize chip time-hopping modulation to obtain a chip time-hopping signal s_TH(t)：

s_TH(t)＝s_b(t)·p_pulse(t)

And 3, modulating the radio frequency. The carrier wave generator generates a radio frequency carrier wave, performs radio frequency modulation with the chip time hopping signal to generate a radio frequency signal, and broadcasts the radio frequency signal to a user after amplification, filtering and antenna.

The radio frequency modulation can be obtained by the following method:

(1) carrier generator for generating radio frequency carrier cos (2 pi f)_RFt)；

(2) Chip time hopping signal s_TH(t) multiplied by the radio frequency carrier, having s_TH,RF(t)＝s_TH(t)·cos(2πf_RFt)；s_TH,RFAnd (t) after pulse amplifier amplification, filter filtering and antenna broadcasting to users.

The embodiment of the invention is as follows:

the operation steps of the satellite navigation signal based on chip-level pulse time hopping and the generation method disclosed by the invention are shown in fig. 1, and specifically are as follows:

(1) and (4) baseband spread spectrum modulation. The signal pseudo code generator generates a signal pseudo code, carries out chip shaping and then modulates the signal pseudo code and the coded text together to obtain a baseband spread spectrum signal. Message d (t) e {1, -1}, symbol rate R_s100sps, symbol width T_s＝10ms；

The pseudo code sequence generated by the signal pseudo code generator is { c_l}，c_lE {1, -1}, l ═ 0,1,2, …; code rate of R_c10.23Mcps, chip width T_c＝1/R_c。

Carrying out rectangular chip waveform shaping on the code sequence to obtain a pseudo code waveform:

in the formula (I), the compound is shown in the specification,

for a rectangular chip waveform, there are:

modulating the text d (t) and the pseudo code waveform C (t) to obtain a baseband spread spectrum modulation signal s_b(t)：

s_b(t)＝d(t)·C(t)

(2) Chip hopping modulation. The frequency hopping pseudo code generator generates a frequency hopping pseudo code sequence, controls the chip gating pulse generator to generate chip gating pulses, and performs chip time hopping modulation with the baseband spread spectrum signal to obtain a chip time hopping signal.

Will s_b(T) in time domain by chip width T_cGrouping is carried out, every N-16 chips are divided into a group, which is marked as 0,1,2, … and 15, only one chip in every N-16 chips is gated, and the power of N chips is concentrated on one chip.

The time-hopping pseudo-code generator generates a time-hopping pseudo-code sequence c_TH,lMapped by time hopping pseudo code sequence, corresponding to every NT_cTime, in the ith packet, a number L belonging to {0,1,2, …,15} is output_iControlling the chip strobe generator to generate the chip strobe p_pulse(t) of (d). Fig. 2 shows a schematic diagram of a time hopping pseudo code sequence mapping method.

At time T ∈ [ i.N.T_c,(i+1)·N·T_c) The pseudo-random number generated by the time-hopping pseudo-code generator is L_i. Chip strobe p generated by a chip strobe generator_pulse(t) is:

spreading the baseband signal s_b(t) and chip strobe p_pulse(t) multiplying to realize chip time-hopping modulation to obtain a chip time-hopping signal s_TH(t)：

s_TH(t)＝s_b(t)·p_pulse(t)

Base band spread spectrum signal s_b(t), time hopping pseudo code sequence { c_TH,l}、Chip strobe p_pulse(t) and chip time hopping signal s_THThe time domain diagram of (t) is shown in fig. 3. Chip time hopping signal s_THThe baseband waveform of (t) is shown in fig. 4, and the power spectrum is shown in fig. 5.

(3) And (4) radio frequency modulation. The carrier wave generator generates a radio frequency carrier wave, performs radio frequency modulation with the chip time hopping signal to generate a radio frequency signal, and broadcasts the radio frequency signal to a user after amplification, filtering and antenna.

For users with time hopping codes, matched reception can be performed, and the anti-interference capability is improved, for users without time hopping codes, non-matched reception can be performed by adopting a traditional receiving method, and a correlation function of the matched reception and the non-matched reception is shown in fig. 6.

The invention adopts the mode of chip gating pulse to change the position of gating one chip in each group of N chips, thereby realizing the effect of equivalent chip time hopping without changing the frequency spectrum of signals.

The invention realizes the conversion of continuous signals with low average power into random pulse position quasi-continuous signals with high instantaneous power when realizing chip-level pulse skipping at the chip level. Specifically, the power of N chips is concentrated on one chip, and the carrier phase is continuous for one code period processing, so that high-precision application based on carrier phase measurement can be supported. For users with time-hopping code sequences, the anti-interference capability can be improved by 10lg (N) dB. The improvement of the anti-interference capability can be flexibly adjusted by changing the value of N.

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

Claims (8)

Translated fromChinese

1.一种基于码片级脉冲跳时的卫星导航信号生成方法，其特征在于步骤如下：1. a method for generating satellite navigation signals based on chip-level pulse skipping time, is characterized in that the steps are as follows:(1)基带扩频调制；信号伪码发生器生成信号伪码，进行码片赋形后，与编码后的电文调制在一起，得到基带扩频信号；(1) Baseband spread spectrum modulation; the signal pseudo code generator generates a signal pseudo code, which is modulated with the encoded message after chip shaping to obtain a baseband spread spectrum signal;(2)码片跳时调制；跳频伪码发生器生成跳频伪码序列，控制码片选通脉冲发生器，生成码片选通脉冲，与所述基带扩频信号进行码片跳时调制，得到码片跳时信号；(2) Chip time hopping modulation; the frequency hopping pseudo code generator generates a frequency hopping pseudo code sequence, controls the chip gating pulse generator, generates a chip gating pulse, and performs chip time hopping with the baseband spread spectrum signal. Modulation to obtain a chip time-hopping signal;步骤(2)码片跳时调制，具体为：Step (2) Chip time-hopping modulation, specifically:(2.1)将基带扩频调制信号s_b(t)在时域上按照码片宽度T_c进行分组，每N个码片分为一组，记为0,1,2,…,N-1个，每N个码片中只有一个码片被选通，N个码片的功率集中在一个码片上；其中N为大于1的整数，表示每个分组包含的码片个数；(2.1) Group the baseband spread spectrum modulated signal s_b (t) according to the chip width T_c in the time domain, and divide every N chips into a group, denoted as 0, 1, 2,...,N-1 , only one chip in every N chips is gated, and the power of N chips is concentrated on one chip; where N is an integer greater than 1, indicating the number of chips included in each group;(2.2)跳时伪码发生器生成一个跳时伪码序列{c_TH,l}，通过跳时伪码序列映射，对应于每隔NT_c时间，在第i个码片分组，输出一个属于{0,1,2,…,N-1}的数L_i，控制码片选通脉冲发生器生成码片选通脉冲p_pulse(t)；(2.2) The time-hopping pseudo-code generator generates a time-hopping pseudo-code sequence {c_{TH, l} }, through the time-hopping pseudo-code sequence mapping, corresponding to every NT_c time, in the i-th chip grouping, output a The number Li of {0,1,2,...,N-1_} controls the chip strobe pulse generator to generate the chip strobe pulse p_pulse (t);(2.3)在时间t∈[i·N·T_c,(i+1)·N·T_c)，跳时伪码发生器生成的伪随机数为L_i；其中i表示第i个分组，码片选通脉冲发生器生成的码片选通脉冲p_pulse(t)为：(2.3) At time t∈[i·N·T_c ,(i+1)·N·T_c ), the pseudo-random number generated by the time-hopping pseudo-code generator is Li ; where_i represents the ith packet, The chip strobe pulse p_pulse (t) generated by the chip strobe pulse generator is:

(2.4)将基带扩频信号s_b(t)与码片选通脉冲p_pulse(t)相乘，实现码片跳时调制，得到码片跳时信号s_TH(t)：(2.4) Multiply the baseband spread spectrum signal s_b (t) by the chip strobe pulse p_pulse (t) to realize chip time-hopping modulation, and obtain the chip time-hopping signal s_TH (t):s_TH(t)＝s_b(t)·p_pulse(t)；s_TH (t)=s_b (t)·p_pulse (t);(3)射频调制；载波发生器生成射频载波，与所述码片跳时信号进行射频调制，生成射频信号，经放大、滤波后，完成基于码片级脉冲跳时的卫星导航信号的生成，通过天线播发给用户。(3) Radio frequency modulation; the carrier generator generates a radio frequency carrier, performs radio frequency modulation with the chip time hopping signal, generates a radio frequency signal, and after amplifying and filtering, completes the generation of a satellite navigation signal based on chip-level pulse time hopping, broadcast to users through the antenna.2.根据权利要求1所述的一种基于码片级脉冲跳时的卫星导航信号生成方法，其特征在于：所述的基带扩频调制，具体通过以下方法得到：2. a kind of satellite navigation signal generation method based on chip-level pulse hopping according to claim 1, is characterized in that: described baseband spread spectrum modulation is specifically obtained by the following method:(1.1)信号伪码生成；信号伪码发生器生成的伪码序列为{c_l}，c_l∈{1,-1}，l＝0,1,2,…；(1.1) Signal pseudo-code generation; the pseudo-code sequence generated by the signal pseudo-code generator is {c_l }, c_l ∈ {1,-1}, l=0,1,2,...;(1.2)码片波形赋形；对伪码序列进行码片波形赋形，得到伪码波形：(1.2) Chip waveform shaping; perform chip waveform shaping on the pseudo-code sequence to obtain pseudo-code waveform:

式中，

为码片波形，T_c＝1/R_c为码片宽度，R_c为码速率，t为时间变量；In the formula,

is the chip waveform, T_c =1/R_c is the chip width, R_c is the code rate, and t is the time variable;(1.3)基带扩频调制；将电文d(t)与伪码波形C(t)进行调制，得到基带扩频调制信号s_b(t)＝d(t)·C(t)，电文d(t)∈{1,-1}。(1.3) Baseband spread spectrum modulation; modulate the message d(t) and the pseudo code waveform C(t) to obtain the baseband spread spectrum modulation signal s_b (t)=d(t) C(t), the message d( t)∈{1,-1}.3.根据权利要求2所述的一种基于码片级脉冲跳时的卫星导航信号生成方法，其特征在于：所述步骤(1.2)对伪码序列进行码片波形赋形，具体为：3. a kind of satellite navigation signal generation method based on chip-level pulse skipping time according to claim 2, is characterized in that: described step (1.2) carries out chip waveform shaping to pseudo-code sequence, is specifically:在卫星导航信号中，采用矩形码片波形或者二进制偏移载波波形；In satellite navigation signals, rectangular chip waveforms or binary offset carrier waveforms are used;对于矩形码片波形，有：For rectangular chip waveforms, there are:

二进制偏移载波波形即为正弦BOC码片波形，对于正弦BOC码片波形，有The binary offset carrier waveform is the sinusoidal BOC chip waveform. For the sinusoidal BOC chip waveform, there are

式中，f_s为BOC调制的子载波频率，2f_s/R_c为整数。In the formula, f_s is the sub-carrier frequency of BOC modulation, and 2f_s /R_c is an integer.4.根据权利要求1所述的一种基于码片级脉冲跳时的卫星导航信号生成方法，其特征在于：步骤(2.2)中所述跳时伪码序列映射，通过以下方法实现：4. a kind of satellite navigation signal generation method based on chip-level pulse hopping according to claim 1, is characterized in that: described in step (2.2), the time hopping pseudo-code sequence mapping is realized by the following method:(2.2.1)将跳时伪码序列{c_TH,l}，c_TH,l∈{1,0}，l＝0,1,2,…，进行串并转换为

路，

表示向上取整，即每M个码片映射出一个整数L_i，第i个分组，对应的M路二进制码序列为{c_1,i}、{c_2,i}、…、{c_M,i}；(2.2.1) Convert the time-hopping pseudocode sequence {c_{TH, l} }, c_{TH, l} ∈ {1, 0}, l = 0, 1, 2, ... to serial-parallel conversion into

road,

Represents rounding up, that is, an integer L_i is mapped to every M chips, the i-th packet, the corresponding M binary code sequences are {c_1,i }, {c_2,i },...,{c_{M , i} };(2.2.2)译码器将第i个分组对应的M个二进制码片值译为一个属于{0,1,2,…,2^M-1}的十进制数，即(2.2.2) The decoder decodes the M binary chip values corresponding to the i-th packet into a decimal number belonging to {0, 1, 2, ..., 2^M -1}, that is,

(2.2.3)将L_M,i对N进行求模，得到属于{0,1,2,…,N-1}的数L_i，即(2.2.3) Take L_M,i modulo N to obtain the number L_i belonging to {0,1,2,...,N-1}, namelyL_i＝L_M,i mod N。Li =L_M,imod N.5.根据权利要求1所述的一种基于码片级脉冲跳时的卫星导航信号生成方法，其特征在于：步骤(3)射频调制，通过以下方法实现：5. a kind of satellite navigation signal generation method based on chip-level pulse hopping according to claim 1, is characterized in that: step (3) radio frequency modulation is realized by the following method:(3.1)载波发生器生成射频载波cos(2πf_RFt)；f_RF是射频载波频率，t是时间变量；(3.1) The carrier generator generates the RF carrier cos(2πf_RF t); f_RF is the RF carrier frequency, and t is the time variable;(3.2)码片跳时信号s_TH(t)与射频载波相乘，有s_TH,RF(t)＝s_TH(t)·cos(2πf_RFt)；(3.2) The chip time-hopping signal s_TH (t) is multiplied by the radio frequency carrier, there is s_{TH, RF} (t)=s_TH (t)·cos(2πf_RF t);s_TH,RF(t)经脉冲放大器放大、滤波器滤波后，通过天线播发给用户。s_TH,RF (t) is amplified by the pulse amplifier and filtered by the filter, and then broadcast to the user through the antenna.6.一种根据权利要求1所述的卫星导航信号生成方法实现的基于码片级脉冲跳时的卫星导航信号生成系统，其特征在于包括：6. A satellite navigation signal generation system based on chip-level pulse skipping realized by the satellite navigation signal generation method according to claim 1, it is characterized in that comprising:基带扩频调制模块：通过信号伪码发生器生成信号伪码，进行码片赋形后，与编码后的电文调制在一起，得到基带扩频信号；Baseband spread spectrum modulation module: generate signal pseudo code by signal pseudo code generator, after chip shaping, modulate together with the encoded message to obtain baseband spread spectrum signal;码片跳时调制模块：通过跳频伪码发生器生成跳频伪码序列，控制码片选通脉冲发生器，生成码片选通脉冲，与基带扩频调制模块生成的基带扩频信号进行码片跳时调制，得到码片跳时信号；Chip time-hopping modulation module: generate a frequency-hopping pseudo-code sequence through a frequency-hopping pseudo-code generator, control the chip-gating pulse generator, generate a chip-gating pulse, and conduct the baseband spread-spectrum signal generated by the baseband spread-spectrum modulation module. Chip time hopping modulation to obtain chip time hopping signal;射频调制模块：通过载波发生器生成射频载波，与所述码片跳时信号进行射频调制，生成射频信号，经放大、滤波后，完成基于码片级脉冲跳时的卫星导航信号的生成，通过天线播发给用户；RF modulation module: generate a radio frequency carrier through a carrier generator, perform radio frequency modulation with the chip time-hopping signal, and generate a radio frequency signal. After amplification and filtering, the generation of a satellite navigation signal based on chip-level pulse time-hopping is completed. The antenna broadcasts to the user;码片跳时调制，具体为：Chip time-hopping modulation, specifically:(2.1)将基带扩频调制信号s_b(t)在时域上按照码片宽度T_c进行分组，每N个码片分为一组，记为0,1,2,…,N-1个，每N个码片中只有一个码片被选通，N个码片的功率集中在一个码片上；其中N为大于1的整数，表示每个分组包含的码片个数；(2.1) Group the baseband spread spectrum modulated signal s_b (t) according to the chip width T_c in the time domain, and divide every N chips into a group, denoted as 0, 1, 2,...,N-1 , only one chip in every N chips is gated, and the power of N chips is concentrated on one chip; where N is an integer greater than 1, indicating the number of chips included in each group;(2.2)跳时伪码发生器生成一个跳时伪码序列{c_TH,l}，通过跳时伪码序列映射，对应于每隔NT_c时间，在第i个码片分组，输出一个属于{0,1,2,…,N-1}的数L_i，控制码片选通脉冲发生器生成码片选通脉冲p_pulse(t)；(2.2) The time-hopping pseudo-code generator generates a time-hopping pseudo-code sequence {c_{TH, l} }, through the time-hopping pseudo-code sequence mapping, corresponding to every NT_c time, in the i-th chip grouping, output a The number Li of {0,1,2,...,N-1_} controls the chip strobe pulse generator to generate the chip strobe pulse p_pulse (t);跳时伪码序列映射，通过以下方法实现：The time-hopping pseudo-code sequence mapping is implemented by the following methods:(2.2.1)将跳时伪码序列{c_TH,l}，c_TH,l∈{1,0}，l＝0,1,2,…，进行串并转换为

路，

表示向上取整，即每M个码片映射出一个整数L_i，第i个分组，对应的M路二进制码序列为{c_1,i}、{c_2,i}、…、{c_M,i}；(2.2.1) Convert the time-hopping pseudocode sequence {c_{TH, l} }, c_{TH, l} ∈ {1, 0}, l = 0, 1, 2, ... to serial-parallel conversion into

road,

Represents rounding up, that is, an integer L_i is mapped to every M chips, the i-th packet, the corresponding M binary code sequences are {c_1,i }, {c_2,i },...,{c_{M , i} };(2.2.2)译码器将第i个分组对应的M个二进制码片值译为一个属于{0,1,2,…,2^M-1}的十进制数，即(2.2.2) The decoder decodes the M binary chip values corresponding to the i-th packet into a decimal number belonging to {0, 1, 2, ..., 2^M -1}, that is,

(2.2.3)将L_M,i对N进行求模，得到属于{0,1,2,…,N-1}的数L_i，即(2.2.3) Take L_M,i modulo N to obtain the number L_i belonging to {0,1,2,...,N-1}, namelyL_i＝L_M,i mod N；L_i =L_M,i mod N;(2.3)在时间t∈[i·N·T_c,(i+1)·N·T_c)，跳时伪码发生器生成的伪随机数为L_i；其中i表示第i个分组，码片选通脉冲发生器生成的码片选通脉冲p_pulse(t)为：(2.3) At time t∈[i·N·T_c ,(i+1)·N·T_c ), the pseudo-random number generated by the time-hopping pseudo-code generator is Li ; where_i represents the ith packet, The chip strobe pulse p_pulse (t) generated by the chip strobe pulse generator is:

(2.4)将基带扩频信号s_b(t)与码片选通脉冲p_pulse(t)相乘，实现码片跳时调制，得到码片跳时信号s_TH(t)：(2.4) Multiply the baseband spread spectrum signal s_b (t) by the chip strobe pulse p_pulse (t) to realize chip time-hopping modulation, and obtain the chip time-hopping signal s_TH (t):s_TH(t)＝s_b(t)·p_pulse(t)。s_TH (t)=s_b (t)·p_pulse (t).7.根据权利要求6所述的基于码片级脉冲跳时的卫星导航信号生成系统，其特征在于：所述的基带扩频调制，具体通过以下方法得到：7. The satellite navigation signal generation system based on chip-level pulse time hopping according to claim 6, is characterized in that: described baseband spread spectrum modulation is specifically obtained by the following method:(1.1)信号伪码生成；信号伪码发生器生成的伪码序列为{c_l}，c_l∈{1,-1}，l＝0,1,2,…；(1.1) Signal pseudo-code generation; the pseudo-code sequence generated by the signal pseudo-code generator is {c_l }, c_l ∈ {1,-1}, l=0,1,2,...;(1.2)码片波形赋形；对伪码序列进行码片波形赋形，得到伪码波形：(1.2) Chip waveform shaping; perform chip waveform shaping on the pseudo-code sequence to obtain pseudo-code waveform:

式中，

为码片波形，T_c＝1/R_c为码片宽度，R_c为码速率，t为时间变量；In the formula,

is the chip waveform, T_c =1/R_c is the chip width, R_c is the code rate, and t is the time variable;在卫星导航信号中，采用矩形码片波形或者二进制偏移载波波形；In satellite navigation signals, rectangular chip waveforms or binary offset carrier waveforms are used;对于矩形码片波形，有：For rectangular chip waveforms, there are:

二进制偏移载波波形即为正弦BOC码片波形，对于正弦BOC码片波形，有The binary offset carrier waveform is the sinusoidal BOC chip waveform. For the sinusoidal BOC chip waveform, there are

式中，f_s为BOC调制的子载波频率，2f_s/R_c为整数；In the formula, f_s is the sub-carrier frequency of BOC modulation, and 2f_s /R_c is an integer;(1.3)基带扩频调制；将电文d(t)与伪码波形C(t)进行调制，得到基带扩频调制信号s_b(t)＝d(t)·C(t)，电文d(t)∈{1,-1}。(1.3) Baseband spread spectrum modulation; modulate the message d(t) and the pseudo code waveform C(t) to obtain the baseband spread spectrum modulation signal s_b (t)=d(t)·C(t), the message d( t)∈{1,-1}.8.根据权利要求6所述的基于码片级脉冲跳时的卫星导航信号生成系统，其特征在于：射频调制，通过以下方法实现：8. The satellite navigation signal generation system based on chip-level pulse hopping according to claim 6, is characterized in that: radio frequency modulation is realized by the following method:(3.1)载波发生器生成射频载波cos(2πf_RFt)；f_RF是射频载波频率，t是时间变量；(3.1) The carrier generator generates the RF carrier cos(2πf_RF t); f_RF is the RF carrier frequency, and t is the time variable;(3.2)码片跳时信号s_TH(t)与射频载波相乘，有s_TH,RF(t)＝s_TH(t)·cos(2πf_RFt)；(3.2) The chip time-hopping signal s_TH (t) is multiplied by the radio frequency carrier, there is s_{TH, RF} (t)=s_TH (t)·cos(2πf_RF t);s_TH,RF(t)经脉冲放大器放大、滤波器滤波后，通过天线播发给用户。s_TH,RF (t) is amplified by the pulse amplifier and filtered by the filter, and then broadcast to the user through the antenna.

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