第 30 卷 第 23 期 农 业 工 程 学 报 Vol.30 No.23 232 2014 年 12月 Transactions of the Chinese Society of Agricultural Engineering Dec. 2014

Research and design of technology for tracking and positioning wild stocking animals

Lei Hongzhou, Yang Lu※ (College of Information and Electrical Engineering of China Agricultural University, Beijing 100083, China)

Abstract: Wild stocking animals become a trend as the animals activate a lot and their meat are delicious. But the stocking animals are often lost which leads to increase cost in farming. Therefore, it is very important to research on positioning technology, which is essential for wild stocking animal management. Although the mature satellite positioning technology - GPS, Compass, Wi-Fi positioning (cell network, WLAN and wireless sensor network-assisted positioning system) and wildlife radio-tracking technology can be applied in positioning, but it is extremely difficult to track the wild stocking animals because of the complex geographical environment the animals active, the affordability of farmers and other affecting factors. Combined with GPS positioning and wireless mobile cell network positioning technology, this study researches on the positioning technology of pseudo-cellular wireless mobile network for locating and tracking wild animals. Pseudo-cellular base station location, PCBSL for short, is a mobile communications network based on the principle of a positioning radiolocation and tracking technology, different from wireless mobile communications cellular network positioning, which is a direct application of mobile communication network positioning technology. In the technology of mobile communication, to determine the location of a mobile terminal in the network, it is calculated by the relative position of the device with the different base stations. The position of mobile terminals is determined through base station. The base station divided the whole communication area into many individual cells, the diameter of each cell ranged from tens of meters to thousands of meters mobie terminals actually get online through one of these cells, and then transfer data (voice, text, or multimedia data) via internet. Therefore, when a mobile terminal communicates in the internet, it is always connected to one of the cells, so the position of the mobile terminal can be determined by which cell it connected to the base station. Pseudo wireless mobile cellular network is similar in principle to build the base station network with base station as the core. The whole system consists of base station and mobile beacon and the composition is much simpler than mobile communication network. In PCBSL system, the main function of BS is to position RB and data forwarding. RB is a mobile device carried by livestock which could emit positioning signals. There are two kinds of PCBSL positioning: Single base station location which relies on a single base station, and Multi- station location, which uses multiple base stations to cooperate. The former achieves coarse positioning of beacons, of which the algorithm is similar to the TOA / TDOA algorithm of GSM. The latter can achieve relatively accurate positioning of beacons, of which there are AHLos algorithm, RADAR algorithm, the centroid algorithm, DV-HOP algorithm, APIT algorithm, MAP algorithm and so on, or the improved algorithms of them. When precise geographic information is needed, then GPS or Beidou system is invoked to provide more accurate location data. In order to adapt to the complex geographical environment, using functions like intelligent power management and remote device settings to control continuous work of devices, which reduces the complexity and high cost from simple GPS and meets the positioning demand of wild livestock stocking. Key words: PS; wireless networks; location; wild grazing; fake cellular base stations; single base station; multi-base station doi：10.3969/j.issn.1002-6819.2014.23.029 CLC number: s24 Document code: A Article ID: 1002-6819(2014)-23-0232-06 Lei Hongzhou, Lu Yang. Research and design of technology for tracking and positioning wild stocking animals[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2014, 30(23): 232－237. (in English with Chinese abstract) 雷宏洲，杨 璐. 野外放养牲畜跟踪与定位技术的探索和设计[J]. 农业工程学报，2014，30(23)：232－237.

scope of activities of the domestic animals and control

0 Introduction the geographical location of the feeding area in order Using the wild stock-based feed method for to manage the herds more effectively to prevent the domestic animals, the farmers need to understand the loss of animals. Meanwhile farmers can also obtain the food ingredients from the composition of the plant

species in the feeding area to determine if the natural Received date：2014-11-26 Revised date：2014-12-19- Foundation item：National Science and technology support item 2014BAD04B05, grassland is available to supply the nutrients needed 2013BAD19B09 for life, growth, development, multiplication and so Biography：Lei Hongzhou, Associate Professor, China Agricultural University. on. Therefore, it is extremely important to be timely Beijing College of Information and Electrical Engineering of China informed of the locations of domestic animals for the Agricultural University, 100083, China. Email: [email protected] ※Corresponding author：Yang Lu，Beijing College of Information and feeding and management of domestic animals. Electrical Engineering of China Agricultural University, 100083. If see from a technical perspective, we usually Email: [email protected] choose the Global Positioning System (GPS) technology

第 23 期 雷宏洲等：野外放养牲畜跟踪与定位技术的探索和设计 233 to locate the position of the domestic animals in the stocking the activities of the herd to some extent, field, or other techniques, such as BeiDou Navigation getting the position at real-time or regularly, it can not Satellite System(BDS), mobile wireless networks, RF only reduce labor intensity of grazing member and positioning. However, in the actual environment, farmers, but also reduce the economic losses as much considering the geographical environment of grazing as possible. Even if it is lost, the device can provide a area, weather conditions, farmers’ affordability and trace that will help to promote the possibility of found. cost factors, the existing positioning products are The demand for the location of domestic animals is difficult to meet the demand. Because the stocking mainly from this form, or similar stocking way. fields are often in mountains or forested areas, where Either form is inevitably affected by the geographical environment is complex, it is often ecological environment conditions, geography, the blocked or interfered with radio or electromagnetic climate of the season, the level of economic waves. Moreover, livestock sometimes exceed the development and scientific and cultural quality of fixed grazing area, which makes the location more producers in the distribution area for domestic animals, difficult. But at present, there is no positioning the demand of domestic animal breeders for equipment and technology related to livestock positioning equipment is not the same as the usual stocking. Thus, it is necessary to study positioning civilian equipment, summed up in the following equipment and its technology that is suitable for characteristics: working long hours in the field, easy to catch wireless ● Less demanding positioning accuracy in most signals, at a low cost and easy to operate. cases, achieving visual range. Due to the complexity of positioning system used ● The positioning sensors or beacon device is in the field of livestock, here we only discuss its small, light, and easy to wear and use, able to work in relevant technical and functional requirements, in a relatively poor geographical and climatic condition. combination of the characteristics of backyard ● Low-power for the device, long time power livestock. supply, charging time and frequency as small as possible. 1 Positioning Characteristics and Technologies ● Low cost for the system, especially cheap for for domestic animals in the field sensors or beacons, suitable for large-scale use. There are many forms for domestic animals in ● Delay positioning, i.e., non-real-time positioning the field, which can be divided into: Wild grazing and for domestic animals. Because there are grazing Scattered grazing at fixed location. members, we often do not need to know the location Wild grazing needs a special Grazing member. in real time of domestic animals, and we consider After the herd entering, the grazing member need to locating or tracking them when accident happens. visually guard and watch the herd, maintaining a In the existing mature positioning: Global certain distance, command and control animals with a Positioning (GPS)/(A-GPS), the Compass, IP particular call, voice or password, accompanied by positioning, WIFI positioning, sonar positioning, throwing small stones. As the grazing member always RFID tags to identify the location, Bluetooth keeps in contact with the domestic animals, he can positioning, sonar positioning and cell base station effectively control the herd, which will avoid the positioning. phenomenon of loss of the domestic animals. But GPS positioning consists of 24 operating when the herd is large, it still needs a locating satellites. It needs to measure firstly the distance equipment to help manage the herd. between the known-position satellite and the user Scattered grazing at fixed location is choosing a receiver, and then we can know the exact location of relatively fixed location in the wild in order that the the receiver with the data of multiples satellites. GPS domestic animals are relatively scattered, feeding systems use civilian C/A code and the military P(Y) freely, so that each domestic animal can be fed more code, two kinds of Pseudo code：The civil accuracy is forage in a relative large area. The grazing member do about 10 meters and the military precision is about not have to keep in contact with the herd for long time, one meter. The advantages of GPS positioning are just checking the timing of their activities, whether high accuracy, no radiation, but weak penetration, back to the barn in time, whether injured or sick, and unable to penetrate reinforced concrete so that field so on. Because the grazing members no maintain signals are affected by the weather; when the signal is contact with the herd, the activities of the herd cannot blocked or cut, the positioning will appear in the drift, be kept up at any time. The domestic animal is able to and it cannot be used indoor or enclosed space. go far away, or even get lost. If we use the device for Because of these shortcomings of GPS, it needs

234 农业工程学报 2014 年 assistance to help complete the location for positioning 2 Field positioning method for domestic system, that is, firstly initial positioning with base animals station or WIFI AP, then finding satellite and GPS positioning quickly according to the GPS satellite The pseudo-cell base station location (PCBSL) is table stored in the machine, known as A-GPS [1,2]. one of the technologies for positioning of the cell The base station positioning divide the mobile communication system, using the positioning communication area into some cells, several tens of principles and methods of GSM cell base station meters for the small cells, or several kilometers for big location for domestic animal field positioning. Similar cells. The mobile devices are actually connected to as the GSM base station location, the pseudo-cell base GSM network through a base station of a cell, then station (Base Station) divides the positioned area into transmit the data (voice data, text data, multimedia lots of cells (cell), composing of a cell network shown data, etc.) through the GSM network. When the in Figure 1. The cell size can be determined according communication in GSM happens, it always requires a to the need, tens of meters for small cells, several base station for the cell connection, or one of the cells. kilometers for large cells. The cell base station of the cells is used for GSM The domestic animals which stay in the cell carry positioning. The advantage of this positioning a radio beacon (Radio Beacon) or mobile device approach is to start quickly with high penetration (Mobile Device). The position of domestic animals of ability for signal, received interiorly. The the cell network is received from one or several cell disadvantage is the high accuracy of positioning, and base stations, determined by the positioning signal the base station needs expensive special equipment. emitted by the beacon or mobile device, that is, one or WIFI AP positioning relies on mobile devices to more cell base stations are required to receive the locate the MAC address of the AP. The devices firstly signal when positioning, as shown in Figure 1. One collect and scan nearby AP signal, detecting the signal base station location is called single base station strength for each AP point, and then they send the location, similar to the COO GSM positioning. The information to the server on the network. Using this accuracy of the positioning is low, which can only get information, the Based Server check the coordinates approximate location, but it is also the lowest-cost of each point in the records of AP database , and then positioning. The positioning done by three or more computing, so that the exact location of the client can base stations is multi-base station location, similar to be checked out. This method is not affected by the GSM in the TOA / TDOA positioning. The accuracy terrain, suitable for buildings in the city or indoors. of the positioning is relatively high, and the cost will The disadvantage is that the service must be covered increase accordingly. by WIFI with the point of access. RFID is an abbreviation for Radio Frequency Identification, known as electronic tags. It is a non-contact automatic identification technology, which automatically identifies the target RF signal and obtains relevant data. The identifying work does not need human intervention, which cannot be directly used to determine the location, not for field positioning, either. Based on the characteristics of the field stocking Fig.1 Setting for pseudo-cell base station location location, it cannot be used directly whether GPS, base station location of honeycomb communities, or WIFI 1) Single base station location AP positioning. Because these methods of positioning The single base station location determines the require relatively high power supply and short position, based on the location of the cellular base duration; mobile device and receiver of high price are station which receives the beacon signal, as shown in not applied for large-scale use of domestic animal Figure 2. Obviously, the positioning accuracy depends feeding. Therefore, we are here discussing a on the radius of a cell. The smaller the cell divides, the technology of cell base station location ,based on cell greater the number is, and the higher intensity of the base station location, combined with radio tracking base station is, the more layers of a multilayer are, the and GPS technology, also known as pseudo-cell base higher the positioning accuracy is. In contrast, if the station location (Pseudo-cell base station location), base are distributed dispersedly and the radius of cell referred to as “PCBSL”. is large, the positioning accuracy is low. If it reaches

第 23 期 雷宏洲等：野外放养牲畜跟踪与定位技术的探索和设计 235 several kilometers, it means the positioning accuracy Wherein, d1, d2, d3 are respectively the distances from is only a rough to several kilometers. the three base stations to RB. The distance from RB to The technology base of single base station BS can be generally used the time of arrival (TOA), positioning is COO positioning technology for GSM time difference of arrival (TDOA), angle of arrival Cell-ID based positioning(Cell of Origin),i.e., (AOA) and a received signal strength (RSS), or other determining the location by getting Cell-ID number ranging methods. from mobile device. Throughout the whole system, we (2) Multi-base station location pre-collect the location data of cell sites on the map When determining the position of the beacon and the data in the radius of the cell, storing the with four or more base stations (Figure 4), the location of data into a database system. The system accuracy of location obtained has to be accurate than can determine the located cell when it receives a the location determined by tree base station location. signal from beacon or mobile device and then get its The common positioning algorithms references are: location. The accuracy of the cell depends on the Ranging based: AHLos algorithm, RADAR radius of the cell. In Figure 2, the positions of the base algorithm: station BSa and BSb are known. The beacon RB is No Ranging: Centroid algorithm, DV-HOP located in the cell of BSb. Know the location of RB algorithm, APIT algorithm, MAP algorithm, amorphous can be checked out by querying the location database. algorithms, convex programming algorithms and Ring-Overlapping positioning algorithm. The above algorithms have advantages and disadvantages with different algorithm complexity. Here convex programming positioning algorithm is selected as the basic positioning algorithm.

Fig.2 Single base station positioning

2) Multi-base station positioning In the multi-base station positioning the current position of the beacon consists of three or more single base stations. The more the base stations are, the better the accuracy is, as shown in Figure 3.

Fig.4 Fcour or more base station location

Convex Programming positioning algorithm: if two nodes can communicate directly, the distance between them must be less than the communication radius of nodes. In Figure 4, the position of beacon RB node is unknown, but the positions of base station BS1, BS2, BS3 and BS4 have been determined. If RB

Fig.3 Multi-base station location can communicate with BS1-BS4, the RB has to be within a radius of the circle the center of which is BS. (1) Three base station positioning The intersecting region of several circles must contain In Figure 3, the positions of base station BS1, RB, as the gray area in Figure 4. Then, the position of RB can be calculated by the centroid of the rectangle BS2, BS3, BS4 are known , namely BS1(x1,y1), composed of the intersection area. BS2(x2,y2), BS3(x3,y3), BS4(x4,y4). The location of beacon RB is RB(x,y), which is near BS1, BS2 and 3 System components BS3.Therefore, RB (x, y) can be obtained according to the three known locations of base stations , namely: PCBSL system mainly consists of two parts, 222 namely base station system and beacons. ⎧()()x −+−=xyyd111 ⎪ 3.1 The base station 222（ ） ⎨()()x −+−=xyyd212 1 In the pseudo-cell base station location (PCBSL) ⎪ 222 ⎩()()x −+−=xyyd333 system, the base station (BS) is responsible for the

236 农业工程学报 2014 年 location of beacon (RB) and data forwarding, as GSM base stations build network via wire, Wi-Fi, GRPS or mainly applying voice calls. Therefore, the function other ways. Which way should be taken depends on and composition of BS is simply, compared with the the affordability and local information infrastructure. GSM, and the cost will be much lower. Key features 3.2 The radio beacon of PCBSL station include: Radio Beacon (RB) is carried by the domestic ● receiving information issued by beacon code animal, a mobile device sending a positioning signal. (RB) and encoding the code . It consists of five parts, a signal transmitter ● storing or forwarding coding. (transmitter), the encoder/decoder (encoder / decoder), ● Receiving / forwarding commands issued by command receiver (command receiver) (optional), I/O console . device and antenna (antenna), as shown in Figure 6. ● Base networking. The base station system consists of the following components, as shown in Figure 5: ● Beacon signal receiver (RB-ID receiver), which is responsible for receiving the identification code issued by beacon and positioning the beacon device corresponding to the code, and then coding the location information and identification code . ● Code memory (memory),which is responsible for storing the encoded beacon information. ● Data forwarder (data forwarder), which is Fig.6 Radio beacon responsible for forwarding the encoded data stored in the code memory. There are three ways to forward The main function of the signal transmitter is data: timing forwarding, real-time forwarding and transmitting RB positioning information. According to local forwarding. location information, the base station determines the ● Command forwarder(command forwarder), location of the RB device, radio tracker is also based which is responsible for receiving commands issued on the signal tracing RB. The location information by the console, and then sending to the beacon device includes the device identification code encoded and within the range of base station. additional RB data. The encoder / decoder is ● Antenna (antenna), including the receiving responsible to generate positioning information from antenna and transmitting antenna. RB device identification code and additional data, or ● Power. In accordance with the surroundings the decode command code received by the command power of base station is optional, AC power, batteries, receiver. solar cells or other forms. According to the operating 4 Conclusions state of base station, the power management system provides power, or controls the operation of base The location system of fake cell base stations station according to the need, such as timing applies the method of single base station location, and forwarding. assisted with multi-station location method, it is used as individual livestock position location system for backyard livestock in rural field. The single base station location provides a rough location of domestic animal, providing the approximate range of activities. If precise location is needed, multi-station positioning method can be used, or use radio tracking for positioning tracking. The base station is the core of the system, the basic function of which is to receive the positioning signal emitted by the beacon. Its architecture and circuits are relatively simple with low Fig.5 The logical structure of base station cost. Radio Beacon is actually radio transmitter that Each base station is a complete independent the domestic animals wear. The main function is to system that can work in standalone mode alone, and issue a positioning signal, which can be received by also multi-machine network. If it needs more base base station for calculation, or received by radio stations to constitute the wireless sensor network, the tracking.

第 23 期 雷宏洲等：野外放养牲畜跟踪与定位技术的探索和设计 237

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野外放养牲畜跟踪与定位技术的探索和设计

雷宏洲，杨 璐※ （中国农业大学信息与电气工程学院，北京 100083）

摘 要：野外放养牲畜，牲畜活动量大、肉质鲜美，很受商家推崇。但是牲畜经常走失，使养殖成本增大，研究一种能够对 牲畜定位技术对牲畜野外放养管理有很重要的意义。成熟的卫星定位技术——GPS、北斗、无线网络定位（蜂窝网络、WLAN 和无线传感器网络辅助定位系统）和野生动物无线电追踪技术都可以直接应用，但受放养家畜活动地域地理环境复杂，以及 经济承受能力等因素影响，实际应用有相当的难度。该文结合 GPS 定位和无线移动蜂窝网络定位技术原理，探索研究一种 伪无线移动蜂窝网络定位技术用于野外家畜的定位和跟踪。分析表明，该技术能够满足复杂地理环境，同时利用智能电源管 理和远程设备设定等功能控制设备可持续工作，这样就降低了单纯卫星定位的复杂性和高成本，可以满足野外放养牲畜的定 位需求。这种对野外放养家畜的定位管理简单、实用、成本低，并可为更进一步研究提供基础支持。 关键词：GPS；无线网络；定位；野外放牧；仿蜂窝基站；单基站；多基站