Proximity-based navigation method

1. A method for improving accuracy of a raw GPS positioning of an untargeted pedestrian device, the method comprising:

(a) providing a vehicle device, nearby to the untargeted pedestrian device, comprising an identifying name field of the vehicle device,

wherein the identifying name field comprises information that identifies the vehicle device and a calculated offset between a raw GPS location of the vehicle device and a corrected location of the vehicle device;

(b) the untargeted pedestrian device receiving from the vehicle device nearby in Bluetooth™ communication range a message containing the identifying name field, and is received without a need for pairing between the two devices;

(c) the untargeted pedestrian device ensuring the vehicle device is within a sufficiently respective narrow range of the untargeted pedestrian device so the calculated offset is applicable to the untargeted pedestrian device, wherein the sufficiently respective narrow range is within a range capable of detecting a Bluetooth signal, wherein the detecting the Bluetooth signal is selected from a group of detecting methods comprising:

employing a Bluetooth™ protocol that permits mutual communication only within the sufficiently respective narrow range; and

relating only to respective signals from a passing vehicle whose measured respective signal strength exceeds a predetermined threshold;

(d) the untargeted pedestrian device decoding the message to extract the calculated offset; and

(e) applying the calculated offset to the raw GPS positioning of the untargeted pedestrian device so as to obtain a more accurate location of the untargeted pedestrian device.

2. The method according to claim 1 , wherein the vehicle device is configured to:

(a) obtain a coarse location of the vehicle device;

(b) obtain a corrected location of the vehicle device;

(c) compute the calculated offset; and

(d) encode the calculated offset in the Bluetooth™ in the message of the vehicle device for decoding by the untargeted pedestrian device when in communication range of the vehicle device.

3. The method according to claim 1 , further including the following operations carried out by the untargeted pedestrian device:

(a) receiving multiple respective signals from different vehicles in communication range of the untargeted pedestrian device, each signal containing a respective offset {ΔX, ΔY};

(b) for each received signal determining a respective signal intensity (Received Signal Strength Indication, RSSI); and

(c) using the respective offset {ΔX, ΔY} from whichever of the signals has maximal RSSI.

4. The method according to claim 1 for allowing a vehicle to locate a pedestrian, the method further including:

(a) receiving from the untargeted pedestrian device a corrected location; and

(b) locating the pedestrian based on the received corrected location.

5. The method according to claim 1 , wherein at least one of the untargeted pedestrian device and the vehicle device filters out fluctuating satellite signals by:

(a) receiving from at least four satellites respective GPS signals identifying time of transmission;

(b) determining a time of receipt of the GPS signals;

(c) computing an effective time of transit and a pseudo-range between the satellite and the untargeted pedestrian device and/or the vehicle device;

(d) repeating (a) to (c) for successive signals so as to obtain successive values of the pseudo-range between each satellite and the pedestrian device and/or vehicle device;

(e) computing fluctuations between the successive values of the pseudo-range for each satellite; and

(f) while an amplitude of the fluctuations or a function thereof for a given satellite exceeds a preset threshold, ignoring the signals from the given satellite.

6. The method according to claim 5 , wherein ignoring the fluctuating signals is achieved by setting a signal SNR of the signals to a preset value below a threshold in which the signals are ignored by GPS positioning software in the untargeted pedestrian and vehicle devices.

7. A non-transitory computer readable medium storing computer program instructions which when executed by a vehicle navigation device cause the vehicle navigation device to:

(a) obtain a coarse location of a vehicle;

(b) obtain a corrected location of the vehicle;

(c) compute an offset; and

encode the offset in Bluetooth™ in a message of the vehicle navigation device for decoding by a pedestrian device when in comp range of the vehicle navigation device.

8. A non-transitory computer readable medium storing computer program instructions which when executed by a pedestrian positioning device cause the pedestrian positioning device to:

(a) receive from a nearby vehicle device in Bluetooth™ communication range a message containing an identifying name field without a need for pairing between the pedestrian positioning device and the vehicle device;

(b) ensure the vehicle is within a sufficiently respective narrow range of the pedestrian positioning device so a received offset is applicable to the pedestrian positioning device, wherein the sufficiently respective narrow range is within a range capable of detecting a Bluetooth signal, wherein the detecting the Bluetooth signal is selected from a group of detecting methods comprising

employing a Bluetooth™ protocol that permits mutual communication only within the sufficiently narrow range; and

relating only to respective signals from a passing vehicle whose measured respective signal strength exceeds a predetermined threshold;

(c) decode the message to extract the received offset; and

(d) apply the received offset to the raw GPS positioning of the pedestrian positioning device so as to obtain a more accurate location of the pedestrian positioning device.