131 results about "Low latitude" patented technology

The present invention proposes a one-axis solar tracker system and apparatus which is simple to install, lower cost and with the provision of an electric-magnetic locking device to resist from medium to strongest wind condition like hurricane or typhoon. Solar farms is more and more popular to use one-axis tracker due to lower cost, higher wind resistance and easier for large scale solar farm installation, especially at lower latitude tropic zones. This disclosure proposes a one-axis tracker with multiple posts support using a single or dual linear actuators driving mechanism for rotation. It is also equipped with a wind lock device to lock the solar tracker in horizontal neutral position during strong wind condition such as hurricane or typhoon. The stepwise wind lock device can further be applied to locking the solar tracker following each step of linear actuator activation enabling the disclosed solar tracker to operate in windy conditions.

The invention relates to a radiation therapy device of a multi-alignment body which comprises a shield, and a source body and a final alignment body which are arranged on the shield, wherein a plurality of radioactive sources are loaded in the source body, at least one middle alignment body is arranged between the source body and the final alignment body, the source body, the middle alignment body and the final alignment body are respectively connected with a gear power transmission mechanism, which can independently rotate relative to the same rotary center line, the final alignment body comprises various groups of through holes with different diameters, the middle alignment body comprises at least one group of though hole, at least one group of through hole in high-latitude regions and at least one group of through hole in low-latitude regions. In the process of treatment, the invention can automatically combine radiation beam according to the need of treatment proposal, the dynamic conformity of a dose field is realized, the auxiliary time of the radiation therapy is shortened, and the efficiency of the radiation therapy is improved.

The present invention proposes a one-axis solar tracker system and apparatus which is simple to install, lower cost and with the provision of an electric-magnetic locking device to resist from medium to strongest wind condition like hurricane or typhoon. Solar farms is more and more popular to use one-axis tracker due to lower cost, higher wind resistance and easier for large scale solar farm installation, especially at lower latitude tropic zones. This disclosure proposes a one-axis tracker with multiple posts support using a single or dual linear actuators driving mechanism for rotation. It is also equipped with a wind lock device to lock the solar tracker in horizontal neutral position during strong wind condition such as hurricane or typhoon. The stepwise wind lock device can further be applied to locking the solar tracker following each step of linear actuator activation enabling the disclosed solar tracker to operate in windy conditions.

Golf ball 2 has three or more different kinds of dimples 8. The total number of the dimples 8 is 300 or more. A ratio Pn of the number of the dimples 8 with a diameter of equal to or greater than 3.40 mm to the total number is equal to or greater than 90%. The golf ball 2 meet the following formulae (I) and (II).NL−NH≧0   (I)NL>NHm≧NHp   (II)NL represents the number of kinds of the dimples being located in a low latitude region ZL and having a diameter of equal to or greater than 3.40 mm, NH represents the number of kinds of the dimples being located in a high latitude region ZH and having a diameter of equal to or greater than 3.40 mm, NHm represents the number of kinds of the dimples being located in a middle latitude region ZHm and having a diameter of equal to or greater than 3.40 mm and NHp represents the number of kinds of the dimples being located in a polar region ZHp and having a diameter of equal to or greater than 3.40 mm.

The invention provides a medium and low orbit constellation satellite beam frequency resource allocation method. The medium and low orbit constellation satellite beam frequency resource allocation method comprises the steps of: performing initial sub-band allocation on each beam, and taking a certain fixed carrier in the sub-band allocated by each beam as the carrier of a broadcasting channel, wherein the initial sub-band of each beam is at least a sub-band; according to the odd number or even number of the orbit planes of the satellite constellation, determining a main orbit plane and a supplementary orbit plane; realizing coverage of partial areas to the ground including the two poles through single coverage composed of a satellite in the main orbit plane, and performing beam opening orclosing on the satellite in the supplementary orbit plane, so that the coverage of a blank area to the ground at the medium and low latitudes is completed; performing frequency resource allocation oneach terminal by taking the carrier as the unit, and, if the number of access terminals under a certain beam is beyond the user number born by the initial sub-band, increasing available sub-bands or carriers for the satellite beam; and realizing complete coverage. By means of the medium and low orbit constellation satellite beam frequency resource allocation method in the invention, constellationbeam frequency resource allocation can be realized better; and the method has the characteristics of being simple, high-efficiency and high in engineering practicability.

The invention discloses a foamed polystyrene curtain plate sheet and a manufacturing method thereof. The foamed polystyrene curtain plate sheet consists of the following components in part by weight: 100 parts of polystyrene, 1 to 50 parts of blended resin, 1 to 50 parts of filler, 0.1 to 20 parts of compatilizer, 0 to 1 part of antioxidant, 0 to 5 parts of processing aid, 0.1 to 10 parts of foaming agent and 0.1 to 10 parts of cross-linking agent. The foamed polystyrene curtain plate sheet manufactured according to a formula of the invention has light weight, aging resistance, corrosion resistance, heat insulation and insulating property, and the most outstanding advantage of high thermal deformation resistance, and can adapt to direct sunlight under a hot weather condition in summer in low-latitude regions. The manufacturing method of the foamed polystyrene curtain plate sheet is simple and practical, and has wide application prospect.

The invention relates to a semi-opening greenhouse cultivation technology for a peach tree in a low-latitude plateau area. The technology is characterized in that a greenhouse frame is arranged on one surface of a greenhouse; a layer of inspect proof nets and a layer of heat preserving quilts sequentially cover the frame; the heat preserving quilts are controlled by a contracting and stretching bracket to the contracted and stretched, and therefore, the temperature in the greenhouse of the peach tree can be controlled in different growth periods and under the changeful air temperature condition at the low-latitude plateau area; meanwhile, the technologies like the water and fertilizer control technology and the special fruit bag utilizing technology are adopted, thus the damage factor under the natural condition is removed, and the natural growth state of the peach tree is remained to the maximum; the applied pesticide is about 20% that under the common planting condition, the applied chemical fertilizer is about 30% that under the common planting method, the water irrigated is about 40% that under the common planting condition, and the output is more than 150% that under the common planting condition; in addition, the peach quality is far more than that of common peach; the market price is the peach is more than 5 time that of the common peach.

The invention discloses a polar inertial navigation method based on a horizontal wandering coordinate system. The method includes the steps: building a horizontal earth ellipsoid coordinate system, a horizontal geographic coordinate system and the horizontal wandering coordinate system, setting a traditional geographic coordinate system of initial navigation time as an initial horizontal wandering coordinate system and performing mechanical layout by taking the horizontal wandering coordinate system as a navigation coordinate system of a strap-down inertial navigation system; solving the problem of strap-down algorithm failure based on the geographic coordinate system due to meridian convergence in polar regions based on the inertial navigation layout mode of the horizontal wandering coordinate system. Besides, mechanical layout is performed in wandering azimuth at low latitudes, the internal integrity of a global navigation resolving algorithm is ensured by combining the modes, switching logic design of different latitudes and the transformational relationship between parameters of different navigation coordinate systems are avoided in the strap-down inertial navigation system, and complicated physical platform switching is avoided in a platform inertial navigation system.

The invention discloses a low-quality face comparison method based on a deep convolution neural network. The method comprises the following steps: each image in a face training database is sent to a constructed deep convolution neural network for feature extraction; the extracted features are inputted to a fully-connected layer and are projected to a projection matrix in low-latitude space throughaffine; feature vectors obtained and calculated by the projection matrix are trained through a two-norm normalized spherical loss function; through a gradient descent method, the weight value of eachfilter in the fully-connected layer and the deep convolution neural network is found out, and the deep convolution neural network with a comparison passing rate to be the highest is selected; and thefeature vector of a to-be-detected face image and the feature vector of each fact answer image in a low-quality face test database are subjected to cosine distance calculation, and the same person isjudged if the cosine value is smaller than a threshold. The method is used for high-efficiency comparison on a low-quality face, fewer calculation resources are used, and both the face comparison precision and the comparison speed can be considered at the same time.

The invention discloses a GEO-LEO satellite network for global information distribution. The GEO-LEO satellite network comprises an outer-layer backbone network composed of three GEO satellites and an inner-layer enhanced network composed of at least one LEO satellite, the three GEO satellites are located over the terrestrial equator, the fixed point longitude difference is 120 degrees, the GEO satellites are connected through fixed inter-satellite links, the height of an LEO satellite orbit is 1,450 km, the orbit inclination is 84.5 degrees, the outer-layer backbone network and the inner-layer enhanced network carry out information distribution in a broadcast mode, the outer-layer backbone network and the inner-layer enhanced network carry out broadcast in a rate-free coding mode, and the GEO-LEO satellite network and the ground carry out broadcast in a rate-free coding mode. According to the GEO-LEO satellite network, seamless and enhanced coverage on the middle and low latitudes can be achieved only through few satellites, meanwhile, coverage on the south and north polar regions is considered, and worldwide interruption-tolerant distribution of information is achieved.

The invention discloses an involute spherical gear transmission pair. The involute spherical gear transmission pair comprises two spherical gears, wherein involute gear teeth are uniformly distributed on the circumferences in the weft directions of the spherical surfaces of spherical cap sections on spherical caps; the tooth thickness directions are along the weft directions of the spherical caps; the numbers of the teeth on the wefts at different heights are variable; the number of the teeth on low-latitude parts is large; the number of the teeth on high-latitude parts is small; a plurality of tooth rings from the high latitude to the low latitude are formed. The spherical gears are sectioned over the axis; the outer contours of the sections of the tooth rings form the outer contours of the involute spherical gear teeth along the meridians in the tooth thickness directions; the outer counters of the gear teeth formed by the sections of the tooth rings are divided into two groups; odd-number groups and even-number groups are respectively the same as the shapes of the end surface teeth of two straight gears of which the gear teeth are placed in a staggered way.

The invention discloses a summering cultivation method for seedlings of Hizikia fusiform (Harv)Okamura juvenile sporophytes, comprising the following steps: raising seedlings in a north sea area at a high latitude during the high temperature stage; and transferring the cultivated seedlings to a south cultivation sea area at a low latitude after summering for cultivation. In the invention, seedling raising and cultivation are performed in different levels and sea areas, thus overcoming the disadvantageous sea conditions in cultivation sea areas, and avoiding high energy consumption in an indoor temperature-reduction cultivation mode.

The invention discloses a method for forecasting the occurrence probability of ionospheric scintillation in low-latitude areas of China. The method includes: an ionospheric irregularity intensity CkL inversion method based on an ionospheric scintillation index S4, a probability density distribution model of ionospheric irregularity intensity CkL of low-latitude areas of China which changes with solar activity index Rz, geomagnetic activity index Kp, geographical position, season and time, and an ionospheric scintillation occurrence probability calculation method. The method provided by the invention can calculate the occurrence probability of an ionospheric scintillation event under conditions of designated place, time, solar activity index Rz, geomagnetic activity index Kp, working frequency band, ionospheric scintillation index S4 threshold value and the like according to user demands.

The invention relates to a parachute, specifically to a parachute for low altitude lifesaving, belonging to the technical field of parachute structure, wherein the low altitude lifesaving parachute comprises a parachute canopy and parachute ropes connected with the parachute canopy and is characterize in that: the parachute canopy is uniformly distributed with multiple column-shaped gas bundles for supplying a gas source by a high-pressure gas inflating cylinder which is communicated with the multiple column-shaped gas bundles; and the column-shaped gas bundles are communicated with the high-pressure gas inflating cylinder by high-pressure inflating pipes with one-way inflating valves. The low altitude lifesaving parachute of the invention is featured with reasonable structure and reliable and safe operation; the invention solves the problems of fast opening parachutes and stable landing under a low altitude condition and supplies a new method for escaping and lifesaving of people on high buildings when the disasters such as earthquake, fire and the like happens; and the escaping method further suits for the low latitude landing from cliff in the open air.

The invention discloses a four-crop-a-year cultivation method for a low-latitude high-elevation area dry land. The method is characterized in that the first crop is potato, the second crop is vegetable, the third crop is corn, and the four crop is cereal or vegetable; the potato is sown from the last ten days of December of last year to the middle ten days of January of the following year; the second-crop vegetable is sown when the third-crop corn is transplanted between corn lines; the third-crop corn is transplanted after the first-crop potato is harvested; and the four-crop cereal or vegetable is sown after the second-crop vegetable is harvested. According to the four-crop-a-year cultivation method for the low-latitude high-elevation area dry land, which is disclosed by the invention, the staggering and the collocation of different crops in time and space are fully considered, a proper cultivation mode is adopted to realize the four-crop-a-year cultivation method with high yield and high efficiency, good harvest is obtained, the multiple cropping index is improved, and the income of each acre is above 5300yuan. Compared with the traditional planting mode in the area, the economic income is improved by 41.6-66.87%, and a new cultivation technical mode is provided for the poverty alleviation and economic development of farmers in the area.

The invention discloses an online temperature measuring method for an overhead wire. The online temperature measuring method includes steps of 1, monitoring a temperature value of the overhead conducting wire and a temperature value of a shell of online temperature measuring equipment; and 2, substituting the monitored temperature value of the overhead conducting wire and the monitored temperature value of the shell of the online temperature measuring equipment into a dynamic capacity-increasing heat circuit model to acquire real-time permissible maximum carrying capacity of a circuit, namely maximum capacity-increasing space. The online temperature measuring method has the advantages of high accuracy of measurement results obtained in low-latitude regions or regions with strong summer sunlight or in periods with strong summer sunlight, and the like.

The application provides a file processing method, and provides a novel data storage mode which mainly depends on fingerprint database and file information database to realize data storage. the data fingerprint database and the file information database are associated through the data fingerprint, based on this, when a file needs to be stored, the file is divided into low-latitude chunks of data,then whether the same data has been stored in the storage system based on the data blocks is judged, so that the same data is not stored repeatedly. The invention only needs to record the correlationbetween the file and the data block in the file information base, so that the space occupied by the duplicate file or similar file in the storage system can be greatly reduced, the storage resources are saved, and the utilization ratio of the storage space is provided to relieve the pressure of the large data storage. In addition, the present application also provides the corresponding devices andapparatuses.

A non-rigid target detection method comprises the following steps of performing like-object detection on an input image and finding out rectangular areas which are possibly provided with like-object targets in the input image; performing characteristic extraction on every obtained rectangular area through a pre-trained non-rigid target model and obtaining HSC characteristics and textural features of every rectangular area; forming into a characteristic pyramid; performing PCA projection on the characteristic pyramid and classifying modes on characteristic pyramid space at the low latitude; convolving every scale of the pyramid through every root and obtaining a root scoring chart of every layer of the pyramid; convolving every corresponding part layer of the root layer through part filters and obtaining a root score chart of all parts; performing distance transformation to reconstruct all part scores of every root, comparing and judging a threshold value of the same model and obtaining a position of a non-rigid target of the rectangular areas. The non-rigid target detection method is good in detection effect, rapid in speed and low in leak detection rate.

The invention discloses a grid curved surface reconstruction method for scene understanding, and belongs to the field of three-dimensional graphics. The method comprises the following steps of: automatically identifying abnormal data through a mathematical model based on an undirected graph network, and estimating and adjusting a point cloud normal vector in an internal curved surface mapping manner; solving low-latitude feature information of the point cloud model, extracting a skeleton center curve, and designing a block segmentation mode of a complex branch area; for the point cloud from which the branches are removed, adopting a depth map mapping mode to identify and construct a visual field visible area of the point cloud, and designing a visual clustering-based slice body segmentation mode; constructing a self-learning scene understanding model based on the segmentation result, and realizing automatic restoration of the missing region; finally, designing a point cloud reconstruction algorithm based on a hyperspherical mapping mechanism, and surface data reconstruction loyalty of the original point cloud is achieved, and the method can be applied to efficient and accurate reconstruction of a CAD model, a building, an organism and a point cloud model mixed with multiple scenes.

The invention relates to a method for culturing seedlings of Portunus tritubereulatus in the north and breeding the Portunus tritubereulatus in the south, which comprises the following steps: obtaining brood Portunus tritubereulatus from a natural sea area in the north of the Taiwan Strait or a Portunus tritubereulatus culture pond from August to mid-October, then performing artificial breeding on the brood Portunus tritubereulatus or breeding the brood Portunus tritubereulatus in an earthen pond in the north to obtain juvenile Portunus tritubereulatus; and conveying the juvenile Portunus tritubereulatus serving as the seedlings of the Portunus tritubereulatus to the sea area at a low latitude in the south of the Taiwan Strait, and performing out-of-season breeding on the Portunus tritubereulatus. The Portunus tritubereulatus which is bred in the north can be bred in the south, so that the Portunus tritubereulatus appears on the market in the seasons when the Portunus tritubereulatus cannot be bred in the north from December to next March, and the out-of-season breading of the Portunus tritubereulatus is carried out by using the advantages that the temperature in the south at the low latitude is higher and the brood Portunus tritubereulatus exists in the northern autumn.

The boiler smoke purification device comprises a cleaning and absorbing component at the relatively higher position, being able to absorb slid grain wastes, poisonous gas, particularly an alkali lye diffusion component for absorbing oxides of sulfur wastes. Smoke goes into the above cleaning absorbing component, then the cleaning absorbing circulation component of lower latitude, with the latter connected to the said cleaning absorbing component. The cleaning absorbing circulation component can be used for the separation of solid grain wastes and treatment of poisonous gases. It is low in investment, small in energy consumption, strong in gas treatment ability, high in efficiency, applicable for mass mode industrial application.

The invention discloses a method for calculating geomagnetically induced current (GIC) of a grid in a middle-low latitude region. According to the method, on the basis of a global three-dimensional magnetosphere numerical model (a PPMLR-MHD (Lagrangian version of Piecewise Parabolic Method-Magnetohydrodynamic) model), solar wind parameters observed by a satellite serve as input conditions, geomagnetic disturbance generated by current is calculated by performing integration on a magnetic layer and an ionized layer current system, the geomagnetically induced current in the ground grid is calculated, the problem that the transitional predicting method is not suitable for calculating the GIC in the middle-low latitude region is solved, and the GIC of the grid in the middle-low latitude region calculated by the method can reflect the basic characteristic of the induced current which is actually monitored and is calculated by geomagnetic disturbance. By the method, people can timely calculate the GIC of the grid in the middle-low latitude region according to the solar wind parameters observed by an upstream satellite, whether the grid is invaded by a disastrous space weather event or not is estimated, and an active prevention measure is taken to prevent serious economic and social loss.

The invention aims to solve the technical problem of providing an angle stepping rotary dividing method for carrying out non-along-track strip division on a region target so as to solve the problem of high cost of observing the region target in an initiative push-scanning imaging manner. The invention adopts the technical scheme that initial information is acquired; visibility calculation is carried out on an observed target; a datum division scheme is determined; and the angle stepping rotary dividing method is adopted to carry out screening of division schemes and feasibility verifying. The angle stepping rotary dividing method has the beneficial effects that by adopting the non-along-track strip dividing method, a division direction is optimized, and the number of strips for dividing the same region target is reduced, so that observing time is reduced; by adopting a strip overlapping ratio, an offset error caused by on-orbit satellite attitude control can be avoided; optimization is carried out by adopting an observing sequence next to reciprocating push-scanning, so that attitude maneuver time and an attitude maneuver amplitude among strips are reduced; optimization of the observing time reduces an attitude maneuver amplitude of the push-scanning process; feasibility testing on the observing scheme ensures feasibility of the observing scheme.

The invention discloses a clustering-based low-earth-orbit satellite failure discovery method. The clustering-based low-earth-orbit satellite failure discovery method comprises the following steps: by adopting a double-layer satellite network architecture of a geostationary-earth-orbit (GEO) satellite / a low-earth-orbit (LEO) satellite, by virtue of a clustering concept, and with an axis penetrating through the south and north poles as a boundary, dividing a circular LEO satellite orbit into two LEO satellite clusters in the east and west hemispheres; in each cluster, selecting the LEO satellite with the lowest latitude as a cluster head of the cluster for collecting failure information of the LEO satellites in the cluster, sending the collected failure information to the GEO satellite covering the LEO satellites, and uniformly mastering the failure information of the LEO satellites by the GEO satellite with strong on-board processing capability. By the clustering-based low-earth-orbit satellite failure discovery method, LEO satellite failure discovery breaks away from a traditional ground station measurement and control technology with strong geographical dependence, so that failure discovery flexibility of the LEO satellite is greatly improved.

The invention discloses a short-term prediction method for ionospheric scintillation in middle and low latitude regions, comprising: obtaining the average value of the ionospheric scintillation index after filtering and averaging the measured scintillation indices; The strength and phase of the signal, analyze the ionospheric heterogeneous body characteristic parameters, obtain the current moment ionospheric heterogeneous body distribution state according to the ionospheric heterogeneous body characteristic parameters; according to the current moment ionospheric heterogeneous body distribution state, Using the analyzed characteristic parameters of ionospheric heterogeneity, the distribution of ionospheric heterogeneity in the future time is obtained; according to the distribution status of ionospheric heterogeneity in the future and user information, the ionospheric scintillation on a given link is obtained Intensity; the present invention provides short-term scintillation forecasting services for various spatial information systems in the middle and low latitudes of my country, and can know the impact of ionospheric scintillation that user systems may encounter in real time or in advance according to system parameters and specific use environments.

The invention discloses a structure variable mixed-orbit satellite constellation, comprising a GEO (Geosynchronous Orbit) sub constellation, an IGSO (Inclined Geo Stationary Earth Orbit) sub constellation and an MEO (Medium Earth Orbit) sub constellation. The GEO sub constellation comprises n GEO satellites distributed on n orbit positions of a geosynchronous orbit, and coverage areas between the adjacent satellites are connected and cover medium and low latitude areas in a full longitude manner. The IGSO sub constellation comprises five IGSO satellites, wherein the IGSO1, IGSO2 and IGSO3 satellites are located in the same orbit plane, and the phase difference between the adjacent satellites is 120 degrees; and simultaneously, the IGSO3, IGSO4 and IGSO5 satellites have the same ground track. The MEO sub constellation comprises m*k satellites distributed on k orbit planes, m satellites are on each orbit plane, and the MEO sub constellation has global coverage capability. When the structure of the constellation is reconstructed, the IGSO4 and IGSO5 satellites flexibly enter an HEO (High-altitude Earth Orbit) and run. The constellation has excellent global coverage capability, self management capability and flexible and variable structure.

The invention relates to a low-latitude out-of-season seeding and culturing method for portunus trituberculatus, which includes the following steps of getting incubation portunus trituberculatus from the natural waters or portunus trituberculatus ponds in the north of Taiwan Strait in August to mid-October; transferring the incubation portunus trituberculatus to low-latitude seas in the south (south of the Taiwan Strait) for artificially breeding or breeding in earth ponds to obtain the juvenile portunus trituberculatus. The juvenile portunus trituberculatus is used as seed to breed the portunus trituberculatus for out-of-season culturing. Therefore the portunus trituberculatus from the north can be cultured in the south. During the season from December to March in the next year when portunus trituberculatus can not be cultured in the North, the portunus trituberculatus can be bought in market. The invention utilizesthe advantages of low latitude and higher temperature in the south and the advantages of available portunus trituberculatus in autumn in the north to conduct out-of-season seeding and culturing of the portunus trituberculatus.

The invention designs an algorithm flow for carrying out cross positioning tracing by using rhumb lines of two observation stations on the earth surface. The invention provides a method for positioning and tracing a plurality of moving targets through crossing the rhumb lines by using two passive direction-finding sensors in a region which is at low latitude on the earth surface, so as to solve the problems of the traditional method that the adaptable region range is small, the positioning and tracing precision is low and the calculation amount is too great. The algorithm is characterized in that (1) in the algorithm principle, longitude and latitude coordinates of the two observation stations are positioned and the positions of a target relative to the two stations are respectively obtained by direction finding, so as to determine the rhumb lines which pass through each observation station from the measured azimuth angles; if the same target is observed, the two rhumb lines are crossed at one point and an approximate target position is obtained by revising a crossed point coordinate; (2) an algorithm formula derivation process is provided; and (3) the algorithm flow of intensive type cross positioning tracing and the algorithm flow of distribution type cross positioning tracing are provided based on the algorithm principle and the formula. The method disclosed by the invention is applicable to rapidly and accurately positioning and tracing of a plurality of moving targets, and has important applications values on aspects of military use and civil use.

The invention provides a global map data storage and organization method and a calling method. The global map data storage and organization method includes the steps of projecting a global map to a global coordinate frame, establishing a global geographic grid frame according to the global coordinate frame, slicing the global map to obtain tile data corresponding to the global map, and packaging and storing the tile data according to the geographic grid frame. The calling method includes the steps of receiving a map displaying request carrying longitude and latitude coordinates and displayinggrades, determining tile packets corresponding to the longitude and latitude coordinates according to the longitude and latitude coordinates and the displaying grades, and obtaining the tile data corresponding to the longitude and latitude coordinates from the tile packets. The complete global map is established by means of the Mercator projection in low-latitude areas and the ortho-axis azimuth projection in high-longitude areas; when the packaged and stored tiles are called, the target tile packets are retrieved from a relatively small number of tile packets, then the target tile data is retrieved from the target tile packets, the time consumed for retrieval is short, and the calling speed and efficiency of mass tiles are improved.