POSITIONING DEVICE, METHOD AND PROGRAM WITH ABSOLUTE POSITIONING AND RELATIVE POSITIONING MODES

• US 20120283947A1
• Filed: 02/21/2012
• Published: 11/08/2012
• Est. Priority Date: 05/24/2007
• Status: Active Grant

• Current Assignee: TomTom Navigation B.V (TomTom NV)
• Original Assignee: TomTom Navigation B.V (TomTom NV)
• Inventors: T'Siobbel, Stephen
• Granted Patent: US 9,134,429 B2
• Time in Patent Office: Days
• US Class Current: 701/469
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type

Abstract

The invention relates to a positioning device (PD) arranged to determine a position using an absolute positioning system and a relative positioning system. The positioning device is arranged to work in a first mode, in which the position is determined using the absolute positioning system and possibly the relative positioning system, and in a second mode, in which the position is determined using the relative positioning system and possibly the absolute positioning system. In the first mode the absolute positioning system being weighted more heavily than in the second mode and the positioning device is arranged to switch from the first to the second mode. The positioning device (PD) has access to a digital map database (DMD, 3DMD) and the switch from the first to the second mode is decided based on at least the determined position in combination with information stored in the digital map database (DMD, 3DMD).

Claims

1-23. -23. (canceled)

24. A positioning device comprising:

a processor to determine a position using an absolute positioning system and a relative positioning system, the positioning device being configured to work in a first mode, in which the position is primarily determined using the absolute position system, and a second mode, in which the position is primarily determined using the relative positioning system, and

the positioning device being configured to switch from the first mode to the second mode, the positioning device being further configured to maintain a history file, the history file comprising data representing measurements determined by the relative positioning system and measurements of positions determined by the absolute positioning system, wherein the switch from the first mode to the second mode is made dependent on an accuracy level of at least one position determined by the absolute positioning system and stored within the history file.

25. The positioning device according to claim 24, wherein:

the history file is maintained over a predetermined distance.

26. The positioning device according to claim 24, wherein:

the history file is maintained over a predetermined time interval.

27. The positioning device according to claim 24, wherein:

the history file is maintained only if a geographical object that may result in a switch is approached.

28. The positioning device according to claim 27, wherein:

the device is configured to compute if said geographical object is approached based on extrapolation of velocity and direction or based on a planned route.

29. The positioning device according to claim 24, wherein, in the switch from the first mode to the second mode, a selecting of a starting position is from a plurality of positions in the history file and is based upon the associated said accuracies.

30. The positioning device according to claim 24, wherein the absolute positioning system is one of a satellite based positioning system and a terrestrial positioning system.

31. The positioning device according to claim 30, wherein the relative positioning system is at least one of a gyroscope, an accelerometer, a compass, a velocity measurement module, a distance meter, an inclinometer and a module to detect steering actions of a steering wheel.

32. The positioning device according to claim 24, wherein the relative positioning system is at least one of a gyroscope, an accelerometer, a compass, a velocity measurement module, a distance meter, an inclinometer and a module to detect steering actions of a steering wheel.

33. The positioning device according to claim 24, wherein the positioning device is configured to determine said accuracy level, compare the determined accuracy level with a threshold value, and, if the accuracy level is below the threshold value store the associated position determined by the absolute positioning system as a geographical object with an advised mode associated with said determined position, the advised mode being different from the first mode.

34. The positioning device according to claim 33, wherein the advised mode is the second mode.

35. A method for determining a position using an absolute positioning system and a relative positioning system, the method comprising:

switching from a first mode, in which the position is primarily determined using the absolute position system, and a second mode, in which the position is primarily determined using the relative positioning system; and

maintaining a history file, the history file comprising data representing measurements determined by the relative positioning system and measurements of positions determined by the absolute positioning system, wherein the switch from the first mode to the second mode is dependent on an accuracy level of at least one position determined by the absolute positioning system and stored within the history file.

36. The method according to claim 35, wherein the absolute positioning system is one of a satellite based positioning system and terrestrial positioning system.

37. The method according to claim 36, wherein the absolute positioning system (APS) is configured to determine the position based on signals received from a plurality of transmitters being part of the satellite based positioning system or the terrestrial positioning system.

38. The method according to claim 35, wherein the relative positioning system is at least one of a gyroscope, an accelerometer, a compass, a velocity measurement module, a distance meter, a module to detect steering actions of a steering wheel, and an inclinometer.

39. The method according to claim 35, further comprising:

selecting, upon the switch being made from the first mode to the second mode, a starting position for the relative positioning system from the history file.

40. The method according to claim 39, wherein the selecting of the starting position is from a plurality of starting positions and is based upon the associated said accuracies.

41. The method according to claim 39, wherein:

the history file is maintained over a predetermined distance.

42. The method according to claim 39, wherein:

the history file is maintained over a predetermined time interval.

43. The method according to claim 39, wherein:

the history file is maintained only if a geographical object that may result in a switch is approached.

44. The positioning device according to claim 43, wherein:

computing whether said geographical object is approached based on extrapolation of velocity and direction or based on a planned route.

45. The method according to claim 35, further comprising:

determining an accuracy of the determined position in one of the first mode and second mode;

comparing the determined accuracy of the determined position with a threshold value; and

storing, in case the comparison indicates that the accuracy is below the threshold value, the determined position as a geographical object with an associated advised mode, the advised mode being different from the one of the first mode and second modes.

46. The method according to claim 45, wherein there are a plurality of non-zero available accuracies and the threshold value is non-zero.

47. A non-transitory computer readable medium comprising program segments which, when executed on a computer device, perform the method of claim 35.