Position detection system and method using sensor

1. A position detection system comprising:

a sensor unit comprising a plurality of sensors for transmitting a transmission signal and receiving a reflection signal reflected from an obstacle and configured to acquire a time of flight (TOF) of the received reflection signal;

a storage unit configured to pre-store a position map of the obstacle for respective sensors depending on the TOF of the reflection signal on a grid map comprising a plurality of cells; and

a position estimator configured to estimate a position of the obstacle based on the TOF of the reflection signal received by the sensor unit and the position map of the obstacle pre-stored in the storage unit,

wherein:

the position estimator estimates a cell occupied by the obstacle depending on the TOF of the received reflection signal on pre-stored position maps of the obstacle and estimates the position of the obstacle based on the estimated occupied cell;

the position estimator estimates that the object is positioned in a cell in which occupied cells overlap each other using a position map of the obstacle based on a direct wave or an indirect wave or using position maps of the obstacle respectively estimated by the plurality of sensors, as the position of the obstacle; and

the position estimator applies a higher weight to an occupied cell estimated using the position map of the obstacle based on the direct wave than to an occupied cell estimated using the position map of the obstacle based on the indirect wave.

2. The position detection system of claim 1 , wherein the plurality of sensors are spaced apart from each other in a lateral direction on front and rear sides of a vehicle and transmit different transmission signals.

3. The position detection system of claim 2 , wherein the grid map comprising the plurality of cells comprises a plurality of rows and columns that extend parallel to longitudinal and lateral directions of the vehicle from the front or rear side of the vehicle.

4. The position detection system of claim 1 , wherein the storage unit pre-stores each of:

a position map of the obstacle based on a direct wave in a case in which the sensor for transmitting the transmission signal and the sensor for receiving the reflection signal are the same; and

a position map of the obstacle based on an indirect wave in a case in which the sensor for transmitting the transmission signal and the sensor for receiving the reflection signal are different.

5. The position detection system of claim 4 , wherein the position maps of the obstacle based on the direct wave are pre-stored as a range of a distance by which the obstacle is spaced apart from the sensors depending on the TOF of the reflection signal on the grid map.

6. The position detection system of claim 4 , wherein the position maps of the obstacle based on the indirect wave are pre-stored as a range of a distance by which the obstacle is spaced apart from the sensors depending on the TOF of the reflection signal, which is a sum of a distance to a position of the sensor for transmitting the transmission signal and a distance to a position of the sensor for receiving the reflection signal on the grid map.

7. The position detection system of claim 1 , wherein the position estimator divides the grid map into a plurality of sections and estimates the position of the obstacle using only a reflection signal that is transmitted or received by some sensors that are preset among the plurality of sensors for each section resulting from division.

8. The position detection system of claim 1 , wherein the position estimator divides the grid map into a plurality of sections, and when a number of positions of the obstacle estimated in the sections resulting from division is equal to or greater than a preset number, the number of positions of the obstacle is reduced by clustering the positions of the obstacle.

9. A position detection method comprising:

pre-storing a position map of an obstacle for each of a plurality of sensors depending on a time of flight (TOF) of a reflection signal on a grid map comprising a plurality of cells;

acquiring the TOF of the reflection signal received by the plurality of sensors for transmitting a transmission signal and receiving the reflection signal reflected from the obstacle; and

estimating a position of the obstacle by using the TOF of the reflection signal received by each sensor to pre-stored position maps of the obstacle,

wherein the estimating the position of the obstacle comprises:

estimating a cell occupied by the obstacle depending on the TOF of the reflection signal received on the pre-stored position maps of the obstacle and estimating the position of the obstacle based on the estimated occupied cell;

estimating that the object is positioned in a cell in which occupied cells overlap each other using the position map of the obstacle based on a direct wave or an indirect wave or using position maps of the obstacle respectively estimated by the plurality of sensors; and

applying a higher weight to an occupied cell estimated using the position map of the obstacle based on the direct wave than to an occupied cell estimated using the position map of the obstacle based on the indirect wave.

10. The position detection method of claim 9 , wherein the storing the position map of the obstacle comprises storing each of position maps of the obstacle based on a direct wave in a case in which a sensor for transmitting a transmission signal and a sensor for receiving a reflection signal are the same and an indirect wave in a case in which the sensor for transmitting the transmission signal and the sensor for receiving the reflection signal are different.

11. The position detection method of claim 9 , wherein the estimating the position of the obstacle comprises dividing the grid map into a plurality of sections and estimating the position of the obstacle using only a reflection signal that is transmitted or received by some sensors that are preset among the plurality of sensors for each section resulting from division.

12. The position detection method of claim 9 , further comprising: after the estimating the position of the obstacle, dividing the grid map into a plurality of sections and reducing a number of positions of the obstacle by clustering the positions of the obstacle when a number of the positions of the obstacle estimated in the sections resulting from division is equal to or greater than a preset number.