Apparatus for assisting the mobility of visually impaired people in road traffic

Abstract

The apparatus comprises a wireless communication device which is to be carried by the person and has a GPS receiver, a blind guiding device with an acoustic source, a position memory, a second GPS receiver and a comparator for comparison of the position data of the GPS receivers. The communication device continuously sends attention information and, upon receipt of the attention information, the blind guiding device switches on pedestrian orientation signals, an optical release signal and acoustic release signals and/or changes their volume.

Claims

1. An apparatus for assisting the mobility of a visually impaired person in road traffic, comprising a wireless communication device which is to be carried or is carried by a visually impaired person and is equipped at least with a first data transmitter, a first data receiver and a GPS receiver, at least two blind guiding devices for a road traffic system with at least two pedestrian crossings each of which is equipped with a respective blind guiding device; each of respective blind guiding device being, is equipped at least with an acoustic source, a position memory a second data receiver and a second data transmitter, wherein at least one of the blind guiding devices is equipped with a second GPS receiver, a comparator which is designed to compare the position data of the GPS receiver of the wireless communication device with the position data of the second GPS receiver or the content of the position memory of the respective blind guiding device, wherein the once determined relative position of the individual blind guiding devices to each other is stored in their position memories as an offset and only one or more of the blind guiding devices is configured to measure the position of the communication device by comparison of the position data of the GPS receiver of the communication device with the position data of the GPS receiver of the respective blind guiding device and the transmit the position to all other blind guiding devices, wherein all other blind guiding devices are configured to include the stored offset into a distance calculation and to determine the distance of the wireless communication device of the visually impaired person.

2. The apparatus according to claim 1, the communication device thereof being a mobile phone, in particular a smartphone.

3. The apparatus according to claim 1, the blind guiding devices thereof and the communication device thereof each being equipped with a wireless near range communication interface, in particular a Bluetooth LE interface.

4. The apparatus according to claim 1, for a road traffic installation with several pedestrian crossings which are each equipped with a blind guiding device.

5. The method for the operation of the apparatus according to claim 1, for a road traffic installation with several pedestrian crossings which are each equipped with a blind guiding device, in which the relative position of the individual blind guiding devices to each other is determined once and stored in their position memories as an offset, and the position of the communication device is measured by only one or a few blind guiding devices and then transmitted to all others, whereupon all further blind guiding devices then include the stored offset into the distance calculation and determine the distance of the communication device of the visually impaired.

6. A method for the operation of the apparatus according to claim 5, in which the communication device continuously sends an attention information and upon receipt of the attention information the blind guiding device switches on an optical release signal, sends pedestrian orientation signals and/or acoustic release signals and/or changes their volume.

7. A method for the operation of the apparatus according to claim 5, in which the blind guiding device continuously sends a ready signal and upon receipt of the ready signal the communication device sends an attention information, upon receipt of which the blind guiding device switches on an optical release signal, sends acoustic pedestrian orientation signals and/or acoustic release signals and/or changes their volume.

8. The method according to claim 5, in which the relative position of the blind guiding devices to each other is determined once, in particular with a portable GPS device and stored in the position memories.

9. The method according to claim 5, for the operation of an apparatus with several blind guiding devices, in which the relative position of the individual blind guiding devices to each other is determined once, in particular with a portable GPS device and stored in their position memories.

10. The method according to claim 5, in which the current position of the communication device is transmitted to the blind guiding device or the blind guiding devices, is compared thereat to the content of the position memory, and the volume of the orientation signals and/or release signals is set dependent on the comparison result.

11. The method according to claim 10, in which after the carrier of the communication device stayed in the direct vicinity of the blind guiding device for a predetermined amount of time, the optical release signal is switched on and acoustic release signals are emitted.

12. The method according to claim 10, for a road traffic installation with several pedestrian crossings running in various directions, which are each equipped with a blind guiding device, in which dependent on the direction of movement of the carrier of the communication device one of the blind guiding devices to be controlled is addressed.

13. The method according to claim 5, in which the current position of the communication device is continuously newly determined and transmitted to the blind guiding device, is compared thereat to the content of the position memory and, from the respective difference, the direction of movement of the carrier of the communication device is determined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention result from the following description which in connection with the enclosed drawings explains the invention on the basis of an embodiment.

(2) FIG. 1 shows a road intersection with pedestrian crossings secured with traffic lights.

(3) FIG. 2 shows a block diagram of an inventive apparatus.

DETAILED DESCRIPTION

(4) In FIG. 1, an intersection 10 with lanes 12 and pedestrian crossings 14 is illustrated. At non-illustrated traffic light posts, there are, in addition to likewise not illustrated optical traffic lights and request buttons, blind guiding devices A1-A4 which are described in more detail on the basis of FIG. 2 and each have inter alia an acoustic source and a GNSS receiver. A visually impaired person with a GNSS receiver M1 is in the vicinity of the intersection 10 (GNSS=global navigation satellite system, e.g. GPS, Glonas, Beidou, Galileo).

(5) FIG. 2 shows a block diagram of an inventive apparatus. Therein, a smartphone to be carried by a visually impaired person is identified with the reference sign 16 and a blind guiding device is identified with 18. The central unit 20 of the smartphone 16 that is known per se is equipped with a first GPS receiver 22 and a first Bluetooth interface 24. The blind guiding device 18 comprises a second GPS receiver 26, the received position data of which are stored in a position memory 28, a second Bluetooth interface 32, a comparator 30 and a traffic light control unit 34. To the latter, at least one request button 36, an acoustic source 38 and a pedestrian traffic light 40 are connected. The components 36, 38, 40 are mounted to a traffic light post 42.

(6) The blind guiding device 18 continuously sends a ready signal via the second Bluetooth interface 32. As soon as the smartphone 16 receives this ready signal via its first Bluetooth interface 24, it sends an attention information which transmits the position data of the smartphone 16 via the Bluetooth connection 24, 32 to the comparator 30. When the comparator 30 has recognized a predeterminable minimum distance between the smartphone 16 and the blind guiding device 18, the blind guiding device 18 activates an optical and acoustic release signal. Already upon receipt of the first attention information, acoustic pedestrian orientation signals are emitted and their volume changed and after switching on the pedestrian release signals their volume is changed dependent on the distance between the smartphone 16 and the blind guiding device 18.

(7) The position G measured via GNSS is determined as follows:
G=P+F1+F2+F3+F4+F5

(8) Wherein

(9) G: measured position

(10) P: actual exact position

(11) F1: error of the measurement receiver (calculation and rounding error, influence by satellite geometry)

(12) F2: error caused by multipath propagation

(13) F3: error caused by troposphere

(14) F4: error caused by ionosphere

(15) F5: satellite error (variations of the satellite orbits, clock errors of the satellites)

(16) According to http://www.kowoma.de/gps/Fehlerquellen.htm there result the following values for the errors:

(17) TABLE-US-00002 disturbances caused by the ionosphere ±5 m variations of the satellite orbits ±2.5 m satellite clock errors ±2 m multipath effect ±1 m disturbances caused by the troposphere ±0.5 m calculation and rounding errors ±1 m From this, there results a total error of ±12 m.

(18) The calculated distance D from the blind guiding device A1 to the visually impaired person M1 is then GA-GM. Since the distance of the two GNSS receivers is very little, the error caused by the troposphere and the ionosphere is assumed to be identical. Two cases are observed for the multipath propagation. The resulting error is the same for both receivers, which is to be assumed in the case of very little distances.

(19) For the distance, then the two formulas result:

(20) error in the case of identical multipath propagation:
D=(PA+F1A+F2+F3+F4+F5)−(PM+F1M+F2+F3+F4+F5)
D=(PA+F1A)+(F2+F3+F4+F5)−(PM+F1M)−(F2+F3+F4+F5)
D=(PA+F1A)−(PM+F1M)+(F2+F3+F4+F5)−(F2+F3+F4+F5)
D=(PA+F1A)−(PM+F1M)

(21) error in the case of different multipath propagation
D=(PA+F1A+F2A+F3+F4+F5)−(PM+F1M+F2M+F3+F4+F5)
D=(PA+F1A+F2A)+(F3+F4+F5)−(PM+F1M+F2M)−(F3+F4+F5)
D=(PA+F1A+F2A)−(PM+F1M+F2M)+(F3+F4+F5)−(F3+F4+F5)
D=(PA+F1A+F2A)−(PM+F1M+F2M)

(22) In both cases, the highest sources of errors are eliminated. The error is approximately reduced by the factor 5 in the case of different multipath propagation. The closer the two GNSS get to each other, the more likely the receivers will be subjected to the same multipath propagation errors. In the case of immediately adjacent positions, also the multipath propagation errors are identical within the required accuracy. If also the error caused by the multipath propagation is eliminated, then the error is halved once more. Altogether, the error is reduced by approximately a power of ten by the inventive method.

(23) After the GNSS receiver has received a position, the calculated position is transmitted via radio e.g. via Bluetooth LE to the counterpart. On both sides (blind guiding device Ax—visually impaired person M1), the difference between the own position and the position transmitted via radio is calculated. The difference is the distance between the blind guiding device Ax and the visually impaired person M1. This distance is evaluated by the blind guiding device 18.