Emergency service warning system

Title: Emergency service warning system

The invention relates to an emergency service warning system, adapted to alert a user of approaching emergency services, comprising:

-at least one movable emergency service channel; and

-at least one receiver, arranged to receive signals transmitted by the emergency service transmitter.

Such a system is known from US 4,238,778. The known system can make known the presence of an approaching emergency service vehicle (for example an ambulance), in order to adjust speed depending on the hearing and seeing of the warning signals of the emergency service vehicle.

In the known system, the emergency service vehicle is provided with a separate transmitter, which transmits a radio frequency warning signal. The warning signal has a predetermined frequency, for example in the VHF or UHF area. Another motor vehicle is provided with a receiver adapted to receive the radio frequency warning signal transmitted by the emergency service vehicle. The receiver tuned to the predetermined frequency emits an audible signal to warn a driver of the motor vehicle upon receipt of the warning signal.

According to US 778, a communication option is preferably offered in which a driver of the emergency service vehicle can give commands to the driver of a motor vehicle to be warned via the transmitter. An advantage is that the driver of a motor vehicle can be alerted in good time to the approach of an emergency service vehicle, and can take suitable measures, for example by being sidelined in time.

A drawback of the known system is that it is relatively complex.

The present invention aims at solving the above problems. In particular, the invention contemplates an emergency service warning system that can efficiently alert a user of one or more approaching emergency services.

To this end, the system according to the invention is characterized by the features of claim 1.

The system is advantageously provided with at least one stationary emergency service communication device for communication with said emergency service transmitter using emergency service signals, the system also being provided with at least one user receiver which is adapted to detect emergency service signals and to emit a warning signal when detecting an auxiliary service signal.

Emergency services are usually already provided with communication means, for example a specific emergency service communication network. Such a communication network is often well protected against eavesdropping. Unauthorized persons can therefore not use such an emergency services communication network.

Such a network comprises, for example, a stationary communication units (for example, transmission masts) spread over a relatively large area, and mobile communication equipment (for example radios, mobile radios and the like), wherein the communication equipment can send said emergency service signals to the stationary units.

An idea of ​​the present invention comprises the advantageous use of such emergency service communication means, which are in themselves already in circulation (usually not interceptable by 'normal road users'), as part of an emergency service warning system.

To that end, at least one user receiver is arranged to detect the emergency service signals (which are already available in themselves) and to give a warning signal upon detection of an emergency service signal (originating from a mobile transmitter of an approaching emergency service).

In particular, the system according to the invention is arranged not to make use of specific (emergency services to be carried) warning transmitters to send specific warning signals to user receivers. In this way, emergency services do not have to be provided with separate warning transmitters. A relatively simple, relatively inexpensive, easily implementable and particularly efficient warning system can thus be obtained. Here, the emergency services can moreover apply the aforementioned emergency service signals in their unchanged form for their own use, for example for internal (ie between the emergency services themselves) transmission of position information, voice and / or other communication information. Preferably, this is internal emergency service communication (ie at least comprising the signals transmitted by a said emergency service transmitter) encrypted in a known manner, so that the content of the emergency service communication cannot be intercepted by others (e.g., normal road users who are not provided with specific emergency service transmitters).

In particular, a user receiver of the present system is not adapted to decode signals transmitted by an emergency service transmitter, for example coded digital signals. Moreover, the user receiver is in particular not provided with or associated with its own emergency service transmitter. A user of the user receiver is therefore unable to send emergency service signals.

The receiver is preferably adapted to only detect (the presence of) emergency service signals, and to give a warning signal upon detection of such a signal, without deciphering a possible content of the emergency service signals.

Furthermore, the user receiver is preferably adapted to determine the strength (in particular field strength) of a received emergency service signal, for instance to be able to estimate how far a respective emergency service has been removed from the receiver. The receiver may, for example, provide a warning signal that is dependent on a measured strength of a received emergency service signal, the warning signal preferably also being dependent on a receiving direction of the received signal.

The invention further provides a method for issuing a warning to an approaching emergency service, wherein the emergency service transmits respective signals, a plurality of stationary emergency service communication devices being arranged to receive emergency service signals, wherein at least one user receiver associated with a user checks or an emergency service signal is transmitted, and issues a warning signal if an emergency service signal is detected.

In this way the above advantages can be achieved. According to a further elaboration, the method comprises associating a detected emergency service location with position information, for example position information supplied by a GPS system, and preferably storing the position information, more preferably in a database. To this end, the system may, for example, be provided with, or integrated with, the road traffic control warning system for road users, which is known per se from Dutch patent NL1026352, which patent is deemed to be incorporated entirely in the present application by reference.

In addition, the invention provides a user receiver of a system according to the invention. The receiver is then preferably adapted for use in a method according to the invention, and can offer the above-mentioned advantages, in particular in combination with one or more said emergency service transmitters and one or more said stationary emergency service emergency service communication devices.

Further advantageous elaborations of the invention are described in the subclaims. The invention will now be elucidated on the basis of a non-limitative exemplary embodiment and the drawing. It shows:

Figure 1 shows diagrammatically an exemplary embodiment of the invention; and

Figure 2 shows a schematic example of a user receiver according to an exemplary embodiment of the invention.

In this application, the same or corresponding measures are indicated by the same or corresponding reference numerals.

Figure 1 shows an example of a system provided with movable emergency service transmitters T, and receivers M, R, adapted to receive signals transmitted by the emergency service transmitters T.

In particular, the system comprises several emergency service transmitters T (only one of which is shown) and several emergency service emergency service communication devices M, which form part of a national or regional emergency service communication network. Said transmitters T are in particular mobile transmitters, which can be carried, for example, by emergency services (e.g. vehicles and / or personnel, from for example ambulance services, police, fire brigade, and the like). A said emergency service transmitter T may, for example, comprise a two-way radio and / or form part of an emergency service vehicle; arrow x in figure 1 indicates movement of an emergency service vehicle comprising such a transmitter T.

The system is in particular provided with stationary emergency service transmitter / receiver devices M for communication with said mobile emergency service transmitters T, using emergency service signals (ie radio signals associated with the emergency service) S. The emergency service signals S may for example encoded digital signals S, a encoded message, conversation or other information to be communicated, during communication via the sender T. As explained below, the communication signals S preferably in any case include periodic signals, which are, for example, transmitted when the transmitter T is in an active state (in particular to report presence of the transmitter T to the network ).

The stationary emergency service communication device M comprises in particular stationary network stations, for example transmission masts. The network stations M are, for example, arranged in such a way that a relatively large coverage area, preferably national or regional, is obtained, so that the emergency services can maintain communicative contact with the network as reliably as possible (via those network stations M, using the transmitters T).

The emergency service communication network T, M may, for example, comprise a stable and reliable digital communication network, for example arranged to transmit speech and data in digitally coded form from mobile units (which are provided with the transmitters T) via the stations M to one or more central monitoring rooms N and / or send from other mobile users (not shown). The emergency service communication network T, M is preferably based on the Tetra standard known per se; the network T, M may, for example, be the C2000 system in use in the Netherlands, or a similar system.

An aspect of the invention provides for an advantageous use of the digital communication network T, M. In particular, the invention provides an emergency service warning system, arranged to alert a user of approaching emergency services, wherein the signals S transmitted by the mobile transmitters T can provide additional functionality to deliver.

As shown in FIG. 1, the system is provided for this purpose with at least one user receiver R which is adapted to detect emergency service signals S and to issue a warning signal upon detection of an emergency service signal, to warn a respective user that an emergency service is nearby. On the basis of the warning signals, the receiver R can preferably indicate what a global distance is and direction is from the transmitter T that has sent the signals. The user receiver R is associated, for example, with a respective user, for example a road user, who in particular is not part of the emergency service. The present system is designed in such a way that this user cannot use the user receiver R to make content of communication sent via the communication network T, M available.

Said user receiver R can be designed in various ways. A non-limitative example of the receiver is shown in FIG. 2, and is further explained below.

The receiver R can be made portable for example by a user. The receiver R can be adapted to be coupled to a user vehicle, for example built-in. Moreover, the receiver R can for instance form part of a user vehicle. The receiver R can for instance be provided with means for stably placing the receiver in a user vehicle.

FIG. 1 schematically shows a moving (arrow y) user vehicle that has such a receiver R with it. In the example, the emergency service vehicle is rearward relative to the user vehicle, however, the system also works, for example, with an oncoming emergency service vehicle. The user receiver R can timely warn a respective driver (ie road user) that an emergency service vehicle is approaching, so that the user can take measures.

According to a further elaboration, said auxiliary service signals S may comprise at least one signal transmitted periodically by the transmitter T (with a constant period of, for example, one or a few seconds). Said user receiver R is then preferably adapted to detect, for example to recognize, said periodic signals for the purpose of detecting the respective transmitter T. Said periodically transmitted signal per se comprises, for example, a relatively short signal, for example with a length of less than 1 second, in particular less than 0.1 second. Preferably, the transmitter T always transmits this periodic signal, for example at least if the transmitter T is in an active mode and, for example, is not used to carry a coded conversation. In this way the user receiver R can properly distinguish an emergency service signal S from noise and possible interference signals, whereby detection of the emergency service is possible even if the respective transmitter T is in the active mode.

Furthermore, it is advantageous if said transmitter T is arranged to send signals via different communication channels, within a predetermined frequency band. Said frequency band can for instance comprise the frequency range between 380 and 385 Mhz, or another frequency band. In particular, the frequency band is above 200 Mhz, and for example below 1 Ghz. A bandwidth of the predetermined frequency band can, for example, be greater than 1 MHz, and in particular be at least 5 MHz.

The user receiver R is then preferably configured to receive signals from the entire predetermined frequency band in order to be able to receive all said channels simultaneously. In other words: the user receiver R is preferably arranged not to be tuned to a single channel of the said different communication channels of the network.

According to a further elaboration, the system comprises one or more stationary emergency service transmitters, for example transmitters of said monitoring rooms N. It is then advantageous if the stationary emergency service transmitters N and mobile emergency service transmitters T use different communication bands. It is furthermore preferred here if each user receiver R is designed not to search for signals possibly transmitted by the stationary emergency service stations N (for example, by not specifically searching for signals which are transmitted in a respective communication band of, for example, base stations, control rooms or main offices) ).

Use of the device shown in FIG. The system shown in Fig. 1 preferably comprises a method for issuing a warning that an emergency service is approaching. As the figure shows, the (in itself mobile) emergency service transmits said emergency service signals S, over a communication channel within the predetermined frequency band, and for example periodically, to stationary emergency service communication devices M,

A stationary emergency service communication device M can receive the signals S from a nearby emergency service transmitter T to provide communication via the emergency service communication network. The signals S may, for example, comprise periodically transmitted sign-on signals, provided with digital information, to periodically register the emergency service transmitter T to the network, or to maintain periodic contact with the network.

The user receiver R checks whether an emergency service signal S is transmitted, in particular by listening to signals on said predetermined frequency band (preferably instantaneously on all frequencies within the frequency band). Preferably, the user receiver R processes all the signals received by the receiver R to detect the periodic emergency service signals. In particular, the present receiver R is unable to decode encoded information possibly contained in the emergency service signals S.

The user receiver R then issues a warning signal if the receiver detects an emergency service signal. To this end, the receiver R can for instance be provided with, or coupled to, a suitable warning device 9, for example a loudspeaker, display, or the like.

As mentioned, the emergency service signals S can be transmitted via different channels within the predetermined frequency band. The user receiver R therefore preferably receives signals from the entire predetermined frequency band, including all said channels, and processes the signals to detect emergency service signals.

The user receiver R may, for example, be arranged to determine the strength and reception direction of a received emergency service signal S. Determination of a receiving direction can for instance be carried out using suitable antennas for this purpose, for instance a number of direction-sensitive antennas and the like. The warning signal emitted by or under the influence of the receiver R can then provide information regarding the strength and the direction of the emergency service signal.

As mentioned, it is furthermore advantageous if position information is available, for example information supplied by a GPS system. The user receiver R can, for example, be arranged to generate such position information, for example when the receiver R is provided with a GPS receiver. In that case, the user receiver R can, for example, associate the location where an emergency service is detected with the position information, and preferably store it, for example in a central (e.g. stationary) database. The database can for instance be the database described in NL1026352.

Figure 2 shows schematically an example of a said user receiver R. The receiver R has a relatively simple and inexpensive embodiment, and can surprisingly reliably detect said signals.

The receiver is provided with an antenna 1 to receive radio frequency signals. The antenna 1 can be designed in itself in various ways, and is in particular adapted to receive signals within a large bandwidth.

The present user receiver R is provided with a first band pass filter 2, coupled to the antenna 1 to receive the signals thereof, and adapted to pass only signals that are within a certain frequency band. In this way, a first delimitation can be achieved, to search more specifically for signals S transmitted by a transmitter T. The first filter 2 can, for example, prevent overcharging of the receiver, and for example that other parts of the receiver R are disturbed by, for example, signals that lie outside a band to be received.

The receiver R is preferably provided with a signal amplifier 3 to amplify received signals. In the example, such a signal amplifier 3 is connected to an output of the first filter 2 in order to amplify at least the frequency band transmitted by the filter 2.

A particularly advantageous embodiment comprises the use of a mixer 4 and an oscillator 5 (for example a crystal-controlled oscillator) which are adapted to mix signals received by the receiver R back to a center frequency. As shown in FIG. 2, the mixer 4 is arranged to process the signals passed through the first bandpass filter 2 (and amplified by amplifier 3). In this way, a good filter can be made relatively easily to be selective for the signals to be received. A said intermediate frequency is, for example, below the predetermined frequency band.

Emergency service signals can be particularly well detected from the signal supplied by the mixer 4. To this end, it is advantageous to provide a second band-pass filter 6 to re-filter the signals processed by the mixer.

The second filter 6 can ensure that only those signals are passed that actually have to be received. The second filter 6 can achieve the desired selectivity of the receiver. The second filter 6 is preferably relatively broad-banded and relatively steep in the flanks. Good results are obtained if the second filter 6 has at least a 5^e order filter (preferably, for example, a 7^Θ order filter), with a band pass width of, for example, 5 MHz (or another width). This is particularly advantageous if the emergency service transmitters T use different channels within a certain frequency band.

A second signal amplifier IF is preferably provided to amplify the signals supplied by the second filter 6, and to provide an RSSI ('Received Signal Strength Indication') signal. A buffer and filter V is provided to filter the RSSI signal (among other things to prevent aliasing) and to buffer (to make a correct adjustment for the analog-to-digital converter 7).

The receiver R further comprises an analog-to-digital converter 7, adapted to digitize the analog signals filtered and processed by the means 2-6, IF, V, for digital data processing by a digital signal processor 8. The converter 7 may, for example, be part of the processor 8, or be a separate part. The converter 7 may furthermore be provided, for example, with anti-aliasing means, in order to prevent aliasing in a signal sampling to be carried out by that converter.

The signal processor 8 is arranged to distinguish certain emergency service signals from interference signals, and can be designed in various ways. The signal processor 8 may, for example, comprise suitable signal processor microelectronics, a microcontroller, or the like. The processor 8 can be arranged to recognize a said period (of broadcast emergency service signals) in the digitized signals, and to issue a warning signal as soon as the processor recognizes such a period. Furthermore, the processor 8 may be designed, for example, to adapt the warning signal to a strength and direction of a received, recognized emergency service signal.

In the example, the receiver R itself comprises a warning device 9, designed to provide a user with information that the receiver R has detected an emergency service signal. Alternatively, the warning device can be a separate component, which can be controlled, for example, by the receiver R, or connectable to the receiver, for example via a suitable interface.

Preferably, a second signal amplifier IF is provided (not shown) to amplify the signals supplied by the second filter 6, and to output an RSSI ('Received Signal Strength Indication') signal. After filtering (to prevent aliasing, among other things) and buffering (making the correct adjustment for the A / D converter), the RSSI signal can be supplied to the A / D converter 7 for subsequent digital processing.

The system described above is particularly well suited for use by road users. For example, the user receiver R can inform a road user in good time about an approaching emergency service, independently of whether or not warning signals (siren, flashing light) are being sent by the emergency service. The receiver R can receive, for example, emergency service radio signals S, and automatically warn the road user with suitable acoustic and visual signals if emergency service radio signals S are recognized by the receiver (e.g. recognition based on a said constant period in such signals s). This particularly increases safety if, for example, an accident has occurred, in bad weather conditions (fog, snow, or heavy rainfall). The user receiver R can prevent false reports particularly well, which can be achieved in particular by using suitable filtering means 2-6 in combination with a digital signal processor, and more particularly with said second signal amplifier IF.

By using an optional GPS receiver, the system can be easily expanded to store emergency service locations (automatically) in a central, external database. In this way, emergency service locations can be shared with other drivers to provide additional security.

It is self-evident that the invention is not limited to the exemplary embodiment described. Various changes are possible within the scope of the invention as set forth in the following claims.

For example, the term "one" in this application may mean only one, at least one, or a number.

Furthermore, a said communication between the stationary emergency service communication device and said emergency service transmitter may comprise at least transmission of radio signals from the transmitter to the receiver.

According to a further elaboration, the mobile transmitter forms part of a mobile emergency service communication unit (for example a radio) arranged to provide two-way communication via the emergency service communication network.

A said warning signal to be issued by (or under the influence of) the user receiver may comprise, for example, an audio signal, a visual signal or both, or another suitable warning signal.

Furthermore, it is advantageous if a said emergency service transmitter T is designed to transmit respective (for example periodic) signals continuously (or for example intermittently), in particular as long as the transmitter T is switched on, for instance to report to the network periodically.

The user receiver R is, for example, adapted to automatically and continuously search for emergency service signals transmitted by mobile transmitters T, within a predetermined (relatively broad) frequency band.