GB2485541A

GB2485541A - Apparatus for navigating a boat

Info

Publication number: GB2485541A
Application number: GB1019349.8A
Authority: GB
Inventors: Christopher Shelton
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-16
Filing date: 2010-11-16
Publication date: 2012-05-23
Also published as: WO2012066288A1; GB201019349D0

Abstract

An apparatus is provided for navigating a boat 1. The apparatus comprises direction detection and indicating means, the output of which can be logged by an electronic control unit. The direction detection and indicating means may comprise a wind sensor, a compass or GPS. The navigational apparatus further comprises display means 2 in the form of an LED display bar. The display means 2 is arranged to be located in a field of view of a user, and to provide an indicator showing an intended direction to the user. When the user has determined the intended direction, it is logged by the electronic control unit and displayed on the display means 2. The electronic control unit is adapted to compare the actual direction with the intended direction, and in the event that the actual and intended directions differ by more than a predetermined amount, the position of the indicator of the intended direction on the display means 2 is adjusted. The invention is particularly suited to overcoming the problems associated with conventional navigation arrangements which require a user to both look down at a small display showing heading, whilst simultaneously looking out to sea in order to steer a boat.

Description

Follow a Star The invention related to an apparatus and method for navigation, in particular, but not exclusively, for use in boats.

There is a longstanding problem with steering a boat on a compass course, that also arises in certain other featureless environments such as deserts. It is inherently hard to look down at a small display of a heading whilst simultaneously looking out to sea and trying to deal with the effect of wind and waves on the heading of the boat. The time honoured solution is to iollow a star". Once a helmsman has put the boat on its desired heading, he or she looks for and chooses a star which is dead ahead. The star then serves as a reference point for the chosen course, thereby making it much easier to keep watch and to follow to wind and sea but remain going in the intended direction.

The follow a star method suffers from two main defects. The first is that a star may not be visible due to the weather conditions such as fog or cloud. The second is that even if a suitable star is available, it will move at 15°/hr due to the rotation of the Earth.

The present invention seeks to provide an apparatus and method for navigation that obviates these problems.

According to the invention there is provided navigational apparatus comprising direction detection and indicating means, the output of which can be logged by an electronic control unit, the navigational apparatus further comprising display means, wherein the display means is adapted to be located in a field of view of a user and to provide an indicator of an intended direction visible to the user, wherein when the user has determined the intended direction, the intended direction is logged by the electronic control unit and displayed on the display means, wherein the electronic control unit is adapted to compare the actual direction with the intended direction and in the event that the actual and intended directions differ by more than a predetermined amount, the electronic control unit adjusts the position of the indicator of intended direction on the display means so that the indicator corresponds substantially to the intended direction.

Preferably, the LEDs have a pitch of 2-10mm, more preferably 3-5mm. Preferably, the direction detection and indicating means comprises at least one of a compass, OPS unit or wind sensor. Preferably, the display means comprises a substantially horizontal display bar. Preferably, the display means comprises a plurality of LEDs.

Preferably, the display means is further adapted to provide a fixed position indication corresponding to the longitudinal axis of a vehicle in which the apparatus is installed.

In a preferred embodiment, the electronic control unit is adapted to calculate an average of the difference between the actual and intended directions. Preferably, the display means is adapted to display the average error such as a flashing LED.

An exemplary embodiment of the invention will now be described in greater detail with reference to the drawing in which: Fig. I shows schematically a boat with the apparatus of the invention; Fig. 2a shows a display bar in a first position Fig. 2b shows a display bar in a second position Figure 1 shows schematically a boat I with a helm located towards the stern (rear) of the boat. The wheel 3 controlling the boat's rudder and the instrumentation are located at the helm and a helmsman is shown holding the wheel 3.

A display bar 2 is located centrally between the sides of the boat perpendicular to the longitudinal axis of the boat. The display bar 2 is located just past the mid point of the boat towards the bow of the boat at a distance D from the wheel. The display bar is provided with LEDs 5-7.

Figure 2a-b shows the display bar 2 in more detail. The display bar comprises a number of biue LEDs, wherein each LED is substantially equidistantly spaced from the LEDs adjacent to it on either side. The LEDs will typically have a pitch of 2- 10mm, and be constructed from a series of long thin PCBs, each of which PCB5 has its own micro-controller to control the LEDs and to minimise the number of conductors The centre LED is surrounded by two or four equidistantly spaced yellow LEDs, the light from which in use will tend to blend into a circle around the central blue LED, thereby highlighting it.

As an alternative to the four equidistantly spaced yellow LED's, it would be possible to use two LEDs mounted between the blue LEDs at the centre of the bar or reverse lit LED's could be mounted on the back of the bar and adapted to shine through holes on adjacent to the central blue LED. Alternatively, a bicolour LED could be used The boat is also provided with a standard compass that is linked to a junction box housing a PCB. The PCB is provided with inputs from a wind sensor and a GPS with a way point (WPT) bearing and has a microcontroller which is adapted to control the display on the display bar 2. The display bar can indicate whether the data it has been using comes from the wind sensor, the compass or the GPS.

The display bar is arranged such that it is close to the line of sight of the helmsman and in the initial position the display bar is centred. The illumination of the LEDs is controlled by the PCB in dependence on the input signals from at least one of the wind sensor, compass or the GPS.

Initially the helmsmen will select a course using the compass in the known manner and once the course is selected, the helmsman will fix the setting by eg pressing a button on the helm so that the microcontroller on the PCB can log the compass setting.

Once this is done, the microcontroller will illuminate the display bar 2. The signal from any one of wind sensor, compass or GPS will indicate the heading of the boat, any deviation in the heading of the boat from the intended direction stored by the microcontroiler is detected. In the event of a deviation, the iliuminated LEDs on the display bar can be indexed left or right in dependence on the deviation from the intended heading. The amount of the movement of the point corresponds to the change in course required by the helmsmen to correct the course so that the helmsmen can see where the fixed point on the horizon should be.

In the example shown in Fig. 2a, the centre LED indicates the actual direction of the boat and the illuminated LED on the left indicates the intended direction of the boat.

This provides an easy indication for the helmsman to manoeuvre the boat. Figure 2b shows the case where the boat's actual and intended direction co-incide. In use, the helmsman will steer the boat so that the LEDs co-incide.

In Figure 1 the plan view shows when the boat is turning clockwise. The display feature point is set to the centre of the display 5 when the boat is on the desired course. When the heading increases by and amount on angle 6 the display moves to a new point, 6, such that in the line of sight of the helmsman the point has moved by the same angle 6. Thus the distance between the two points on the display 5 and 6 is given by 6 = aID in radians, where D is the distance of the display bar 2 from the helmsmen Theoretically there is an error if 6 is large due to the fact that the display might be constructed by linear means whereas the correct form might be circular with the helmsman as the centre. Such error is negligible for small angles and can be corrected by computational means between the compass and the display system.

For example ifS = 1/6 or approximately 10° then: A= D16 and so if D = 3m then a = 1/2 m If the display were to be implemented by a number of discrete points, i.e. the LEDs, then in the above example 500mm represents 100 and 50mm would represent 1° and 5mm would represent 0.10. In the above example an LED pitch of 5mm would equate to a resolution to 0.10. A change of heading from 6 = 0 to 6 = 100 would result in each LED being lit briefly until the 100th remains lit corresponding to 10°.

Similarly if the boat were to turn so as decrease the heading then the point would move to the right to a new point 7.

But if the display were to be moved nearer to the helmsman to, say, 2m distant then the relationship would have to changed. In this new case of D=2m and 6 = 1/6 radians then a = D/6 = 2/6 = 1/3m.

Thus the movement of 10° would be represented not by the 100th LED but by the 67th. Similarly if D were to increase to 4m then the same movement would be indicated by the 33rd LED.

There is therefore also a means of making the system adjustable so that the point remains fixed to the horizon over a range of D. In certain situations, it is possible for the boat to drift and so whilst the helmsman may steer the boat back towards the intended direction, it will nonetheless be out of position. Therefore in a further embodiment, the display can be adapted to provide not only the instantaneous error but also an average error such as the average error since the last reset. One way of providing this indication would be to indicate by a flashing LED what the average error was in addition to the LED showing instantaneous error. The average error can be calculated by the microcontroller, which can log the instantaneous errors.

Depending on the exact situation, the helmsman may want to steer the boat to compensate or eliminate the average error depending on the precise navigational circumstances. Once the error is eliminated, the instantaneously correct course can be followed. This average error could also be useful as a training or competitive tool.

The display could also be by any means such a pointer moved by electric motor and screw or belt but it is illuminated so that it is useful at night.

It may or may not include a display of the heading digitally. It may include markers for port and starboard and at set degree intervals such as every 5° and it would most preferably include a point which does not move for the zero.

Claims

Claims 1. Navigational apparatus comprising direction detection and indicating means, the output of which can be logged by an electronic control unit, the navigational apparatus further comprising display means, wherein the display means is adapted to be located in a field of view of a user and to provide an indicator of an intended direction visible to the user, wherein when the user has determined the intended direction, the intended direction is logged by the electronic control unit and displayed on the display means, wherein the electronic control unit is adapted to compare the actual direction with the intended direction and in the event that the actual and intended directions differ by more than a predetermined amount, the electronic control unit adjusts the position of the indicator of intended direction on the display means so that the indicator corresponds substantially to the intended direction.
2. Navigational apparatus according to Claim 1, wherein the direction detection and indicating means comprises at least one of a compass, GPS unit or wind sensor.
3. Navigational apparatus according to Claim I or Claim 2, wherein the display means comprises a substantially horizontal display bar.
4. Navigational apparatus according to any one of Claims I to 3, wherein the display means comprises a plurality of LEDs.
5. Navigational apparatus according to Claim 4, wherein the pitch of the individual LEDs is 2-10mm
6. Navigational apparatus according to any one of Claims 1 to 5, wherein the display means is further adapted to provide a fixed position indication corresponding to the longitudinal axis of a vehicle in which the apparatus is installed.
7. Navigational apparatus according to any one of Claims I to 6, wherein the electronic control unit is adapted to calculate an average of the difference between the actual and intended directions.
8. Navigational apparatus according to Claim 7, wherein the display means is adapted to display the average error.
9. Navigational apparatus according to Claim 8, wherein the display comprises a flashing LED.
10. Navigational apparatus substantially as described herein with reference to and as illustrated in the accompanying drawings.