Method and apparatus for estimating time delay of GPS receiver in hybrid navigation system

• US 20050137800A1
• Filed: 06/15/2004
• Published: 06/23/2005
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hong, Hyun-Su
• Granted Patent: US 7,124,026 B2
• Time in Patent Office: Days
• US Class Current: 701/216
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/52 Determining velocity

Abstract

An method and apparatus for estimating a time delay of a GPS receiver in a hybrid navigation system is disclosed. In the hybrid navigation system including the GPS receiver and a DR system, a time difference between a time, at which a velocity measured by the DR system becomes equal to a reference velocity, and a time, at which a velocity measured by the GPS receiver becomes equal to the reference velocity, is measured to calculate the time delay of the GPS receiver, so that a GPS/DR system having a loosely-coupled structure which considers the time delay can be realized. Further, in the system, when a vehicle moves from a GPS reception area to a non-reception area and a GPS/DR system mode changes into a DR system mode, an initial velocity value can be estimated while a time delay is considered for a DR system. Furthermore, since a velocity measurement apparatus for vehicles designed in accordance with the apparatus and the method has a performance superior to a velocity measurement apparatus for vehicles in the prior art, it can ultimately contribute to the position estimation accuracy of a position measurement apparatus for vehicles.

Claims

1. A method for estimating a time delay of a GPS receiver in a hybrid navigation system, the hybrid navigation system including a DR system and the GPS receiver, the method comprising the steps of:

a) setting a reference velocity for estimating the time delay of the GPS receiver;

b) detecting velocity measurement results of the GPS receiver and the DR system;

c) setting a moment, at which the detected velocity measurement result of the DR system is equal to or exceeds the reference velocity, as a first reference time, and repeating step b);

d) setting a moment, at which the velocity measurement result of the GPS receiver is equal to or exceeds the reference velocity, as a second reference time; and

e) calculating the time delay of the GPS receiver by subtracting the first reference time from the second reference time.

2. The method as claimed in claim 1, wherein, in step a), the reference velocity is set as ‘

0’

.

3. A method for estimating a time delay of a GPS receiver in a hybrid navigation system, the hybrid navigation system including a DR system and the GPS receiver, the method comprising the steps of:

a) detecting velocity measurement results of the GPS receiver and the DR system;

b) sensing a reference velocity for estimating the time delay of the GPS receiver when at least one of the detected velocity measurement results of the GPS receiver and the DR system is ‘

0’

, and repeating step a);

c) capturing a moment at which the detected velocity measurement result of the GPS receiver is equal to or to exceeds ‘

0’

in a state in which the velocity measurement result of the DR system is more than ‘

0’

, setting the moment as a first reference time, setting the velocity measurement result of the DR system at the first reference time as the reference velocity, and repeating step a);

d) capturing a moment at which the detected velocity measurement result of the GPS receiver is equal to or exceeds the reference velocity, and setting the moment as a second reference time; and

e) calculating the time delay of the GPS receiver by subtracting the first reference time from the second reference time

4. An apparatus for estimating a time delay of a GPS receiver in a hybrid navigation system, the hybrid navigation system including a DR system and the GPS receiver, the apparatus comprising:

a velocity detection unit for detecting velocities measured by the GPS receiver and the DR system;

a velocity comparison unit for storing a reference velocity for estimating the time delay of the GPS receiver, and capturing a moment at which each velocity measured by the GPS receiver and the DR system equals or exceeds the reference velocity; and

a time delay calculation unit for calculating a time difference between the moment at which the velocity measured by the GPS receiver equals or exceeds the reference velocity and the moment at which the velocity measured by the DR system equals or exceeds the reference velocity, and estimating the time difference as the time delay of the GPS receiver.

5. The apparatus as claimed in claim 4, wherein the velocity comparison unit stores ‘

0’

as a value of the reference velocity.

6. An apparatus for estimating a time delay of a GPS receiver in a hybrid navigation system, the hybrid navigation system including a DR system and the GPS receiver, the apparatus comprising:

a velocity detection unit for detecting velocities measured by the GPS receiver and the DR system;

a velocity comparison unit for capturing a moment at which the velocity measured by the GPS receiver equals or exceeds ‘

0’

to set the moment as a first reference time, setting the velocity measurement result of the DR system at the first reference time as a reference velocity, and capturing a moment at which the velocity measured by the GPS receiver equals or exceeds the reference velocity to set the moment as a second reference time, and

a time delay calculation unit for calculating a time difference between the first reference time and the second reference time, and estimating the time difference as the time delay of the GPS receiver.