Apparatus and method for detecting location information using navigation algorithm
A method and apparatus for detecting location information using a navigation algorithm are provided. The method includes searching for neighboring Global Positioning System (GPS) satellites, receiving, if at least one GPS satellite is detected, pseudo-range information from at least one of the detected GPS satellites and storing the received pseudo-range information, calculating a displacement of a pedestrian terminal based on step detection of a pedestrian, correcting the calculated displacement of the pedestrian terminal using the received pseudo-range information, and measuring the location of the pedestrian terminal is measured using the corrected displacement.
1. A method for measuring a location of a pedestrian terminal, the method comprising:
receiving pseudo-range information from at least one of Global Positioning System (GPS) satellite and storing the received pseudo-range information;
calculating a displacement of a pedestrian terminal based on a detected number of steps taken by a pedestrian;
calculating a distance between the pedestrian terminal and the at least one GPS satellite using the calculated displacement of the pedestrian terminal and orbit information about the at least one GPS satellite;
correcting the calculated displacement of the pedestrian terminal using a difference between the received pseudo-range information and the calculated distance; and
measuring the location of the pedestrian terminal using the corrected displacement.
2. The method of claim 1 , wherein the displacement calculation comprises calculating the displacement of the pedestrian terminal by a Pedestrian Dead Reckoning (PDR) algorithm that estimates a location of a pedestrian terminal according to gait characteristics of the pedestrian.
3. The method of claim 1 , wherein the reception and storing of pseudo-range information comprises receiving the pseudo-range information from the at least one of the detected GPS satellites, detecting and correcting an error of the received pseudo-range information using a filter, and storing the corrected pseudo-range information.
4. An apparatus for measuring a location of a pedestrian terminal, the apparatus comprising:
a user interface configured to interface with a user;
a Global Positioning System (GPS) receiver configured to:
receive pseudo-range information from at least one of the GPS satellites; and
a controller configured to:
calculate a displacement of a pedestrian terminal based on a detected number of steps taken by a pedestrian,
calculate a distance between the pedestrian terminal and the at least one GPS satellite using the calculated displacement of the pedestrian terminal and orbit information about the at least one GPS satellite,
correct the calculated displacement of the pedestrian using a difference between the received pseudo-range information and the calculated distance, and
measure the location of the pedestrian terminal using the corrected displacement.
5. The apparatus of claim 4 , wherein the controller is configured to calculate the displacement of the pedestrian terminal by a Pedestrian Dead Reckoning (PDR) algorithm that estimates a location of a pedestrian according to gait characteristics of the pedestrian.
6. The apparatus of claim 4 , further comprising a filter unit configured to detect and correct an error of the received pseudo-range information.
7. The apparatus of claim 4 , wherein the controller is configured to control selective coupling of two navigation algorithms or to use only one of the two navigation algorithms according to the number of GPS signals received through the GPS receiver.
8. The apparatus of claim 4 , further comprising an accelerometer to measure an acceleration of the apparatus according to a motion of the apparatus.
9. The apparatus of claim 4 , wherein the controller comprises:
a satellite navigation algorithm executor configured to:
receive information about a location of a user from a visible satellite, and
provide information about the location of the user; and
a PDR algorithm executor configured to estimate a location of a user according to gait characteristics of the user.
10. The apparatus of claim 4 , wherein, if the number of GPS signals received through the GPS receiver is 4 or larger, the controller is configured to use a loosely coupled scheme in which a location and velocity of the GPS receiver are used as measurements for a coupled system.
11. The apparatus of claim 4 ,
wherein, if the number of GPS signals received through the GPS receiver is 3 or smaller, the controller is configured to compare strengths of the GPS signals with a threshold, and
wherein, if the strengths of the GPS signals are higher than the threshold, the controller is configured to use a tightly coupled scheme in which pseudo-range information and pseudo-range change rate information received through the GPS receiver are used as measurements.
12. The apparatus of claim 5 , wherein, if no GPS signal is received through the GPS receiver, the controller is configured to detect location information about the user using one of two navigation algorithms, one of the navigation algorithms being the PDR algorithm.
13. The method of claim 3 , wherein the filter is a Kalman filter.
14. The apparatus of claim 6 , wherein the filter unit comprises a Kalman filter.
15. At least one non-transitory processor readable medium for storing a computer program of instructions configured to be readable by at least one processor for instructing the at least one processor to execute a computer process for performing the method as recited in claim 1 .