Independent positioning device and independent positioning method

• US 7,586,440 B2
• Filed: 08/25/2005
• Issued: 09/08/2009
• Est. Priority Date: 08/25/2004
• Status: Active Grant

• Current Assignee: The Ritsumeikan Trust (Ritsumei-Kan University Educational Association), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: The Ritsumeikan Trust (Ritsumei-Kan University Educational Association), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nakamura, Mitsuru, Kubo, Yukihiro, Sugimoto, Sueo, Tajima, Yasuhiro, Kagawa, Kazunori
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/660,793
• Publication Number:
  US 20080258966A1
• Time in Patent Office: 1,475 Days
• Field of Search: 342/357.04, 342/357.12, 342/357.15, 342/357.16, 342/357.13, 701/213, 701/215
• US Class Current: 342/357.23
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

A linear regression equation is comprised of the objective variables and the explanatory variables. The objective variables are comprised of the L1 carrier phases, the L2 carrier phases, the C/A code pseudorange, the P(Y) code pseudorange, the clock error data, the delay data of the ionosphere, and the delay data of the troposphere that related with every satellite respectively. The explanatory variables are comprised of at least the integer ambiguity and a receiver'"'"'s position.

The receiver'"'"'s position has been linear-approximated by using the estimation results of the passed receiver'"'"'s positions. Applying a least square method to the regression equation, the integer ambiguity and the receiver'"'"'s position is estimated.

Claims

1. A point positioning apparatus which estimates distances between a receiver and satellites and a position of the receiver by utilizing satellite signals transmitted from the satellites, comprising:

a satellite data observing device which observes orbit data of the satellites and clock errors of the satellites from a navigation message included in the satellites signals or estimated values by off-line processing;

an ionosphere data getting device which gets delay data of an ionosphere;

a troposphere data getting device which gets delay data of troposphere; and

a position estimating device which;

linear-approximates the position of the receiver by using the estimation results of previous positions of the receiver and the orbit data of the satellites,

sets up explanatory variables, as unknown values, that include the linear-approximated position of the receiver, an integer ambiguity, a clock error of the receiver, clock errors of the satellites, delays of the ionosphere, delays of the troposphere,

sets up objective variables, as observational values, that include carrier phases, code pseudoranges, clock error data of the satellites, delay data of the ionosphere, delay data of the troposphere,

sets a regression equation of the explanatory variables and the objective variables, and

estimates at least the position of the receiver by applying a parameter estimation algorithm to the regression equation.

2. The point positioning apparatus according to claim 1,

wherein the position estimating device estimates the position of the receiver by fixing the integer ambiguity by an integer ambiguity estimation method.

3. The point positioning apparatus according to claim 1,

further comprising a temporary memory device which memorizes the carrier phases, the code pseudoranges, the clock error of the receiver, the orbit data of the satellites, the clock error data of the satellites, the delay data of the ionosphere, the delay data of the troposphere over the number of epochs,

wherein the position estimating device sets the regression equation of every data got over the number of epochs.

4. The point positioning apparatus according to claim 1,

wherein the position estimating device applies a state estimation algorithm to the regression equation.

5. The point positioning apparatus according to claim 1,

wherein:

the position estimating device estimates position of the satellites by utilizing the regression equation;

the objective variables further include the orbit data of the satellites; and

the explanatory variables further include errors of the satellite'"'"'s orbits.

6. A point positioning method for estimating distance between a receiver and satellites and a position of the receiver by utilizing satellite signals transmitted from the satellites, comprising the step of:

observing orbit data of the satellites and clock errors of the satellites from a navigation message included in satellite signals or estimated values by off-line processing;

getting delay data of an ionosphere and delay data of a troposphere;

linear-approximating the position of the receiver by using the estimation results of previous position of the receiver and the orbit data of the satellites;

setting up explanatory variables, as unknown values, that include the linear-approximated position of the receiver, an integer ambiguity, a clock error of the receiver, clock errors of the satellites, delays of the ionosphere, delays of the troposphere;

setting up objective variables, as observational values, that include carrier phases, code pseudoranges, clock error data of the satellites, delay data of the ionosphere, delay data of the troposphere;

setting a regression equation of the explanatory variables and the objective variables; and

estimating at least the position of the receiver by applying a parameter estimation algorithm to the regression equation.

7. The point positioning method according to claim 6,

wherein the position of the receiver is estimated by fixing the integer ambiguity by an integer ambiguity estimation method.

8. The point positioning method according to claim 6,

comprising the step of memorizing the carrier phases, the code pseudoranges, the clock error of the receiver, the orbit data of the satellites, the clock error data of the satellites, the delay data of the ionosphere, the delay data of the troposphere over the number of epochs,

wherein:

the regression equation is set by utilizing every data got over the number of epochs.

9. The point positioning method according to claim 6,

wherein:

a state estimation algorithm is applied to the regression equation.

10. The point positioning method according to claim 6,

wherein:

the positions of the satellites are estimated by utilizing the regression equation;

the objective variables further include the orbit data of the satellites; and

the explanatory variables further include errors of the satellite'"'"'s orbits.

11. A point positioning apparatus which detects distances between a receiver and satellites and a position of the receiver by utilizing satellite signals transmitted from the satellites, comprising:

a satellite data observing device which observes orbit data of the satellites and clock errors of the satellites from a navigation message included in the satellites signals or estimated values by off-line processing;

an ionosphere data getting device which gets delay data of an ionosphere;

a troposphere data getting device which gets delay data of troposphere; and

a position estimating device which;

linear-approximate the position of the receiver with a Linear Taylor series expansion about a estimated receiver'"'"'s position by using the estimation results of previous positions of the receiver and the orbit data of the satellites,

sets up explanatory variables, as unknown values, that include the linear-approximated position of the receiver, an integer ambiguity, a clock error of the receiver, clock errors of the satellites, delays of the ionosphere, delays of the troposphere,

sets up objective variables, as observational values, that include carrier phases, code pseudoranges, clock error data of the satellites, delay data of the ionosphere, delay data of the troposphere,

sets the regression equation by utilizing coefficients, as an operational matrix elements, that are obtained from partial differentiation of the distances linear-approximating with the Linear Taylor series expansion with respect to receiver'"'"'s coordinates, and

estimates at least the position of the receiver by applying a parameter estimation algorithm to the regression equation.

12. A point positioning method for detecting distance between a receiver and satellites and a position of the receiver by utilizing satellite signals transmitted from the satellites, comprising the step of:

observing orbit data of the satellites and clock errors of the satellites from a navigation message included in satellite signals or estimated values by off-line processing;

getting delay data of an ionosphere and delay data of a troposphere;

linear-approximating the position of the receiver with a Linear Taylor series expansion about a estimated receiver'"'"'s position by using the estimation results of previous positions of the receiver and the orbit data of the satellites;

setting up explanatory variables, as unknown values, that include the linear-approximated position of the receiver, an integer ambiguity, a clock error of the receiver, clock errors of the satellites, delays of the ionosphere, delays of the troposphere;

setting up objective variables, as observational values, that include carrier phases, code pseudoranges, clock error data of the satellites, delay data of the ionosphere, delay data of the troposphere;

setting the regression equation by utilizing coefficients, as an operational matrix elements, that are obtained from partial differentiation of the distances linear-approximating with the Linear Taylor series expansion with respect to receiver'"'"'s coordinates; and

estimating at least the position of the receiver by applying a parameter estimation algorithm to the regression equation.