GB2332580A

GB2332580A - Doppler speedometer

Info

Publication number: GB2332580A
Application number: GB9827874A
Authority: GB
Inventors: Simon Todd
Original assignee: BOLTON SCHOOL
Current assignee: BOLTON SCHOOL
Priority date: 1997-12-18
Filing date: 1998-12-18
Publication date: 1999-06-23
Also published as: GB9827874D0; GB2332580A9; GB9726719D0

Abstract

A speedometer for computing the speed of a person (who may be a skier) relative to surrounding terrain. The speedometer transmits a generated output signal, and receives an input signal derived from interaction of the output signal with surrounding terrain. A signal processor then computes the speed of the person using the relationship between output and input signals. In a preferred embodiment the output signal is of microwave frequency and the speed is computed using the principle of the Doppler effect. The speedometer may incorporate two discrete units performing different functions with cordless telecommunication between the units. The device may indicate the speed of the person by audio means or by projecting the speed information on to the ground in front of the person using the device.

Description

2332580 A SKI SPEEDOMETER This invention relates to a "real-time"

speedometer for a person such as a skier, runner, etc.

As with many sports, much of the interest and excitement for a person participating, e.g. runner, skier, etc., is derived from the high speeds reached by the participant. Unfortunately, whilst the speed may be calculated using for example the measured time over the distance travelled a person moving has no way of knowing his/her current speed.

For competitive runners, skiers, etc., speed is of great importance both in training and in competition, however they typically have to use other parameters to measure their progress, e.g. time taken to complete a circuit.

it is an aim of the present invention to overcome or ameliorate some or all of the above identified problems by providing a speedometer for calculating the speed of a skier and communicating this and other related information to the moving person, e.g. skier as he or she is moving.

Accordingly, in one aspect, the invention provides a speedometer for a person to determine the speed of the person, the speedometer comprising a signal generator operative to generate a first output signal, a directional transmitter to transmit said first output signal, a receiver operative to receive an input signal which has been derived from interaction of the first output signal with surrounding terrain, signal processing means to compute the speed of the person using the relationship between the first output signal and the input signal and means for communicating the computed speed to the person.

Preferably the speedometer further includes means for attachment to the person.

This speedometer enables a moving person, e.g. runner or skier to monitor his or her speed constantly whilst moving. This would be of use both to those who ski as a leisure pursuit and to those who ski competitively/professionally, e.g. as part of their training schedule.

The term "skier" here is taken to refer to any type of skier, i.e. any type of board-based travel, for example, a mono skier, a snow boarder, a skater, skateboarder, etc.

The signal generator may take any suitable form and may, for example, be a microwave generator such as a semi-conductor device. One example is a GaAs Gunn diode oscillator.

The use of a semi-conductor device as a microwave generator makes for a simplified and commercially available source of microwaves.

The output signal may alternatively be any form of electro-magnetic wave or sound wave. Preferably the frequency of the wave generated should be high as this affords better resolution.

The input signal may comprise at least a part of the first output signal which has been reflected or scattered from the surrounding terrain.

The signal transmitter may take any suitable form, for example a compact aerial or antenna. Preferably the signal transmitter is orientated to face forward, i.e. to face the direction of travel. Alternatively, it may face rearward. Preferably the signal transmitter is oriented to transmit the signal in the direction of the surrounding terrain, i.e. ground, so that at least some of the signal is scattered/reflected back to the receiver.

This means that at least part of the signal is projected to the surrounding terrain, which is directly in front or behind the person.

The signal receiver may take any suitable form, but preferably it is positioned to receive at least part of the first output signal which has been reflected by the surrounding terrain in front or behind the moving person.

The signal processing means may determine the speed of the moving person using any suitable means/method and may utilise the principle of the Doppler effect.

The signal processing means may include a mixer which produces the difference between the frequency of the first output signal and the input signal to calculate the speed of the skier.

The signal processing means may incorporate signal modification devices.

The device may include power supply means which may include a :-4battery which may be disposable or rechargeable. Preferably, the power supply means further incorporates an intelligent power control and feedback system together with a voltage regulator device.

Preferably the power supply means includes power saving functions enabling the deactivation of the speedometer when the person equipped with the speedometer has not moved for a predetermined period of time. Preferably reactivation occurs when the person equipped with the speedometer moves again. These functions may be achieved by a conventional motion sensor which is incorporated into the device.

The power supply means may also incorporate an LED power indicator to show when the power supply means is active.

The means for attachment ol the speedometer to the person may be of any suitable form but preferably it is attachable to provide secure positioning of the speedometer to the person.

The speedometer may be attachable to any of the person's apparel, equipment.

Typically, a skier is equipped with various forms of ski equipment, for example skis, ski poles, ski jacket and trousers and other apparel, goggles, etc. Advantageously, in the embodiment where the person is a skier, the speedometer is attachable to any of the skier's apparel or equipment.

In a preferred embodiment, the speedometer comprises at least two discrete units, in which the different functions of the speedometer are carried out by different units. The units may be positionable at different locations on the person or his/her equipment/apparel.

Preferably, where the speedometer comprises at least two discrete units, the speedometer incorporates a data transmitter and receiving devices for cordless telecommunication between the units.

In a particularly preferred embodiment the speedometer comprises a main unit and a second unit. The main unit may comprise the signal generator, directional transmitter, receiver, signal processing means and power supply as described above and a data transmitter device for communication with the second unit.

Pre'lerably the signal processing means uses the first output signal and the input signal to produce a second output signal which is in the form of a sine wave of a frequency which is proportional to the speed at which the signal generator, i.e. the person, is travelling towards or away from the surrounding terrain.

Preferably, the signal processing means of the main unit incorporates one or more signal modification devices to modify the second output signal.

These signal modification devices may include pulse shaping circuitry to shape the second output signal so as to produce clean, sharp pulses. One preferred form of pulse shaping circuitry is a Schmitt Trigger circuit.

Preferably, a further signal modification device, i.e. a frequency divider, is used to reduce the required frequency of the second output signal.

Preferably another signal modification device, i.e. a uniform pulse generator, is used to enable pulse uniformity. This may take any suitable form, but preferably this is in the form of a monostable.

Preferably the data transmitter of the main unit is operable to transmit the second output signal which may or may not be modified by the above signal modification devices.

Preferably the main unit is securely positioned so as to orientate the signal transmitter in a forward or rearward facing direction. Preferably the signal transmitter is oriented to transmit the signal in the direction of the surrounding terrain, i.e. ground, so that at least some of the signal is scattered/reflected back to the receiver.

This means that the generated signal, e.g. microwaves, are directed at an object, e.g. surrounding terrain which the person is moving toward or away from, and enables the determination of the speed of the person based on the Doppler shift in frequency of the reflected, i.e. input signal.

In the embodiment where the person is a skier, the main unit may be attached to either a ski or a boot worn by the skier. The weather and conditions that skiers are active in means that a device mounted on a ski or a boot may frequently get wet and/or be at low temperatures. Accordingly, advantageously, the main unit should be contained in a watertight container which is resistant to mechanical shock and thermally insulated so as to insulate its contents, i.e. the power supply, signal generator, etc. The second unit may take any suitable form, but preferably it should be watertight and thermally and electrically insulated and resistant to mechanical shock as described for the main unit.

Preferably, the second unit is releasably or permanently securable to any part of the person's equipment or apparel using attachment means of the conventional type.

Preferably, the second unit comprises a data receiver to receive the second output signal transmitted by the main unit transmitter.

Preferably, the second unit comprises further signal processing means which may be in the form of a decoder, e.g. a programmable microcomputer to convert the second output signal into a form readily understandable by the person.

Preferably, the signal processing means are operative not only to calculate the speed of the person but also to calculate other useful related information such as average speed, maximum speed, trip distance, overall distance, trip time, daily time, and whether the person is travelling above or below his average speed, etc.

Preferably, the second unit incorporates communication means to display the speed (and any other related information calculated as referred to above) above information to the person. This may use conventional means, e.g. an LCD.

The communication means may comprise a projection device which is operable to project an image of the speed (and any other related information) described above onto the ground/ ahead of the person.

As an alternative or in addition to the visual communication means described above, the communication means may include an audio system which is -operable to give a voice read-out of the speed (and any other related information) described above. The audio system may incorporate earphones or alternatively small speakers attachable to a convenient part of the person's equipment/apparel.

Preferably, the second unit incorporates a power supply means which may be in the form of a battery or batteries.

The second unit may be in any suitable form, e.g. a wrist unit attachable to the person's wrist or a cuff of the person's apparel. The wrist unit may be attachable by conventional means, e.g. conventional wrist watch fastenings.

Alternatively, the second unit may be attached or integral to any other part of the person's apparel/equipment, e.g. a skier's ski poles, goggles, visor or glasses, etc.

A specific embodiment will now be described by way of example with reference to the accompanying drawings in which:- Fig. 1 is a diagrammatic illustration of a skier equipped with one form of the speedometer according to the invention which incorporates a main unit and a wrist unit; Fig. 2 is a schematic representation of the main unit of the speedometer of Fig. 1; and Fig. 3 is a schematic representation of the wrist unit of the speedometer of Fig. 1.

Referring to the drawings, a skier 1 is shown skiing across the surrounding terrain 10. The skier is wearing conventional skis 12, and is equipped with other conventional ski equipment, e.g. ski boots 4, ski pole 14, ski-goggles 18. The skier is also equipped with a speedometer according to the invention which comprises two main parts:- a main unit 2 and a second unit which is a wrist unit 6.

The main unit 2 is mounted on one of the skis 12. Alternatively the main unit could be mounted on a ski boot 4. The main unit may be permanently or releasably attached by conventional means such as Velcro, a buckle fastening screws, etc.

The main unit is a compact, lightweight device contained in a watertight container which is lined with polystyrene for thermal insulation and shock-proofing. Other forms of insulation may be used as an alternative to polystyrene.

The main unit 2 includes a signal generator which generates an output signal in the form of microwaves. In this particular embodiment the generator is a GaAs Gunn diode oscillator which generates microwaves having a frequency of 24 Ghz. Other microwave generators could be used, e. g. a quartz crystal oscillator, electron tubes, etc. The main unit also includes a directional antenna transmitter which is forward facing so as to transmit the microwaves toward an object, i.e. the terrain ahead of the skier.

A signal receiver also within the main unit 2 receives an input signal which comprises the microwaves which have been reflected back to the unit 2 by the surrounding terrain 10.

The main unit is operative to compute the speed of the skier using signal processing means. The signal processing means perform operations on the first output signal and the input signals to determine the speed of the skier. These operations are based on the principle of the Doppler effect:the difference (or shift) in the frequency between the generated and reflected waves is proportional to the relative motion between a wave source, i.e. the microwave generator and the surrounding terrain. As a result of these operations, the main unit produces a second output signal which is in the form of a sine wave of a frequency which is proportional to the speed at which the microwave generator, i.e. the skier, is moving away or toward the surrounding terrain 10.

In this particular example, the above functions of microwave generation, receipt and production of second output signal are carried out by a single unit and one commercially available exarnDle is the Philips 24 Ghz Doppler Module CL8990. Other equivalent k-band and m-band microwave modules could also be used.

The main unit also comprises a power supply which in this example is a 9 volt battery, but may alternatively be a 12 volt battery. The power supply is connected to an intelligent power control unit which also provides a regulated 5 volt power supply. The main unit also includes a primary power LED indicator which is illuminated when the 9 volt supply is active, and a secondary power LED indicator which is illuminated when the 5 volt is active. The device also has a battery low indicator and may have several power saving functions including one in which the unit is deactivated when the ski 12 has not moved for a predetermined period of time. The unit is reactivated when the ski 12 moves again. This is done using a simple motion sensor, and the intelligent power control unit.

The intelligent power control unit is connected to a 5 volt regulator which ensures the correct voltage (5 volts) is supplied to the microwave Doppler Module.

The main unit also comprises further signal processing means in the form of the following conventional electronic signal modification devices which modify the second output signal.

The microwave Doppler Module is connected to a signal amplifier which is operable to amplify the second output signal.

This signal amplifier is also connected to a pulse shaping circuit, e.g. Schmitt Trigger, which is operative to shape the second output signal to produce clean, sharp pulses. The Schmitt Trigger circuit is connected to a frequency divider which reduces the frequency of the second output signal. A uniform pulse generator is connected to the frequency divider to ensure that the pulse generated is uniform in length.

The main unit 2 further includes a data transmitter device which is in the form of a compact radio transmitter and which transmits the second output signal.

The wrist unit 6 is in the form of a compact, lightweight construction enclosed in a watertight container, the container is lined with insulating material which is in this case, polystyrene, but could be any conventional insulating material.

The wrist unit 6 is attached to a wrist 8 of the skier 1 by means of a strap member 16 which, in use, is wrapped around the wrist and secured in place by Velcro or alternatively a buckle fastening may be used.

The wrist unit 6 incorporates a receiver which is in this embodiment a compact radio receiver. This receiver is operative to receive the second output signal transmitted by the transmitter of the main unit 2.

The wrist unit 6 is constructed to incorporate a power supply in the form of a 6 volt battery which may be rechargeable or disposable.

This unit also incorporates a further signal conversion means in the form of a programmable micro-computer.

The decoder is operable to convert the input signal received by the 1 4, 6 " receiver o-l the wrist unit. to information which in a form readily understandable by the skier and which includes the speed of the skier, average speed, maximum speed, trip distance, overall distance, trip time, daily time and whether the skier is travelling above or below his/her average speed, etc.

The wrist unit incorporates communication means to display the above information to the skier in a convenient way, e.g. a liquid crystal display (LCD).

In further embodiments the wrist unit is replaced or supplemented by a similar unit which is attached or even integral to other ski equipment, e. g.

-14the ski pole 14, one of the skis 12, the visor, goggles or glasses 18.

Another example of communication means includes a projection device which is operable to project an image of the speed information as described above onto the snow ahead of the skier.

As an alternative or additional to the visual communication means described above, other communication means could be used, one example being an audio system which is operable to give a voice read-out of speed information on demand. The audio system could include earphones or alternatively small speakers attachable to the skier's equipment or clothing, e.g. the lapel on the ski jacket.

While the above embodiments have been described with reference to a snow skier, the speedometer could be used by skiers of all kinds, e.g. snow boarders, mono skiers and skateboarders, etc.

This invention is not intended to be restricted to the details of the above embodiment which is described by way of example only.

Claims

1. A speedometer for a person to determine the speed of the person, the speedometer comprising a signal generator operative to generate a first output signal, a directional transmitter to transmit said first output signal, a receiver operative to receive an input signal which has been derived from interaction of the first output signal with surrounding terrain, signal processing means to compute the speed of the person using the relationship between the first output signal and the input signal and means for communicating the computed speed to the person.

2. A speedometer according to any preceding claim in which the signal generator is a microwave generator.

3. A speedometer according to any preceding claim in which the signal transmitter is orientated to face forward to face the direction of travel of the person or rearward.

4. A speedometer according to any preceding claim in which the signal transmitter is oriented to transmit the first output signal in the direction of the surrounding terrain so that at least some of the said first output signal is reflected back to the receiver.

5. A speedometer according to any preceding claim in which the signal processing means determines the speed of the moving person using the principle of the Doppler effect.

6. A speedometer according to any preceding claim incorporating power supply means having power saving functions enabling the deactivation of the speedometer when the person has not moved for a predetermined period of time, and reactivation of the speedometer when the person moves again.

7. A speedometer according to any preceding claim incorporating at least two discrete units, in which the different functions of the speedometer are carried out by different units.

8. A speedometer according to claim 7 incorporating a data transmitter and receiving devices for cordless telecommunication between the units.

9. A speedometer according to claim 7 or claim 8 in which the main unit comprises the signal generator, directional transmitter, receiver, signal processing means and a power supply and a data transmitter device for communication with the second unit.

10. A speedometer according to claim 9 in which the signal processing means uses the first output signal and the input signal to produce a second output signal which is in the form of a sine wave of a frequency which is proportional to the speed at which the person, is travelling towards or away from surrounding terrain.

11. A speedometer according to claim 10 in which the data transmitter of the main unit is operable to transmit the second output signal.

12. A speedometer according to claim 11 in which the second unit comprises a data receiver to receive the second output signal transmitted by the main unit transmitter.

13. A speedometer accordind to any preceding claim in which the second unit incorporates the communication means to display the computed speed to the person.

14. A speedometer according to any preceding claim in which the communication means comprises a projection device which is operable to project an image of the computed speed onto the ground ahead of the person.

15. A speedometer according to any preceding claim in which the communication means includes an audio system which is operable to give a voice read-out of the computed speed.

16. A speedometer substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.