CN117518210A - Terminal for mine satellite navigation and positioning - Google Patents

Abstract

The invention discloses a terminal for mine satellite navigation and positioning, belongs to the technical field of wireless communication, and is mainly applied to surface mines and ports. The satellite ephemeris injection method for mine satellite navigation positioning solves the technical problem that a terminal is long in cold start positioning time caused by searching satellites for satellite signals in a full day. The satellite ephemeris injection method comprises the following steps: pre-evaluating a first terminal downloading link, a GNSS downloading link and an IGS downloading link in a first terminal to screen the downloading link which accords with a preset standard; downloading and verifying broadcast ephemeris data in a first preset time period based on the download link determined by screening, and determining valid broadcast ephemeris data based on a verification result; preprocessing effective broadcast ephemeris data to screen out healthy satellite broadcast ephemeris data; screening optimal broadcast ephemeris data based on healthy satellite broadcast ephemeris data, and packaging a group package; and injecting the optimal broadcast ephemeris data of the package group package into the second terminal.

Description

Terminal for mine satellite navigation and positioning

The present application is a divisional application of patent application with application number 202310833626X, application number 2023, month 07, 10, and entitled "satellite ephemeris injection method for mine satellite navigation positioning".

Technical Field

The invention relates to the technical field of wireless communication, in particular to a terminal for mine satellite navigation and positioning.

Background

Currently, most GNSS receivers often need to receive the 1 st subframe, the 2 nd subframe and the 3 rd subframe of the navigation message at the time of cold start to obtain the clock correction parameters and the broadcast ephemeris parameters, and then the locking and positioning of the 1 st satellite can be completed, and the receiving time of each subframe often needs 6 seconds.

According to the positioning principle of the GNSS receiver, the terminal can perform backward cross positioning after finishing cold start and positioning by at least 3 satellites and all receivers with the first 3 subframes, so that comprehensive calculation proves that the cold start positioning duration of the traditional GNSS receiver is 18 seconds at the highest. While GNSS receivers produced by current mainstream manufacturers typically require at least 25 seconds for cold start.

Meanwhile, since the GNSS signal is a CDMA (code division multiple access) signal, in general, the search of the satellite signal by the GNSS receiver is a "star searching process on a full day", that is, a pseudo-random code (i.e., PRN number) corresponding to all satellites in the sky is to be searched. Thus, when a GNSS receiver moves from an area to an area at least 500KM away, it may take a long time, typically greater than 45 seconds, for the first cold start position fix.

Therefore, it is necessary to provide a satellite ephemeris injection method for mine satellite navigation positioning, which can shorten the locking time of the first satellite for rear intersection positioning and solve the technical problem of long terminal cold start positioning time caused by searching for satellites in full days.

Disclosure of Invention

In order to solve at least one aspect of the above problems and defects in the prior art, the present invention provides a satellite ephemeris injection method for mine satellite navigation positioning, which can at least partially solve the technical problem of long cold start positioning time of a terminal caused by searching satellites in a full day for satellite signals. The technical scheme is as follows:

according to an aspect of the present invention, there is provided a satellite ephemeris injection method for mine satellite navigation positioning, the satellite ephemeris injection method comprising the steps of:

pre-evaluating a first terminal downloading link, a GNSS downloading link and an IGS downloading link in a first terminal to screen the downloading link which accords with a preset standard;

downloading and verifying broadcast ephemeris data in a first preset time period based on the download link determined by screening, and determining valid broadcast ephemeris data based on a verification result;

Preprocessing the effective broadcast ephemeris data, and screening out the broadcast ephemeris data of healthy satellites;

screening out first locked satellite and optimal broadcast ephemeris data based on the broadcast ephemeris data of the healthy satellite, and packaging the optimal broadcast ephemeris data;

and injecting the optimal broadcast ephemeris data of the package group package into a second terminal.

Specifically, the method for screening the download link meeting the preset standard comprises the following steps:

determining whether broadcast ephemeris parameters in broadcast ephemeris data acquired based on the first terminal download link, the GNSS download link and the IGS download link within a second preset time period meet the preset standard,

when the broadcast ephemeris parameters meet the preset criteria, the stability of the download link corresponding thereto is tested,

when the download link under test is a stable link, then downloading broadcast ephemeris data for the first preset time period based on the download link under test,

when the tested download link is an unstable link, rejecting the tested download link;

and when the broadcast ephemeris parameters do not meet the preset standards, eliminating the download link corresponding to the broadcast ephemeris parameters.

Further, the first terminal download link obtains the broadcast ephemeris data based on a GPS module of the first terminal, the GNSS download link obtains the broadcast ephemeris data based on a GNSS base station, the IGS download link obtains the broadcast ephemeris data based on an IGS station,

Parsing the broadcast ephemeris data to obtain broadcast ephemeris parameters,

analyzing GNSS original measurement data in the first terminal to obtain longitude and latitude information of the current position of the first terminal and analyzed navigation message information, wherein PRN data in the analyzed navigation message information is PRN numbers of broadcast ephemeris parameters in broadcast ephemeris data in a second preset time period obtained based on a GNSS base station,

resolving the broadcast ephemeris data for a second predetermined period of time based on the IGS station obtains the PRN number of the broadcast ephemeris parameter corresponding thereto,

and analyzing broadcast ephemeris data in a second preset time period obtained based on the GPS module to obtain the PRN number of the broadcast ephemeris parameters of the visible satellite in the current position.

Specifically, the preset criteria include:

the broadcast ephemeris parameters of each satellite in the downloaded broadcast ephemeris data of a plurality of satellites at a certain reference moment meet a preset format;

the second row data period age of the broadcast ephemeris parameters at a certain reference moment is consistent with the seventh row data period age; and

when the GNSS download link of the first terminal is in a connected state, the similarity between the PRN number in the broadcast ephemeris parameter at a certain reference time in the broadcast ephemeris data obtained based on the first terminal download link and the IGS download link and the PRN number in the broadcast ephemeris parameter at the certain reference time in the broadcast ephemeris data obtained based on the GNSS download link is larger than a preset proportion, or

When the GNSS download link of the first terminal is in a non-connected state, the similarity between the PRN number in the broadcast ephemeris parameter at a certain reference moment in the broadcast ephemeris data obtained by the download link of the first terminal and the PRN number in the broadcast ephemeris parameter at the certain reference moment in the broadcast ephemeris data obtained by the IGS download link is larger than a preset proportion.

Preferably, the method of determining valid broadcast ephemeris data comprises the steps of:

verifying whether broadcast ephemeris parameters in all broadcast ephemeris data meet the preset standard or not based on the downloaded broadcast ephemeris data in the first preset time period so as to screen out all broadcast ephemeris data meeting the preset standard;

and screening the broadcast ephemeris data downloaded by the download link with the highest priority from the screened broadcast ephemeris data based on the link selection priority, and obtaining the effective broadcast ephemeris data.

Specifically, the link selection priority is broadcast ephemeris data in a first preset time period downloaded based on the GNSS download link, broadcast ephemeris data in a first preset time period downloaded based on the IGS download link and broadcast ephemeris data in a first preset time period downloaded based on the first terminal download link in sequence from high to low.

Preferably, the broadcast ephemeris parameters include reference time, PRN number, kepler orbit parameters, satellite clock correction, clock speed and rate of change of clock speed,

the method for preprocessing the effective broadcast ephemeris data and screening the broadcast ephemeris data of healthy satellites comprises the following steps:

obtaining the satellite-ground distance between each satellite and the first terminal and the satellite-ground azimuth of each satellite respectively through a rear intersection method based on the longitude and latitude information of the current position of the first terminal and the broadcast ephemeris data of each satellite,

determining PRN numbers of visible satellites and transit moments of the visible satellites in the plurality of satellites at the current position based on the satellite-to-ground distance of each satellite, the satellite-to-ground azimuth of each satellite and the kepler orbit parameters of each satellite;

screening out broadcast ephemeris data of the visible satellites in all the valid broadcast ephemeris data based on the PRN numbers of the visible satellites;

and evaluating the broadcast ephemeris data of all the visible satellites based on a weighted evaluation method, and screening the broadcast ephemeris data of the healthy satellites from all the visible satellites.

More preferably, the weight evaluation method includes the steps of:

determining satellite elevation angles of all visible satellites based on the kepler orbit parameters of all visible satellites;

Acquiring weighted elevation angles of all satellites based on the satellite elevation angles and elevation angle preset weights, and acquiring satellite elevation angle sequences according to the order from big to small based on the weighted elevation angles of all visible satellites;

obtaining signal-to-noise ratios for all the visible satellites based on broadcast ephemeris data for all the visible satellites; acquiring weighted signal-to-noise ratios of all the visible satellites based on the signal-to-noise ratios and the signal-to-noise ratio preset weights, and acquiring satellite signal-to-noise ratio sequences according to the sequence from big to small based on the weighted signal-to-noise ratios of all the visible satellites;

obtaining weighted clock correction, weighted clock speed change rate and weighted satellite-to-ground distance of all the visible satellites based on the satellite clock correction and clock speed preset weight, clock speed change rate and change rate preset weight and satellite-to-ground distance and distance preset weight of all the visible satellites respectively;

based on the weighted clock correction, the weighted clock speed change rate and the weighted satellite-to-ground distance of all the visible satellites, sequencing the visible satellites according to the sequence from small to large, and respectively obtaining a satellite clock speed sequence, a satellite clock speed change rate sequence and a satellite-to-ground distance sequence;

Selecting the visible satellites positioned at the front N bits from each sequence respectively based on the satellite elevation sequence, the satellite signal-to-noise ratio sequence, the satellite clock difference sequence, the satellite clock speed change rate sequence and the satellite ground distance sequence so as to obtain preselected healthy satellites of each sequence respectively;

and screening out visible satellites which are positioned at the first N bits in all sequences simultaneously based on the preselected healthy satellites of the sequences to obtain the healthy satellites and broadcast ephemeris data corresponding to the healthy satellites.

Specifically, the method for screening out optimal broadcast ephemeris data based on the broadcast ephemeris data of the healthy satellite comprises the following steps:

sequencing broadcast ephemeris data of all healthy satellites according to the sequence from first to last of the satellite transit time to obtain a healthy satellite sequence and a healthy satellite broadcast ephemeris data sequence;

and taking the broadcast ephemeris data positioned at the first position in the broadcast ephemeris data sequence of the healthy satellite as optimal broadcast ephemeris data, wherein the satellite corresponding to the optimal broadcast ephemeris data is the first locking satellite.

Specifically, the first terminal is used as a circle center, the distance between the first terminal and the first locking satellite is used as a radius, at least two locking satellites closest to the inter-satellite distance of the first locking satellite are searched in the healthy satellite sequence,

The inter-satellite distances are obtained based on the satellite-to-ground bearing and the kepler orbit parameters of corresponding satellites in the healthy satellite broadcast ephemeris data sequence,

the first terminal injects broadcast ephemeris of the at least two locking satellites into the second terminal based on the Bluetooth module, and the second terminal obtains longitude and latitude information of the current position of the second terminal based on broadcast ephemeris data of the first locking satellite and the at least two locking satellites.

The satellite ephemeris injection method for mine satellite navigation positioning according to the embodiment of the invention has at least one of the following advantages:

(1) The satellite ephemeris injection method for mine satellite navigation positioning can solve the technical problem of long cold start positioning time of a terminal caused by searching satellites on a satellite signal all the day;

(2) The satellite ephemeris injection method for mine satellite navigation positioning can shorten the locking time of the first satellite for rear intersection positioning, so that the cold starting time of the terminal is shortened;

(3) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention avoids satellite ephemeris data injection failure by screening the sources of satellite ephemeris data and pre-evaluating broadcast ephemeris data;

(4) The satellite ephemeris injection method for mine satellite navigation positioning reduces the injection of a large amount of redundant ephemeris data (such as the ephemeris data of a non-visible satellite) by screening the sources of the satellite ephemeris data, thereby avoiding failure of solving the positioning information by using the ephemeris data or overlong solving time of the terminal and further shortening the cold starting time of the terminal;

(5) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention enables the satellite ephemeris injection method to know the current position (for example, longitude and latitude) in advance by analyzing the navigation message information downloaded by the GPS download link of the terminal in advance, so that the passing satellite can be prejudged according to the preloaded broadcast ephemeris data, the targeted satellite ephemeris package is realized, the data quantity and the injection quantity of the satellite ephemeris package are further reduced, the operation load of the terminal positioning is further reduced, and the power consumption is reduced;

(6) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention avoids the risk that the satellite ephemeris is not available for terminal injection through multiple times of screening of the download link and multiple times of screening of broadcast ephemeris data, and simultaneously avoids the risk that the cold start time is prolonged due to the unavailable satellite ephemeris;

(7) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention combines the terminal with the Bluetooth module, so that broadcast ephemeris data is more convenient and flexible to pre-inject.

Drawings

These and/or other aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart of a satellite ephemeris injection method for mine satellite navigation positioning in accordance with an embodiment of the invention;

FIG. 2 is a communication schematic diagram of the first terminal shown in FIG. 1 receiving and transmitting broadcast ephemeris data;

FIG. 3 is a schematic diagram of the satellite ephemeris injection method of FIG. 1;

fig. 4 is a schematic diagram of the broadcast satellite ephemeris data of fig. 1.

Detailed Description

The technical scheme of the invention is further specifically described below through examples and with reference to the accompanying drawings. In the specification, the same or similar reference numerals denote the same or similar components. The following description of embodiments of the present invention with reference to the accompanying drawings is intended to illustrate the general inventive concept and should not be taken as limiting the invention.

In the existing ephemeris injection technology, part of technologies inject ephemeris data into a terminal by adopting a mode of combining an upper computer with a serial port, and the scheme is complex, is not beneficial to the convenience of application and is also not beneficial to large-scale application. There are also some techniques that use long-term ephemeris injection at the terminal injection ephemeris, i.e. the actual ephemeris data is an ephemeris almanac, which has only kepler orbit 6 parameters and clock error parameters and contains no perturbation correction, instead of real-time broadcast ephemeris data, so that the technique is not usable when using a GNSS receiver as terminal positioning. There are also some techniques for injecting satellite ephemeris data into a GNSS receiver terminal by RFID radio frequency technology, which has two points of application: (1) The RFID radio frequency is interfered by electromagnetic waves, so that the packet loss phenomenon is easy to occur; (2) The transmission rate of RFID radio frequency is about 8KB/S, which is very disadvantageous for satellite ephemeris data transmission with large data volume.

Therefore, the invention provides a satellite ephemeris injection method for mine satellite navigation positioning aiming at the defects and the shortcomings of the prior art.

Referring to fig. 1, a satellite ephemeris injection method for mine satellite navigation positioning is shown in accordance with an embodiment of the invention. The satellite ephemeris injection method comprises the following steps:

pre-evaluating a first terminal downloading link, a GNSS downloading link and an IGS downloading link in a first terminal to screen the downloading link which accords with a preset standard;

downloading and verifying broadcast ephemeris data in a first preset time period based on the download link determined by screening, and determining valid broadcast ephemeris data based on a verification result;

preprocessing the effective broadcast ephemeris data, and screening out the broadcast ephemeris data of healthy satellites;

screening out optimal broadcast ephemeris data based on the broadcast ephemeris data of the healthy satellite, and packaging the optimal broadcast ephemeris data;

and injecting the optimal broadcast ephemeris data of the package group package into a second terminal.

The term "cold start" is to be understood broadly herein as the process of starting up a wireless communication module in a strange environment until the wireless communication module contacts surrounding satellites and calculates its own coordinates. The following cases all belong to cold start: (1) when the terminal is used for the first time; (2) when the terminal battery is exhausted, resulting in loss of ephemeris information; (3) The terminal is started again after being moved by more than 1000 km under the shutdown state. It follows that a cold start is the necessary procedure from the start of the terminal to the completion of the positioning.

The term "cold start time" is to be understood broadly herein as the time of positioning at the back of 3 satellites, which is a time index measuring the time from the start-up of the terminal to the acquisition of the positioning result. Typically 3 satellites collect the 1, 2, 3 sub-frames (6 seconds/frame at the receiving rate) of the navigation message (e.g., ephemeris almanac) in sync, which takes 18 seconds. While ephemeris reception for non-injection applications typically takes more than 18 seconds, since non-injection ephemeris requires signal de-modulation spreading and is more time consuming.

The term "ephemeris data" should be understood broadly herein as all satellite orbit parameters used to describe and locate the satellites in detail.

It will be appreciated by those skilled in the art that ephemeris data includes a satellite almanac, which is not useful for positioning since the satellite orbit parameters of the satellite almanac are only a fraction of the ephemeris data, i.e. the abbreviated satellite orbit parameters. Typically, a satellite almanac includes 10 satellite orbit parameters, while ephemeris data includes 16 satellite orbit parameters. At the same time, the update frequency of the satellite almanac is far lower than the update frequency of the ephemeris data. Typically, the update period of ephemeris data is 4 hours/time, while the update period of satellite almanac is half a year/time. In one example, the first terminal 10 may be a desktop computer, a portable computer, or an embedded computer. Such as desktop computers, cell phones, palm computers, tablet computers, notebook computers, car computers, head-mounted computers, and the like. The second terminal may be the same as the first terminal or may be different from the first terminal. Preferably, the first terminal is a mobile phone, the second terminal is a mining vehicle, and more preferably, the second terminal is a mining unmanned vehicle.

In one example, the first terminal 10 and the second terminal 20 are each provided with a bluetooth module through which the first terminal 10 and the second terminal 20 transmit broadcast ephemeris data. And the first terminal 10 is further provided with a GPS module to receive its own positioning data.

In one example, the first terminal 10 may download real-time broadcast satellite data through 3 links, respectively. The 3 links include a first terminal download link, a GNSS download link, and an IGS download link. The first terminal download link obtains the broadcast ephemeris data through the GPS module of the first terminal 10, the GNSS download link obtains real-time broadcast ephemeris data based on the GNSS base station, and the IGS download link obtains real-time broadcast ephemeris data based on the IGS station.

In one example, a GNSS encompasses a multi-constellation navigation satellite system. IGS is a non-physical module formed by NASA organization, i.e. a database system, that provides services to users mainly through networks. The user may acquire the relevant data not limited to the GNSS through FTP or the like.

In one example, parsing (e.g., resolving) the broadcast ephemeris data may obtain broadcast ephemeris parameters. The broadcast ephemeris parameters include reference time, PRN number, kepler orbit parameters, satellite clock correction, clock speed, clock rate of change, first perturbation correction, second perturbation correction, satellite positioning accuracy, satellite health status, ionospheric delay, cycle slip ratio, signal to noise ratio, clock slip, inter-satellite bias, cycle slip ambiguity, and PDOP precision factor.

In one example, as shown in fig. 2, the first terminal 10 is provided with a positioning system that enables link connectivity and acquisition of broadcast ephemeris data by configuring the corresponding network interface.

For example, the first terminal 10 may be configured to communicate the GNSS download link and obtain the raw measurement data of the GNSS through the GnssMeasurement interface. And then analyzing the acquired GNSS original measurement data to obtain positioning data and navigation message binary information. And then the positioning data is calculated based on PVT algorithm, so that the longitude and latitude information of the current position of the first terminal 10 is obtained, the longitude and latitude of the current position of the first terminal 10 are known in advance, preparation is made for the follow-up prejudgment of the satellite, the problem of time consuming cold start caused by searching for the satellite all the day is avoided, and then the cold start time is shortened.

After the first terminal 10 parses the GNSS raw measurement data to obtain navigation message binary information, the navigation message binary information is resolved to obtain resolved data in the Rinex format, where the resolved data includes PRN numbers of satellites transmitting the GNSS raw measurement data.

For example, the first terminal 10 is provided with a continuous reference station data input interface that obtains differential information (i.e. RTK data) of the GNSS base stations based on the configured Ntrip protocol. The RTK data includes broadcast ephemeris data. The first terminal 10 parses the broadcast ephemeris data to obtain the PRN number of the satellite that propagated the RTK data. The configuration of the Ntrip protocol can be realized by configuring parameters such as an IP address, a port number, a mounting point address, a user name, a password and the like.

For example, a URL site is preset in the first terminal 10, and then the URL site is accessed by configuring a TCP/IP protocol based on an ethernet interface, thereby linking IGS sites to acquire broadcast ephemeris data. For example, the CDDIS global data centers in the united states of the IGS station may be linked to obtain the broadcast ephemeris data, although those skilled in the art may link the remaining 5 global data centers of the IGS station to obtain the broadcast ephemeris data. The PRN number of the satellite transmitting the broadcast ephemeris data is then derived by parsing the broadcast ephemeris data.

As shown in connection with fig. 1-3, when the second terminal 20 has an ephemeris injection requirement, the first terminal 10 connected thereto is turned on a positioning system (e.g., an app installed on the first terminal 10) by sending a request to inject ephemeris, when the first terminal 10 receives the request of the second terminal 20. The first terminal 10 respectively tries to link the first terminal download link, the GNSS download link (e.g., GNSS reference station) and the IGS download link to determine the communication status of each download link, then downloads the broadcast ephemeris data in the second preset period from the communicated download link, and verifies whether the broadcast ephemeris data in the second preset period meets the preset standard, thereby eliminating the download link which does not meet the preset standard, thereby reducing the data amount of the subsequently processed satellite ephemeris data, and further shortening the time for locking (i.e., locating) the first satellite, i.e., shortening the time for cold start.

For example, if the first terminal 10 pre-detects that the first terminal download link and the GNSS download link of the first terminal download link, the GNSS download link and the IGS download link may be connected, broadcast ephemeris data in the second preset time period is downloaded through the two download links. Of course, the first terminal 10 may also pre-detect that all of the 3 download links may be connected, and download the broadcast ephemeris data in the second preset period from the 3 download links.

It will be appreciated by those skilled in the art that the second preset time period may be set to 15s, 20s, or 30s, i.e. the first terminal 10 downloads a small piece of broadcast ephemeris data in advance, which is sufficient for pre-evaluating whether the integrity of the broadcast ephemeris data downloaded by the corresponding download link, etc. meets the preset criteria. That is, the person skilled in the art can set the second preset time period according to the actual needs, as long as the data amount of the downloaded broadcast ephemeris data is enough to be used for judging whether it meets the preset standard.

For example, the connected download links are a GNSS download link and a first terminal download link, through which the first terminal 10 downloads a part of broadcast ephemeris data in advance, respectively, for 30 seconds, for verifying the integrity of the broadcast path data downloaded in the two download links and the stability of the links.

In one example, the first terminal 10 will download the broadcast ephemeris data for a plurality of satellites in each pre-detected determined download link, and the broadcast ephemeris data downloaded by each satellite is broadcast ephemeris data for the same period of time. For example, broadcast ephemeris data for about 30 satellites is downloaded in each link, and the broadcast ephemeris data downloaded by each satellite is broadcast ephemeris data in the current update period or in the last update period. In one example, the update period of the broadcast ephemeris data for a satellite is, for example, once every 2 hours.

In one example, as shown in fig. 4, the broadcast ephemeris data in the downloaded second preset time period needs to meet the following 3 points at the same time, i.e. the preset criteria include:

(1) Broadcast ephemeris data of a plurality of satellites downloaded by each download link, wherein broadcast ephemeris parameters of each satellite in the broadcast ephemeris data of the plurality of satellites at a certain reference moment meet a preset format. For example, the 3 links download broadcast ephemeris data for 30 satellites simultaneously, and the broadcast ephemeris data for each satellite is 8 rows and 4 columns for the broadcast ephemeris parameters at reference time t.

(2) The second row data period age of the broadcast ephemeris parameters at a reference time coincides with the seventh row data period age. For example, the age of the broadcast ephemeris data for each satellite at reference time t is exactly the same as the age of the data at line 2 and 7 of the broadcast ephemeris parameters.

(3) The similarity between the PRN number in the broadcast ephemeris parameter at a certain reference time in the broadcast ephemeris data obtained based on the first terminal download link and the IGS download link and the PRN number in the broadcast ephemeris parameter at the certain reference time in the broadcast ephemeris data obtained based on the GNSS download link is larger than a preset ratio when the GNSS download link of the first terminal 10 is in the connected state, or the similarity between the PRN number in the broadcast ephemeris parameter at a certain reference time in the broadcast ephemeris data obtained based on the first terminal download link and the PRN number in the broadcast ephemeris parameter at the certain reference time in the broadcast ephemeris data obtained based on the IGS download link is larger than a preset ratio when the GNSS download link of the first terminal 10 is in the disconnected state.

For example, when the communicated download link determined at the time of pre-detection is the following, then the PRN numbers of the broadcast ephemeris data are all compared with the PRN numbers of the broadcast ephemeris data in the GNSS download link. Case one: the connected download link includes a GNSS download link, a first terminal download link, and an IGS download link, in case two: the connected download link includes a GNSS download link and a first terminal download link, case three: the linked download links include a GNSS download link and an IGS download link. When the similarity between the PRN numbers of the broadcast ephemeris data of the first terminal downloading link and the IGS downloading link and the PRN numbers of the broadcast ephemeris data downloaded by the GNSS downloading link is larger than 80%, determining that the broadcast ephemeris data downloaded by the corresponding downloading link meets the preset standard (3), otherwise, determining that the broadcast ephemeris data downloaded by the corresponding downloading link does not meet the preset standard (3).

When the communicated download link determined during pre-detection is the first terminal download link and the IGS download link, namely, when the GNSS download link is in a non-communicated state, the PRN number in the broadcast ephemeris data downloaded by the first terminal download link, namely, the PRN number obtained by resolving the navigation message information, is supposed to be more than 80% similar to the PRN number in the broadcast ephemeris data downloaded by the IGS download link, and the broadcast ephemeris data downloaded by the first terminal download link and the IGS download link is determined to accord with the preset standard (3).

It will be appreciated by those skilled in the art that the predetermined ratio may be greater than 80%, although it may be greater than 85%, or the dissimilar ratio may be less than 20%, less than 25%, etc.

After the broadcast ephemeris data downloaded by the download link meets the preset standard (1) - (3), the stability of the download link should be tested, and when the download link is determined to be unstable, the unstable download link is removed, so as to further reduce the amount of the subsequent redundant broadcast ephemeris data, and further shorten the cold start time of the second terminal 20.

Therefore, the method for screening the download links meeting the preset standard comprises the following steps:

judging whether broadcast ephemeris parameters in broadcast ephemeris data in a second preset time period acquired based on a first terminal downloading link, a GNSS downloading link and an IGS downloading link meet the preset standard or not: when the broadcast ephemeris parameters meet the preset standards, testing the stability of the download link corresponding to the broadcast ephemeris parameters, and when the tested download link is a stable link, downloading broadcast ephemeris data in the first preset time period based on the tested download link; when the tested download link is an unstable link, rejecting the unstable download link; and when the broadcast ephemeris parameters do not meet the preset standard, eliminating the downloading link corresponding to the broadcast ephemeris parameters which do not meet the preset standard.

In one example, the GNSS download link and IGS download link may verify download link stability through a network handshake protocol. For example, when the GNSS download link downloads the broadcast ephemeris data, the first terminal 10 sends a connection establishment request to the GNSS base station through the ntrip1.0 protocol, and establishes a connection, and then the GNSS base station pushes Range original data or RTCM data to the CORS server, and when the Range original data is included in the GNSS original detection data received by the first terminal 10, the first terminal 10 determines that the GNSS download link can acquire the broadcast ephemeris data in real time and the GNSS download link is a stable link. When the GNSS original detection data is RTCM data, it is determined that the GNSS download link cannot acquire broadcast ephemeris data in real time, then whether navigation message information is contained in the RTCM data needs to be judged, when the navigation message information is contained, the GNSS download link is determined to be a stable link, and when the navigation message information is not contained, the GNSS download link is determined to be an unstable link.

In one example, the IGS download link performs acquisition of broadcast ephemeris data mainly through FTP, and establishes a connection with the FTP server through a TCP three-way handshake. And carrying out loop handshake verification on the data URL corresponding to the IGS site in the domestic area to determine the stability of the IGS download link.

In one example, the first terminal download link determines the stability of the first terminal download link by the GPS module determining the signal strength of the first terminal 10.

Through the heavy screening, a stable and reliable downloading link can be obtained, so that the risk that subsequently downloaded broadcast ephemeris data is unavailable is avoided.

After establishing a reliable download link, the first terminal 10 begins to download the complete broadcast ephemeris data for a first predetermined period of time. For example, each download link downloads broadcast ephemeris data for 30 satellites, and downloads broadcast ephemeris data for the previous period when the satellite is during the current update period, and downloads broadcast ephemeris data that is currently updated in real-time when the satellite is during the current update period. That is, the downloaded ephemeris data is not only the ephemeris data but also other necessary data except for the ephemeris, i.e., the downloaded ephemeris data is the broadcast ephemeris data of the previous update period or the entire current update period. It will be appreciated by those skilled in the art that the first preset time period is the time it takes for the first terminal 10 to download the broadcast ephemeris data of the previous update period or the current update period, and may be set to 1min, 1.5min, 2min.

For example, the GNSS download link may update ephemeris data once at 2 hours. The GNSS reference station device acquires the latest updated ephemeris data, and the differential data service merchant continuously and repeatedly transmits the ephemeris data to the user according to service requirements. The user can collect the ephemeris data sent by the service provider within 2 minutes.

In one example, the update period may be set to 30 min/time, 1 hour/time, 2 hours/time, 3 hours/time, etc., as may be done by those skilled in the art depending on the actual situation. The broadcast ephemeris data acquired during the previous period is downloaded when the satellite is during the new update period (i.e., during the update interval), and the real-time broadcast ephemeris data is updated when the satellite is just in the current update period (i.e., during the update interval).

And after each download link downloads all the real-time broadcast ephemeris data, screening and verifying the downloaded broadcast ephemeris data again to obtain effective and reliable broadcast ephemeris data, namely rejecting broadcast ephemeris data which do not meet the requirements, so as to avoid unavailability of subsequent broadcast ephemeris data.

The method of determining valid broadcast ephemeris data comprises the steps of:

verifying whether broadcast ephemeris parameters in all broadcast ephemeris data meet the preset standard or not based on the downloaded broadcast ephemeris data in the first preset time period so as to screen out all broadcast ephemeris data meeting the preset standard;

And screening the broadcast ephemeris data downloaded by the download link with the highest priority from the screened broadcast ephemeris data based on the link selection priority, and obtaining the effective broadcast ephemeris data.

That is, it is preferred that all the broadcast ephemeris data downloaded at this time be verified according to the preset standard for verifying the broadcast ephemeris data in the second time period, and the preset standard for verifying the method and the reference are completely consistent with the principle and standard of the method for verifying the broadcast ephemeris data in the second time period, which are not described in detail herein.

After verifying all broadcast ephemeris data downloaded by each download link, eliminating broadcast ephemeris data which do not meet the preset standard, and reserving broadcast ephemeris data which meet the preset standard. And selecting effective broadcast ephemeris data from the broadcast ephemeris data meeting the preset standard again based on the link selection priority, namely, selecting the broadcast ephemeris data from the most reliable downloading link and simultaneously downloading the data meeting the preset standard, namely, finally obtaining the most reliable broadcast ephemeris data.

In one example, the link selection priorities are, in order from high to low, broadcast ephemeris data in a first preset time period downloaded based on the GNSS download link, broadcast ephemeris data in a first preset time period downloaded based on the IGS download link, and broadcast ephemeris data in a first preset time period downloaded based on the first terminal download link.

For example, when only the GNSS download link and the first terminal download link download broadcast ephemeris data (i.e., complete broadcast ephemeris data) for a first predetermined period of time, all broadcast ephemeris data downloaded by them are filtered according to the predetermined criteria. When the complete broadcast ephemeris data downloaded by the GNSS download link and the first terminal download link meet the preset standard, determining the effective broadcast ephemeris data according to the link selection priority. And determining the broadcast ephemeris data downloaded by the GNSS download link as valid broadcast ephemeris data because the priority of the GNSS download link is higher than that of the first terminal download link.

In one example, the method of preprocessing the valid broadcast ephemeris data and screening out broadcast ephemeris data for healthy satellites comprises the steps of:

acquiring satellite-ground distance between each satellite and the first terminal and satellite-ground azimuth of each satellite through a rear intersection method based on longitude and latitude information of the current position of the first terminal and broadcast ephemeris data of each satellite;

determining PRN numbers of visible satellites and transit moments of the visible satellites in the plurality of satellites at the current position based on the satellite-to-ground distance of each satellite, the satellite-to-ground azimuth of each satellite and the kepler orbit parameters of each satellite;

Screening out broadcast ephemeris data of the visible satellites in all the valid broadcast ephemeris data based on the PRN numbers of the visible satellites;

the broadcast ephemeris data of all the visible satellites are evaluated based on a weighted evaluation method to screen the broadcast ephemeris data of the healthy satellites from all the visible satellites.

In one example, the latitude and longitude data of the WGS84 coordinate system of each satellite are calculated according to the broadcast ephemeris data of each satellite, and the satellite-to-ground distance between each satellite and the first terminal and the satellite-to-ground azimuth of each satellite are calculated according to the latitude and longitude information of the current position of the first terminal 10 and the latitude and longitude data of the WGS84 coordinate system through a back intersection method. Then, a visible range of a satellite sky between 10 degrees of an altitude angle (ELV) and zenith angles is determined based on longitude and latitude information of the current position, and then PRN numbers of satellites in the visible range and transit moments of the satellites in the visible range can be obtained based on the visible range, the satellite-to-ground distance of each satellite, the satellite-to-ground azimuth of each satellite and the Kepler orbit parameters of each satellite, and the satellites found based on the PRN numbers are visible satellites. Satellites outside the visible range will be rejected from the valid satellites as non-passing satellites, where only valid broadcast satellite data for the visible satellites is retained. By such a design, the cold start time is further reduced.

In one example, the visible satellite is a satellite that is within a visible range. In one example, the method of determining a visible satellite may also be determined based on an elevation angle formed between the first terminal 10 and the satellite. For example, when the satellite elevation angle of the first terminal 10 with respect to the ground plane is set to 0, the satellite elevation angle formed between the first terminal 10 and the satellite is within the satellite elevation angle range of 0 to 90 °, and it is determined as a visible satellite. In one example, the back-convergence method is to determine the longitude and latitude of the satellite based on the satellite elevation and azimuth of the visible satellite. The satellite-to-earth distance is the distance between the satellite and the first terminal 10, and the latitude and longitude of the first terminal 10 are obtained via broadcast ephemeris data downloaded by GPS. The satellite-ground distance is obtained through calculation of longitude and latitude of a satellite and longitude and latitude of a first terminal. In one example, the azimuth angle is obtained by kepler orbit parameter calculation of the satellite.

In one example, the weighted evaluation method includes the steps of:

determining satellite elevation angles of all visible satellites based on kepler orbit parameters of all visible satellites;

acquiring weighted elevation angles of all satellites based on the satellite elevation angles and elevation angle preset weights, and acquiring satellite elevation angle sequences according to the sequence from large to small based on the weighted elevation angles of all visible satellites;

Obtaining signal-to-noise ratios of all the visible satellites based on broadcast ephemeris data of all the visible satellites; acquiring weighted signal-to-noise ratios of all the visible satellites based on the signal-to-noise ratios and preset signal-to-noise ratio weights, and acquiring satellite signal-to-noise ratio sequences according to the sequence from big to small based on the weighted signal-to-noise ratios of all the visible satellites;

the method comprises the steps of respectively obtaining weighted clock correction, weighted clock speed change rate and weighted satellite-ground distance of all visible satellites based on satellite clock correction and clock speed preset weight, clock speed change rate and change rate preset weight and satellite-ground distance and distance preset weight of all visible satellites;

based on the weighted clock correction, the weighted clock speed change rate and the weighted satellite-to-ground distance of all the visible satellites, sequencing the visible satellites according to the sequence from small to large, and respectively obtaining a satellite clock speed sequence, a satellite clock speed change rate sequence and a satellite-to-ground distance sequence;

based on the satellite elevation angle sequence, the satellite signal-to-noise ratio sequence, the satellite clock difference sequence, the satellite clock speed change rate sequence and the satellite ground distance sequence, respectively selecting the visible satellite positioned at the front N bits from each sequence to respectively obtain preselected healthy satellites of each sequence;

The satellites in view are screened based on the preselected healthy satellites for each sequence, with all sequences being located at the top N simultaneously, to obtain the healthy satellite and the corresponding healthy satellite.

In one example, the elevation preset weight may be set in a range of 0.4 to 0.8, preferably 0.7;

the setting range of the preset weight of the signal to noise ratio can be 0.3-0.7, and is preferably 0.6;

the setting range of the clock difference preset weight can be 0.15-0.5, and is preferably 0.3;

the setting range of the clock speed preset weight can be 0.2-0.5, and is preferably 0.3;

the setting range of the preset weight of the clock rate change rate can be 0.25-0.6, and is preferably 0.25;

the set range of the star-to-ground distance preset weight can be 0.3-0.8, and is preferably 0.75.

In one example, N represents a natural number, and the value range of N may be set to 3 to 20. Of course, the value of N can be determined according to the number of visible satellites obtained by screening, and the value range of N can be 20 minutes to 50 minutes of the total number of visible satellites. For example, when the total number of visible satellites obtained after screening is 20 and 50 is 10, N may be set to 10, i.e., the satellites located in the first 10 bits of the current sequence are screened as preselected healthy satellites. When the satellites at the first 10 bits are selected from the satellite elevation sequence, the satellite signal-to-noise sequence, the satellite clock difference sequence, the satellite clock speed change rate sequence, and the satellite earth distance sequence, respectively, the satellites at the first 10 bits of all sequences constitute the preselected healthy satellite.

The preselected healthy satellites are then screened and satellites that have appeared in each sequence at the same time can be found out as healthy satellites. For example, from among the preselected healthy satellites A, B, C, D and F, only the a and C satellites are simultaneously present in the first 10 bits of each of the satellite elevation sequence, the satellite signal-to-noise sequence, the satellite clock difference sequence, the satellite clock speed rate of change sequence, and the satellite ground distance sequence, the a and C satellites are determined to be healthy satellites.

That is, the broadcast ephemeris data of the satellite with higher satellite positioning precision, better satellite health state, smaller first perturbation correction, smaller second perturbation correction, smaller ionospheric delay, smaller cycle slip ratio, high signal to noise ratio and smaller clock error can be obtained through the weighted evaluation screening. For example, broadcast ephemeris data of 4 to 6 satellites are selected from all broadcast ephemeris data, and the broadcast ephemeris data of 4 to 6 satellites are broadcast ephemeris data of healthy satellites.

For example, the complete broadcast ephemeris data of all satellites downloaded by the GNSS download link is firstly selected from the broadcast ephemeris data of the visible satellites based on the latitude and longitude information of the current position of the first terminal 10, then 4 to 6 visible satellites are selected again as healthy satellites based on the weighted evaluation method, and the broadcast ephemeris data of the 4 to 6 visible satellites are used as the broadcast ephemeris data of the healthy satellites.

In one example, the screening of optimal broadcast ephemeris data based on broadcast ephemeris data of the healthy satellite comprises the steps of:

sequencing broadcast ephemeris data of all healthy satellites according to the sequence from first to last of the satellite transit time to obtain a healthy satellite sequence and a healthy satellite broadcast ephemeris data sequence;

and taking the broadcast ephemeris data positioned at the first position in the broadcast ephemeris data sequence of the healthy satellite as optimal broadcast ephemeris data, wherein the satellite corresponding to the optimal broadcast ephemeris data is the first locking satellite. For example, the obtained broadcast ephemeris data of 6 healthy satellites are ranked according to the sequence of their transit moments (calculated in the previous step) to obtain a healthy satellite sequence and a healthy satellite broadcast ephemeris data sequence, so that the broadcast ephemeris data of the satellite in the earliest transit can be arranged in the forefront, and the broadcast ephemeris data of the satellite in the latest transit can be arranged in the rearmost. And then, determining the broadcast ephemeris data of the earliest healthy satellite in the border, namely the broadcast ephemeris data ranked first as optimal broadcast ephemeris data, and determining the satellite corresponding to the optimal broadcast ephemeris data as the first locked satellite.

In one example, the order of the broadcast ephemeris data may also be determined based on a preset PRN priority when obtaining the optimal broadcast ephemeris data. For example, when the PRN number of the A satellite has a higher priority than the PRN number of the C satellite, then the broadcast ephemeris data of the A satellite is determined to be the optimal broadcast ephemeris data and the A satellite is determined to be the first locked satellite.

In one example, the broadcast ephemeris data may also be obtained from other download links at the same time as the encapsulation of the optimal broadcast ephemeris data for the first locked satellite. For example, when the optimal broadcast ephemeris data is broadcast ephemeris data downloaded by the GNSS download link, the broadcast ephemeris data downloaded by the GPS download link may be packaged at the same time for standby.

When the broadcast ephemeris of the first locked satellite is packaged, part of broadcast ephemeris parameters in broadcast ephemeris data at a single moment are subjected to data preposition, so that the second terminal 10 can perform calculation and positioning faster and better when in positioning operation. For example, the 17 th-24 th row of broadcast ephemeris parameters of broadcast ephemeris data at a single moment are mentioned to the 9 th-16 th row, and the original 9 th-16 th row of broadcast ephemeris parameters are placed on the 17 th-24 th row to realize data preposition. Broadcast ephemeris data of the first locked satellite packaged by the package is injected into the second terminal 20, and the first terminal 10 may perform a rear-intersection calculation with the first locked satellite search to locate at least two locked satellites of the second terminal 20.

In one example, after the 1 st positioning satellite is locked, i.e., the first locked satellite is determined, a circle is drawn with the first terminal 10 as a center of a circle and a distance between the first terminal 10 and the first locked satellite as a radius (e.g., 20 km, 50 km), and a satellite sky within the circle is the determined search range. And searching at least two locking satellites closest to the inter-satellite distance of the first locking satellite based on the satellite searching range and the healthy satellite sequence. In one example, the at least two locked satellites may be 2 locked satellites, 3 locked satellites, i.e., 2 or 3 locked satellites closest to the first locked satellite in the range of the search satellite and in the healthy satellite sequence.

Of course, those skilled in the art can also determine the second and third locked satellites that can be used for back-intersection calculation with the first locked satellite by taking the satellite-to-ground distance and the transit time into consideration. And then, the optimal broadcast ephemeris data of the second locking satellite and the third locking satellite are injected into the second terminal 20 through the Bluetooth module, and the second terminal 20 calculates longitude and latitude information of the current position of the second terminal 20 based on the broadcast ephemeris data of the first locking satellite, the second locking satellite and the third locking satellite, so that the cold starting process of the whole second terminal 20 is completed.

The satellite ephemeris injection method for mine satellite navigation positioning according to the embodiment of the invention has at least one of the following advantages:

(1) The satellite ephemeris injection method for mine satellite navigation positioning can solve the technical problem of long cold start positioning time of a terminal caused by searching satellites on a satellite signal all the day;

(2) The satellite ephemeris injection method for mine satellite navigation positioning can shorten the locking time of the first satellite for rear intersection positioning, so that the cold starting time of the terminal is shortened;

(3) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention avoids satellite ephemeris data injection failure by screening the sources of satellite ephemeris data and pre-evaluating broadcast ephemeris data;

(4) The satellite ephemeris injection method for mine satellite navigation positioning reduces a large amount of redundant ephemeris data injection by screening the sources of satellite ephemeris data, thereby avoiding failure of solving the positioning information by using the ephemeris data or overlong solving time of the terminal and shortening the cold starting time of the terminal;

(5) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention enables the satellite ephemeris injection method to know the current position (for example, longitude and latitude) in advance by analyzing the navigation message information downloaded by the GPS download link of the terminal in advance, so that the passing satellite can be prejudged according to the preloaded broadcast ephemeris data, the targeted satellite ephemeris package is realized, the data quantity and the injection quantity of the satellite ephemeris package are further reduced, the operation load of the terminal positioning is further reduced, and the power consumption is reduced;

(6) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention avoids the risk that the satellite ephemeris is not available for terminal injection through multiple times of screening of the download link and multiple times of screening of broadcast ephemeris data, and simultaneously avoids the risk that the cold start time is prolonged due to the unavailable satellite ephemeris;

(7) The satellite ephemeris injection method for mine satellite navigation positioning provided by the invention combines the terminal with the Bluetooth module, so that broadcast ephemeris data is more convenient and flexible to pre-inject.

Although a few embodiments of the present general inventive concept have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims (11)

1. A terminal for mine satellite navigation positioning, wherein,

the terminal is a first terminal, a positioning system is arranged in the first terminal, the first terminal and the second terminal are both provided with Bluetooth modules, the first terminal and the second terminal transmit broadcast ephemeris data through the Bluetooth modules,

when the second terminal has ephemeris injection requirement, the first terminal connected with the second terminal sends a request for injecting ephemeris, when the first terminal receives the request of the second terminal, the positioning system is opened, the positioning system realizes the communication of a link and the acquisition of broadcast ephemeris data by configuring a corresponding network interface,

The ephemeris injection method comprises the following steps:

pre-evaluating a first terminal downloading link, a GNSS downloading link and an IGS downloading link in the first terminal so as to screen the downloading link which accords with a preset standard;

downloading and verifying broadcast ephemeris data in a first preset time period based on the download link determined by screening, and determining valid broadcast ephemeris data based on a verification result;

preprocessing the effective broadcast ephemeris data, and screening out the broadcast ephemeris data of healthy satellites;

screening out first locked satellite and optimal broadcast ephemeris data based on the broadcast ephemeris data of the healthy satellite, and packaging the optimal broadcast ephemeris data;

and injecting the optimal broadcast ephemeris data of the package group package into a second terminal.

2. The terminal for mine satellite navigation positioning of claim 1, wherein,

the method for screening the download links meeting the preset standard comprises the following steps:

determining whether broadcast ephemeris parameters in broadcast ephemeris data acquired based on the first terminal download link, the GNSS download link and the IGS download link within a second preset time period meet the preset standard,

when the broadcast ephemeris parameters meet the preset criteria, the stability of the download link corresponding thereto is tested,

When the download link under test is a stable link, then downloading broadcast ephemeris data for the first preset time period based on the download link under test,

when the tested download link is an unstable link, rejecting the tested download link;

and when the broadcast ephemeris parameters do not meet the preset standards, eliminating the download link corresponding to the broadcast ephemeris parameters.

3. The terminal for mine satellite navigation positioning of claim 2, wherein,

the GNSS download link and IGS download link verify the stability of the download link through a network handshake protocol,

the first terminal download link obtains the broadcast ephemeris data based on a GPS module of the first terminal, the GNSS download link obtains the broadcast ephemeris data based on a GNSS base station, the IGS download link obtains the broadcast ephemeris data based on an IGS station,

parsing the broadcast ephemeris data to obtain broadcast ephemeris parameters,

analyzing GNSS original measurement data in the first terminal to obtain longitude and latitude information of the current position of the first terminal and analyzed navigation message information, wherein PRN data in the analyzed navigation message information is PRN numbers of broadcast ephemeris parameters in broadcast ephemeris data in a second preset time period obtained based on a GNSS base station,

Resolving the broadcast ephemeris data for a second predetermined period of time based on the IGS station obtains the PRN number of the broadcast ephemeris parameter corresponding thereto,

and analyzing broadcast ephemeris data in a second preset time period obtained based on the GPS module to obtain the PRN number of the broadcast ephemeris parameters of the visible satellite in the current position.

4. A terminal for mine satellite navigation positioning according to claim 2 or 3, wherein,

the preset standard comprises the following steps:

the broadcast ephemeris parameters of each satellite in the downloaded broadcast ephemeris data of a plurality of satellites at a certain reference moment meet a preset format;

the second row data period age of the broadcast ephemeris parameters at a certain reference moment is consistent with the seventh row data period age; and

when the GNSS download link of the first terminal is in a connected state, the similarity between the PRN number in the broadcast ephemeris parameter at a certain reference time in the broadcast ephemeris data obtained based on the first terminal download link and the IGS download link and the PRN number in the broadcast ephemeris parameter at the certain reference time in the broadcast ephemeris data obtained based on the GNSS download link is larger than a preset proportion, or

When the GNSS download link of the first terminal is in a non-connected state, the similarity between the PRN number in the broadcast ephemeris parameter at a certain reference moment in the broadcast ephemeris data obtained by the download link of the first terminal and the PRN number in the broadcast ephemeris parameter at the certain reference moment in the broadcast ephemeris data obtained by the IGS download link is larger than a preset proportion.

5. The terminal for mine satellite navigation positioning of claim 4, wherein,

the method of determining valid broadcast ephemeris data comprises the steps of:

verifying whether broadcast ephemeris parameters in all broadcast ephemeris data meet the preset standard or not based on the downloaded broadcast ephemeris data in the first preset time period so as to screen out all broadcast ephemeris data meeting the preset standard;

and screening the broadcast ephemeris data downloaded by the download link with the highest priority from the screened broadcast ephemeris data based on the link selection priority, and obtaining the effective broadcast ephemeris data.

6. The terminal for mine satellite navigation positioning of claim 5, wherein,

the link selection priority is, from high to low, broadcast ephemeris data in a first preset time period downloaded based on a GNSS download link, broadcast ephemeris data in a first preset time period downloaded based on an IGS download link and broadcast ephemeris data in a first preset time period downloaded based on a first terminal download link.

7. The terminal for mine satellite navigation positioning of claim 5, wherein,

broadcast ephemeris parameters include reference time, PRN number, kepler orbit parameters, satellite clock correction, clock speed and clock speed rate of change,

The method for preprocessing the effective broadcast ephemeris data and screening the broadcast ephemeris data of healthy satellites comprises the following steps:

obtaining the satellite-ground distance between each satellite and the first terminal and the satellite-ground azimuth of each satellite respectively through a rear intersection method based on the longitude and latitude information of the current position of the first terminal and the broadcast ephemeris data of each satellite,

determining PRN numbers of visible satellites and transit moments of the visible satellites in the plurality of satellites at the current position based on the satellite-to-ground distance of each satellite, the satellite-to-ground azimuth of each satellite and the kepler orbit parameters of each satellite;

screening out broadcast ephemeris data of the visible satellites in all the valid broadcast ephemeris data based on the PRN numbers of the visible satellites;

and evaluating the broadcast ephemeris data of all the visible satellites based on a weighted evaluation method, and screening the broadcast ephemeris data of the healthy satellites from all the visible satellites.

8. The terminal for mine satellite navigation positioning of claim 7, wherein,

the weighting evaluation method comprises the following steps:

determining satellite elevation angles of all visible satellites based on the kepler orbit parameters of all visible satellites;

Acquiring weighted elevation angles of all satellites based on the satellite elevation angles and elevation angle preset weights, and acquiring satellite elevation angle sequences according to the order from big to small based on the weighted elevation angles of all visible satellites;

obtaining signal-to-noise ratios for all the visible satellites based on broadcast ephemeris data for all the visible satellites; acquiring weighted signal-to-noise ratios of all the visible satellites based on the signal-to-noise ratios and the signal-to-noise ratio preset weights, and acquiring satellite signal-to-noise ratio sequences according to the sequence from big to small based on the weighted signal-to-noise ratios of all the visible satellites;

obtaining weighted clock correction, weighted clock speed change rate and weighted satellite-to-ground distance of all the visible satellites based on the satellite clock correction and clock speed preset weight, clock speed change rate and change rate preset weight and satellite-to-ground distance and distance preset weight of all the visible satellites respectively;

based on the weighted clock correction, the weighted clock speed change rate and the weighted satellite-to-ground distance of all the visible satellites, sequencing the visible satellites according to the sequence from small to large, and respectively obtaining a satellite clock speed sequence, a satellite clock speed change rate sequence and a satellite-to-ground distance sequence;

Selecting the visible satellites positioned at the front N bits from each sequence respectively based on the satellite elevation sequence, the satellite signal-to-noise ratio sequence, the satellite clock difference sequence, the satellite clock speed change rate sequence and the satellite ground distance sequence so as to obtain preselected healthy satellites of each sequence respectively;

and screening out visible satellites which are positioned at the first N bits in all sequences simultaneously based on the preselected healthy satellites of the sequences to obtain the healthy satellites and broadcast ephemeris data corresponding to the healthy satellites.

9. The terminal for mine satellite navigation positioning of claim 7, wherein,

the set range of the preset weight of the signal to noise ratio can be 0.3-0.7, the set range of the preset weight of the clock difference can be 0.15-0.5, the set range of the preset weight of the clock speed can be 0.2-0.5, the set range of the preset weight of the clock speed change rate can be 0.25-0.6, and the set range of the preset weight of the star-to-ground distance can be 0.3-0.8.

10. The terminal for mine satellite navigation positioning of claim 8, wherein,

the method for screening out the optimal broadcast ephemeris data based on the broadcast ephemeris data of the healthy satellite comprises the following steps:

Sequencing broadcast ephemeris data of all healthy satellites according to the sequence from first to last of the satellite transit time to obtain a healthy satellite sequence and a healthy satellite broadcast ephemeris data sequence;

and determining broadcast ephemeris data positioned at the first position in the healthy satellite broadcast ephemeris data sequence as optimal broadcast ephemeris data, wherein a satellite corresponding to the optimal broadcast ephemeris data is the first locking satellite.

11. The terminal for mine satellite navigation positioning of claim 10, wherein,

searching at least two locking satellites closest to the inter-satellite distance of the first locking satellite in the healthy satellite sequence by taking the first terminal as a circle center and taking the distance between the first terminal and the first locking satellite as a radius,

the inter-satellite distances are obtained based on the satellite-to-ground bearing and the kepler orbit parameters of corresponding satellites in the healthy satellite broadcast ephemeris data sequence,

the first terminal injects broadcast ephemeris of the at least two locking satellites into the second terminal based on the Bluetooth module, and the second terminal obtains longitude and latitude information of the current position of the second terminal based on broadcast ephemeris data of the first locking satellite and the at least two locking satellites.