CN221261245U

CN221261245U - GNSS receiver is solved to big dipper front end

Info

Publication number: CN221261245U
Application number: CN202322831468.2U
Authority: CN
Inventors: 刘诗云; 郭倩倩; 满永利; 周志华; 廖忠浈; 魏平新; 郑志文; 李秀娟; 彭银波; 孙伟; 祁凌
Original assignee: Guangdong General Team Of China Building Materials Industry Geological Exploration Center; Guangdong Province Geological Environmental Monitoring Station; South Surveying & Mapping Technology Co ltd
Current assignee: Guangdong General Team Of China Building Materials Industry Geological Exploration Center; Guangdong Province Geological Environmental Monitoring Station; South Surveying & Mapping Technology Co ltd
Filing date: 2023-10-20
Publication date: 2024-07-02
Anticipated expiration: 2033-10-20

Abstract

The utility model discloses a Beidou front-end resolving GNSS receiver which comprises a radio station module, a frequency converter, a signal channel, a memory, a CPU and a display, wherein the radio station module is connected with the frequency converter; the frequency converter comprises a frequency amplifier and a frequency synthesizer, and the signal channel comprises a signal despreading demodulator and a pseudo-random code generator; the output end of the frequency amplifier is in signal connection with the input end of the signal despreading demodulator, the frequency synthesizer is in signal connection with the signal despreading demodulator and the pseudo random code generator, the output end of the signal despreading demodulator is in signal connection with the memory, the output end of the memory is in signal connection with the display, the memory is in signal connection with the CPU, the output end of the CPU is in signal connection with the display, and the radio station module is in signal connection with the CPU; according to the utility model, the GNSS receiver is solved by the Beidou front end, high-precision positioning, constant speed and timing are realized, and meanwhile, under the condition of no public network, data are transmitted to the base station through the radio station module, so that the timeliness of monitoring is ensured.

Description

GNSS receiver is solved to big dipper front end

Technical Field

The utility model relates to the technical field of navigation positioning, in particular to a Beidou front-end resolving GNSS receiver.

Background

The Beidou satellite navigation system consists of a space section, a ground section and a user section, can provide high-precision, high-reliability positioning, navigation and time service for various users all around the clock and all over the day in the global scope, has short message communication capability and has regional navigation, positioning and time service capability. The Beidou front end resolving GNSS receiver is an important part in Beidou navigation and is used for receiving signals from a satellite navigation system, then sending the signals to the base station, and the base station sends the signals to a user terminal, so that the user terminal determines accurate geographic position, speed and time information of a monitored target. The GNSS receiver is mainly used for receiving radio station antenna signals, processing and transmitting the signals, and the receiving capacity and the processing capacity of the GNSS receiver for the signals are the precondition of the Beidou navigation system for realizing high-precision positioning.

Disclosure of utility model

The utility model aims to provide a Beidou front end resolving GNSS receiver, which realizes high-precision positioning, fixed speed and timing, and simultaneously transmits data to a base station through a radio station module under the condition of no public network, so that monitoring timeliness is ensured.

The technical scheme of the utility model relates to a Beidou front-end resolving GNSS receiver which comprises a radio station module, a frequency converter, a signal channel, a memory, a CPU and a display; the frequency converter, the signal channel, the memory, the CPU and the display are sequentially connected through signals; the frequency converter comprises a frequency amplifier and a frequency synthesizer, and the signal channel comprises a signal despreading demodulator and a pseudo-random code generator;

The output end of the frequency amplifier is in signal connection with the input end of the signal despreading demodulator, the frequency synthesizer is in signal connection with the signal despreading demodulator and the pseudo random code generator, the output end of the signal despreading demodulator is in signal connection with the memory, the output end of the memory is in signal connection with the display, the memory is in signal connection with the CPU, the output end of the CPU is in signal connection with the display, and the radio station module is in signal connection with the CPU.

Preferably, the signal output by the output end of the signal despreading demodulator includes a D (t) signal, a pseudo code signal, a carrier phase signal and a doppler shift signal, where the D (t) signal and the pseudo code signal are both input into the memory.

Preferably, the pseudo-random code generator comprises a C/A code generator and a P code generator, and the C/A code generator and the P code generator are both in signal connection with the frequency synthesizer.

Preferably, the radio station module communicates with the CPU through a serial port.

Preferably, the input end of the frequency amplifier is connected with a pre-signal amplifier, and the pre-signal amplifier is conducted with the GNSS antenna signal.

Preferably, the GNSS receiver further comprises a receiver housing and a power supply, wherein the power supply supplies power to the GNSS receiver, and the pre-signal amplifier, the GNSS antenna, the radio station module, the frequency converter, the signal channel, the memory, the CPU and the display are all hermetically installed in the receiver housing.

The technical scheme of the utility model has the beneficial effects that the Beidou front end resolving GNSS receiver is as follows: the GNSS signals are accurately tracked and efficiently demodulated to obtain positioning information with good timeliness, and the information can be sent to the base station through a telegraph text or a network without delay, so that the timeliness of acquiring the information by a user side is ensured.

Drawings

Fig. 1 is a schematic diagram of a Beidou front-end resolving GNSS receiver according to the technical scheme of the present utility model.

Fig. 2 is a schematic circuit diagram of a radio station module in the technical scheme of the utility model.

Fig. 3 is a schematic diagram of double difference observation of a solution embodiment in the technical scheme of the present utility model.

Detailed Description

For the convenience of understanding the technical scheme of the present utility model, the technical scheme of the present utility model will be further described with reference to specific examples and drawings in the specification.

The technical scheme of the utility model relates to a Beidou front-end resolving GNSS receiver which comprises a radio station module, a frequency converter, a signal channel, a memory, a CPU and a display. The frequency converter, the signal channel, the memory, the CPU and the display are connected in sequence in a signal mode. The radio station module is communicated with the CPU signals, and the radio station module transmits the signals which are calculated and output by the CPU back to the base station, the background server or the monitoring platform in a Beidou short message mode, so that the problem that the GNSS observation data quantity is large and the Beidou short message transmission short board cannot be used is solved.

In this scheme, the frequency converter includes a frequency amplifier and a frequency synthesizer. The signal passing through the pre-signal amplifier is still very weak, and the frequency amplifier is used for gain of the weak signal, so that a stable high-gain signal is obtained. The frequency synthesizer is used for combining a plurality of input frequencies into a required output frequency, namely, when the frequency synthesizer inputs the required input specified reference frequency, the frequency synthesizer is used for combining the reference frequencies, and the obtained output frequency is used for amplifying a signal received by the preposed signal amplifier by the frequency amplifier, so that the subsequent signal channel is convenient for demodulating, processing and other operations on the Beidou signal received by the receiver.

In this scheme, the signal path includes a signal despreader demodulator and a pseudorandom code generator. The signal output by the output end of the signal despreading demodulator comprises a D (t) signal, a pseudo code signal, a carrier phase signal and a Doppler frequency shift signal, wherein the D (t) signal and the pseudo code signal are input into a memory. The pseudo-random code generator comprises a C/A code generator and a P code generator, and the C/A code generator and the P code generator are both in signal connection with the frequency synthesizer. The main functions of the signal channel include searching satellites, dragging and tracking satellites, despreading the navigation message data signals, demodulating the navigation message, and performing pseudo-range measurement, carrier phase measurement and Doppler frequency shift measurement. The C/a code generator emits pseudo-random codes for coarse positioning of satellite signals and fast searching of the receiver. The P-code generator emits pseudo-random codes for more accurate positioning and time measurement.

In the scheme, the output end of the frequency amplifier is in signal connection with the input end of the signal despreading demodulator, the frequency synthesizer is in signal connection with the signal despreading demodulator and the pseudo random code generator, the output end of the signal despreading demodulator is in signal connection with the memory, the output end of the memory is in signal connection with the display, the memory is in bidirectional signal connection with the CPU, and the output end of the CPU is in signal connection with the display.

The memory stores satellite ephemeris, satellite almanac, code phase pseudorange observations, carrier phase observations and doppler shifts acquired by the receiver.

In the scheme, after the GNSS receiver captures and tracks the satellites, the GNSS satellite ephemeris is interpreted according to the data codes output by the tracking loop. When 4 satellites are locked simultaneously, the three-dimensional position of the measuring station is calculated by the C/A code pseudo-range observation value and ephemeris, and the coordinates of the points are continuously updated according to the preset position data updating rate. According to the measured point coordinates and GNSS satellite almanac, the lifting time, azimuth and altitude of all the in-orbit satellites are obtained, and the number of the in-orbit satellites and the working conditions thereof are provided for a user side, so that healthy positioning satellites with proper distribution are selected, and the purpose of improving the point location accuracy is achieved.

In this scheme, radio station module communicates with the CPU through the serial ports. The built-in radio station module of the GNSS receiver can realize two signal transmission modes of network data signal transmission and radio station data transmission on the ground section of Beidou, and the two signal transmission modes are standby. In particular, under the condition of no public network, each monitoring terminal can only transmit data to the base station gateway host through the radio station, and the base station gateway host transmits the data of the terminal to the server through 4G or short messages. If the terminal is mainly transmitted by the 4G signal, when the 4G signal of the terminal is abnormal, the terminal is switched to a radio station to transmit data to a base station gateway, so that the monitoring data of the terminal is ensured to be continuously transmitted to a server. In other words, a built-in radio station module of the GNSS receiver adopts the GNSS receiver radio station ad hoc network technology, and a plurality of Beidou monitoring receivers can construct a local area network with the Beidou reference station receivers through the radio station module under the public network-free environment so as to complete data transmission and convergence. After the CPU built in the GNSS receiver completes front end resolving, the receiver can directly output resolving results without returning original observation data to a background server, so that timeliness of monitoring information is ensured. In the scheme, the monitoring information data can be compatible with Beidou short message transmission, so that the problems of emergency communication and data transmission of a network coverage area are solved.

In the scheme, the built-in CPU of the GNSS receiver completes front end calculation, the networking distance can reach 5km under the non-shielding environment, networking of a plurality of monitoring stations and reference stations between single or adjacent hidden danger points is met, and communication cost is greatly reduced. Meanwhile, front-end networking realizes the convergence of front-end data, is a precondition for realizing front-end calculation, effectively avoids the problem of data packet loss caused by unstable 4G signals, and greatly improves the quality and precision of data calculation. And the short board which can not transmit Beidou short messages due to large GNSS observation data quantity is also solved.

In this scenario, the CPU resolution steps include, but are not limited to: firstly, correcting an observed pseudo range of a mobile station by using a pseudo range difference of a reference station according to a pseudo range difference method to obtain a pseudo range observed value corrected by the mobile station; smoothing the corrected pseudo-range observation value by using the carrier phase observation value of the mobile station to obtain a smoothed pseudo-range observation value of the mobile station; and finally, calculating the coordinates of the mobile station according to a pseudo-range difference method and evaluating the precision.

In the scheme, the input end of the frequency amplifier is connected with a preposed signal amplifier, and the preposed signal amplifier is conducted with the GNSS antenna signal.

In this scheme, the GNSS receiver still includes receiver casing and power, and the power is GNSS receiver power supply, and leading signal amplifier, GNSS antenna, radio module, frequency converter, signal path, memory, CPU and display all seal mounting in the receiver casing, realize preventing wind rain-proof dampproofing, extension GNSS receiver life ensures each part normal work in the GNSS receiver, ensures GNSS receiver and receives and stabilize efficient processing signal.

To facilitate a further understanding of the role of the present solution by those skilled in the art, a specific embodiment of the signal processing procedure is provided below with respect to the CPU.

The CPU calculates the monitoring signal transmitted by the signal channel to obtain a big Dipper short message compatible with the big Dipper short message, and the big Dipper short message is directly displayed through the display. The resolving process is as follows: firstly, correcting an observed pseudo range of a mobile station by using a pseudo range difference of a reference station according to a pseudo range difference method to obtain a pseudo range observed value corrected by the mobile station; smoothing the corrected pseudo-range observation value by using the carrier phase observation value of the mobile station to obtain a smoothed pseudo-range observation value of the mobile station; and finally, calculating the coordinates of the mobile station according to a pseudo-range difference method and evaluating the precision.

The specific resolving process is as follows: GNSS receivers arranged at two end points of the base line are fixed relative to surrounding reference objects, full observation data is obtained through continuous observation, and a base line vector is calculated and is called static relative positioning.

S static relative positioning generally adopts a measured phase pseudo-range observation value as a basic observed quantity.

The static baseline calculation process is as follows: firstly, a mathematical model is selected to establish an observation equation, then a floating solution is obtained according to the selected mathematical model (such as least square or Kalman filtering), then an ambiguity fixed solution is calculated according to the ambiguity floating solution and a variance covariance matrix fixed ambiguity thereof (using an LAMBDA method or other ambiguity searching methods), and finally the ambiguity fixed solution is calculated to be a final base line solution.

The GNSS receivers T _i (i=1, 2) disposed at the baseline end point, with respect to satellites S ^j and S ^k, make simultaneous observations at epoch T _i (i=1, 2), so that the following independent carrier phase observations can be obtained:

In static relative positioning, the relative positioning is performed by utilizing different combinations of observables to calculate differences, so that errors contained in the observables are eliminated, and the relative positioning precision is improved;

There are three ways of solving the difference: single difference, double difference and triple difference.

The single difference is the difference between the observed quantity obtained by different observation stations synchronously observing the same satellite,

The double difference is the difference between the observed quantity single differences obtained by synchronously observing the same group of satellites by different observation stations,

The three differences are the difference between the observed quantity and the double differences obtained by synchronously observing the same group of satellites in different epochs,

The phase-measuring pseudo-range observation equation according to the single-difference observation equation is as follows:

Applying the phase-measurement pseudo-range observation equation of the formula (4) to the measuring station T ₁、T₂ and substituting the equation into the formula (1) to obtain:

Let Δt (t) =δt ₂(t)-δt₁ (t),

The single difference observation equation can be written as:

it can be seen from formula (6): the clock-skew effect of the satellite can be eliminated. Meanwhile, as the distance between the two stations is short (< 100 km), the ionosphere and troposphere delay errors on the propagation paths from the same satellite to the two stations are similar, and the effect of atmospheric delay can be further obviously weakened by taking the single difference.

The double difference observation equation can be expressed as:

When the double-difference model is adopted, two GNSS receivers are arranged at a measuring station T ₁、T₂, the single difference of the satellite S ^j is delta phi ^j (T), and the single difference of the satellite S ^k is delta phi ^k (T);

As can be seen in equation (7) above, the receiver clock bias effect is completely eliminated and the atmospheric refraction residual takes the secondary difference to be negligible. The method can unify the data processing modes of the Beidou system, the GPS and the GLONASS, namely, the three systems can be processed independently, and the combination of the three systems can be processed jointly.

In conclusion, through the radio station module, on the one hand, the accurate position of monitoring points can be obtained, on the other hand, under the no public network environment, a plurality of big dipper monitoring receivers can be used for constructing a local area network with big dipper reference station receivers through the radio station module, and data transmission and convergence are completed. And the front-end calculation is completed based on the CPU calculation algorithm, the receiver directly outputs the calculation result, and the original observation data is not required to be transmitted back to the background server. The result data can be compatible with Beidou short message transmission, so that emergency communication is realized, and the problem of data transmission in a coverage area without a network is solved.

While the present utility model has been described above by way of example with reference to the embodiments and the accompanying drawings, it is apparent that the specific implementation of the present utility model is not limited by the foregoing, and it is within the scope of the present utility model to apply the inventive concept and technical solution to other situations without any substantial improvement or improvement.

Claims

1. The Beidou front-end resolving GNSS receiver is characterized by comprising a radio station module, a frequency converter, a signal channel, a memory, a CPU and a display; the frequency converter, the signal channel, the memory, the CPU and the display are sequentially connected through signals; the frequency converter comprises a frequency amplifier and a frequency synthesizer, and the signal channel comprises a signal despreading demodulator and a pseudo-random code generator;

2. The Beidou front-end resolution GNSS receiver of claim 1, wherein the signals output by the output end of the signal despreading demodulator comprise a D (t) signal, a pseudo code signal, a carrier phase signal and a Doppler shift signal, and the D (t) signal and the pseudo code signal are input into the memory.

3. The Beidou front-end resolution GNSS receiver of claim 1, wherein the pseudo-random code generator comprises a C/A code generator and a P code generator, and the C/A code generator and the P code generator are both in signal connection with the frequency synthesizer.

4. The beidou front-end resolution GNSS receiver of claim 1 wherein the station module communicates with the CPU through a serial port.

5. The Beidou front-end resolution GNSS receiver of claim 1, wherein an input end of the frequency amplifier is connected with a pre-signal amplifier, and the pre-signal amplifier is in signal conduction with a GNSS antenna.

6. The beidou front-end resolution GNSS receiver of claim 5 further comprising a receiver housing and a power supply, the power supply powering the GNSS receiver, the pre-signal amplifier, the GNSS antenna, the station module, the frequency converter, the signal channel, the memory, the CPU and the display being hermetically mounted within the receiver housing.