CN113406677B - Navigation signal broadcasting method and device and navigation signal receiving method - Google Patents

Navigation signal broadcasting method and device and navigation signal receiving method Download PDF

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Publication number
CN113406677B
CN113406677B CN202110579588.0A CN202110579588A CN113406677B CN 113406677 B CN113406677 B CN 113406677B CN 202110579588 A CN202110579588 A CN 202110579588A CN 113406677 B CN113406677 B CN 113406677B
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parameter
navigation signal
parameters
main frame
data
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CN113406677A (en
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邓中亮
刘炳勋
尹露
罗恺
刘京融
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Beijing University of Posts and Telecommunications
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Beijing University of Posts and Telecommunications
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/30—Acquisition or tracking or demodulation of signals transmitted by the system code related
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/25—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS
    • G01S19/256—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS relating to timing, e.g. time of week, code phase, timing offset
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/25—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS
    • G01S19/258—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/29—Acquisition or tracking or demodulation of signals transmitted by the system carrier including Doppler, related
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/396—Determining accuracy or reliability of position or pseudorange measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position

Abstract

The embodiment of the invention provides a navigation signal broadcasting method and device and a navigation signal receiving method, which are applied to the technical field of communication, wherein the navigation signal broadcasting method is applied to each low-orbit satellite in a low-orbit satellite navigation system and comprises the following steps: acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters; determining a first data code; performing spread spectrum modulation on the first data code by using a data path pseudo code corresponding to the low-orbit satellite; quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component, and a first navigation signal is broadcast through a first frequency band; performing spread spectrum modulation on the second data code by using the data path pseudo code corresponding to the low-orbit satellite; and performing Quadrature Phase Shift Keying (QPSK) modulation on the second data component and the pilot frequency component to obtain a second navigation signal, and broadcasting the second navigation signal through a second frequency band. The time required by precise positioning is reduced, and the rapid and precise positioning is realized.

Description

Navigation signal broadcasting method and device and navigation signal receiving method
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for broadcasting a navigation signal, and a method for receiving a navigation signal.
Background
The global navigation satellite system (Global Navigation Satellite System, GNSS) is an important space-time information infrastructure, is an air-based radio navigation positioning system capable of providing all-weather 3-dimensional coordinates and speed and time information for users at any place on the surface of the earth or in the near-earth space, plays an important role in the fields of national economy construction and national defense security, and has been widely applied to numerous fields of navigation, positioning and time service. In recent years, with the development of fifth-generation mobile communication technology (5th Generation Mobile Communication Technology,5G), internet of things, artificial intelligence, unmanned driving and other technologies, the demands of social production and life on accurate space-time information reach unprecedented heights, and the technologies have been developed from rough, post, static and regional in the past to accurate, real-time, dynamic and global in the present. Taking an unmanned automobile as an example, not only real-time lane-level navigation accuracy is needed, but also continuous availability of all road conditions is needed. There are many other technologies that need to be improved for satellite navigation systems themselves. In the existing mode, positioning is performed through the B1I signal, and because the B1I signal is broadcast by means of Beidou navigation satellite, the geometric diversity is slow in change, and the time required for performing precise positioning is long due to the fact that the convergence time required for performing precise positioning is long by utilizing the telegraph text of the B1I signal.
Disclosure of Invention
The embodiment of the invention aims to provide a navigation signal broadcasting method and device and a navigation signal receiving method, so as to reduce the time required by precise positioning. The specific technical scheme is as follows:
the embodiment of the invention provides a navigation signal broadcasting method which is applied to each low-orbit satellite in a low-orbit satellite navigation system, and comprises the following steps:
acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters;
determining a first data code corresponding to a first parameter, wherein the first parameter comprises the time parameter, the ephemeris parameter and the integrity parameter;
performing spread spectrum modulation on the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component;
quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component to obtain a first navigation signal, and the first navigation signal is broadcast through a first frequency band so that a ground receiver receives the first navigation signal; wherein the pilot component is generated based on a pilot path pseudo code;
determining a second data code corresponding to a second parameter, wherein the second parameter comprises the time parameter, the ephemeris parameter, the integrity parameter, the precise positioning parameter, the ionosphere parameter and the almanac parameter;
Performing spread spectrum modulation on the second data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component;
and performing Quadrature Phase Shift Keying (QPSK) modulation on the second data component and the pilot frequency component to obtain a second navigation signal, broadcasting the second navigation signal through a second frequency band, enabling the ground receiver to receive the second navigation signal, and positioning based on the first navigation signal and the second navigation signal, wherein the second frequency band is different from the first frequency band.
The embodiment of the invention also provides a navigation signal receiving method which is applied to the ground receiver and comprises the following steps:
receiving a first navigation signal broadcasted by a low-orbit satellite through a first frequency band in a low-orbit satellite navigation system, wherein the first navigation signal is generated by performing Quadrature Phase Shift Keying (QPSK) modulation on a first data component and a pilot frequency component, the pilot frequency component is generated based on a pilot frequency path pseudo code, the first data component is obtained by performing spread spectrum modulation on a first data code by using a data path pseudo code corresponding to the low-orbit satellite, the first data code corresponds to a first parameter, and the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter;
Receiving a second navigation signal broadcasted by the low-orbit satellite through a second frequency band, wherein the second navigation signal is obtained by performing Quadrature Phase Shift Keying (QPSK) modulation on a second data component and a pilot frequency component, the second data component is obtained by performing spread spectrum modulation on a second data code by utilizing a data path pseudo code corresponding to the low-orbit satellite, the second data code corresponds to a second parameter, and the second parameter comprises the time parameter, the ephemeris parameter, the integrity parameter, the precise positioning parameter, the ionosphere parameter and the almanac parameter; wherein the second frequency band is different from the first frequency band;
positioning is performed based on the first navigation signal and the second navigation signal.
The embodiment of the invention has the beneficial effects that:
the method and the device for broadcasting the navigation signal and the method for receiving the navigation signal provided by the embodiment of the invention can be applied to each low-orbit satellite in a low-orbit satellite navigation system, and comprise the following steps: acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters; determining a first data code corresponding to a first parameter, wherein the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter; spreading and modulating the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component; quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component to obtain a first navigation signal, and the first navigation signal is broadcast through a first frequency band so that a ground receiver receives the first navigation signal; wherein, the pilot frequency component is generated based on the pilot frequency channel pseudo code; determining a second data code corresponding to a second parameter, wherein the second parameter comprises a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter and an almanac parameter; performing spread spectrum modulation on the second data code by using the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component; and performing Quadrature Phase Shift Keying (QPSK) modulation on the second data component and the pilot frequency component to obtain a second navigation signal, broadcasting the second navigation signal through a second frequency band, enabling the ground receiver to receive the second navigation signal, and positioning based on the first navigation signal and the second navigation signal, wherein the second frequency band is different from the first frequency band. The first navigation signal and the second navigation signal take the characteristics of the low orbit satellite into consideration, broadcast ephemeris and precise ephemeris are adopted, other signals are not required to be received for resolving like the traditional precise single-point positioning, in the embodiment of the invention, the first navigation signal with time parameters, ephemeris parameters and integrity parameters is broadcast through the first frequency band, the ground receiver can quickly capture the satellite based on the first navigation signal, namely, the positioning of the satellite is realized, the second navigation signal with the time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters is broadcast through the second frequency band, the ground receiver can realize continuous satellite tracking and precise positioning based on the second navigation signal, and the time required by precise positioning can be reduced, namely, the quick precise positioning is realized.
Of course, not all of the above advantages need be achieved simultaneously in the practice of any one product or method of the present invention.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and other embodiments may be obtained according to these drawings to those skilled in the art.
Fig. 1 is a flowchart of a navigation signal broadcasting method according to an embodiment of the present invention;
fig. 2 is a flowchart of a navigation signal receiving method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of broadcasting navigation signals using different frequency bands according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a signal modulation scheme according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a navigation message frame structure of a first navigation signal according to an embodiment of the present invention;
FIG. 6A is a schematic diagram of a frame 1 information parameter layout format of a navigation message of a first navigation signal according to an embodiment of the present invention;
FIG. 6B is a schematic diagram of a frame 2 information parameter layout format of a navigation message of a first navigation signal according to an embodiment of the present invention;
FIG. 6C is a schematic diagram of a frame 3 information parameter layout format of a navigation message of a first navigation signal according to an embodiment of the present invention;
FIG. 6D is a schematic diagram of a navigation message subframe 4 information parameter layout format of a first navigation signal according to an embodiment of the present invention;
FIG. 6E is a schematic diagram of a navigation message subframe 5 information parameter layout format of a first navigation signal according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a navigation message frame structure of a second navigation signal according to an embodiment of the present invention;
fig. 8A is a schematic diagram of a navigation message main frame 1 subframe 1 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 8B is a schematic diagram of a navigation message main frame 1 sub-frame 2 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 8C is a schematic diagram of a navigation message main frame 1 subframe 3 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 8D is a schematic diagram of a navigation message main frame 1 subframe 4 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 8E is a schematic diagram of a navigation message main frame 1 sub-frame 5 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 8F is a schematic diagram of a navigation message main frame 1 subframe 6 information parameter formatting of a second navigation signal according to an embodiment of the present invention.
Fig. 9 is a schematic diagram of a navigation message main frame 2 subframe information parameter arrangement format of a second navigation signal according to an embodiment of the present invention.
Fig. 10 is a schematic diagram of a parameter arrangement format of a main frame 3 subframe information of a navigation message of a second navigation signal according to an embodiment of the present invention;
fig. 11 is a schematic structural diagram of a navigation signal broadcasting device according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of a navigation signal receiving device according to an embodiment of the present invention;
fig. 13 is a schematic structural diagram of an electronic device according to an embodiment of the present invention;
fig. 14 is a schematic structural diagram of another electronic device according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, those of ordinary skill in the art will be able to devise all other embodiments that are obtained based on this application and are within the scope of the present invention.
The low orbit satellite navigation system adopts a low orbit constellation, so that the information broadcasting time delay is small and the transmission data amount is large; the signal power is strong, the anti-interference and anti-deception performances are good, and the service performance of indoor and other shielding areas can be enhanced; the low orbit satellite has short earth-surrounding period and obvious change of geometric distribution diversity, and the signal can also obviously accelerate the convergence of precise positioning ambiguity, thereby providing more effective data sources for combined orbit determination, space weather monitoring and the like. In terms of coverage, although the coverage of a single satellite of a low orbit satellite is small, a constellation of a plurality of satellites can provide global information and signal enhancement including bipolar areas. The low-orbit constellation has the advantages of strong ground receiving signals and quick geometric figure change, can form complementation with the middle-orbit GNSS constellation, and is hopeful to realize comprehensive enhancement of the precision, the integrity, the continuity and the usability of the navigation system.
The convergence time can be shortened by adopting the low-orbit satellite to transmit the low-orbit signal, so that the problem of long precise positioning time of the traditional GNSS is solved; the low-orbit satellite is not suitable for the traditional GNSS signals, the low-orbit navigation signal designed by the invention considers the characteristics of the low-orbit satellite, and the traditional broadcast ephemeris and precise ephemeris are adopted for broadcasting together, so that the problem that other signals need to be received for resolving in the traditional precise single-point positioning is solved.
The embodiment of the invention provides a navigation signal broadcasting method which is applied to each low-orbit satellite in a low-orbit satellite navigation system and can comprise the following steps:
acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters;
determining a first data code corresponding to a first parameter, wherein the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter;
spreading and modulating the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component;
quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component to obtain a first navigation signal, and the first navigation signal is broadcast through a first frequency band so that a ground receiver receives the first navigation signal; wherein, the pilot frequency component is generated based on the pilot frequency channel pseudo code;
Determining a second data code corresponding to a second parameter, wherein the second parameter comprises a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter and an almanac parameter;
performing spread spectrum modulation on the second data code by using the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component;
and performing Quadrature Phase Shift Keying (QPSK) modulation on the second data component and the pilot frequency component to obtain a second navigation signal, broadcasting the second navigation signal through a second frequency band, enabling the ground receiver to receive the second navigation signal, and positioning based on the first navigation signal and the second navigation signal, wherein the second frequency band is different from the first frequency band.
In the embodiment of the invention, the first navigation signal and the second navigation signal consider the characteristics of a low-orbit satellite, broadcast ephemeris and precise ephemeris are adopted, other signals are not required to be received for resolving like the traditional precise single-point positioning, in the embodiment of the invention, the first navigation signal with time parameters, ephemeris parameters and integrity parameters is broadcast through a first frequency band, a ground receiver can quickly capture the satellite based on the first navigation signal, namely, the positioning of the satellite is realized, and the second navigation signal with the time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters is broadcast through a second frequency band, so that the ground receiver can realize continuous satellite tracking and precise positioning based on the second navigation signal, and the time required by precise positioning can be reduced, namely, the quick precise positioning is realized.
Fig. 1 is a flowchart of a navigation signal broadcasting method according to an embodiment of the present invention. The navigation signal broadcasting method provided by the embodiment of the invention can be applied to each low-orbit satellite in the low-orbit satellite navigation system, and referring to fig. 1, the navigation signal broadcasting method provided by the embodiment of the invention can comprise the following steps:
s101, acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters.
In one implementation, the time parameter may include at least one of the following parameters: the system comprises a whole week count, a seconds count in the week, a subframe count, an on-board device delay difference, a clock data age, a clock difference parameter, a time synchronization parameter with world coordination time (Coordinated Universal Time, UTC), a time synchronization parameter with a global positioning system (Global Position System, GPS), a time synchronization parameter with Galileo, a time synchronization parameter with Grosvens GLONASS, and a time synchronization parameter with a Beidou satellite navigation system (BeiDou Navigation Satellite System, BDS).
In one implementation, the ephemeris parameters may comprise at least one of the following parameters: ephemeris data age, ephemeris reference time, difference between long half shaft and orbit design long half shaft, eccentricity, orbit inclination of reference time, ascent point right-hand warp calculated according to reference time, near-place amplitude angle, mean-short point angle of reference time, radial length change rate, orbit inclination change rate, ascent point right-hand warp change rate, difference between satellite average motion rate and calculated value, satellite average motion rate first order change rate, satellite average motion rate second order change rate, amplitude of cosine harmonic correction term of latitude amplitude angle, amplitude of sine harmonic correction term of latitude amplitude, amplitude of sine harmonic correction term of orbit radius, amplitude of cosine harmonic correction term of orbit inclination angle, amplitude of sine harmonic correction term of orbit inclination angle, orbit radial correction, orbit tangential correction and orbit normal correction.
The integrity parameters may include at least one of the following: user distance accuracy index, satellite autonomous health identification, satellite health information, integrity and differential information health identification, low orbit satellite system integrity information satellite identification, regional user distance accuracy index, clock correction and inter-code deviation correction.
The fine positioning parameters may include at least one of the following: grid point ionosphere vertical delay parameters, grid point ionosphere vertical delay correction error index.
The almanac parameters may include at least one of the following: the method comprises the steps of calendar number, calendar week count, calendar reference time, long half-axis deviation, eccentricity, near-place amplitude angle, average point angle of reference time, longitude of intersection point, right-angle change rate of intersection point, correction of orbit reference inclination angle of reference time, difference between average satellite movement rate and calculated value, satellite clock error and satellite clock speed.
S102, determining a first data code corresponding to a first parameter, wherein the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter.
It is understood that the first parameter is encoded to obtain the first data code.
And S103, performing spread spectrum modulation on the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component.
The data path pseudo code is a weil code.
The performing spread spectrum modulation on the first data code by using the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component may include:
and (3) performing spread spectrum modulation on the first data code by using the data path pseudo code corresponding to the low-orbit satellite through code division multiple access (Code Division Multiple Access, CDMA) to obtain a first data component.
S104, quadrature phase shift keying (Quadrature Phase Shift Keying, QPSK) modulation is carried out on the first data component and the pilot frequency component, a first navigation signal is obtained, and the first navigation signal is broadcast through the first frequency band, so that the ground receiver receives the first navigation signal.
Wherein the pilot component is generated based on the pilot path pseudocode.
The first navigation signal is thus programmed with time parameters, ephemeris parameters and integrity parameters.
S105, determining a second data code corresponding to a second parameter, wherein the second parameter comprises a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter and an almanac parameter.
It is understood that the first parameter is encoded to obtain the first data code.
And S106, performing spread spectrum modulation on the second data code by using the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component.
And performing spread spectrum modulation on the second data code by using the data path pseudo code corresponding to the low orbit satellite through Code Division Multiple Access (CDMA) to obtain a second data component.
In the process of the first navigation signal to be broadcasted by the first frequency band, CDMA is adopted for signal multiplexing, and the weil code is selected as the ranging code.
S107, quadrature phase shift keying QPSK modulation is carried out on the second data component and the pilot frequency component to obtain a second navigation signal, the second navigation signal is broadcast through a second frequency band, so that the ground receiver receives the second navigation signal and positions the ground receiver based on the first navigation signal and the second navigation signal, and the second frequency band is different from the first frequency band.
The second navigation signal is programmed with time parameters, ephemeris parameters, integrity parameters, fix parameters, ionosphere parameters, almanac parameters.
The ground receiver obtains the signal transmission time from the ground receiver to the satellites through the time parameters and the data path pseudo codes in the received navigation signals, the transmission time is multiplied by the speed of light to obtain the distance from the ground receiver to the satellites, the position of the satellites is calculated by using the ephemeris parameters, and the position of the ground receiver can be calculated by combining the positions of more than 4 satellites and the distances from the ground receiver to the satellites. The distance accuracy from the ground receiver to the satellite is a key factor affecting the resolving accuracy, and satellite signals need to pass through an ionosphere above the earth during transmission, so that signal delay is caused, and the distance accuracy is seriously affected. If the ground receiver only receives the signal of the single frequency band, the ionosphere parameter or the precise positioning parameter in the navigation signal can be used for compensating part of ionosphere delay, so that the distance precision is improved. The dual-band navigation signal can directly eliminate the influence caused by ionospheric delay by utilizing the relation between different frequencies and the ionospheric delay, thereby greatly improving the distance accuracy.
In the embodiment of the invention, the first navigation signal is broadcast through the first frequency band, and the second navigation signal is broadcast through the second frequency band, namely, the navigation message is broadcast through the two frequency bands. The broadcasting signal adopts QPSK modulation, the I path (in-phase component of the signal) is used for placing the data component containing navigation message information, and the Q path (quadrature component) is used for placing the pilot frequency component. Therefore, the ground receiver, namely the ground navigation signal receiver, can realize minute-level quick cold start by utilizing the first navigation signal through the received navigation signal broadcast based on the low-orbit satellite; and then the second navigation signal is used for continuously tracking the satellite position, and the carrier signal circumferential ambiguity is quickly converged when the receiver position is resolved due to the characteristic of obvious geometric diversity change caused by high angular velocity when the low-orbit satellite operates, so that quick and precise positioning can be realized.
Fig. 2 is a flowchart of a navigation signal receiving method according to an embodiment of the present invention. The navigation signal receiving method provided by the embodiment of the invention can be applied to a ground receiver, and referring to fig. 2, the navigation signal receiving method provided by the embodiment of the invention can comprise the following steps:
s201, receiving a first navigation signal broadcast by a low-orbit satellite through a first frequency band in a low-orbit satellite navigation system, wherein the first navigation signal carries out quadrature phase shift keying QPSK modulation on a first data component and a pilot frequency component, the pilot frequency component is generated based on a pilot frequency path pseudo code, the first data component is obtained by carrying out spread spectrum modulation on a first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite, the first data code corresponds to a first parameter, and the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter;
S202, receiving a second navigation signal broadcasted by a low-orbit satellite through a second frequency band, wherein the second navigation signal is obtained by performing Quadrature Phase Shift Keying (QPSK) modulation on a second data component and a pilot frequency component, the second data component is obtained by performing spread spectrum modulation on a second data code by utilizing a data path pseudo code corresponding to the low-orbit satellite, and the second data code corresponds to a second parameter, and the second parameter comprises a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter and an almanac parameter; wherein the second frequency band is different from the first frequency band;
s203, positioning is performed based on the first navigation signal and the second navigation signal.
The ground receiver can realize minute-level rapid cold start by utilizing the first navigation signal through the received navigation signal which is broadcasted based on the low-orbit satellite; and then the second navigation signal is used for continuously tracking the satellite position, and the carrier signal circumferential ambiguity is quickly converged when the receiver position is resolved due to the characteristic of obvious geometric diversity change caused by high angular velocity when the low-orbit satellite operates, so that quick and precise positioning can be realized.
In an alternative embodiment, as shown in fig. 3, the navigation signal is broadcast through a first frequency channel (also known as a first frequency channel) and a second frequency channel (also known as a second frequency channel) of the low-orbit satellite, where the first frequency channel occupies a 20MHz bandwidth of 5010 to 5030 MHz; the second frequency band occupies 10MHz bandwidth of D2:7065-7075 MHz.
As shown in fig. 4, the navigation signals of both frequency bands are QPSK modulated. The data component is generated by using the data containing the positioning text information and the data path pseudo code, and the data component is modulated on the carrier wave in quadrature with the pilot frequency component generated by the pilot path pseudo code, namely, the navigation signal is obtained by QPSK modulation. The signal multiplexing mode adopts Code Division Multiple Access (CDMA), and the pseudo code (ranging code) sequence is generated by adopting weil code truncation. The navigation signals of the two frequency bands are determined in the mode shown in fig. 4, and the two navigation signals are broadcast through the two frequency bands respectively, so that the ground receiver receives the navigation signals and performs positioning based on the navigation signals.
In one implementation, as shown in fig. 5, the first navigation signal, i.e. the navigation signal broadcast by the first frequency band, is composed of a main frame and a subframe. Each main frame is 1500 bits, each main frame is composed of 5 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits. Each word consists of two parts of text information and check code. Every sub-frame 1 st word is synchronous information, error correction coding is not carried out, other 9 words are all error correction coded by adopting a broadcast channel (Broadcast Channel, BCH) (15,11,1) plus interleaving mode, and the total information bits are 22 bits.
Referring to fig. 6A, 6B, 6C, 6D, and 6E, in the embodiment of the present invention, each main frame in the first navigation signal has 5 subframes, each subframe is divided into 10 words, and the first word of each subframe includes 20bits of synchronization information (i.e., a frame synchronization header Pre). And the high-order broadcasting mode is adopted when the sub-frames are broadcast. The first frequency band signal navigation message is provided with time parameters, ephemeris parameters and integrity parameters.
Table 1 shows the data fields of the time parameters and the meaning of the respective data fields.
TABLE 1
Table 2 shows the data fields of the ephemeris parameters and the meaning of the respective data fields.
TABLE 2
Table 3 shows the data fields of the integrity parameters and the meaning of the individual data fields.
In one implementation, referring to fig. 7, the second navigation signal consists of 3 main frames: main frame 1, main frame 2, main frame 3, each main frame length is different; main frame 1 is 1800 bits, composed of 6 subframes, each subframe is 300 bits, each subframe is composed of 10 words, each word is 30 bits; main frame 2 is 9600 bits, and is composed of 32 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits; the main frame 3 is 648000 bits and consists of 1800 subframes, each subframe is 360 bits, each subframe is composed of 12 words, each word is 30 bits, wherein the 1 st word of each subframe is synchronous information, error correction coding is not carried out, other words are error correction coded by adopting a BCH (15,11,1) plus interleaving mode, and the total information bits are 22 bits;
Broadcasting a second navigation signal through a second frequency band, comprising: and broadcasting the main frame 1, the main frame 2 and the main frame 3 in sequence through the second frequency band.
Referring to fig. 8A, 8B, 8C, 8D, 8E, and 8F, in an embodiment of the present invention, the second band signal message 1 st main frame broadcast time parameter, ephemeris parameter, integrity parameter, ionosphere parameter. The first word of each subframe contains 20bits of synchronization information (i.e., a frame synchronization header Pre). The main frame count FraID indicates the current main frame number. The main frame 1 subframe count FraID1 represents the subframe number of the current main frame 1. And the high-order broadcasting mode is adopted when the sub-frames are broadcast. Specifically, the timeThe parameters, ephemeris parameters and integrity parameters are shown in the above tables 1, 2 and 3, and the ionosphere parameters correspond to alpha in the 8-parameter Klobuchar model 0 、α 1 、α 2 、α 3 、β 0 、β 1 、β 2 、β 3 Ionospheric vertical delay correction of global low-orbit satellite navigation signals can be calculated, wherein alpha 0 、α 1 、α 2 、α 3 The four parameters are the amplitude component, beta, of the average radiant flux of the sun 0 、β 1 、β 2 、β 3 The four parameters are the periodic components of the average radiant flux of the sun.
Referring to fig. 9, in the embodiment of the present invention, the 2 nd main frame in the second navigation signal message broadcasts a precision positioning (grid point ionosphere) parameter. The precise positioning parameters are expressed by Ion and comprise grid point ionosphere vertical delay parameters and grid point ionosphere vertical delay correction error indexes. The coverage area of the ionosphere grid is 70-145 degrees, the north latitude is 7.5-55 degrees, the grid points are formed by dividing the coverage area into 320 grid points according to the longitude and latitude of 5 multiplied by 2.5 degrees, the ionosphere vertical delay parameter of the grid point represents the ionosphere vertical delay of the signal at a certain grid point, and a user needs to interpolate the ionosphere correction of the grid point to obtain the ionosphere correction at the puncture point of an observation satellite so as to correct the observation pseudo range; the grid point ionosphere vertical delay correction error index is used to describe the accuracy of the grid point ionosphere delay correction. Ion (Ion) i,n The grid points numbered 10 x (Pnum 2-1) +n are shown, and ionospheric delay information of 10 grid points is broadcast per subframe. The main frame 2 subframe count FraID2 represents the subframe number of the current main frame 2. And the high-order broadcasting mode is adopted when the sub-frames are broadcast.
Referring to fig. 10, in the embodiment of the present invention, the 3 rd main frame of the second navigation signal text broadcasts the almanac parameters. Each sub-frame of the 3 rd main frame broadcasts an almanac for one satellite. The main frame 3 subframe count FraID3 indicates the subframe number of the current main frame 3, and a high-order first broadcasting mode is adopted when the subframes are broadcasted.
Table 4 shows the data fields of the almanac parameters and the meaning of each data field.
TABLE 4 Table 4
The method comprises the steps that a dual-band broadcasting mode is adopted, and a first navigation signal carries time parameters, ephemeris parameters and integrity parameters and is used for rapidly capturing satellites; the second navigation signal carries time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters, almanac parameters for continuously tracking the satellite and precisely positioning.
Corresponding to the method for broadcasting the navigation signal provided in the foregoing embodiment, the embodiment of the present invention further provides a device for broadcasting the navigation signal, which is applied to each low-orbit satellite in the low-orbit satellite navigation system, as shown in fig. 11, where the device may include:
An acquisition module 1101 for acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters, and almanac parameters;
a first determining module 1102, configured to determine a first data code corresponding to a first parameter, where the first parameter includes a time parameter, an ephemeris parameter, and an integrity parameter;
a first modulation module 1103, configured to spread spectrum modulate the first data code with a data path pseudo code corresponding to the low-orbit satellite, so as to obtain a first data component; quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component, and a first navigation signal is obtained;
a first broadcasting module 1104, configured to broadcast a first navigation signal through a first frequency band, so that a ground receiver receives the first navigation signal; wherein, the pilot frequency component is generated based on the pilot frequency channel pseudo code;
a second determining module 1105, configured to determine a second data code corresponding to a second parameter, where the second parameter includes a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter, and an almanac parameter;
a second modulation module 1106, configured to spread spectrum modulate the second data code with a data path pseudo code corresponding to the low-orbit satellite, so as to obtain a second data component; quadrature phase shift keying QPSK modulation is carried out on the second data component and the pilot frequency component, and a second navigation signal is obtained;
The second broadcasting module 1107 is configured to broadcast a second navigation signal through a second frequency band, so that the ground receiver receives the second navigation signal and performs positioning based on the first navigation signal and the second navigation signal, where the second frequency band is different from the first frequency band.
Optionally, the data path pseudo code is a weil code;
the first modulation module 1103 is specifically configured to spread spectrum modulate the first data code by using a data path pseudo code corresponding to the low-orbit satellite through CDMA, so as to obtain a first data component.
Optionally, the ephemeris parameters comprise at least one of the following parameters: ephemeris data age, ephemeris reference time, difference between long half shaft and orbit design long half shaft, eccentricity, orbit inclination of reference time, ascent point right-hand warp calculated according to reference time, near-place amplitude angle, mean-short point angle of reference time, radial length change rate, orbit inclination change rate, ascent point right-hand warp change rate, difference between satellite average motion rate and calculated value, satellite average motion rate first order change rate, satellite average motion rate second order change rate, amplitude of cosine harmonic correction term of latitude amplitude angle, amplitude of sine harmonic correction term of latitude amplitude, amplitude of sine harmonic correction term of orbit radius, amplitude of cosine harmonic correction term of orbit inclination angle, amplitude of sine harmonic correction term of orbit inclination angle, orbit radial correction, orbit tangential correction and orbit normal correction.
Optionally, the fine positioning parameters include at least one of the following: grid point ionosphere vertical delay parameters, grid point ionosphere vertical delay correction error index.
Optionally, the almanac parameters include at least one of the following: the method comprises the steps of calendar number, calendar week count, calendar reference time, long half-axis deviation, eccentricity, near-place amplitude angle, average point angle of reference time, longitude of intersection point, right-angle change rate of intersection point, correction of orbit reference inclination angle of reference time, difference between average satellite movement rate and calculated value, satellite clock error and satellite clock speed.
Optionally, the time parameter includes at least one of the following parameters: whole week count, intra-week second count, subframe count, on-board device delay difference, clock data age, clock difference parameter, UTC time synchronization parameter with world coordination time, GPS time synchronization parameter with global positioning system, galileo time synchronization parameter with Grosvens GLONASS time synchronization parameter with Beidou satellite navigation system BDS time synchronization parameter.
Optionally, the integrity parameter comprises at least one of the following parameters: user distance accuracy index, satellite autonomous health identification, satellite health information, integrity and differential information health identification, low orbit satellite system integrity information satellite identification, regional user distance accuracy index, clock correction and inter-code deviation correction.
Optionally, the second navigation signal consists of 3 main frames: main frame 1, main frame 2, main frame 3, each main frame length is different; main frame 1 is 1800 bits, composed of 6 subframes, each subframe is 300 bits, each subframe is composed of 10 words, each word is 30 bits; main frame 2 is 9600 bits, and is composed of 32 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits; the main frame 3 is 648000 bits and consists of 1800 subframes, each subframe is 360 bits, each subframe is composed of 12 words, each word is 30 bits, wherein the 1 st word of each subframe is synchronous information, error correction coding is not carried out, other words are error correction coded by adopting a BCH (15,11,1) plus interleaving mode, and the total information bits are 22 bits;
the second broadcasting module 1107 is specifically configured to broadcast the main frame 1, the main frame 2, and the main frame 3 in sequence through the second frequency band.
Corresponding to the navigation signal receiving method provided in the above embodiment, the embodiment of the present invention provides a navigation signal receiving device, which is applied to a ground receiver, as shown in fig. 12, and the device includes:
the first receiving module 1201 is configured to receive a first navigation signal broadcast by a low-orbit satellite through a first frequency band in a low-orbit satellite navigation system, where the first navigation signal is generated by performing quadrature phase shift keying QPSK modulation on a first data component and a pilot component, the pilot component is generated based on a pilot path pseudo code, the first data component is obtained by performing spread spectrum modulation on a first data code by using a data path pseudo code corresponding to the low-orbit satellite, the first data code corresponds to a first parameter, and the first parameter includes a time parameter, an ephemeris parameter and an integrity parameter;
The second receiving module 1202 is configured to receive a second navigation signal broadcasted by the low-orbit satellite through the second frequency band, where the second navigation signal is obtained by performing quadrature phase shift keying QPSK modulation on a second data component and a pilot component, the second data component is obtained by performing spread spectrum modulation on a second data code by using a data path pseudo code corresponding to the low-orbit satellite, and the second data code corresponds to a second parameter, where the second parameter includes a time parameter, an ephemeris parameter, an integrity parameter, a precise positioning parameter, an ionosphere parameter, and an almanac parameter; wherein the second frequency band is different from the first frequency band;
the positioning module 1203 is configured to perform positioning based on the first navigation signal and the second navigation signal.
The embodiment of the present invention further provides an electronic device, as shown in fig. 13, including a processor 1301, a communication interface 1302, a memory 1303, and a communication bus 1304, where the processor 1301, the communication interface 1302, and the memory 1303 complete communication with each other through the communication bus 1304.
A memory 1303 for storing a computer program;
the processor 1301 is configured to implement the method steps of the navigation signal broadcasting method when executing the program stored in the memory 1303.
The embodiment of the invention also provides an electronic device, as shown in fig. 14, which comprises a processor 1401, a communication interface 1402, a memory 1403 and a communication bus 1404, wherein the processor 1401, the communication interface 1402 and the memory 1403 communicate with each other through the communication bus 1404.
A memory 1403 for storing a computer program;
the processor 1401 is configured to execute the program stored in the memory 1403, thereby implementing the method steps of the navigation signal receiving method.
The communication bus mentioned above for the electronic devices may be a peripheral component interconnect standard (Peripheral Component Interconnect, PCI) bus or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, etc. The communication bus may be classified as an address bus, a data bus, a control bus, or the like. For ease of illustration, the figures are shown with only one bold line, but not with only one bus or one type of bus.
The communication interface is used for communication between the electronic device and other devices.
The Memory may include random access Memory (Random Access Memory, RAM) or may include Non-Volatile Memory (NVM), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the aforementioned processor.
The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; but also digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.
In still another embodiment of the present invention, a computer readable storage medium is provided, where a computer program is stored, and the computer program when executed by a processor implements the method steps of the navigation signal broadcasting method described above.
In a further embodiment of the present invention, a computer readable storage medium is also provided, in which a computer program is stored, which computer program, when being executed by a processor, implements the method steps of the navigation signal receiving method described above.
In yet another embodiment of the present invention, a computer program product containing instructions is also provided, which when run on a computer, causes the computer to perform the method steps of the navigation signal broadcasting method described above.
In a further embodiment of the present invention, a computer program product comprising instructions is also provided which, when run on a computer, causes the computer to perform the method steps of the navigation signal receiving method described above.
In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present invention, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), etc.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for the apparatus, electronic device, computer readable storage medium, and computer program product embodiments, the description is relatively simple, as relevant to the method embodiments being referred to in the section of the description of the method embodiments.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (9)

1. The navigation signal broadcasting method is characterized by being applied to each low-orbit satellite in a low-orbit satellite navigation system, and comprises the following steps:
acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters;
determining a first data code corresponding to a first parameter, wherein the first parameter comprises the time parameter, the ephemeris parameter and the integrity parameter;
performing spread spectrum modulation on the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component;
quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component to obtain a first navigation signal, and the first navigation signal is broadcast through a first frequency band so that a ground receiver receives the first navigation signal; the pilot frequency component is generated based on a pilot frequency path pseudo code, wherein a first data component is placed on an I path and a pilot frequency component is placed on a Q path in the broadcasted first navigation signal;
Determining a second data code corresponding to a second parameter, wherein the second parameter comprises the time parameter, the ephemeris parameter, the integrity parameter, the precise positioning parameter, the ionosphere parameter and the almanac parameter;
performing spread spectrum modulation on the second data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component;
quadrature phase shift keying QPSK modulation is carried out on the second data component and the pilot frequency component to obtain a second navigation signal, the second navigation signal is broadcast through a second frequency band, so that the ground receiver receives the second navigation signal and positions the ground receiver based on the first navigation signal and the second navigation signal, wherein the second frequency band is different from the first frequency band, and the second data component and the pilot frequency component are placed in an I path and the pilot frequency component are placed in a Q path of the broadcast second navigation signal;
the second navigation signal consists of 3 main frames: main frame 1, main frame 2, main frame 3, each main frame length is different; main frame 1 is 1800 bits, composed of 6 subframes, each subframe is 300 bits, each subframe is composed of 10 words, each word is 30 bits; main frame 2 is 9600 bits, and is composed of 32 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits; the main frame 3 is 648000 bits and consists of 1800 subframes, each subframe is 360 bits, each subframe is composed of 12 words, each word is 30 bits, wherein the 1 st word of each subframe is synchronous information, error correction coding is not carried out, other words are error correction coded by adopting a BCH (15,11,1) plus interleaving mode, and the total information bits are 22 bits;
The broadcasting the second navigation signal through the second frequency band includes:
sequentially broadcasting a main frame 1, a main frame 2 and a main frame 3 through a second frequency band, wherein the main frame 1 is used for broadcasting time parameters, ephemeris parameters, integrity parameters and ionosphere parameters; the main frame 2 is used for broadcasting precise positioning parameters; the main frame 3 is used to announce the almanac parameters.
2. The method of claim 1, wherein the data path pseudo code is a weil code;
the step of performing spread spectrum modulation on the first data code by using the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component comprises the following steps:
and performing spread spectrum modulation on the first data code by using the data path pseudo code corresponding to the low-orbit satellite through Code Division Multiple Access (CDMA) to obtain a first data component.
3. The method of claim 1, wherein the ephemeris parameters comprise at least one of: ephemeris data age, ephemeris reference time, difference between long half shaft and orbit design long half shaft, eccentricity, orbit inclination of reference time, ascent point right-hand warp calculated according to reference time, near-place amplitude angle, mean-short point angle of reference time, radial length change rate, orbit inclination change rate, ascent point right-hand warp change rate, difference between satellite average motion rate and calculated value, satellite average motion rate first order change rate, satellite average motion rate second order change rate, amplitude of cosine harmonic correction term of latitude amplitude angle, amplitude of sine harmonic correction term of latitude amplitude, amplitude of sine harmonic correction term of orbit radius, amplitude of cosine harmonic correction term of orbit inclination angle, amplitude of sine harmonic correction term of orbit inclination angle, orbit radial correction, orbit tangential correction and orbit normal correction.
4. A method according to claim 3, wherein the fine positioning parameters comprise at least one of the following: grid point ionosphere vertical delay parameters, grid point ionosphere vertical delay correction error index.
5. The method of claim 4, wherein the almanac parameters comprise at least one of the following parameters: the method comprises the steps of calendar number, calendar week count, calendar reference time, long half-axis deviation, eccentricity, near-place amplitude angle, average point angle of reference time, longitude of intersection point, right-angle change rate of intersection point, correction of orbit reference inclination angle of reference time, difference between average satellite movement rate and calculated value, satellite clock error and satellite clock speed.
6. The method of claim 5, wherein the time parameter comprises at least one of the following parameters: whole week count, intra-week second count, subframe count, on-board device delay difference, clock data age, clock difference parameter, UTC time synchronization parameter with world coordination time, GPS time synchronization parameter with global positioning system, galileo time synchronization parameter with Grosvens GLONASS time synchronization parameter with Beidou satellite navigation system BDS time synchronization parameter.
7. The method of claim 6, wherein the integrity parameters comprise at least one of: user distance accuracy index, satellite autonomous health identification, satellite health information, integrity and differential information health identification, low orbit satellite system integrity information satellite identification, regional user distance accuracy index, clock correction and inter-code deviation correction.
8. A navigation signal receiving method, characterized by being applied to a ground receiver, the method comprising:
receiving a first navigation signal broadcasted by a low-orbit satellite through a first frequency band in a low-orbit satellite navigation system, wherein the first navigation signal carries out Quadrature Phase Shift Keying (QPSK) modulation on a first data component and a pilot frequency component, the pilot frequency component is generated based on a pilot frequency path pseudo code, the first data component is obtained by carrying out spread spectrum modulation on a first data code by utilizing a data path pseudo code corresponding to the low-orbit satellite, the first data code corresponds to a first parameter, the first parameter comprises a time parameter, an ephemeris parameter and an integrity parameter, wherein the broadcasted first navigation signal is provided with a first data component placed in an I path and a pilot frequency component placed in a Q path;
Receiving a second navigation signal broadcasted by the low-orbit satellite through a second frequency band, wherein the second navigation signal is obtained by performing Quadrature Phase Shift Keying (QPSK) modulation on a second data component and a pilot frequency component, the second data component is obtained by performing spread spectrum modulation on a second data code by utilizing a data path pseudo code corresponding to the low-orbit satellite, the second data code corresponds to a second parameter, and the second parameter comprises the time parameter, the ephemeris parameter, the integrity parameter, the precise positioning parameter, the ionosphere parameter and the almanac parameter; the second frequency band is different from the first frequency band, wherein an I path of the second navigation signal is provided with a second data component and a Q path of the second navigation signal is provided with a pilot frequency component; the second navigation signal consists of 3 main frames: main frame 1, main frame 2, main frame 3, each main frame length is different; main frame 1 is 1800 bits, composed of 6 subframes, each subframe is 300 bits, each subframe is composed of 10 words, each word is 30 bits; main frame 2 is 9600 bits, and is composed of 32 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits; the main frame 3 is 648000 bits and consists of 1800 subframes, each subframe is 360 bits, each subframe is composed of 12 words, each word is 30 bits, wherein the 1 st word of each subframe is synchronous information, error correction coding is not carried out, other words are error correction coded by adopting a BCH (15,11,1) plus interleaving mode, and the total information bits are 22 bits; the second navigation signal broadcast through the second frequency band is to broadcast a main frame 1, a main frame 2 and a main frame 3 in sequence through the second frequency band, wherein the main frame 1 is used for broadcasting time parameters, ephemeris parameters, integrity parameters and ionosphere parameters; the main frame 2 is used for broadcasting precise positioning parameters; the main frame 3 is used for broadcasting the almanac parameters;
Positioning is performed based on the first navigation signal and the second navigation signal.
9. A navigation signal broadcasting device, characterized in that is applied to each low-orbit satellite in low-orbit satellite navigation system, the navigation signal broadcasting device includes:
the acquisition module is used for acquiring time parameters, ephemeris parameters, integrity parameters, precise positioning parameters, ionosphere parameters and almanac parameters;
a first determining module, configured to determine a first data code corresponding to a first parameter, where the first parameter includes the time parameter, the ephemeris parameter, and the integrity parameter;
the first modulation module is used for performing spread spectrum modulation on the first data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a first data component; quadrature phase shift keying QPSK modulation is carried out on the first data component and the pilot frequency component, and a first navigation signal is obtained;
the first broadcasting module is used for broadcasting the first navigation signal through a first frequency band so that a ground receiver receives the first navigation signal; the pilot frequency component is generated based on a pilot frequency path pseudo code, wherein a first data component is placed on an I path and a pilot frequency component is placed on a Q path in the broadcasted first navigation signal;
The second determining module is used for determining a second data code corresponding to a second parameter, wherein the second parameter comprises the time parameter, the ephemeris parameter, the integrity parameter, the precise positioning parameter, the ionosphere parameter and the almanac parameter;
the second modulation module is used for performing spread spectrum modulation on the second data code by utilizing the data path pseudo code corresponding to the low-orbit satellite to obtain a second data component; quadrature phase shift keying QPSK modulation is carried out on the second data component and the pilot frequency component, and a second navigation signal is obtained;
the second broadcasting module is used for broadcasting the second navigation signal through a second frequency band so that the ground receiver receives the second navigation signal and positions the ground receiver based on the first navigation signal and the second navigation signal, wherein the second frequency band is different from the first frequency band, and an I path and a Q path of the broadcasted second navigation signal are used for placing a second data component and a Q path of the broadcasted second navigation signal are used for placing a pilot frequency component;
the second navigation signal consists of 3 main frames: main frame 1, main frame 2, main frame 3, each main frame length is different; main frame 1 is 1800 bits, composed of 6 subframes, each subframe is 300 bits, each subframe is composed of 10 words, each word is 30 bits; main frame 2 is 9600 bits, and is composed of 32 subframes, each subframe is 300 bits, each subframe is composed of 10 words, and each word is 30 bits; the main frame 3 is 648000 bits and consists of 1800 subframes, each subframe is 360 bits, each subframe is composed of 12 words, each word is 30 bits, wherein the 1 st word of each subframe is synchronous information, error correction coding is not carried out, other words are error correction coded by adopting a BCH (15,11,1) plus interleaving mode, and the total information bits are 22 bits;
The broadcasting the second navigation signal through the second frequency band includes:
sequentially broadcasting a main frame 1, a main frame 2 and a main frame 3 through a second frequency band, wherein the main frame 1 is used for broadcasting time parameters, ephemeris parameters, integrity parameters and ionosphere parameters; the main frame 2 is used for broadcasting precise positioning parameters; the main frame 3 is used to announce the almanac parameters.
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