Patent Description:
A golf course is an area comprising a series of holes, in which the game of golf is played. Typically, a golf course with <NUM> holes occupies as much as <NUM> hectares (approximately <NUM> acres) of land and has an average of <NUM> hectares (approximately <NUM> acres) of maintained turf. Determining a position on a golf course is useful in several circumstances. One example is providing an autonomous vehicle to perform a maintenance task on the golf course, such as cutting grass, picking up trash, or removing dew. The ability to determine the current position allows the autonomous vehicle to, for example, process a trajectory, move along an appropriate path on the golf course, or decide which movement to perform next. Another example is a golf player deciding on how to perform a stroke during a round of golf. When making that decision, an important information to consider is the distance from the position of the ball being played to the target hole. The distance can be obtained if the player knows the position of the hole before-hand and is able to determine his/her position on the golf course.

However, there are challenges in determining a position with accuracy on the golf course. A significant error can sabotage the action that is performed based on the determined position. For example, an autonomous lawn mower will require accurate positions to be determined when cutting the grass on a putting green, otherwise the resulting putting green may differ from the planned design. Or the autonomous lawn mower will require accurate positions to be determined when circumventing hazards, such as bunkers or water streams, otherwise it may move into a location that will block it from moving further or even damage it. Another example, is a player selecting an incorrect club when performing a stroke, the selection being performed based on an incorrect determination of his/her position, of the position of the ball, and/or of the position of a hole on the golf course.

A known solution for determining a position on a golf course is a receiver for a satellite navigation system such as the Global Positioning System (GPS), the GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema), or the Galileo system. However, in practice it is observed that the determined position will present an error approximately between <NUM> and <NUM> meters. With such an error, it is not safe, for example, for an autonomous lawn mower to move on a path that is <NUM> meters wide. A player will also determine his/her position with a significant error, which renders this solution insufficient in many situations.

Document <CIT> discloses a solution for determining distances to targets such as targets on a golf course using a wireless communication device. The wireless device is configured with an application to determine the distance to target, such as a golf cup, which may be subjected to location changes. The targets on a golf course are provided with an asset tag including a GPS receiver. The use of differential GPS is mentioned in the context of the wireless device. The system disclosed may also include further network devices, such as a position determining entity, for improving the GPS signals received through the asset tags.

Document <CIT> discloses a distance measuring system in which a user in possession of a portable distance calculator can determine the distance between an actual position and a fixed position. Satellite state position data of the fixed position is determined periodically and supplied through the calculator, which includes a satellite position receiver and a processor which permit the distance to be determined. Error correction may be performed by determining a satellite differential position error at a known survey reference location and supplying the error to the calculator for correction of the actual position and, where necessary, the fixed position.

Document <CIT> discloses an error correcting location system including a ground station with fixed reference coordinates. The ground station may receive satellite broadcast messages from a plurality of satellites. The ground station may determine location coordinates based on the satellite messages and compare the location coordinates to the fixed reference coordinates to determine a compensation value. In addition, the ground station may send the compensation value to location system devices, which upon receipt of the compensation value may utilize the latter to generate highly accurate location coordinates.

Document <CIT> discloses a system for providing distance information in which a portable terminal transmit its own positioning data obtained from a GPS receiver to a central apparatus via communication system. The central apparatus reads out course information pertaining to a golf course where a player is playing from a course information stored in advance. Then, in relation to this specified course information, distances between the portable terminal and preassigned registered points, for example pins, ponds, bunkers, etc are transmitted to the portable terminal. Consequently, a player holding that portable terminal can determine his relative position to any point of the golf course, accurately and on a personalized basis.

Document <CIT> discloses an apparatus for providing position information, the apparatus having a central apparatus capable of duplex communication with a portable terminal that is provided with position detecting means for measuring a position thereof. The central apparatus reads out course information pertaining to a golf course where a player is playing, from course information stored in advance. The apparatus allows a player holding the portable terminal to establish his relative position from the point where the player is playing to points on a golf course.

Document <CIT> discloses a golf ball position measurement method involving measuring distance and direction between fixed GPS receiver and pin, and between fixed GPS receiver and golf ball. The distance between golf ball and pin is calculated, using distance and direction between fixed GPS receiver and pin, and between fixed GPS receiver and golf ball. The distance and direction between GPS receiver and golf ball are calculated using distance and direction between mobile GPS receiver and ball and between fixed and mobile GPS receivers.

The present invention will now be disclosed.

According to an aspect of the present invention there is provided a system for determining a position on a golf course, the system comprising a master unit, a first slave unit, a second slave unit, and a server adapted to communicate through a telecommunications network. Each of the master unit, the first slave unit and the second slave unit comprises a processing unit, a memory, a receiver for a satellite navigation system, and is adapted to communicate through the telecommunications network. The server comprises a database for storing a difference processed by the master unit and also for storing at least one corrected position of a slave unit. The receiver of the master unit is operable at a fixed position on the golf course and the memory of the master unit is configured with the fixed position, wherein the master unit is configured to:.

Moreover, the second slave unit is configured to:.

By providing a master unit with a receiver for a satellite navigation system and by having the receiver to be operable at a known fixed position on the golf course it becomes possible to compare the position determined by the receiver against the fixed position. This allows to process the difference of the position determined by the receiver, in other words an error. It has been realised that, if the difference is made available to the at least one slave unit, the latter can then make use of it to improve any position determined therein. Thus, although the system may process the difference at a fixed location, it still enables the at least one slave unit to improve the determination of its position, even if it changes its position on the golf course.

The configured step of the master unit to process the difference may comprise processing the difference of latitude and longitude between the obtained position and the fixed position.

The configured step of the first slave unit to correct the obtained position of the first slave unit based on the difference processed by the master unit may comprise correcting the obtained position based on the inversion of a difference of latitude and longitude processed by the master unit.

The configured step of the second slave unit to correct the obtained position of the second slave unit based on the difference processed by the master unit may comprise correcting the obtained position based on the inversion of a difference of latitude and longitude processed by the master unit.

The system may comprise a flag for marking the position of a hole on a golf course, the flag comprising the first slave unit.

The system may comprise a portable device for determining a position on a golf course, the portable device comprising the second slave unit.

The system may comprise an autonomous vehicle operable to move on a golf course, the autonomous vehicle comprising the second slave unit. The autonomous vehicle may be an autonomous lawn mower.

According to another aspect of the present invention there is provided a golf course comprising the system described above. A hole of the golf course may comprise a first slave unit.

In the golf course illustrated in <FIG>, a round of golf consisting of the three holes therein (<NUM>, <NUM>, and <NUM>) could be played by starting from the teeing ground <NUM>. A ball would be played from there with successive strokes until it would be at rest within the hole <NUM>. Then, moving to the second teeing ground <NUM>, the ball would be played towards the hole <NUM>. And finally, moving to the third teeing ground <NUM>, the ball would be played towards the hole <NUM>. The player who finishes the three holes with the lowest number of strokes would win.

<FIG> illustrates general invention embodiments of a master unit <NUM> and of a slave unit <NUM>.

The master unit <NUM> includes a processing unit, a GPS receiver, and a memory preconfigured with the fixed coordinates of the GPS receiver. The GPS receiver could instead be a receiver for any other satellite navigation system. The operation of the master unit <NUM> requires its memory to be configured with the fixed coordinates of the GPS receiver. Afterwards, these coordinates are used as a reference to compare coordinates determined by the GPS receiver.

The master unit <NUM> also includes a communication interface for communicating through the Internet. The connection may be performed by wire, for example via Ethernet, or wirelessly, for example via WiFi or via a digital cellular network.

The slave unit <NUM> is illustrated as being installed on a flag for marking the position of the hole <NUM> on the golf course. This arrangement is useful because it can be used to determine the position of the hole <NUM> with a few changes of the already existing elements of on the golf course.

<FIG> illustrates a system invention embodiment showing how a difference <NUM> is processed by the master unit <NUM> and propagated to a slave unit <NUM>, which then uses it to improve the position determined by the receiver of the slave unit <NUM>.

For this example, the system comprises a server (not shown) remotely accessible through the Internet. Initially, the memory of the master unit <NUM> is configured with the fixed position at which the receiver of the master unit <NUM> is operating. This may be done by any prior art method for that purpose, such as by reading the coordinates of the fixed position using a map or by collecting position samples from the receiver of the master unit <NUM> during several days and, at the end, processing a statistical indicator for representing the fixed position.

After the initial configuration of the memory of the master unit <NUM>, the following occurs. The master unit <NUM> obtains a position determined by its receiver and processes the difference <NUM> by comparing the obtained position and the fixed position configured in its memory. In this respect, the master unit <NUM> processes the difference of latitude and longitude between the obtained position and the fixed position, which is represented by the arrow <NUM> in the figure. Once the difference <NUM> has been processed, the master unit <NUM> may then communicate the processed difference <NUM> to the server, for example via a wired connection to Internet. The server stores the difference <NUM> data in its database. Thus, the master unit <NUM> makes the difference <NUM> available to the slave unit <NUM>, which can then communicate with the server to obtain it.

The slave unit <NUM> communicates with the server through the Internet, for example via a wireless connection, and obtains the difference <NUM>. Then, the slave unit <NUM> obtains a position determined by its receiver. This position is then filtered based on the obtained difference <NUM>. In particular, the slave unit <NUM> corrects the obtained position based on an inversion of the difference of latitude and longitude processed by the master unit <NUM>, ie the inverted difference <NUM>. Thus, the slave unit <NUM> processes a filtered position using the inverted difference <NUM>.

It will be appreciated that the inverted difference <NUM> may be processed by some other component of the system, for example by the server or by the master unit <NUM> before communicating it to the server.

This system invention embodiment allows improving the determination of a position at the slave unit <NUM>. Thus, the slave unit <NUM> may be installed on an autonomous vehicle, which would use the position determined by the embodiment as an input to its navigation system. As described for <FIG> and illustrated in <FIG>, the slave unit <NUM> may also be installed on a flag for marking the position of a hole on a golf course.

<FIG> illustrates how a system invention embodiment may be installed and used on a golf course, so that a golf player is able to determine the distance from his/her position to the hole <NUM>. In this example, the clubhouse <NUM> is chosen as the location where the master unit <NUM> is installed however any other location in the golf course could have been chosen. Further, the example includes two slave units: a first slave unit <NUM> installed on the flag of the hole <NUM>, as illustrated in <FIG>; and a second slave unit <NUM> being carried by the golf player.

After the first slave unit <NUM> has processed its filtered position in a similar manner as explained for <FIG>, it then communicates this result to the server through the internet, which stores the result in its database. This arrangement may allow for the server to store filtered positions from several slave units in a centralised manner.

After having performed the tee-off stroke, ie the initial stroke performed from the teeing ground <NUM>, the golf player now has to perform his/her next stroke from the fairway, ie the part of the golf course between the teeing ground <NUM> and the smooth area of short grass surrounding the hole <NUM> (known as the putting green). An important information for the golf player to consider when deciding on how to perform the next stroke is the distance from his/her current position to the hole <NUM>.

A stroke is a movement of the club made with the intention of striking at and moving the ball. A player may decide on several aspects when performing the stroke. The following are a few examples. There are various kinds of clubs (eg wood, iron, or putter) that the player can choose from and each kind has different features to consider (eg the length of the shaft or the angle of inclination of its face). Another aspect to decide upon is the movement to be performed, for example a full swing, a three-quarter swing, or any other kind of swing. A further aspect is the position where the ball is struck at. Any aspect considered for the stroke will influence the way the golf player transmits energy to the ball.

In order to determine the distance, the golf player enables the second slave unit <NUM> to operate as follows. The second slave unit <NUM> determines its filtered position in a similar manner as the first slave unit <NUM> did: obtain the difference processed by the master unit <NUM> from the server; obtain the position determined by its receiver; and filter the obtain position based on the obtained difference. Then, it obtains the filtered position of the intended target, which is first slave unit <NUM>. In particular, the second slave unit <NUM> communicates with the server to obtain this information. And then it calculates the distance between the two filtered positions.

This solution allows to solve a problem that is observed nowadays. In order to save the putting green surrounding a hole, many golf courses are managed so that the wear due to the golf player stepping on it is minimised. One strategy in particular, is to regularly move the hole and flag on the putting green. This may be achieved by removing the components of the hole, typically a cup with the appropriate dimensions, filling in the cavity left behind and covering it with pre-grown grass, and then inserting the components of the hole in another location of the putting green. This has the advantage for the owners of the golf course that the wear of the putting green is spread throughout in an homogenous manner. However, this strategy also has the consequence that the hole will be changing position regularly within a significant area, typically with <NUM> square meters. Consequently, many prior art solutions using a centralised database with positions of holes will provide an error of several meters when estimating the distance between an initial position on the golf course and a hole, independently of the accuracy of the initial position on the golf course. The present invention, and in particular the example explained with reference to <FIG>, allows solving this problem.

Invention embodiments may have some or all of the following advantages:.

Generally, the terms used in this description and claims are interpreted according to their ordinary meaning the technical field, unless explicitly defined otherwise. Notwithstanding, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms are not interpreted to exclude the presence of other features, steps or integers. Furthermore, the indefinite article "a" or "an" is interpreted openly as introducing at least one instance of an entity, unless explicitly stated otherwise. An entity introduced by an indefinite article is not excluded from being interpreted as a plurality of the entity.

Claim 1:
A system for determining a position on a golf course, the system comprising a master unit (<NUM>), a first slave unit (<NUM>) a second slave unit (<NUM>), and a server adapted to communicate through a telecommunications network,
wherein each of the master unit (<NUM>), the first slave unit (<NUM>) and the second slave unit (<NUM>) comprises a processing unit, a memory, a receiver for a satellite navigation system, and is adapted to communicate through the telecommunications network,
wherein the server comprises a database for storing a difference (<NUM>) processed by the master unit (<NUM>) and also for storing at least one corrected position of the first slave unit (<NUM>),
wherein the receiver of the master unit (<NUM>) is operable at a fixed position on the golf course and the memory of the master unit (<NUM>) is configured with the fixed position,
wherein the master unit (<NUM>) is configured to:
- obtain a position determined by the receiver of the master unit (<NUM>);
- process the difference (<NUM>) between the obtained position and the fixed position; and
- make the processed difference (<NUM>) accessible to the first slave unit (<NUM>) and the second slave unit (<NUM>) by communicating the processed difference (<NUM>) to the server through the telecommunications network, and
characterized in that the first slave unit (<NUM>) is configured to:
- communicate with the server through the telecommunications network so as to obtain the difference (<NUM>) processed by the master unit (<NUM>);
- obtain a position determined by the receiver of the first slave unit (<NUM>);
- correct the obtained position of the first slave unit (<NUM>) based on the obtained difference (<NUM>) processed by the master unit (<NUM>); and
- communicate the corrected position of the first slave unit (<NUM>) through the telecommunications network to the server,
wherein the second slave unit (<NUM>) is configured to:
- communicate with the server through the telecommunications network so as to obtain the difference (<NUM>) processed by the master unit (<NUM>) and the corrected position of the first slave unit (<NUM>);
- obtain a position determined by the receiver of the second slave unit (<NUM>),
- correct the obtained position of the second slave unit (<NUM>) based on the obtained difference (<NUM>) processed by the master unit (<NUM>); and
- calculate a distance between the corrected position of the second slave unit (<NUM>) and the corrected position of the first slave unit (<NUM>).