CN212460560U

CN212460560U - Data transmission system based on GPRS (general packet radio service) land use after data collection change

Info

Publication number: CN212460560U
Application number: CN202021724938.5U
Authority: CN
Inventors: 蔡靖宇
Original assignee: Jiangsu Province Jinwei Mapping Service Center
Current assignee: Jiangsu Jinwei Surveying And Mapping Co ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2021-02-02
Anticipated expiration: 2030-08-18

Abstract

Data transmission system after utilizing change data acquisition based on GPRS land includes: GPS satellite: accurately positioning and collecting the position information of the land use change pattern spots, realizing field data collection, and transmitting the collected field data to the mobile terminal in real time; a mobile terminal: a database and a management system thereof which are established based on land survey are built in, so that data acquisition and data analysis of land utilization change are realized; the mobile terminal also comprises a built-in GPS satellite positioning antenna receiver, a GIS system and a GPRS module; the GPS satellite positioning antenna receiver: receiving field data sent by a GPS satellite, and leading the field data into a GIS system in real time through a serial port so as to enable positioning information of the GPS to be displayed on an electronic map accurately in real time; the GPRS module realizes wireless link between the mobile terminal and the remote server through a GPRS network.

Description

Data transmission system based on GPRS (general packet radio service) land use after data collection change

Technical Field

The utility model relates to a data transmission system especially relates to a data transmission system based on behind GPRS land use change data acquisition.

Background

Land utilization change investigation is the most basic and important link in land management, is extremely complex work and needs to process a large amount of data. The traditional means such as performing field survey and painting by using tools such as aerial survey pictures, total stations, tape gauges and the like not only needs to invest a large amount of manpower and material resources, but also has tedious internal processing, overlong investigation period and can not ensure the precision of data. How to improve the efficiency and quality of land information change is very important for land management informatization construction.

The current technical means are mainly GPS/PDA, aerial survey, satellite remote sensing and field paper inspection. The development of the GPS/PDA realizes that manual labor is changed into intelligent operation, the working efficiency of workers in the land management basic level is improved, the GPS/PDA takes the PDA as a basic hardware platform, the storage capacity is small, the image operation is slow, the operation of each layer is limited, and the GPS/PDA is mainly applied to field positioning acquisition at present and needs to be combined with the field to complete the work. Aerial survey is mainly suitable for updating investigation, and is difficult to apply in changing investigation due to high price, complex processing technology and long period; satellite remote sensing is superior to dynamic monitoring of land utilization, and field investigation can be guided by finding out a change pattern spot; the currently widely adopted 'direct field survey and drawing' method is to measure by a conventional method by taking a paper picture as a work base picture, manually record related change information by changing a survey table, and then perform field data processing and area statistics, and has a large workload.

The Geographic Information System (GIS for short) is a product of the development of modern science and technology and social requirements, and is a product of crossing various disciplines including natural science, engineering technology, social science and the like. Since the formation of geographic information systems in the sixties of the twentieth century, along with the development of related technologies such as computer technology, database technology, remote sensing technology, digital graphic image technology, etc., geographic information systems have been widely used in the fields of surveying and mapping, geology, environment, land management, etc. In the nineties of the twentieth century, along with the development of internet technology, the combination of a geographic information system and the internet generates an internet geographic information system, the internet geographic information system changes the means and the mode for combining the acquisition, sharing, distribution and analysis of spatial information, is a geographic information system running on the internet, and can also be called a Web-based geographic information system, not only provides distributed geographic information data for global users, but also provides a tool for distributed geographic information processing and analysis, the internet geographic information system provides hypermedia, interactive and distributed spatial information for the users by using superior networks, shows the advantages that the traditional GIS does not have, the appearance and the development of devices such as palm computers bring opportunities for the development of movement, the mobility and the portability of the devices provide good support for the movement, since information in life is related to spatial information, people hope to obtain real-time geographic information in a mobile environment urgently along with development and wide application of embedded information devices, a mobile GIS is born on the background, integrates advanced computer technology, mobile communication technology and satellite navigation positioning technology, expands the application field of the GIS system, improves convenience and real-time performance of information acquisition and data processing, is a comprehensive digital information system of various advanced technologies, can provide a convenient, quick and reliable information query and decision-making means for clients, is an embedded latest development form, meets the requirement of modern life characterized by high mobility, and can represent the future development trend of the geographic information system. In a conventional GIS, the relationship between spatial objects is constant or relatively static, but in a mobile GIS, the described objects can change the positions of objects around the described objects, and the mobile GIS not only refers to using the GIS in a mobile environment, but also more importantly, uses the GIS to describe the moving objects, and the mobile GIS mainly comprises a mobile terminal device, a wireless communication network, a geographic application server and a spatial database.

The geographic information server is the core of the mobile GIS and is mainly responsible for functions of data management, data storage, data updating, spatial information query and analysis, service release, service management and the like of the system. The geographic information server can be a distributed system, the execution of the service can be distributed on different servers, and the geographic information server can be connected with the mobile GIS client through the mobile wireless network, so that the data synchronization of the mobile client and the server is realized. AieGISServer from Esri, SuperMapiserver from hypergraph, open-source Geoservermapserver, etc. are geographic information servers.

The mobile GIS system is finally operated on various mobile terminal devices, and the main purpose of the mobile GIS system is to facilitate users to use related functions of the GIS in the movement, such as mobile data acquisition, confirmation of land use change, navigation positioning and the like, so that the mobility is the most remarkable characteristic of the mobile GIS. The mobile terminal comprises mobile terminal equipment such as a GPS intelligent mobile phone, a vehicle-mounted mobile terminal, a portable computer and the like.

The mobile terminal device is a portable, low-function device, suitable for geographic application, and can be used for fast and accurate positioning and geographic identification, the hardware mainly comprises a portable computer, a palm computer, a GPS positioning instrument and the like, the software mainly comprises application software such as an embedded GIS and the like, a user sends a service request to a remote geographic information server through the terminal, then receives a calculation result transmitted by the server and displays the calculation result, the application of the mobile GIS is based on the mobile terminal device, and the mobile terminal device has the characteristics of portability, low consumption, strong calculation capability and the like, and is increasingly becoming the first choice of the user.

The GPS system mainly comprises a space constellation part, a ground monitoring part and user equipment. The GPS space part consists of 24 GPS working satellites, 21 working satellites and 3 in-orbit spare satellites jointly form a GPS satellite constellation which is distributed on 6 orbital planes with 55-degree inclination angles, each orbital plane is provided with 4 satellites, and at least four GPS satellites are observed when positioning is carried out by utilizing GPS signals. The ground monitoring system comprises a master control station positioned in the United states of America Colorado, three injection stations and five monitoring stations which are distributed globally, and the monitoring of the operation of the GPS satellite is realized. The user equipment part mainly refers to a GPS receiver and consists of a host, an antenna, a power supply, data processing software and the like. The satellite tracking system has the main functions of receiving signals transmitted by satellites and tracking the operation of the satellites, after the receiver captures the tracked satellite signals, the change rate of the pseudo distance and the distance from a receiving antenna to the satellites can be measured, so that data such as satellite orbit parameters can be calculated, and a microprocessor in the receiver can calculate information such as longitude, latitude, altitude, current time and the like of the geographical position of a user according to the data. At present, the positioning accuracy provided by the GPS system is better than 10m, and to obtain higher positioning accuracy, a differential GPS technology is generally adopted, wherein a GPS receiver is arranged on a reference station for observation, the distance correction number from the reference station to a satellite is calculated according to the known precise coordinates of the reference station, the data is sent out by the reference station in real time, and a user receiver also receives the correction number sent by the reference station and corrects the positioning result while carrying out GPS observation, so that the positioning accuracy is improved.

The wireless communication network is a bridge connecting a client terminal and an application server, transmits the requirements of a user to the geographic information application server through wireless, and transmits the analysis result of the server to the client terminal. The third mobile communication based on cellular system is the most widely used one, and it will be one of the main communication networks for mobile GIS to operate in the future.

The basis of remote sensing technology (RS) is to observe electromagnetic waves to interpret and analyze the targets and phenomena on the earth's surface, wherein the characteristics of the electromagnetic waves of the ground features, that is, "all objects have the characteristics of reflecting or radiating electromagnetic waves with different wavelengths due to different types and environmental conditions", and remote sensing is also a technology of recognizing the existence of the objects and the environmental conditions of the objects by observing the electromagnetic waves by using the inherent characteristics of the objects of reflecting or radiating the electromagnetic waves. In the remote sensing technology, a device for receiving electromagnetic waves reflected or radiated from a target is called a remote Sensor (remote Sensor), and environmental information can be monitored more rapidly and objectively by using the remote sensing technology; meanwhile, due to the spatial distribution characteristic of the remote sensing data, the remote sensing data can be used as an important data source of a geographic information system and can be used for updating a land utilization spatial database in real time in land investigation.

The spatial database is used for organizing and storing spatial information related to geographic positions, is a data storage center of the mobile GIS, can provide various spatial position information for mobile application, can provide data sources of the geographic information for a geographic application server, and can enable mobile equipment to interact with various data sources, shield different fixed network environments and optimize query conditions.

Prior art, as in chinese patent application: application No.: CN2009101006678, publication No.: CN 101604326A, which discloses a land use data updating and analyzing method based on event semantics, the method extracts corresponding geographic events in land use change services through event semantics, and defines a linkage relationship between the events; establishing a change information recording table by taking an event as a core for recording the reason and time for driving the land use data state to change and the linkage relation among data; realizing cascade updating of land utilization data based on events, and recording information of a change process; historical backtracking query is carried out through the event sequence by utilizing the genetic inheritance relationship, and rapid analysis of land utilization data is realized. The method and the system have the advantages that the change process information is accurately recorded while the land utilization change business operation is simplified, the integrity and the cohesion of the time-space data are guaranteed, the historical backtracking efficiency is improved, the rapid analysis of the land utilization data is realized, and the method and the system have important practical significance for establishing dynamic monitoring of land utilization and strengthening land management.

As another example, the prior art, such as chinese patent application: application No.: CN2018108942697, publication No.: CN 109144976A discloses a database established based on land survey and a management system thereof, which includes: (1) inputting data; (2) change analysis; (3) checking data; (4) outputting data; (5) and (6) counting data. The system can complete the inquiry, storage and statistics of different types of data, and realize the superposition of current data and changed data through the process library, thereby analyzing the flow direction and change of various types of land and outputting reports; through the historical library, the data of misoperation can be recovered, the past data can be inquired and revisited, the land change investigation management system can dynamically analyze the data in different periods, and the land change investigation management system has strong pertinence, is a flexible and convenient data change processing tool, manages and maintains a plurality of special data, and is favorable for information sharing and data maintenance.

However, the above-mentioned prior art only provides the settings of the land use data updating, the database building and the management system thereof, and there is no description on what kind of technical means is adopted to upload the land use updated data to the service center to make scientific judgment on the updated land use data for the leader or the engineer in a targeted manner so as to make a correct land policy, that is, the above-mentioned prior art (the above-mentioned two listed patent applications) does not convert the patent application technology thereof into productivity so as to make scientific decision for the upper-level building to make policy.

SUMMERY OF THE UTILITY MODEL

The utility model aims at being exactly on prior art's basis, especially two patents to land use data update spatial database at prior art: "Chinese patent application: application No.: CN2009101006678, publication No.: CN 101604326A, invention name: a land use data updating and analyzing method based on event semantics and the application number: CN2018108942697, publication No.: CN 109144976A, title of the invention: on the basis of a database established based on land survey and a management system thereof, the method is combined with modern transmission technical means to realize that collected land utilization change data can be rapidly sent to a decision maker in real time, and accurate and reliable practical basis is provided for the decision maker to make or adjust the land policy.

Data transmission system after data acquisition is changed based on GPRS land use, characterized by:

GPS satellite: accurately positioning and collecting the position information of the land use change pattern spots to realize field data collection; transmitting the collected field data to the mobile terminal in real time;

a mobile terminal: the mobile terminal also comprises a built-in GPS satellite positioning antenna receiver, a GIS system and a GPRS module; the GPS satellite positioning antenna receiver receives field data sent by a GPS satellite and introduces the field data into the GIS system in real time through a serial port so as to enable positioning information of the GPS to be displayed on an electronic map accurately in real time; the GPRS module realizes wireless link between the mobile terminal and the remote server through a GPRS network. The GPRS module main control chip adopts a GPRS chip model as follows: LPC824, the GPRS chip is respectively connected with EEPROM, RS485 and SIM868, and meanwhile, the GPRS chip receives electric energy from the battery through LDO; the battery outputs 4V direct current voltage through a DC/DC converter to supply power to a communication module SIM868, and the SIM868 is connected with an antenna and an SIM card respectively.

Preferably: the mobile terminal comprises a GPS smart phone, a vehicle-mounted mobile terminal and a portable computer.

Preferably: a built-in GPS satellite positioning antenna receiver core module: the GPS module model is as follows: LEA-5H chip.

Preferably: and the power supply input end of a sixth pin of the LEA-5H chip is connected with a low dropout regulator chip with the chip model of LP 3996.

Preferably: and the sixteenth pin of the LEA-5H chip is connected with the antenna interface through an external 50-ohm resistor.

Preferably: the DC/DC converter adopts a TSP54331 chip to reduce the voltage of the battery to 4.0V, and a capacitor with the capacitance value of 2000uF and a Schottky diode are connected in parallel with a power supply end of the SIM868 chip; an enable pin EN of the TSP54331 chip is connected with a central processing unit MCU of the mobile terminal so as to control the working state of the TSP54331 chip through the MCU.

Preferably: the SIM card holder is a six-pin Micro card holder; VSIM of a card seat power supply end of the SIM card is connected into a 200nF capacitor, and 22pF capacitors are added to card seat signal lines of the SIM card to prevent the SIM card from radio frequency interference; 22R resistors are connected in series between the SIM card and the SIM868 chip, and the electrostatic protection capability of the SIM card is enhanced.

The utility model discloses beneficial effect:

the method is combined with modern transmission technical means to realize that the collected land utilization data can be timely and accurately sent to a decision maker, and an accurate and reliable practical basis is provided for the decision maker to timely and accurately make or adjust the land policy.

Drawings

Fig. 1 is the utility model discloses change data transmission system data transmission schematic diagram based on GPRS land use.

Fig. 2 is the utility model discloses land use changes data collection work route schematic diagram based on GPRS land use changes data transmission system earlier stage.

Fig. 3 is the utility model discloses change data transmission system GPS module's hardware schematic diagram based on GPRS land use.

Fig. 4 is the utility model discloses change data transmission system GPRS module transmission device's structural block diagram based on GPRS land use.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

The applicant has again emphasized that: the invention aims to provide a powerful factual basis for transmitting data to a decision maker through a modern communication technology so as to make the decision maker make a land policy after the land utilization change data is investigated by utilizing the prior art (application number: CN2009101006678, publication number: CN 101604326A; application number: CN2018108942697, publication number: CN 109144976A). The invention does not relate to an algorithm of how to collect data, namely software, and the invention is designed for solving the technical problem of how to upload collected data to a remote server after the data collection of land use change, and the data transmission communication is realized based on the prior art, such as the prior transmission technologies of GPRS, GPS, mobile terminal and the like, and the hardware adopted by the data transmission belongs to the prior art, and the data transmission mode only adopts a transmission format which meets the hardware requirement, but not how to process and transmit the data, namely, the transmission mode and the hardware related to the application transmission data belong to the prior art.

a mobile terminal: a database and a management system thereof which are established based on land survey are built in, so that data acquisition and data analysis of land utilization change are realized; the data analysis is realized by adopting a land utilization data updating and analyzing method based on event semantics in the prior art (application number: CN 2009101006678);

the mobile terminal also comprises a built-in GPS satellite positioning antenna receiver, a GIS system and a GPRS module; the GPS satellite positioning antenna receiver receives field data sent by a GPS satellite and introduces the field data into the GIS system in real time through a serial port so as to enable positioning information of the GPS to be displayed on an electronic map accurately in real time; the GPRS module realizes wireless link between the mobile terminal and the remote server through a GPRS network.

The utility model discloses an utilize the positional information of GPS collection change pattern spot, be connected with GPS satellite positioning antenna receiver through mobile terminal, with GIS and GPS integration, pass through the real-time leading-in GIS of serial ports with differential GPS's real-time data, can make GPS's positional information obtain real-time accurate demonstration on electronic map, change the navigation for discovering the land use.

Firstly, we will review the working route taken by using the GPS and GIS integration technology to realize the collection of land use change data, as shown in fig. 2:

1. data processing and preparation, including geometric correction of remote sensing images, preparation of orthophotographs, coordinate transformation, image fusion and the like;

2. performing field investigation, namely determining the position of a changed pattern spot by overlapping an RS image and a current land utilization map, and then performing field data acquisition by using a GPS and GIS integrated system;

3. by adopting the database change method in the prior art: "Chinese patent application: application No.: CN2009101006678, publication No.: CN 101604326A, invention name: a land use data updating and analyzing method based on event semantics and the application number: CN2018108942697, publication No.: CN 109144976A, title of the invention: a database and a management system thereof built based on land survey update data of the database.

The acquisition of the space data is mainly realized by storing in the terminal equipment and displaying the space data acquired by the GPS through the terminal equipment, the realization process is to connect the GPS with the terminal equipment by a serial port line to realize the real-time signal receiving and map positioning functions, the essential function of the serial port is used as a code converter between a central processing unit Intel PXA250 chip and serial equipment adopted by the mobile terminal, when the data is sent out from the Intel PXA250 chip through the serial port, the byte data is converted into serial bits, and when the data is received, the serial bits are converted into byte data.

The data points collected by the GPS are displayed on an electronic map in real time, the point location coordinates collected by the GPS must be converted into coordinate values under the same coordinate system as the electronic map, in the field space data collection process, the coordinates of the data collected by the GPS belong to a WGS-84 coordinate system, a plane coordinate system (the coordinate system is a Beijing 54 coordinate system or a Xian 80 coordinate system) is adopted in a land utilization current map, and therefore the coordinates collected by the GPS need to be converted into plane coordinates suitable for land utilization change investigation.

In the following, we will explain in detail the structural composition of the mobile terminal further including the built-in GPS satellite positioning antenna receiver, GPRS module, and other functional components.

Hardware design of GPS satellite positioning antenna receiver built in mobile terminal

As shown in fig. 3. The built-in GPS satellite positioning antenna receiver is provided with a satellite positioning receiver which receives satellite signals, carries out mobile communication and stores data; the selection requirement of the GPS receiver is also from the aspects of low cost and low power consumption, and the GPS receiver is required to be packaged in a miniaturized manner, thereby facilitating the development of users and the integration of systems. Another consideration is the interface type and start-up time of the module. The core module of the GPS receiver is a GPS module, and an external interface of the GPS module is a universal serial port so as to be capable of better communicating with a processor in the mobile terminal. Meanwhile, the response time of the module is required to be fast, and the module can be successfully started in a short time. By comparing modules of various models, a GPS module of an LEA-5H model of U-blox company is selected.

The design principle of the built-in GPS satellite positioning antenna receiver is shown in a circuit diagram of figure 3. The levels of a signal output pin RXD1 and a TXD1 of the LEA-5H module are 3.3V, the 16 th pin of the LEA-5H module is an antenna receiving pin, the passive antenna is weak IN signal, so that the design requirement of an antenna part is influenced by other wireless RF as little as possible, the high-frequency impedance of a PCB connecting line from an antenna port to an RF _ IN pin adopts 50 omega impedance matching, and the wiring of an antenna input end of the RF _ IN end needs to be as short as possible to ensure that the sensitivity of the module is not influenced. The No. 24 pin of the LEA-5H module is a power supply pin of the USB, and when the power supply of the USB is not adopted, the pin must be grounded, because when the LEA-5H module adopts a VCC pin for power supply and VCC is in a power-off state, a digital part of the module does not work at the moment, but if the state of a VDDSBus pin is suspended, a host of the USB considers that the module is still in a normal working state, so that misjudgment of the USB host is caused, and the pin must be grounded when the module is not used.

Since GPS is susceptible to interference sources, it is particularly affected by instability of the power supply. Therefore, the GPS power supply part needs to be processed relatively, and for this reason, an LDO (low dropout regulator) chip LP3996 is added in front of the power supply interface of the LEA-5H module, wherein the LP3996 is an LDO chip with a control switch and produced by the national semiconductor company of America, can convert 3.6V input voltage into 3.3V voltage for stable output, has the characteristic of low ripple, and just meets the requirement of low ripple input of the GPS module. The use of the LDO chip LP3996 has two advantages: the power supply can provide a stable power supply for the module, and the impedance change of the power supply caused by the change of the power supply voltage can be avoided when the rear part of the module works; LDO can the impure front end signal of filtering, can carry out effectual noise reduction to improve received signal's reliability and degree of accuracy.

GPRS module hardware structure design

Referring to fig. 4, the GPRS module main control chip adopts a GPRS chip model: LPC824, the GPRS chip is respectively connected with EEPROM, RS485 and SIM868, and meanwhile, the GPRS chip receives electric energy from the battery through LDO; the battery outputs 4V direct current voltage through a DC/DC converter to supply power to a communication module SIM868, and the SIM868 is connected with an antenna and an SIM card.

The master control chip of the GPRS data transmission device adopts an LPC824 chip produced by NXP. The chip is designed based on an ARM Cortex-M0+ kernel, and is a 32-bit microcontroller with a simplified instruction set and ultra-low power consumption, the pin function is distributed or enabled through a switch matrix, and the interface operation is flexible. LPC824 working temperature range is-40 ℃ - +85 ℃, the power supply voltage range is 2.4V-3.6V, the low power consumption mode of sleep, deep sleep, power down, deep power down has four kinds, the current is less than 1uA under the lowest power consumption mode, and the low power consumption requirement in industrial design can be met.

The communication module selects a SIM868 wireless transmission module designed by the SIMCom company, supports 4-frequency GSM/GPRS, has working frequency bands of GSM850, EGSM900, DCS1800 and PCS1900MHz, supports GSM/GPRS and AT instruction control, has rich hardware interfaces, comprises a full-function serial port, a USB interface, an I2C interface and supports double SIM cards. The module is designed by adopting a power-saving technology, the consumed current is as low as 0.65mA in the sleep mode, and the SMS and the data information can be transmitted with low power consumption. The working temperature range of the SIM868 is-40 ℃ to +85 ℃, the size is 17.6mm 15.7mm 2.3mm, and the performance is stable. The SIM868 is rich in peripheral interfaces and is provided with 2 serial ports and an I2C interface. And respectively connecting the SIM868 with two serial ports of the mobile terminal MCU. The UART1 realizes the data transmission function, and the UART2 realizes the parameter configuration function of the MCU to the SIM 868. The voltage input range of the SIM868 module is 3.4V to 4.4V, when the module is transmitted with the maximum power, the instantaneous peak value of the current may be as high as 2A, which may cause the module to have a large voltage drop, and if the voltage is lower than 3.0V, the module may be shut down due to insufficient voltage. In order to ensure normal and stable operation of the module, when a chip circuit is designed, a DC/DC converter is adopted, a TPS54331 chip is used for reducing the voltage of a battery to 4.0V for power supply, a large capacitor of 2000uF is connected in parallel close to a power supply end, sudden voltage drop is reduced, and simultaneously, the maximum 2A current required by the module in the moment of operation is provided. To prevent damage to the chip from surges, a schottky diode SS34 is added to the power pin. An enable pin EN of the TSP54331 is connected with a central processing unit MCU of the mobile terminal, namely the MCU controls the working state of the TSP54331 chip. In order to reduce the power consumption of the system, the TSP54331 and further the SIM868 need to be turned off when there is no data transmission demand, and then enabled when there is a data transmission demand, so that the waste of the power consumption of the system can be reduced. The SIM868 module can directly supply power to the SIM card interface and support the SIM cards with two different voltages of 1.8V and 3.0V. The SIM card cassette can be divided into 6 feet and 8 feet, and the system does not need the SIM card to detect the position, so the 6 feet Micro cassette is selected for use during the design. Because SIM card circuit easily receives the interference, consequently insert 200nF electric capacity to SIM card power VSIM, the SIM card signal line all increases 22pF electric capacity, prevents that the SIM card from receiving radio frequency interference. 22R resistors are connected in series between the SIM card and the SIM868 chip, and the electrostatic protection capability of the SIM card is enhanced.

The DC/DC converter chip is selected from voltage reduction chip TPS54331 of Texas Instruments (TI). The input voltage range of the chip is 3.5V-28V, the output voltage range is 0.8V-25V, the highest output current of 3A can be provided, and the maximum current requirement of the SIM868 can be met. The slope compensation design in the chip is utilized to simplify external compensation calculation, use of external elements is reduced, the off current of the chip is as low as 0.1uA, and the chip is suitable for being used in a battery-powered design.

The EEPROM adopts CAT1025 produced by an ON company for storing initialization parameters of the system and preventing the possible parameter loss and the like when the system is in power failure or is restarted and the like. The CAT1025 has a 2K bit storage space, a 16-byte page writing buffer area, and a low-power CMOS technology is adopted, so that the low-power design requirement can be further met, a system power supply monitoring circuit for power failure protection is integrated, the system power supply monitoring circuit can be erased and written for hundreds of thousands of times, data can be stored for many years, and the reliability of the system is improved.

The GPRS module selects SP3072EEN as a serial port to 485 module. It is a low power consumption half-duplex RS-485 transceiver developed by the company EXAR (SIPEX). The operating voltage is 3.3V, the maximum communication speed is 250Kbps, the standby current is 0.05uA, and the static current is 0.8mA, so that the low power consumption requirement of the system can be well met.

In the following we describe the procedure of the GPRS module communicating with the remote server:

the SIM868 is respectively connected with two serial ports of the MCU, namely UART1 and UART2, the UART1 realizes a data transmission function, and the UART2 realizes a parameter configuration function of the MCU to the SIM 868. And the MCU completes the tasks of parameter configuration of GPRS and establishment of communication connection through the AT instruction.

Before the SIM868 realizes data transmission, the mobile terminal central processing unit MCU needs to set it (this setting is an inevitable step in mobile terminal applications), such as inquiring signal quality, inquiring network registration conditions: when the network connection is successful, the module feeds back 'OK'. When the module is powered on, the base station is automatically searched to establish connection with the base station, but for the MCU, the GPRS data transmission can be carried out only after the module is successfully attached to the network, so that the waiting time of the MCU is reduced, the power consumption is reduced, the feedback of the module needs to be obtained, when the command is sent, the GPRS module feeds back the MCU, and when the second parameter is fed back to be 1 or 5, the module is successfully network registered, and the next action can be carried out; attaching the module to the GPRS network: if the connection returns to the OK, the GPRS connection is successful, and if the connection returns to the ERROR, the GPRS module activation is failed; the method comprises the steps of setting APN according to an actual network, activating a mobile scene, establishing network connection with a server side, and sending data to the server by a GPRS module after the network connection. After the remote server receives the land use change data, the data is stored in real time on one hand, and on the other hand, the acquired data is displayed in real time through a liquid crystal display screen; the service center staff can operate the data displayed in real time according to the requirements, such as the operations of amplifying and reducing the data image, imaging resolution, screen capturing and the like.

Emphasis here is given to: the communication process between the GPRS module and the remote server is a communication process that is necessarily experienced by the GPRS module and the remote server as long as the communication process between the GPRS module and the remote server is involved in the prior art, and the purpose of describing the communication process is to ensure that the present invention is fully disclosed and a way for realizing data communication between the GPRS module and the remote server is provided.

The utility model discloses a change data transmission system based on GPRS land use is to two patents in the land use data update spatial database at prior art: "application number: CN2009101006678, publication No.: CN 101604326A, invention name: a land use data updating and analyzing method based on event semantics and the application number: CN2018108942697, publication No.: CN 109144976A, title of the invention: on the basis of a database established based on land survey and a management system thereof, the method combines modern transmission technical means to realize that collected land utilization change data can be rapidly sent to a decision maker in real time, and provides accurate and reliable practical basis for the decision maker to make or adjust a land policy, thereby solving the problem of establishing scientific practical basis for converting the prior art into productivity to make a scientific decision for an upper-layer building in making the policy.

The basic principles, main features and advantages of the present invention have been described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the principles of the present invention may be applied to any other embodiment without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The data transmission system after data acquisition is changed based on GPRS land utilization comprises a GPS satellite, a mobile terminal, a GPRS network and a remote server; it is characterized in that:

GPS satellite: accurately positioning and collecting the position information of the land use change pattern spots to realize the collection of field data; transmitting the collected field data to the mobile terminal in real time;

a mobile terminal: the system comprises a built-in GPS satellite positioning antenna receiver, a GIS system and a GPRS module; the GPS satellite positioning antenna receiver is used for receiving field data sent by a GPS satellite and leading the field data into the GIS system in real time through a serial port;

the GPRS module built in the mobile terminal realizes wireless link with a remote server through a GPRS network; the GPRS module main control chip adopts a GPRS chip model as follows: LPC824, the GPRS chip is respectively connected with EEPROM, RS485 and communication module SIM868, and meanwhile, the GPRS chip receives electric energy from the battery through LDO; the battery outputs 4V direct current voltage through a DC/DC converter to supply power to a communication module SIM868, and the communication module SIM868 is connected with an antenna and an SIM card respectively.

2. The GPRS-based land use modification data post-collection data transmission system of claim 1, wherein: the mobile terminal comprises a GPS smart phone, a vehicle-mounted mobile terminal and a portable computer.

3. The GPRS-based land use modification data post-collection data transmission system of claim 1, wherein: a built-in GPS satellite positioning antenna receiver core module: the GPS module model is as follows: LEA-5H chip.

4. A GPRS-based land use modification data post collection data transmission system according to claim 3, wherein: and the power supply input end of a sixth pin of the LEA-5H chip is connected with a low dropout regulator chip with the chip model of LP 3996.

5. A GPRS-based land use modification data post collection data transmission system according to claim 3, wherein: and the sixteenth pin of the LEA-5H chip is connected with the antenna interface through an external 50-ohm resistor.

6. The GPRS-based land use modification data post-collection data transmission system of claim 5, wherein: the DC/DC converter adopts a TSP54331 chip to reduce the voltage of the battery to 4.0V, and a capacitor with the capacitance value of 2000uF and a Schottky diode are connected in parallel with a power supply end of the SIM868 chip; an enable pin EN of the TSP54331 chip is connected with a central processing unit MCU of the mobile terminal so as to control the working state of the TSP54331 chip through the MCU.

7. The GPRS-based land use modification data post-collection data transmission system of claim 6, wherein: the SIM card holder is a six-pin Micro card holder; a card holder power end VSIM of the SIM card is connected to a 200nF capacitor, and 22pF capacitors are added to card holder signal lines of the SIM card; 22R resistors are connected in series between the SIM card and the SIM868 chip.