SE542278C2 - A method and a system for monitoring rhinoceroses - Google Patents

Abstract

A method and system for tracking rhinos utilizing a Bluetooth Low Energy (BLE) device put on the rhino, preferably in the horn at a young age. The BLE device has a unique Bluetooth device address from the manufacturer, which is associated with the individual rhino. BLE base stations are placed at strategic positions in sanctuaries, e.g., one at each waterhole. The BLE base station sends out a ping regularly, and all BLE devices within range of the base station wake up and send back pings with their respective identity numbers. The BLE base station records which animals are within range. It may also store time and other meta data, such as received signal strength (RSS).

Description

A METHOD AND SYSTEM FOR MONITORING RHINOCEROSES FIELD OF THE INVENTION This invention relates to animal monitoring, and more specifically to determining the position of rhinoceroses.

BACKGROUND Animal monitoring is a classical branch of conservation and animal studies aiming at remotely observing fine-scale movements, to understand animal behavior in different environments, and how animals react and change behavior to external stimulus and changes in the environment. This is used by ecologists to study more or less all kind of animals, and there is in particular an urgent need to study endangered animals such as the rhinoceros in their natural habitats.

Further, poaching has become a serious threat to our fauna, and the rhinoceros (or “rhino”) is seriously threatened. There are a lot of actions to mitigate poaching and wildlife trafficking, from preventive actions, harder penalties and influencing the demand side.

Monitoring the rhinos to mitigate poaching is thus another urgent need, in addition to monitoring for conservation studies in general. The official statistics that are so important for decision makers hinge on timely and reliable reports from the field. In principle all remaining rhinos today live in national parks or sanctuaries, i.e. enclosed areas guarded by park rangers. These park rangers are responsible for protecting the rhinos from poachers, which requires military training, and also to analyze the population for unhealthy individuals, new calves, and, in particular, dead rhinos. If the horn has been removed from a dead rhino, it is considered a poaching incident. The park rangers patrol the sanctuary several times per day to look for animals, dead or alive, as well as looking for signs of intrusion of possible poachers in their new roles as security personnel.

The rangers also participate in regular censuses that take place a couple of times per year. During the dry season and full moon, the rangers guard the waterholes and wait for the rhinos. They look for the ear marking that identifies each rhino uniquely. If a rhino is not seen for more than a year, it is declared to be dead. Often an airplane is used for the census, where the rangers look for animals on the ground in daylight. This is time consuming, expensive and fault prone, since both the identity and number of animals are quite uncertain with this method.

Ear marking is an important part of the process, and it takes place when the calf is young. In general, the rhinos should not be tranquilized more than once or twice during their life-time since it causes stress, and for the cows it can imply miscarriage or a temporary loss of fertility.

There have been attempts to improve the process described above by using new technology. The classical way is to put a radio transmitter on the animal, and use radio receivers configured to detect the signal and determine the angle of arrival. With a network of such receivers, the rhino’s position can be triangulated. The main drawback of this approach is that also poachers can use the same technology to find their victims. Battery life time is another issue, since radio transmission consumes a lot of energy.

A more advanced method is to put a GPS device on the rhino. The position can be transmitted regularly, either via a dedicated radio channel, the cellular network or satellite communication. There are several problems with this approach however: • Battery fife-time is limited to a couple of years with today’s technology, since GPS requires a lot of energy to amplify the weak satellite signals.

• The usual placement of GPS is on a collar around the neck of the animals. But the rhino has no neck, in contrast to most mammals on land, and thus a collar is not a conceivable solution for the rhino. All external positions are also subject to heavy wear and tear, and the lifespan of the device in practice is limited.

• One common suggestion is to place the GPS device on the horn. But the hom grows, just as hair and fingernails, and the device will almost invariably fall off after a couple of years.

• GPS determines the position, but a radio transmitter is needed to send this information to a dedicated infrastructure. Any radio transmitter is subject to radio detectors and bearing determination, and such devices can be used by poachers to find the animals.

For these reasons, GPS is used primarily on animals that are moved from one area to another, to study their behavior in a new environment for a couple of years.

There have also been attempts to mark the horns in different ways, e.g. by drilling holes and filling them with a mixture of the following: • A non-lethal poison that makes human consumers sick but not dead.

• Color so that the horns are easily detected as being from a poached animal.

• Radio-active substances so the hom can be detected in the customs.

The preventive effect of these techniques is still unsettled, and some critics question whether the animals may react negatively in the long term to these chemical substances.

Further approaches include cutting off horns in a systematic way to make poaching less attractive or to sell the cut off horns on a legal market, or to saturate the market with artificial keratin substances that are hard to distinguish from real rhino horn. All these methods are both ethically questionable and generally ineffective in the fight against poaching.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved method and a device that at least partly alleviates one or more of the aforementioned drawbacks.

The main idea is to utilize the new Bluetooth standard called Bluetooth Low Energy (BLE). A BLE device consists of at least a BLE chipset, a battery and an antenna. The device can in one embodiment be put in a cylinder to fit a drilled hole in the rhino horn.

The method works as follows: • The BLE device is put on the rhino, preferably in the horn at a young age, for instance when the ear marking takes place anyway. This is to avoid unnecessary use of tranquillizers. The BLE device has a unique Bluetooth device identity number (MAC address) from the manufacturer, which is associated with the individual rhinos.

• BLE base stations are placed at strategic positions in the sanctuaries, e.g. one at each waterhole. A standard smartphone can be programmed to work as a BLE base station.

• The BLE base station sends out pings regularly, e.g. once per minute.

• All the BLE devices within the range of the base station wakes up and sends back pings with their respective identity number.

• The BLE base station receives the information of animals within range. It also stores time and other meta data, such as received signal strength (RSS). The base station either stores this information, or sends it to a central node, a server or the cloud, either instantaneously, or at regular time intervals if this is considered more secure.

The main advantages compared to existing solutions include: The battery life that is almost unlimited, at least exceeding the lifespan of the rhino. With an AA lithium metal battery, for instance, battery life can be several hundred years.

The device gives the rhino’s identity with high certainty, compared to manually checking ear markings, which often takes place in the dark.

The two-way ping mechanism implies that the device is quite until a registered base station sends a ping to make the device awake up from sleep mode. The device does not react to any other requests. Besides saving energy and battery life, this also makes it impossible to locate the rhino via the radio detection and bearing estimation devices used by the poachers. This is of the highest importance for security reasons.

The signal strengths for BLE are orders of magnitudes larger than for GPS. This means that possible damping of radio signals by the keratin in the hom is not a critical problem, as it might be for GPS.

There are several extensions of this principle: With a local network of BLE base stations, the received signal strength (RSS) values from the BLE device to each base station can be used to triangulate the position of the animal, and to track its movements.

A BLE base station can be equipped with multiple antennas, enabling direction of arrival (DOA) estimation. That is, one single base station can provide a rough position estimate of the rhino by combining range (from RSS) and DOA angle.

In small confinement as zoos, wildlife parks, animal orphanages and hospitals, the base station network can be dense enough to keep track of the animals anytime and everywhere.

The BLE device can be complemented with other sensors to monitor the activity of the animal over time. For instance an accelerometer can be used to distinguish the activity states resting, standing still, walking and running. The accelerometer consumes very little energy, and this can fit into the battery life time budget. Each time the animal is close to a base station, this information is included in the return message.

With inertial sensors and magnetometer in the device, dead-reckoning principles can be used to approximately compute the approximate trail of the animal, between trips passing close to a base station.

The BLE device can further be equipped with Ultra Wide Band (UWB) techniques to provide more accurate ranging, and thus in the end more accurate positioning.

The BLE device can yet further include low energy network assisted GPS technology, which is several order of magnitudes more energy efficient than conventional stand-alone GPS receivers. This is possible due to the network of base stations that perform the positioning based on low-level satellite measurements at the BLE devices, which are transmitted in the returned ping signal.

The BLE devices can be set up to detect each other. That is, the rhinos keep track of themselves and register every time they come close to each other, and how close they are (for instance one meter, 10 meters or 100 meters). Again, these meta data are transmitted to the base station once they are connected.

The BLE device can be detected from an airborne census where the aircraft is equipped with a large antenna increasing the range to say 500 meters. In this way, census operations can be made very effective and also autonomous, since a skilled observer is no longer needed, and tedious and error prone manual operation can be replaced by technology.

Further, airborne localization of missing animals or stolen horns from poached animals can be performed, the latter when hunting down the poachers after a successful poaching attack.

In particular, the BLE device in a stolen horn can be detected at road posts, in customs, and any other critical point where wildlife trafficking needs to be controlled.

Tactically, a mobile base station in the car or on the patrols can be used when hunting poachers to get an early warning about proximity to the poachers, who are most likely armed.

Any smartphone can be programmed to act as a BLE base station, so each and every ranger can have a base station in their pocket. This can be used in their normal patrol and guard duties to get an early indication of rhinos nearby, which is also an important safety feature for the rangers, it can further be used when tracking down poachers to get an early proximity indication, again with an important safety aspect for the rangers.

Brief Description of the Drawings Figure FIG. 1 illustrates the basic principle that a BLE device is put into the horn of a rhino, and a dedicated BLE base station in range communicates with the device, and in that way gets the identity of the rhino each time it passes by.

Figure FIG. 2 shows a theoretical model of how BLE received signal strength (RSS) decays with distance. This can be used to compute the approximate distance to the rhino from the BLE base station.

Figure FIG. 3 shows an antenna array with its associated antenna beam pattern. The received radio signals at each antenna element can be combined linearly to virtually direct the antenna in a given direction, and conversely software algorithms can be used to compute the direction of arrival (DOA) of any received radio signal.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described more fully hereinafter with reference to the accompanying drawing, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawing, like numbers refer to like elements.

Although this document discusses the use of an innovative location-tracking technique with respect to rhinos, it will be appreciated that the disclosed technique is applicable to numerous other species. In particular, the disclosed technique may be applied to any animal having a hom or other hard body protrusion into which the tracking device may be inserted. Other embodiments include necklace, footband, harness and even insertion into the skin of the animal.

A BLE base station needs a Bluetooth chipset compatible with the Bluetooth 4.0 standard, of which BLE is a part. It also needs a processor programmed to send out pings and register returned pings, and extract the identity number of the other BLE device. It can also store time, RSS and other meta data. This information is stored on a local memory, or transmitted to a central node using any communication interface, including cable and cellular networks. Any modem smartphone can be configured to act as a BLE base station. The BLE device consists at least of a BLE chipset, a power source such as a battery, and an antenna.

GPS satellites transmit 25. 6W 21.000 km above the earth, and the signal strength is -130dBm (10<-13>mW) when reaching the earth. Standard BLE chipsets give a signal strength of -40dBm at one meter distance, which then decays about linearly to logarithmic distance according to the formula P = -40 - 40 log10d, where d is the distance to the rhino. See Figure FIG. 2. The received signal strength indicator (RSSI) ranges from -30dBm to - 110dBm, depending on the device, and the maximum range for BLE according to specifications is 60m. With larger antennas at the BLE base station, this range can be increased to several hundreds of meters, but hardly kilometers. This makes the device secure enough to use for animal monitoring but not suitable for poachers, who would need to track the animals to get to this proximity.

With multiple receiving antenna elements, the relative phase differences between the arriving radio waves can be used to automatically compute the direction of arrival (DOA) for the transmitting source using beamforming methods (see Figure FIG. 3). Together with the approximate distance using RSS, the position relative to the base station can be computed.

A BLE chip consumes less than 1 ?? in sleep mode, and it consumes max 6 mA (in average 3-4 mA) during each ping. A standard ping lasts for 5 ms. A typical lithium metal battery of AA size can provide 2.7 Ah, and such a battery has a natural energy loss of 1% per years (an advantage compared to lithium ion batteries, which will self-discharge within a few years). If the BLE device is programmed to ping once per minute, the total energy requirement for one year is for sleep mode le — 6 · 24 · 365 = 0.0088 Ah and for the ping mode 6e — 3· (5e — 3 · 60)/3600 · 24 · 365 = 0.0044 Ah, respectively. With a total capacity of 2.7Ah, the battery will last for 205 years. The natural self-discharge is the limiting factor in this example. Still, with 1% self-discharge per year, the battery will have 36% charge left after 100 years. A rhino lives for about 40 years.

Radio triangulation by power measurement has been used for a long time for surface ships, underwater vessels, and in cellular networks. BLE is usually used as a proximity sensor, just giving a binary answer to the question whether or not the device is close to the base station or not. BLE is not a technology intended for use on animals. Still, the potential is huge, as described above for rhino monitoring. Basically, each RSS measurements constrains the device to a circle. With two base stations, the two circles intersect twice, causing an ambiguity that sometimes can be resolved by natural constraints (for instance a fence). With three base stations, the solution is unambiguous. The technique to combine circles into a position is called trilateration. In a wildlife park with an enclosure that is about 150 times 150 meters, about 4-10 base stations with external antennas should provide an accurate position to within 10 meters.

Time of flight measurements provide even better range measurements than the signal strength. One suitable technology for accurate time of flight measurements is known as Ultra Wide-Band (UWB). Such UWB chips can be integrated into the device.

Stand-alone GPS chips have the aforementioned drawback of being too energy demanding. The GPS radio has to be turned on for 30 seconds to get all data from the satellites that are needed to compute the position of the device. Assisted GPS (A-GPS) gets some of these data from a cellular network, and that reduces the radio on-time to some seconds, requiring one order of magnitude less energy. This is still too much, and connection to a cellular network cannot be guaranteed. A promising solution is to move all computer and data intensive computations to the network. In this way, the device only measures a couple of milliseconds and computes a time-delay to each satellite in view. If these time-delays are transmitted to the network, the network can compute the position based on open data about satellite configurations and their positions. However, these timedelays can also be stored on the device, and transmitted to the network once the device is connected to a BLE basestation. This is an opportunity in the proposed BLE devices to get GPS position precision, but with four order of magnitudes less energy consumption, due to the fact that the radio only needs to be turned on a few milliseconds instead of a few tens of seconds each time a position fix is needed.

The mean value of an three-axis accelerometer provides the direction of gravity. This can be used to determine if the rhino is standing or lying. Further, the variation in the acceleration indicates if the animal is standing still, walking or running. Other activity states that might be possible to log are eating and drinking. A further advantage is that the mean vector is also a health indicator. The rangers today look at the pitch angle of the head, and a low head indicates bad health. This can be detected from the gravity vector of the horn. The accelerometer needs to be sampled at least twice the running pace (or rather the frequency of the hom movements during running), and as such 4Hz can be one design goal.

The accelerometer provides step detection. Each step gives a peak in acceleration. This gives a rough speed estimate. Together with a magnetic compass (requires a magnetometer), speed and heading can be integrated to a trail, so the device itself determines its path between the observation points. Both accelerometers and magnetometers are today manufactured with MEMS technology and add a small chip to the device. The trail can be communicated to the base station, for instance using what in Android is called BLE advertisement message.

If the security situation allows, the BLE devices can be configured to send out pings themselves. In this way, different BLE devices can register proximity by themselves, without the need for a base station. Later, when any of these devices comes close to a base station, all encounters with other animals equipped with a BLE device can be transmitted, together with identity information and time stamps.

Claims (11)

1. A method performed in a system for determining an identity of a rhino, wherein the rhino is equipped with a device including a Bluetooth Low Energy (BLE) chipset, a battery and an antenna, and the system further includes at least one stationary or moving BLE base station, the method comprising the steps of: receiving at the device a first ping from the BLE base station; checking if the first ping comes from a registered BLE base station; and if this is the case, then returning to the BLE base station from the device a second ping including information of a device identity number; and storing the device identity number at the BLE base station.

2. The method according to claim 1, further comprising storing the received signal strength (RSS) at the BLE base station and using this information as a measure of distance from the BLE base station to the rhino.

3. The method according to claim 1, wherein the BLE base station is configured with multiple antennas, the method further comprising using a direction of arrival estimation method to find the angle to the rhino.

4. The method according to claim 1, wherein at least two BLE base stations form a network of BLE base stations, the method further comprising a method to triangulate the position of the rhino using the received signal strengths (RSS) from the network of BLE base stations.

5. The method according to claim 1, wherein the device and BLE base station include hardware to compute time of flight, and wherein at least two time of flight values are used to triangulate the position of the rhino.

6. The method according to claim 1, wherein the device also includes a GPS chip wherein the device is programmed to compute time delays to satellites, wherein at least one time delay is included in the second ping received by the BLE base station.

7. The method according to claim 1, wherein the device also includes an accelerometer, and wherein the device is programmed to compute an activity state of the rhino, wherein at least one activity state is included in the second ping received by the BLE base station.

8. The method according to claim 1, wherein the device includes an accelerometer and a magnetometer, and wherein the device is programmed to compute a trail of the rhino, where this trail information is included in the second ping.

9. The method according to claim 1, wherein the device is programmed to be able to ping other devices associated with other rhinos, and wherein information about proximity of any two individuals is included in the second ping.

10. The method according to claim 1, wherein the BLE base station is mobile and is one of a handheld BLE base station or a vehicle-borne BLE base station.

11. The method according to claim 10, wherein the vehicle-borne BLE base station is mounted in one of a car and an aircraft.