visibility conditions using wireless

network of signaling devices

Field of technique the invention belongs to:

The invention relates to the field of broadcast communication, more precisely, to the traffic safety and communication methods. The invention provides a specific system for advanced notification to vehicular traffic and it is related to systems for visualization of the road edge in low visibility conditions by the network of the lightening sources which are activated by the vehicle detection.

According to international patent classification (MKP), labeled H04H 20/55.

Specification

The object of this invention is to offer the solution for the problem of visualization of the road edge in low visibility conditions by the array of illuminating sources which are activated by vehicle detection. The illumination sources (signaling devices) are autonomous unities, mounted at the road edge, which exchange the wireless messages between themselves. During the day, while visibility conditions on road are good, system is in hibernated state in which the devices are accumulating electrical energy into the batteries which is obtained and transformed from the solar energy. During the part of the day with low road visibility conditions the system is in active mode which means that the system is capable of detecting the approaching vehicle and for each device to: emit the light for defined period of time and activate the successor device by sending the wireless message _^ Also, every signaling device which turns on its signaling^ light, initiates the turning-on of the signaling light of its signaling device pair at the other side of the road. In this way the array of lighting sources is formed to illuminate both sides of the road in a direction in which vehicle is moving and in a way that road edge.on the road side on which vehicle is moving is marked in red light color while from the other direction road edge is marked with white light. Signaling devices which are passed by the vehicle stop emitting the light. During the day while road visibility conditions are good and over the part of the day with bad visibility conditions when there are no vehicles on the road the system and the devices are in hibernated state (low power consumption). The system is activated as soon as the vehicle is detected or appropriate message is received. System can also work in special signaling, mode in which it provides information to drivers about unusual road circumstances (traffic accidents, road work ahead, traffic jam, passing of vehicles with priority...). System enters this working mode after reception of appropriate message sent from special purpose vehicles (police, fire fighters, ambulance...).

Background of the invention

There are many different solutions related to notification of the road edge existing today, but most of them are not applied and the road is still marked with the reflex reflector piers. Those reflector plates are emitting red color in the vehicle direction and white color in the opposite direction. The main disadvantage of the reflecting plates is poor visibility, therefore, the other solution is proposed in DE4001980. This invention describes the signaling device mounted to the road edge which has LED (light emitting diode) as the source of light, which is powered by independent battery source. Charging of the battery source is done by solar energy by using solar cell. Moreover, the device is comprised of photosensitive sensor for detecting the day and the night which enables accumulation of the energy during the day and emitting the light from LED based on accumulated energy during the night.

The patent WO9705422 refers to the previous invention and, as its main lack, it mentions the usage of the rechargeable batteries as the dependent power source because they have defined lifetime for a few years and afterwards they need to be changed. Instead of the batteries, the patent proposes usage of capacitors as means for accumulation of the solar energy.

Signaling device described in EP0578413 is also composed of solar cell, LED, capacitors for accumulating the electrical energy, but, opposite to the previous inventions, this invention invokes a dynamic into the system. The detection of the vehicle is done by the solar cell which will be switched on by facing the headlights of the vehicle. Additionally, this invention proposes that the accumulated electrical energy is, also, obtained from the headlight of the vehicle. This energy would charge the capacitors which will power the light emitting source while the energy in the capacitor is available (until it is empty). Thus, the signaling light would be turned on in the near distance of the approaching vehicle and it would continue lighting in the short period of time comparatively with the speed of the approaching vehicle. In this way, a lightening track would ^' be visible behind the vehicle and, thus, the notification to the next approaching vehicle would be possible, which would be very helpful in the cases of low road visibility.

All patents mentioned above are filed in the early 1990s and they have many things in common: independent power supply, LED as light source, conversion of the solar energy into the electric energy. Moreover, all patents are describing the signaling devices as independent functional units (no communications between devices). With the expansion of the wireless communications there was a need for connection those independent units in active and practical way. Patent WO2005080689 describes signaling device which, beside other things, has wireless transmitter. As all other solutions, mentioned above, this signaling device is composed of LED, solar cell and independent power source. Signaling devices are capable of receiving and transmitting wireless messages, turning on the light source if the message addresses the device which has received the message and to transmit the message further to the successor device. However, the patent does not explicitly describe the marking of the road edge with such devices, but pedestrian crossroad and other places where there are some road crossing situations, and signalization about incoming traffic from other directions.

Solutions presented in this invention have its processors (mentioned above), but also a clear innovation in the field of road marking, especially at low visibility conditions. Comparing to the first three patents, system described in the current invention has its dynamics (lightening only in front of the detected approaching vehicle - signaling device stops emitting signaling light when the vehicle passes by the device) which is achieved using wireless communication between signaling devices. Last patent mentioned above, describes signal devices which comprises integrated module for wireless communication, but the patent does not cover the problem of marking the road edges, instead it covers marking of the crossroads, pedestrian crossroads and other places with road cross situations. Summary of the invention

The present invention is related to the system for marking the road edge in low visibility conditions with the wireless network of signaling devices that are mounted near the road edge. Those signaling devices emit signaling light dynamically in the vehicle direction. Signaling light is activated by the first signaling device which detects the vehicle and passes the wireless message to the next signaling device in the direction in which vehicle is moving. Next signaling device, after the reception of the message, also activates the signaling light and based on the built in logic, decides whether to pass the message further to the next signaling device. Also, every signaling device which turns on its signaling light, initiates the turning-on of the signaling light of its signaling device pair at the other side of the road. In this way the array of lighting sources is formed to illuminate both sides of the road in a direction in which vehicle is moving and in a way that road edge on the road side on which vehicle is moving is marked in red light color while from the other direction road edge is marked with white light. Signaling devices which are passed by the vehicle stop emitting the light. In this way the system dynamic is achieved in a way that only certain number of devices is emitting the light in one period of time in front of the vehicle. System can also work in special signaling mode in which it provides information to drivers about unusual road circumstances (traffic accidents, road work ahead, traffic jam, passing of vehicles with priority...). System enters this working mode after reception of appropriate message sent from special purpose vehicles (police, fire fighters, ambulance...).

Signaling device comprises of at least housing, means for converting the external power source into the electrical power, means for accumulating the electrical power, microcontroller, subsystem for wireless communication, means for vehicle detection, means for car velocity detection and means for detection of low visibility road conditions. Means for converting the external power source into the electrical power may be realized as solar cell which converts solar energy into electrical energy. Means for detection of vehicle passing detects the vehicle based on oscillations of the road surface which is caused by passing vehicle or based on the light from headlights of the vehicle.

Brief Description of the Drawings

The particular aspects of the invention will now be explained with reference to the embodiment described hereinafter and considered in connection with the accompanying drawings, in which:

Figure 1 - illustrates signaling device - Road Nail.

Figure 2 - illustrates block diagram of signaling device

Figure 3 - illustrates signaling devices installation

Figure 4 - illustrates the system functionality in the case of vehicle detection by first signaling device

Figure 5 - illustrates the system functionality in the case of vehicle passing by the signaling

device

Figure 6 - illustrates the system functionality in case when signaling device has just being

passed by the vehicle

Figure 7 - illustrates the system functionality in case when one signaling device is broken Detail description of the drawings

The detail description of the signaling device, installation of signaling devices and system functionality in different situations is shown in the accompanying drawings.

Road Nail - signaling device is shown in Figure 1. The upper part of signaling device (104) is made from transparent, waterproof material (e.g. glass) to allow passing ray of sunshine to solar cell (105) and to protect electronic components in the case (105, 106, 107, 108 and 109) of the bad weather conditions (e.g. rain or snow). On the front and back side of the housing, there are LED light sources (102 and 111), which are situated within the reflecting backgrounds (103 and 110). The lower part of the device (101) is assembled in to the ground (100), while the rest of the device lies on the surface - road surface.

Inside the housing of the solar cell (105), there is an printed circuit board with microcontroller and subsystem for wireless communication (106), controller of the battery cell (109), large number of sensors (107 - movement detection, velocity detection, detection of low visibility conditions, etc) and independent battery cell (108).

Figure 2 shows logical relationship between functional blocks of the signaling device. Microcontroller is processing the information obtained from the sensor (e.g. information about the presence and velocity of the vehicle, information about the road visibility conditions, etc.), information from the battery controller (amount of energy left in the cells) and information obtained from RF subsystem (messages from other signaling devices). Based on this information and in accordance with built in software, microcontroller controls the system by controlling the separate functional blocks. Microcontroller controls the amount of signaling light, functioning of the battery controller (e.g. whether the energy from the solar cell is transferred to the battery), creates appropriate wireless messages and sends the messages to the other signaling devices using the RF subsystem etc.

Figure 3 shows the way how to install signaling devices. Signaling device (e.g. 201) should be mounted near the road edge (200) in a way that the source of signaling lights (102) is guided towards the movement of upcoming vehicles. Distance between the signaling devices depends on the conditions of the road and line of sight between signaling devices. For straight sections of the road, without physical barriers between the devices, signaling devices can be installed at a distance up to 50m.

Figures 4, 5 and 6 are presenting the time base functionality of the system for marking the edge of roadway with wirelessly connected signaling devices. Now it should be noted that the system only works at low visibility conditions while during the day signaling devices are accumulating electrical energy. Regarding this, interpretation of the system functionality in future text should be that it is in full operational mode (during the low visibility conditions on road).

Figure 4 shows the moment just after the detection of the vehicle by first signaling device. Vehicle (400) is detected for the first time by signaling device (401) after which the system goes from the low power consumption mode to fully operable working mode. After the vehicle (400) has been detected by signaling device (401), signaling device (401) turn the signaling light on, creates appropriate message and transmits it to the next signaling device in the direction the vehicle is moving (402) but also sends the message to its pair signaling device on the other side of the road (411) to switch on appropriate signaling light. Signaling device on the other side of the road (411) without further checking switches on the signaling light according to received message from its pair signaling device (401). After the wireless message has been received by the second signaling device (402) this signaling device analyze the content of the received message (is the message for this nail, should message been forwarded...), checks its own working conditions (whether the system is in special condition or not, for example flickering light as an alert for speeding, is the signaling light already on...), after that signaling device decides upon an action. In general, signaling device (402), upon the reception of the message, turns the signaling light on, sends wireless message to its pair device on the other side of the road (412) and sends wireless message to the next signaling device in the direction the vehicle is moving to (403), which will turn the signaling light on as well, send message to it pair signaling device (413) to turns on the light and pass the message further on... On figure 4 it is shown the moment when first three signaling devices are already in state of emitting red light (401, 402 and 403), their pair devices (411, 412 and 413) are emitting white light and the wireless message (405) is traveling to the next signaling device (404).

Figure 5 shows the moment when vehicle (500) is already passing first signaling device (501) which detected the vehicle and initiate the work of system for marking the road edge. In this moment the light track, which is formed dynamically by the array of light sources emitted from signaling devices, is visible in full scope (on both sides of the road) until the last signaling device (5n).

Figure 6 shows the moment when vehicle (600) is just passed by the signaling device (601). As soon as vehicle (600) passes the signaling device (601), signaling device turns off the signaling light, sends wireless message to its pair signaling device on the other side of the road (611) to switch off signaling light as well and transmits message forward in order to turn on the new signaling light which is located at the end of the light track (60n+l). Message transmitted by the signaling device (601) is accepted by the next signaling device (602) which then parses the message and passes it further to the next signaling device, because the message is not meant to this device. Next device passes the message further on, as long as the message is received by the targeted signaling device (60n+l) which recognize the message, turn on the signaling light accordingly and with wireless message initiate switching-on of signaling light of its pair device (61n+l).

Figure 7 describes how the system reacts in case of occurrence of inoperable signal devices. It is shown the moment immediately after the first signal device (701) detects the vehicle (700). As described, after the process of vehicle detection, the light trace is made. The light trace marks the edge of the roadway. Signal devices communicate mutually with wireless messages. When the vehicle (700) is detected, the signal device (701) turns on the signal light and sends the wireless message to the next signal device (702) in the direction of vehicle movement. The signal device (702) turns on the signal light and sends the message to the signal device (703). During this process every mentioned signaling devices initiate switching-on of signaling light at its pair signaling device on other side of the road (711, 712 and 713). Figure 7 shows the situation in which the malfunctioned signal device (704) cannot process and send the message received by the signal device (703). However, according to the nature of wireless communication, the same message is received by the signal device (714) on the other side of the roadway. The signal device (714) is able to process the message and to send it to the signal device (705) which continues to form the light trace. So, this procedure assures system performance even in the case of presence of inoperable signal devices in the system.

In addition to the primary functions of the system - marking the edge of roadway in order to improve driver visibility, the system has additional features. Since the signal devices have sensors for detecting the speed of passing vehicles, the system is able to monitor the speed and movement of vehicles and if the vehicle speed is over the allowed to warn the driver by activating the signal blinker light in the direction of movement of vehicles. In this way the driver is warned to adjust the speed according to the road conditions. Also, system is capable to show different signaling illumination activated from the wireless subsystem embedded in special purpose vehicles (Ambulance, Fire Fighters, Police ...) in order to inform drivers about unusual traffic circumstances (traffic accidents, road work ahead, traffic jam...) or enable fast drive of priorities vehicles (Ambulance, Fire Fighters...).