Communications: directive radio wave systems and devices (e.g. – Directive – Beacon or receiver
Reexamination Certificate
1998-11-10
2001-09-18
Issing, Gregory C. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Beacon or receiver
C342S419000, C033S35500D
Reexamination Certificate
active
06292137
ABSTRACT:
This invention relates to direction indicating compasses.
A traditional compass, for example as used by an orienteer, comprises a body, a compass needle mounted on the body for indicating North/South, a rotary bezel mounted around the compass needle and marked with the points of the compass, and an indicator (such as an arrow) marked on the body. When the user wishes to travel in a particular direction, they set the bezel so that the required direction is aligned with the indicator, turn themselves and the body until the North marking on the bezel is aligned with the North end of the compass needle, and then set off in the direction of the indicator, keeping the North marking on the bezel aligned with the North end of the compass needle.
With the advent of the global positioning system (“GPS”), GPS receivers have become popular. Some of these receivers, in addition to displaying one's current position, can determine and display the bearing from one's current position to a pre-entered waypoint. The user can then set the bearing on the bezel of a traditional compass, and then use the compass in the traditional way.
U.S. Pat. No. 5,146,231 describes an electronic direction finder which employs a GPS receiver and an electronic compass to provide a user with an indication of a bearing to be taken to get from a current position to a desired destination/waypoint. The device uses a directional antenna which rotates relative to the handset and which identifies the bearing towards a specific GPS satellite whose position is known to the GPS receiver. From this information, the device determines a reference bearing and provides an indication to the user of the required bearing relative to the hand held device in order to get to the desired destination. The device indicates the required direction by displaying an arrow on a liquid crystal display. The display also displays the image of a compass which includes a North, South, East and West indications together with orthogonal line segments connecting North to South and East to West respectively.
Apart from having the disadvantage of requiring a rotating antenna which may be damaged during normal use, the device disclosed in U.S. Pat. No. 5,146,231 also suffers from the disadvantage that two indicators are displayed to a user on a liquid crystal display, one of which changes as the orientation of the hand held device changes. In particular, the display of the compass will change as the orientation of the handset is changed and this may cause confusion to the operator and also draws power from the battery thereby reducing the time that the device can be used without having to recharge the batteries.
In accordance with the present invention, there is provided a portable direction indicating device comprising: a body; means mounted on the body for indicating the direction of a reference bearing; means for receiving a bearing signal representing a required bearing (for example from a GPS receiver); a display responsive to the bearing signal receiving means for indicating a required position of the reference bearing indicating means relative to the body; and an indicator on the body which points to the required bearing when the body is oriented so that the reference bearing indicating means is in the required position relative to the body. The device therefore operates like a conventional compass, but does not require the user to set the required bearing on the device. Preferably, for simplicity, the reference bearing indicating means comprises a compass needle which indicates North/South. Such an embodiment has the further advantage that if the power supply fails, then the user can still use the traditional compass needle in order to navigate.
The invention has a number of important advantages, including: (a) it removes the need for the user to set their bearing on the compass; (b) if the user does not travel exactly along the required bearing, the indicated bearing on the compass automatically adjusts itself; and (c) once the waypoint is reached and a new waypoint is selected, the indicated bearing on the compass is automatically updated.
In one embodiment of the invention, the display comprises a circular array of indicators concentric with the compass needle, a selected one of the indicators being activated to indicate the required position of the compass needle. In another embodiment, the display comprises a rotary indicator concentric with the compass needle and means for turning the rotary indicator so as to indicate the required position of the compass needle.
The signal receiving means may be arranged to receive the bearing signal from a separate navigation aid (such as a GPS receiver), and the invention extends to the compass in combination with such a navigation aid. The body, compass needle and indicator are provided as a first unit, and the bearing receiving means and display are provided as a second unit permanently or releasably attachable to the first unit. The invention also extends to such a second unit per se which can be used with an existing compass.
Alternatively, an integrated device may be provided, with the body housing a navigation aid which supplies the bearing signal to the signal receiving means.
REFERENCES:
patent: 3469262 (1969-09-01), Frieling
patent: 4225867 (1980-09-01), Gell
patent: 4768153 (1988-08-01), Akamatsu
patent: 5146231 (1992-09-01), Ghaem et al.
patent: 5173709 (1992-12-01), Lauro et al.
patent: 5790477 (1998-08-01), Hauke
patent: WO 93 05474A (1993-03-01), None
Patent Abstracts of Japan, vol. 17 No. 550 (P-1624), Oct. 4, 1993 & JP 05 7576 A (Matsushita Electric Ind Co Ltd), Jun. 22, 1993.
Agnew Hugh John
Parfitt Gwyn David Walter
Corbin & Gittes
Issing Gregory C.
Yeoman Marine Limited
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