AU7196794A

AU7196794A - Locator beacon and method of locating

Info

Publication number: AU7196794A
Application number: AU71967/94A
Authority: AU
Inventors: Kenneth Herbert Hay
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-07-19
Filing date: 1994-07-18
Publication date: 1995-02-20
Also published as: WO1995003553A1; ZA945192B

Description

TITLE: LOCATOR BEACON AND METHOD OF LOCATING

The present invention relates to a locator beacon and to a method of using such a locator beacon. The beacon of the present invention is especially useful as a personal beacon i.e. to be carried by trampers, mountaineers, sailors, and so on, but it will be appreciated that the beacon also could be used in a land vehicle, boat, or aircraft.

At present, the most widely used types of personal locator beacons require the user to activate a transmitter to produce a distress call. Clearly, this is useless if the user is ill, disabled, or dead, and cannot operate the beacon.

The typical of this type of beacon is a beacon sold under the Trade Mark PELT. This beacon consists of a small battery-powered transmitter which is activated by the user to produce a radio distress signal which can be detected by a search party equipped with a corresponding radio receiver.

None of the personal locator beacons at present on the market can be activated from a location remote from the user. However, some identification devices broadly similar to beacons are arranged to be remotely activated:- for example, New Zealand Patent No.196256 discloses an electronic identification device for use in identifying objects such as railway waggons. A radio transmitter is located on the waggon, and when triggered by a remote interrogation station, it emits a coded identification pulse.

Similar systems are disclosed for animal identification in New Zealand Patent Nos. 199520, 219408 and 209991. However, none of these systems involve the use of a coded interrogation pulse, nor does the response systems include any kind of timing device or any means for signal comparison, since neither feature is required, or even desirable, for these identification systems. Also, all of these systems are relatively short-range.

Aeroplane locator beacons normally are automatically activated, generally

SUBSTITUTE SHEET by impact, rather than being activated remotely.

A marine locator beacon which can be remotely activated is disclosed in

New Zealand Patent No.216990. In this invention, the beacon is activated by a radar signal. However, the activation signal is not coded in any way, but simply triggers all beacons in the search area. Further, the bacon does not incorporate any timing means or any code identification system.

It is an object of the present invention to provide a locator beacon which is capable of locating its user even if the user cannot activate it, and which can be activated both remotely and selectively i.e. from a location remote from the beacon and such that one beacon out of a number of beacons in the same area, can be activated.

The present invention provides a locator beacon including: radio receiver means connected to radio transmitter means through a code comparison means; said radio receiver means being capable of receiving a remotely generated coded signal and of passing this signal to said code comparison means; said code comparison means being arranged to compare said coded signal with a predetermined signal and to pass a signal to said transmitter means only if said coded signal and said predetermined signal match; said transmitter means being arranged to transmit a predetermined radio distress signal when said signal is received from said code comparison means.

Preferably the locator beacon further comprises timing means connected between a locator beacon as claimed in claim 1, further comprising timing means connected between said code comparison means and said transmitter means; wherein said signal from said code comparison means passes first to said timing means; said timing means being arranged to activate one or more alarm means for a predetermined period and then to pass a signal to said transmitter means, causing said transmitter means to transmit a predetermined radio distress signal.

Preferably said beacon also has provision for manual activation.

By way of example only, a preferred embodiment of the present invention

SUBSTITUTE SHEET is described in detail, with reference to the accompanying drawings, in which:-

Fig. 1 is a block diagram of the principal components of a locator beacon in accordance with the present invention; and

Fig. 2 is a diagram showing the method of use of the locator beacon to find a lost person.

A locator beacon in accordance with the present invention comprises an impact-resistant waterproof housing fitted with a radio aerial and containing the component shown diagrammatically in Fig. 1, plus one or more batteries.

As shown in fig. 1 the locator beacon comprises a radio receiver 1 connected to the aerial 2 and also connected to a code comparison unit 3. The code comparison unit 3 is connected to a timing means 4, which is in turn connected to a radio transmitter 5, fitted with an aerial 6.

The radio receiver and transmitter 1, 5, aerials 2 and 6, code comparison unit 3 and timing means 4, all are of general types which are known in principal. It will be appreciates that the circuitry employed for these components is designed especially for this application i.e. to be robust, reliable, inexpensive, and compact, but the components, are designed in accordance with known principals and techniques.

The radio receiver 1 receives via aerial 2 signals from a remote transmitter which is operated by a searcher. The receiver 1 is designed to receive the approved frequency for search and rescue work. The remote transmitter may be sea- air- or land-carried.

The signal transmitted by the remote transmitter is coded. The code transmitted is a unique code, which corresponds only to one particular locator beacon. Thus, if a search is being conducted e.g. in a National Park, where there could be a number of people carrying beacons, transmission of the coded signal will activate only the selected beacon.

The coded signal received by the receiver 1 is demodulated into digital format and is passed to the code comparison unit 3.

SUBSTITUTE SHEET Each locator beacon stores its own unique identification code which may be stored in memory, or may be hard-wired. Any suitable code may be used, but preferably the code will consist of 12 data bits and the preferred modulation method is frequency shift keying. On receiving the demodulated signal from the receiver 1, the code comparison unit 3 compares the received signal code with the stored identification code. If the two codes differ, nothing further happens. If the two codes match, the code comparison unit 3 sends an activation signal to the timing means 4.

Upon receiving the activation signal, the timing means 4 activates one or more alarms:- these may include a visual alarm 7 (e.g. a light-emitting diode) and/or an audible alarm 8 (e.g. a piezo speaker) or other alarms, as necessary for particular applications.

The timing means 4 also counts out a predetermined delay period, during which the alarms 7 and/or 8 continue to operate. During this delay period, a user may press a reset switch 9, in which case the alarms 7/8 cease and the timing means 4 sends a signal to the transmitter to send a "no-distress" signal to a remote tracking station.

The sending of the "no-distress" signal indicates to the searchers that the locator beacon is operating and that the person being searched for is alive and well and does not require rescue. However, since the "no-distress" signal goes to the remote tracking station, it also gives a position for the person who cancelled the signal. Thus, in the rare, (but known), event of a person being searched for being mentally confused and cancelling the alarms even when the person does in fact need rescue, then location and rescue are still possible. If the user does not press the reset switch 9 during the delay period, then at the end of the delay period, the alarms 7/8 cease and the timing means 4 sends an activation signal to the transmitter 5, which sends out a distress signal via aerial 6. The distress signal is transmitted to the remote tracking station, which locates the beacon in known manner and advises persons searching for the user

SUBSTITUTE SHEET of the beacon of the correct location.

The timing means 4 also is fitted with a manual switch 10, which a user can press to activate the timer manually. When the switch 10 is pressed, the delay and alarm circuits are activated. Thus, if the switch 10 has been pressed unnecessarily (e.g. by a person in the party not authorised to do so) then the alarms 7/8 will alert the rest of the party to the situation, and the delay gives sufficient time for the reset switch 9 to be pressed. The timing means is designed such that if the reset switch 9 is pressed after manual activation, the transmitter

5 is not activated. The above-described equipment is used as shown in Fig. 2. A missing person 15 carries a locator beacon 16, but because of accident or illness is unable to activate the beacon. When the person is reported overdue, searchers use a radio transmitter 17 to send a signal 18 which carries the unique code for the missing beacon. The searchers may be in aircraft 19 or in vehicles, boats, or on foot.

When the beacon receives the coded signal 18 and the code comparison unit 3 matches the received signal with its own preset identity code, the timing means 4 is activated as described above, also activating the alarms 7/8.

If the person does not require rescue, he can press the reset switch 9. If the switch 9 is not pressed, then the timing means activates the transmitter 5, which sends a distress signal 20. This signal 20 is received by a remote tracking station 21 which locates the beacon and advises the searchers of the person's location. It is envisaged that the remote tracking station would be a satellite station, in which case the location information would be transmitted to searchers via a ground station 22, but it may also be possible for the remote tracking station to be ground-based.

The beacon may also be used manually, as described above, if the lost person is physically able to use the manual switch 10.

It will be appreciated that the above-described beacon overcomes the

SUBSTITUTE SHEET major problem of the user being too ill or disabled to activate the beacon, whilst still leaving the user the option of manual activation, and making provision for alerting the user to the beacon activation by means of the alarms.

However, it is also possible to produce the locator beacon without the timing means. In this case, the signal from the code comparison unit goes straight to the transmitter means without delay and without activating any alarms, and the transmitter transmits the distress signal immediately. CLAIMS:

1. A locator beacon which includes radio transmitter means and radio receiver means, characterised in that said locator beacon also includes a code comparison means connected between said receiver means and said transmitter means; said radio receiver means being capable of receiving a remotely generated coded signal and of passing this signal to said code comparison means; said code comparison means being arranged to compare said coded signal with a predetermined signal and to pass a signal to said transmitter means only if said coded signal and said predetermined signal match; said signal to said transmitter means causing said transmitter means to transmit a predetermined radio distress signal.

2. A locator beacon as claimed in claim 1, further comprising timing means connected between said code comparison means and said transmitter means; wherein said signal from said code comparison means passes first to said timing means; said timing means being arranged to activate one or more alarm means for a predetermined period and then to pass a signal to said transmitter means, causing said transmitter means to transmit said predetermined radio distress signal.

3. The locator beacon as claimed in claim 2, further comprising a reset

6

SUBSTITUTE SHEET

Claims

switch arranged such that a user can cancel said alarm means manually.

4. The locator beacon as claimed in claim 3 wherein manual activation of said reset switch to cancel said alarm means after remote activation of the beacon also activates the transmitter means to transmit a predetermined "no-distress' signal.

5. The locator beacon as claimed in claim 3 further comprising means for manual activation of the beacon.

6. The locator beacon as claimed in claim 5 wherein said manual activation means is arranged such that if said reset switch is used to cancel said alarm means after manual activation, the transmitter means is not activated.

7. A method of locating using the locator beacon as claimed in claim 1, comprising the steps of:

1. Equipping a user with the locator beacon as claimed in claim i;

2. Activating the locator beacon by transmitting from a searcher's radio transmitter a radio signal carrying a coded pulse corresponding uniquely to that beacon, thereby activating the transmitter means to transmit a distress signal to a remote tracking station;

3. At the remote tracking station, using said distress signal to locate the user, and communicating this location to the searcher.

8. A method of locating using the locater beacon as claimed in claim 3, comprising the steps of:

1. Equipping a user with the locator beacon as claimed in claim i;

SUBSTITUTE SHEET 2. Activating the locator beacon by transmitting from a searcher's radio transmitter a radio signal carrying a coded pulse corresponding uniquely to that beacon, thereby activating the transmitter means to transmit a distress signal to a remote tracking station; 3. At the remote tracking station, using said distress signal to locate the user, and communicating this location to the searcher.

9. The method as claimed in claim 8 wherein between steps 2 and 3, the user may use a reset switch provided on the beacon to cancel the alarm and to cause the transmitter to transmit to the remote tracking station a no-distress signal.

SUBSTITUTE SHEET