GB2538145A

GB2538145A - Electronic navigation device

Info

Publication number: GB2538145A
Application number: GB1604259.0A
Authority: GB
Inventors: Soto Javier
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-03-12
Filing date: 2016-03-11
Publication date: 2016-11-09
Also published as: GB201504212D0; GB201604259D0

Abstract

There is disclosed a navigation device 650 for attachment to a bicycle, the device comprising: means 652 for receiving data indicative of a compass bearing relative to the bicycle; means 654 for processing positioning data to determine a direction relative to the navigation device that corresponds to the compass bearing; and a display 658 for indicating the relative direction to a user of the bicycle. A further embodiment comprises a navigation device for a bicycle 650, the device being able to indicate the direction to a destination by using the GPS information from a smartphone 600 and an inner magnetometer 656 to establish its own orientation. The device is typically an electronic navigation device which points to the direction of the destination relative to the position of the device by using information from a smartphone GPS module 608. The information about the coordinates may be sent using wireless connection.

Description

1 ELECTRONIC NAVIGATION DEVICE

3 Field of the invention

The present invention relates to a navigation device for attachment to a bicycle, a 6 method of operating a navigation device attached to a bicycle, and a computer 7 readable carrier. The present invention finds particular application in the field of 8 navigation, in particular for bicycles.

Background to the invention

12 When riding on a bicycle within cities or even roads, it has become common to use 13 smartphones to find the route to the final destination, by the use of applications such 14 as Google (RTM) Maps. The use of such devices during a ride can be dangerous, causing accidents because of the lack of attention to road conditions during the 16 process of checking the directions; sometimes the phones are even taken out of a 17 pocket during the ride. Such methods can also delay the arrival, if it is needed to stop 18 to check the directions.

In addition, current software devices don't take into account the possibilities of a mix 21 of journey types between riding the bicycle and walking, in order to save distance or 22 time. The information presented by a smartphone is also sometimes complex to 23 understand, as it has to be processed in order to recognise roads or crossroads.

2 The present invention seeks to address this and other problems in the prior art.

4 Summary of the invention

6 The invention relates to an electronic device that can provide information about the 7 direction to the final destination by using the GPS of a smart phone and a navigation 8 device with simple indications about the direction to the destination and distance. It 9 provides simple information to avoid distracting the rider and to deliver useful indications.

12 Thanks to the simple indication of relative direction to arrive to the destination, the 13 rider need not be distracted by having to look at the smart phone or understanding 14 the extra information provided by it. This can increase the security and allow easier navigation when riding a bicycle.

17 It is one object of the present invention to provide a navigation device that makes use 18 of a wireless connection with a smartphone or similar device equipped with GPS can 19 indicate directions to a destination.

21 This object, as well as other objects which will become apparent from the discussion 22 that follows, can be achieved, in accordance with the present invention, by providing 23 a navigation device with a display connected wirelessly to an electronic device (a 24 smartphone or similar) with functionalities similar to that of a smartphone or handheld computer that is equipped with a GPS module. The navigation device can include a 26 data receiver, data memory, a logic device, an electronic compass and the display for 27 determining the direction based on data sent by the electronic device.

29 In a first aspect, the invention provides a navigation device for attachment to a bicycle, the device comprising: means for receiving data indicative of a compass 31 bearing relative to the bicycle (e.g. data representing a compass bearing relative to 32 the bicycle or data from which a compass bearing relative to the bicycle can be 33 derived); means for processing positioning data (typically including orientation data 34 representing an orientation of the navigation device or from which an orientation of the navigation device can be derived) to determine a direction (typically a direction of 36 a user specified destination location or a direction to one of a sequence of waypoints 1 to a user specified destination) relative to the navigation device (typically with 2 reference to a particular orientation of the said navigation device) that corresponds to 3 the compass bearing; and a display for indicating the relative direction to a user of the 4 bicycle 6 Typically the means for receiving data indicative of a compass bearing is configured 7 to provide data indicative of the compass bearing to the means for processing 8 positioning data. Typically the means for processing positioning data is configured to 9 process the positioning data together with the data indicative of the compass bearing to determine the said direction relative to the navigation device that corresponds to 11 the compass bearing. Typically the display is configured to receive data indicative of 12 the relative direction from the said means for processing positioning data and to 13 indicate the said relative direction received from the said means for processing 14 positioning data.

16 By these means, the processing that is required to be carried out by the navigation 17 device is limited, improving the efficiency of the device and ensuring lower cost, while 18 providing an output that is sufficient for the user's needs.

The navigation device may further comprise a wireless module (using Bluetooth 21 (RTM), Wi-Fi, mobile telephony, or other wireless communication protocol, for 22 example) for communicating with an electronic device (such as a smartphone or 23 other handheld or wearable device) associated with (and preferably carried by or 24 worn by) a user of the bicycle.

26 The navigation device is preferably operable (e.g. configured) to receive the data 27 indicative of a compass bearing from the electronic device, though the compass 28 bearing can be provided locally or from another source. The navigation device is 29 preferably operable (also) to receive at least part of the positioning data from the electronic device. Preferably the navigation device receives absolute positioning data 31 (such as the absolute position of the navigation device, bicycle and/or electronic 32 device, and/or an absolute position or bearing of a desired destination or other 33 location remote from the user).

The navigation device preferably comprises at least one sensor (e.g. one or more of a 36 magnetometer, accelerometer and gyroscope), and is operable to receive at least 1 part of the positioning data (e.g. orientation data) from the or each sensor. In one 2 embodiment, the means for processing positioning data is configured to transmit the 3 positioning data from the or each sensor to the electronic device for computation, and 4 to receive the results of the computation from the electronic device. In other embodiments the processing is carried out locally within the navigation device.

7 Preferably at least part of the positioning data is received from a global positioning 8 system module, magnetometer, accelerometer and/or gyroscope, or any other 9 appropriate relative and/or absolute positioning sensor or device. In the case of the magnetometer, the means for processing positioning data may be operable to apply a 11 correction to the magnetometer readings to take into account ferromagnetic material 12 associated with the bicycle (such as the frame, or metal objects attached thereto).

14 The navigation device may further comprise a user input device (such as keypad, buttons, USB or other physical or wireless data interface) for inputting at least one of 16 the compass bearing and at least a portion of the positioning data (directly).

17 Otherwise, data can be input into the associated electronic device (where present) or 18 transmitted remotely to either the navigation device or electronic device (smartphone 19 and the like), for example via the mobile data network, and/or transmitted from a web page or 'app' interface operated by the user.

22 The navigation device may further comprise means for attaching the navigation 23 device to the bicycle, either temporarily or permanently (for example in a secure 24 fashion to avoid theft, or removably fastenable with Velcro(RTM) and the like, to facilitate repeated attachment at the beginning of a journey and de-attachment at the 26 end of a journey). The navigation device may be built into the bicycle, for example as 27 part of the frame.

29 In a related specific embodiment, the device is able to indicate the direction to a destination by using the GPS information from a smartphone and an inner 31 magnetometer to establish its own orientation.

33 The wireless communication between the smartphone and the navigation device may 34 be done using the Bluetooth(RTM) protocol. Alternatively, the communication between smartphone and electronic device may be done by other wireless (or wired) 36 technology.

2 The direction to the destination (or otherwise) may be indicated using light emitting 3 diodes (LEDs). Alternatively, the direction may be indicated by a mechanical needle.

It may be that the first (or primary) purpose of the navigation device is not to be used 6 in a bicycle. It may be a navigation device for vehicles, or an electronic device of a 7 different kind (including a smartphone, laptop, tablet, and so on).

9 Readings about geometrical bearing may be made by the inner magnetometer of the smartphone and sent directly to the navigation device, and similar for other 11 positioning data and/or sensors.

13 The display may be an OLED screen, or an e-ink display, for example.

The compass beating may be a direction to a destination of the user, or (for example) 16 a direction to one of a sequence of waypoints to a destination. The waypoints may be 17 locations in a commute, or waypoints in a race, for example. The waypoints may be 18 pre-programmed into the navigation device or electronic device, or downloaded to 19 either on demand, for example. The destination and/or waypoints may be specified by the user (for example using a custom app, a mapping app, or a website, and so 21 on) or by a third party, for example as a service or as part of a race, and so on.

23 In another aspect of the invention there is provided a method of operating a 24 navigation device attached to a bicycle, the method comprising: receiving data indicative of a compass bearing relative to the bicycle; processing positioning data to 26 determine a direction relative to the navigation device that corresponds to the 27 compass bearing; and indicating the relative direction to a user of the bicycle.

29 The method may further comprise communicating wirelessly with an electronic device associated with a user of the bicycle, and may further comprise receiving the data 31 indicative of a compass bearing from the electronic device, and/or receiving at least 32 part of the positioning data from the electronic device.

34 The method may comprise receiving at least part of the positioning data from at least one sensor in the navigation device, and in that case may further comprise (where 36 applicable) transmitting the positioning data from the or each sensor to the electronic 1 device for computation, and receiving the results of the computation from the 2 electronic device.

4 As before, at least part of the positioning data may be received from a global positioning system module, magnetometer, accelerometer and/or gyroscope. In the 6 case of the magnetometer, the method may further comprise applying a correction to 7 the magnetometer readings to take into account ferromagnetic material associated 8 with the bicycle.

The method may further comprise receiving user input relating to at least one of the 11 compass bearing and at least a portion of the positioning data. The method may 12 further comprise attaching the navigation device to the bicycle as aforesaid.

14 The method may include indicating the direction to a destination by using the GPS information from a smartphone and an inner magnetometer to establish an 16 orientation, and this feature is also provided in independent form.

18 As before, the wireless communication between the smartphone and the navigation 19 device may be done using the Bluetooth(RTM) protocol or otherwise. The direction may be indicated using light emitting diodes (LEDs) and/or by a mechanical needle 21 and/or by a (e.g. OLED) screen, for example.

23 The readings about geometrical bearing may be made by the inner magnetometer of 24 the smartphone and sent directly to the navigation device.

26 The step of processing positioning data to determine a direction relative to the 27 navigation device that corresponds to the compass bearing may comprise (e.g. the 28 navigation device or the electronic device) processing orientation sensor data from 29 one or more orientation sensors of the navigation device so as to compute the relative direction of the compass bearing relative to the navigation device (typically 31 with reference to a particular orientation of the navigation device).

33 In another aspect of the invention, there is provided computer program code which, 34 when executed by a processor in a navigation device (such as a navigation device according to the first aspect of the invention) attached to a bicycle, causes the 1 navigation device to carry out a method as aforesaid. Similar computer program code 2 may be provided to perform the method carried out by the electronic device.

4 The invention also extends to computer program code which, when executed by a processor in an electronic device (typically an electronic device having a positioning 6 module operable to determine the position of the electronic device) in communication 7 with a navigation device attached to a bicycle (typically a navigation device according 8 to a first aspect of the invention), causes the electronic device to transmit (typically 9 wirelessly) to the navigation device data indicative of a compass bearing relative to the bicycle and/or at least part of the said positioning data. Optionally the computer 11 program code also causes the electronic device to receive positioning data from the 12 or each sensor of the navigation device. In this case it may be that the computer 13 program code also causes the electronic device to compute the positioning data 14 received from the or each sensor, and typically to transmit the results of the computation to the navigation device. It may be that the computer program code also 16 causes the electronic device to receive orientation sensor data from the navigation 17 device and to process the said orientation sensor data so as to compute the relative 18 direction of the compass bearing relative to the navigation device (typically with 19 reference to a particular orientation of the navigation device). It may be that the computer program code also causes the electronic device to transmit the computed 21 relative direction to the navigation device.

23 The present invention also provides a computer readable medium tangibly 24 embodying computer program code as aforesaid.

26 Although the embodiments of the invention described above with reference to the 27 drawings comprise computer apparatus of various types, and also methods of using 28 said apparatus, the invention also extends to program instructions, particularly 29 program instructions on or in a carrier, adapted for carrying out the processes of the invention or for causing a computer or other hardware device to perform as one or 31 more of the devices of the invention. Programs may be in the form of source code, 32 object code, a code intermediate source, such as in partially compiled form, or any 33 other form suitable for use in the implementation of the processes according to the 34 invention. The carrier may be any entity or device capable of carrying the program instructions.

1 For example, the carrier may comprise a storage medium, such as a ROM, for 2 example a CD ROM or a semiconductor ROM, or a magnetic recording medium, for 3 example a floppy disc, hard disc, or flash memory, optical memory, and so on.

4 Further, the carrier may be a transmissible carrier such as an electrical or optical signal which may be conveyed via electrical or optical cable or by radio or other 6 means. When a program is embodied in a signal which may be conveyed directly by 7 cable, the carrier may be constituted by such cable or other device or means.

9 Although various aspects and embodiments of the present invention have been described separately above, any of the aspects and features of the present invention 11 can be used in conjunction with any other aspect, embodiment or feature where 12 appropriate. For example apparatus features may where appropriate be interchanged 13 with method features.

Description of the Drawings

17 The embodiments of the invention are illustrated by way of example and not by way 18 of limitation in the figures of the accompanying drawings in which like references 19 indicate similar elements. It should be noted that references to "an" or "one" embodiment of the invention in this disclosure are not necessarily to the same 21 embodiment, and they mean at least one.

23 Figure 1 is a functional block diagram of a portable navigation device and a portable 24 electronic device with GPS module such as a smartphone; 26 Figure 2 illustrates a portable navigation device and its components in accordance 27 with an embodiment of the present invention; 29 Figure 3 illustrates a possible embodiment of the display; 31 Figure 4 is a functional flow diagram of the mode of operation of the navigation 32 device according to an embodiment of the present invention; 34 Figure 5 illustrates a device in use, pointing to destination from two different positions; 1 Figure 6 is a block diagram of a further embodiment in which the navigation device 2 utilizes a plurality of positioning sensors; 4 Figures 7a to 7e are block diagrams illustrating the structure and data flow of five variants of the embodiment illustrated in Figure 6; 7 Figure 8 is an illustration of an alternative embodiment of the display of the navigation 8 device; and Figure 9 is an illustration of a further embodiment of the display of the navigation 11 device.

13 Detailed Description of an Example Embodiment

An embodiment of the invention with reference to the appended drawings is now 16 explained. While numerous details are set forth, it is understood that some 17 embodiments of the invention may be practiced without these details. In other 18 instances, well-known circuits, structures, and techniques have not been shown in 19 detail so as not to obscure the understanding of this description.

21 Figure 1 is a block diagram of an exemplary portable electronic device 200 and an 22 electronic navigation device 100 in accordance with an embodiment of the invention.

23 The device 200 may be a portable electronic device having the functionality of a 24 smartphone or a handheld computer.

26 The device 200 has a processor 201 that executes instructions to carry out 27 operations associated with the device 200. The instructions may be retrieved from 28 memory 204 and, when executed, control the reception and manipulation of input and 29 output data between various components of device 200. The memory 204 may store an operating system program (not shown) that is executed by the processor 201 and 31 one or more application programs to perform various functions, including those 32 described below. The screen 205 displays a graphical user interface (GUI) to allow a 33 user of the device 200 to interact with various application programs running in the 34 device 200. The GUI displays icons or graphical images that represent application programs, files, and their associated commands on the screen 205. These may 36 include windows, fields, dialog boxes, menus, buttons, cursors, scrollbars, etc. During 1 operation, the user can select and activate various graphical images to initiate 2 functions associated therewith.

4 The device 200 has a GPS module 202 that is able to retrieve information from the GPS satellites to define the current position of the device 200. The device 200 also 6 comprises a wireless module 203 such as a Bluetooth device that is able to send 7 information about the current position tracked by the GPS module 202 and other 8 desired location information indicated by using the Graphic user interface GUI.

The device 100 is an embodiment of the electronic navigation device. It has a 11 processor 101 that executes instructions to carry out operations associated with the 12 device 100. The instructions may be retrieved from the flash memory and use 13 information received through a wireless module 103 such as a Bluetooth module. The 14 device 100 also contains a magnetic sensor 102 that may be a conventional 3-axis magnetometer that senses the local magnetic field and outputs a vector having three 16 components (e.g., x, y and z axis components). The sensor 102 may be implemented Y7 as part of a separate, integrated circuit or microelectronic die referred to as a 18 compass chip. The device 100 has a display 104 that may be an array of LEDs which 19 is used to provide information to the user about the direction to the destination and about the distance to it.

22 The communication 300 between the device 200 and the navigation device 100 23 contains information about the coordinates of the destination and the coordinates of 24 the position of the device 200 or just the absolute direction bearing between the local position and the destination and the distance.

27 The electronic navigation device mode of operation in accordance with the present 28 invention combines the information about the current position from the electronic 29 device 200 and GPS module 202 sent to the navigation device 100 with the relative orientation of the navigation device 100 device obtained from the magnetic sensor 31 102 and displays the direction to follow using the display 104.

33 The mode of operation is illustrated in Figure 3. By using the input from a user about 34 the desired destination location by using the screen 205 of the 200 device, the processor 201 gets the local coordinates from the GPS module 202 and the 1 coordinates of the destination from the memory 204 or from the internet (not shown) 2 and sends this information 300 to the navigation device 100.

4 The electronic navigation device 100 receives the information about the relative position to the destination though the wireless module 103. By use of the input of the 6 magnetic sensor 102 it determines the relative orientation of the navigation device 7 and the direction to the destination and displays the direction to follow and indication 8 of the distance in the display 104. In this way, the relative orientation of the navigation 9 device doesn't affect the absolute direction pointed to by it.

11 Figure 2 illustrates a possible embodiment of the invention with a case with a bottom 12 part A103 with a ring for adapting to a bicycle handle. The board with the electronic 13 components A101 and the battery A104 is encapsulated between the top part A102 14 and the bottom A103.

16 A functional flow diagram of the operation described above is shown in Figure 4. The 17 user inputs 501 the desired location in an electronic device 200 with similar 18 functionality to that of a smart phone or handheld computer. The device obtains the 19 positional coordinates 502 of the destination using its internal memory or access to the internet and also its current coordinates 503 by using its GPS module 202.

22 The electronic device 200 then finds if there is a current wireless connection 504 23 between the device 200 and the navigation device 100. In case the answer is 24 negative, the device attempts to establish the connection 505.

26 When the connection is active, the device 200 sends information 506 about the 27 bearing to go from the device location coordinates to the destination coordinates and 28 distance to the Navigation Device 100.

Once this information is received, the Navigation Device 100 finds its relative 31 orientation regarding the magnetic poles 507 by using its internal magnetic sensor 32 102. With the information about the orientation regarding the poles and the bearing 33 and distance to the destination, the navigation device displays the direction to follow 34 508 using the display direction indicator D103 and the distance by a pattern of D106.

1 The process begins again, getting updated coordinates from 503 in order to know in 2 real time the direction and distance and destination.

4 A possible embodiment of the display indicating the direction and distance to the destination is shown in Figure 3, where there are eight LEDs indicating 8 possible 6 directions, N, NW, W, SW, S, SE, E and NE. By using the magnetic sensor 102 from 7 Figure 1, the Navigation Device can estimate that the north is in the direction of D105, 8 so if the destination is South West from the current position, the D103 will light up 9 pointing the direction to the destination. The central led D106 would flash faster when close to destination, and stay illuminated when close enough.

12 Figure 5 illustrates the display output of Figure 3 in different positions, pointing to the 13 destination. When to the east of the destination location, like in the position 502, the 14 navigation device lights up the LED which is positioned to its west 506, pointing to the position of destination 503.

17 If the navigation device is in position 501, the destination would be at its North East, 18 and then it would be LED 505 lighting up to point to the destination.

Figure 6 is a block diagram of a further embodiment in which the navigation device 21 utilizes a plurality of positioning sensors.

23 The electronic device 600 may, as before, be any appropriate device (such as a 24 smartphone, wearable device, tablet, laptop, which may be carried by or worn by a user of the bicycle) having the following features. The device includes a processor 26 602, memory 604, user interface 606, positioning system 608 and (at least one) 27 wireless module 610 for communication with a corresponding wireless module 652 of 28 a navigation device 650. The device 650 also includes a processor 654, at least one 29 positioning sensor 656 and a display 658.

31 The user interface 606 of the electronic device 600 may include a screen and input 32 device(s) as appropriate, for example to allow selection or inputting of a destination, 33 waypoint or other input which can allow the electronic device 600 to determine a 34 bearing for the user and/or bicycle. In the main embodiment, the desired bearing is transmitted to the navigation device 650 via the wireless modules 610, 652. To this 36 end, the positioning system 608 can provide an absolute or relative position fix for the 1 electronic device 600 and hence user/bicycle. The system 608 may for example be a 2 global positioning system module, such as a GPS receiver in particular. The system 3 608 could alternatively be a positioning system using Wi-Fi access points or cellular 4 telecommunications masts in order to triangulate a position of the user, either locally or using a remote service, and so on. The positioning of the device 600 and thus user 6 may be carried out using processing local to the device 600, with the assistance of 7 the navigation device 650, or using a remote or other device such as a mapping 8 server.

The positioning sensor(s) 656 of the navigation device may include one or more of a 11 magnetometer (to determine a bearing relating to magnetic North), a gyroscope, at 12 least one accelerometer, and so on. The sensor(s) 656 preferably allow a relative 13 position to be determined, such as an orientation of the navigation device 650 relative 14 to magnetic North or any other type of bearing/direction. In the main embodiment the processor 654 processes the output of the sensor(s) 656 to allow an 16 absolute/compass bearing received from the electronic device 600 to be converted 17 into a relative bearing/direction relative to the navigation device 650 which can be 18 displayed on the display 658 of the navigation device 650. As described elsewhere, a 19 point on the navigation device may be associated with 'straight ahead', inherently and/or with reference (using the sensors) to how the navigation device is attached to 21 the bicycle. The navigation device may, for example, be attached at an arbitrary 22 rotation relative to the direction corresponding to 'ahead' on the bicycle.

24 In a variant of the above-described embodiments, the navigation device may be positioned at an arbitrary angle, including out-of-plane with respect to normal 26 compass bearings (that is, it may be mounted sideways). In that case, an error may 27 be displayed, for example using an appropriate output from LEDs or otherwise, or 28 means may be provided to display a bearing with the device positioned in more than 29 one (or any arbitrary) plane relative to the normal 'ground' plane. Account may be taken, for example, of the steepness of the ground on which the bicycle is traversing, 31 which will orient the device out of the normal 'ground' plane.

33 In the main embodiment, multiple sensors 656 are consulted to allow a clearer picture 34 of the relative (and/or absolute) positioning of the navigation device. The sensors may be distributed between the navigation device 650 and electronic device 600 as 36 appropriate. For example, accelerometers and/or gyroscopes and the like in the 1 electronic device 600 Of it is, for example, a smartphone) may be consulted to 2 determine changes in direction and relative movement. The processing of the output 3 of the sensors and/or positioning system 608 may be distributed also as appropriate 4 between the navigation device 650 and electronic device 600, preferably reducing the amount of processing required in the device 650 so as to improve battery life and the 6 efficiency of the device, especially if the navigation device 650 is intended to be 7 attached to the bicycle for long periods or indefinitely.

9 It will be appreciated that the magnetometer provides a direct measurement of the relative orientation of the navigation device (albeit one subject to interference from 11 ferromagnetic material), but that other devices such as GPS and accelerometers, and 12 so on, can allow the relative orientation of the device to be computed by analysing the 13 output of the sensors/devices while the device is moved through a path. Redundancy, 14 and hence greater expected accuracy, is provided by appropriate combination of these methods and sensors.

17 Figures 7a to 7e are block diagrams illustrating the structure and data flow of five 18 variants of the embodiment illustrated in Figure 6.

These figures are exemplary, illustrating the flexibility of the system and five of but 21 many possible arrangements of sensors and processing in the embodiment shown in 22 Figure 6. The variants shown here can also be applied, as and where appropriate, to 23 the other embodiments described herein.

In Figure 7a, the electronic device (such as a smartphone) receives positioning data 26 from the inbuilt GPS receiver, and also receives a selection (or input) of destination 27 data. From these data sources, an absolute bearing can be determined, which is 28 wirelessly (or otherwise) transmitted to the navigation device, along with (optionally) 29 position data which can be used by the navigation device to refine relative positioning estimates. The navigation device receives inputs from a magnetometer (indicating 31 approximate compass bearing), gyroscope and accelerometer, which may for 32 example be 3-or 6-axis devices. Based on the sensor outputs, absolute bearing and 33 (optionally) position data, the navigation device computes a relative bearing, and 34 outputs this on the display as explained above.

1 Sources of interference (such as ferromagnetic material nearby) can affect the output 2 of one or more sensors (such as the magnetometer), and an appropriate algorithm is 3 used (for example using least squares estimation, and so on) sensibly to combine the 4 information from all of the sensors and to correct in part or wholly for the sources of interference. As part of this, a calibration can be carried out, either by the electronic 6 device or navigation device (or both) to determine parameters to be used 7 automatically to correct, for example, for constant interference. For example, the 8 bicycle frame, if made from ferromagnetic material, does not normally change 9 significantly in orientation or distance from the magnetometer, and a correction can be made (at least to a degree) for its constant influence on the detected compass 11 bearing.

13 In Figure 7b, the navigation device 'outsources' (for efficiency) the processing of the 14 sensor outputs to the electronic device. Thus the navigation device transmits to the electronic device (wirelessly or otherwise) the position data received from the 16 magnetometer, gyroscope and/or accelerometer. The electronic device then, with as 17 much knowledge of the navigation device (including past values and calibration 18 settings, user-inputted or otherwise, and so on) processes together all of the sensor 19 inputs, the GPS output and the destination data to produce a relative bearing which is transmitted back to the navigation device for display. Thus, the processing carried out 21 by the navigation device may be essentially minimal, if it is paired with an 22 appropriately configured (for example by means of an 'app') electronic device.

24 Figure 7c corresponds essentially to the system of Figure 7b above, but in this case uses an accelerometer of the electronic device rather than one built into the 26 navigation device. Other (re)arrangements of sensors, including duplications of 27 sensors for redundancy, are of course possible. The navigation device may 28 incorporate its own absolute positioning system (such as GPS receiver) or 29 communicate directly with one.

31 Figure 7d is a modification of the system of Figure 7a, in which one or more 32 accelerometers and a gyroscope associated with the electronic device (such as a 33 smartphone) are used. Additional data from these devices can be included in data 34 transmitted to the navigation device, facilitating the conversion from absolute (compass) bearing to a relative direction (for indication on the device itself).

1 Figure 7e is a final example of a system in which a destination is inputted or selected 2 directly into the navigation device by any appropriate means (such as by user input 3 means or appropriate communication protocol such as USB or wireless 4 transmission), and the electronic device serves to provide additional sensor data from GPS, accelerometer, gyroscope and so on, to assist in the calculation of relative 6 bearing. The magnetometer in this case (and in any other where appropriate) is 7 optional and may be omitted in favour of positioning data obtained by other means.

9 Figure 8 is an illustration of an alternative embodiment of the display of the navigation device.

12 In this device, a total of 24 light emitting diodes (LEDs) are provided, in contrast to the 13 8 provided in the first embodiment. It will be appreciated that the number of LEDs is 14 essentially arbitrary, subject to design constraints, and a higher number will provide a greater accuracy of bearing. In this case the LEDs are spaced equally around the 16 diameter of the navigation device, but it will be appreciated that a different distribution 17 is possible, for example clustering more LEDs near the 'forward' direction so as not to 18 waste LEDs in directions which are not often used, and to allow greater than average 19 accuracy when aligned in the expected direction. The shading of the LEDs is for ease of reference (cardinal directions are shaded darker) and does not indicate a physical 21 attribute of the LEDs. Other arrangements and display options are of course possible.

23 Figure 9 is an illustration of a further embodiment of the display of the navigation 24 device.

26 In Figure 9, a mechanical needle 802 is shown within the face 800 of the navigation 27 device. The needle can swing round by any appropriate means, such as stepper 28 motor or magnets set around the diameter of the face (though this may interfere with 29 the operation of a magnetometer), and so on. The needle (or other pointing means) may for example include a light-emitting or light-reflecting strip or other feature 804, 31 and the diameter may include a similar feature to assist readability of the device 32 without requiring attention to be diverted for any length of time or requiring further or 33 more detailed interpretation of the results.

Other sensors can of course be used, compared to all of those mentioned above. For 36 example, an optical or infra-red sensor in the navigation device may allow orientation, 1 for example (intermittently) with reference to a calculated sun position, user position, 2 or by analysis of movement from one frame to the next, and so on. The display may 3 also be incorporated within any appropriate virtual reality (VR) system, for example 4 transmitting a signal to allow a visual indication to be included within a VP system, for example displayed on a 'heads-up' style display on a headset, and the like. Audio 6 and other cues, including a transmitted/encoded audio signal or a sound output from 7 a loudspeaker, may also be provided, for example to verbally direct the user.

9 The navigation device may be provided by a memory to allow destinations or waypoints to be stored, and so on. A user-input device can allow direct entry of 11 destinations or simple bearings (or otherwise), for example, including a keypad, 12 buttons, directional indicator, and so on, or via an appropriate data connector such as 13 a wireless connection or wired connection via an appropriate interface such as USB, 14 FireWire (RTM), and so on.

16 It will also be appreciated that the device can be used while not on a bicycle, for 17 example while on foot, or riding in a car or some form of public transport (such as a 18 bus or train), in order to gain sufficient information to ensure the user is travelling in 19 the right direction and/or hasn't missed a stop, and so on. The device may thus include other attachment options, or be adapted for handheld use or for wearing in 21 some fashion. The device may, for example, take the form of a watch-like device, or 22 be incorporated into an existing wearable system such as a smartwatch.

24 The invention is not limited to the specific embodiments described above. There are numerous variations to different aspects of the invention described above, which in 26 the interest of conciseness have not been provided in detail. Accordingly, other 27 embodiments are within the scope of the claims.