Method for performing positioning and an electronic device

• US 20010008393A1
• Filed: 01/03/2001
• Published: 07/19/2001
• Est. Priority Date: 01/04/2000
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Valio, Harri, Syrjarinne, Jari
• Granted Patent: US 6,476,762 B2
• Time in Patent Office: Days
• US Class Current: 342/357.02
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0045 Transmission from base station to mobile station G01S5/009 takes precedence

Abstract

The invention relates to a method for positioning a receiver (MS) in positioning means (S, MS). In the method, a code modulated signal transmitted by satellites (SV1-SV4) and formed by an individual code for each satellite (SV1-SV4) is received. In the method, at least one reference point (BS) is selected, whose position is substantially known, In the method, information is transmitted to the positioning means (S, MS) about the position of said at least one reference point, and about Ephemeris data on the satellites (SV1-SV4). Thus, at least the Ephemeris data on each of the satellites (SV1-SV4) to be used in the positioning and the location of said at least one reference point are used in the positioning of the receiver.

Claims

1. A method for positioning a receiver (MS) in positioning means (S, MS), in which method a code modulated signal transmitted by satellites (SV1-SV4) and formed by an individual code for each satellite (SV1-SV4) is received, characterized in that in the method, at least one reference point (BS) is selected, whose position is substantially known, that information is transmitted to the positioning means (S, MS) about the position of said at least one reference point and about Ephemeris data on the satellites (SV1-SV4), wherein at least the Ephemeris data on each of the satellites (SV1-SV4) to be used in the positioning and the location of said at least one reference point are used in the positioning of the receiver.

2. The method according to

claim 1

, characterized in that in the method

the position of said reference point (BS) is used as the default position of the receiver (MS),

first distances (ρ

_m^k) between the satellite (SV1-SV4) and said reference point are determined by determining the moment of transmission ({circumflex over (T)}_ToT^k) of the signal received from each satellite used in the positioning, and by determining estimated time data ({circumflex over (T)}_GPS) at the moment of receiving the signal,

second distances (ρ

_p^k) between the satellite (SV1-SV4) and said reference point are estimated by determining the location of each satellite (SV1-SV4) used in the positioning at the moment of transmission of the signal on the basis of said estimated time data ({circumflex over (T)}_GPS) and Ephemeris data, and

the position ({overscore ({circumflex over (x)})}_u) of the receiver (MS) as well as the difference between the estimated GPS time ({circumflex over (T)}_GPS) and the real GPS time (T_GPS) are calculated at least partly on the basis of said first distances (ρ

_m^k) and said second distances (ρ

_p^k).

3. The method according to

claim 2

, characterized in that in the method, the distances are calculated in time units at a predetermined accuracy, wherein when the value ({circumflex over (N)}_ms^k) calculated for the distance is between two values corresponding to the selected accuracy, the value ({circumflex over (N)}_ms^k) calculated for the distance is rounded to one of said values corresponding to the accuracy.

4. The method according to

claim 3

, characterized in that the code to be used in the modulation is formed of a set of chips, wherein a signal modulated with said set of chips constitutes a code sequence which is iterated in the code modulation, that a reference code (ref(k)) corresponding to the individual code of each satellite is used in the receiver (MS) to determine a change in the code sequence and the code phase (Δ

chip^k), wherein the number (N_chip^k) and code phase (Δ

chip^k) of chips received after the change in the code sequence preceding the moment of positioning are determined in the receiver (MS), wherein the moment ({circumflex over (T)}_ToT^k) of transmission of the signal is determined in the following way;

{circumflex over (T)}_ToT^k=T_GPS−

{circumflex over (N)}_ms^k−

N_chip^k−

Δ

chip^k.

5. The method according to

claim 3

or

4

, characterized in that the accuracy to be used in the determination of the distance ({circumflex over (N)}_ms^k) between each satellite (SV1-SV4) and said reference point is selected to be 1 ms.

6. The method according to

claim 3

,

4

or 5, characterized in that in the method, at least one limit value (r, h) is set as the maximum distance between the receiver (MS) and said reference point (BS), wherein if the position determined for the receiver (MS) is further away than the maximum distance from the reference point, it is examined which calculated distance value ({circumflex over (N)}_ms^k) has been rounded to cause that the maximum distance is exceeded, wherein this distance value is changed by rounding it to the other of said two values corresponding to the accuracy.

7. The method according to any of the

claims 1

to

6

, characterized in that said reference point is a base station (BS) of a mobile communication network, and that information about the position of the reference point and Ephemeris data on the satellites (SV1-SV4) are transmitted to the positioning means (S, MS).

8. The method according to

claim 7

, characterized in that in the method, also the time of propagation of the signal from the mobile station (MS) to three or more base stations (BS, BS′

, BS″

) is determined, and that said propagation time data is transmitted to the receiver (MS) to determine the distance (d, d′

, d″

) in time to at least three base stations (BS, BS′

, BS″

), wherein the position of the receiver calculated on the basis of said distances (d, d′

, d″

) is selected as said reference point.

9. The method according to

claim 7

, characterized in that in the method, also the angle of arrival (α

, α

′

, α

″

) of the signal from the mobile station (MS) to two or more base stations (BS, BS′

, BS″

) is determined, and that said angle of arrival data (α

, α

′

, α

″

) are transmitted to the positioning means (S, MS) to determine the orientation of the receiver (MS) from at least three base stations (BS, BS′

, BS″

), wherein the position of the receiver (MS) determined on the basis of said orientations is selected as said reference point.

10. The method according to

claim 7

, characterized in that in the method, also the time of propagation and the angle of arrival (α

, α

′

, α

″

) of the signal from the mobile station (MS) to at least one base station (BS, BS′

, BS″

) are determined, and that said signal propagation time and angle of arrival data (α

, α

′

, α

″

) are transmitted to the positioning means (S, MS) to determine the orientation and distance (d, d′

, d″

) of the receiver (MS) from at least one base station (BS, BS′

, BS″

), wherein the position of the receiver (MS) determined on the basis of said orientation and distance (d, d′

, d″

) is selected as said reference point.

11. The method according to any of the

claims 1

to

8

, characterized in that in the positioning, the signals transmitted from at least four satellites (SV1-SV4) are used.

12. The method according to any of the

claims 1

to

11

, characterized in that the satellites (SV1-SV4) used are satellites of the GPS system.

13. The method according to any of the

claims 1

to

12

, characterized in that the positioning means (S, MS) used is a computing server (S), wherein a data transmission connection is set up between the computing server (S) and the receiver (MS).

14. The method according to any of the

claims 1

to

12

, characterized in that the positioning means (S, MS) used is the receiver (MS).

15. A positioning system which comprises at least positioning means (S, MS) and a receiver (MS) comprising means (1, 2a-2d) for receiving a code modulated signal transmitted by satellites (SV1-SV4), the code modulated signal being formed by an individual code for each satellite (SV1-SV4), characterized in that the positioning means (S, MS) also comprise means (S, 10, 11) for receiving position data on at least one selected reference point (BS) whose position is substantially known, means (S, 10, 11) for receiving Ephemeris data of the satellites (SV1-SV4), and means (S, 3) for determining the position of the receiver on the basis of at least said Ephemeris data and the position of said at least one reference point (BS).

16. The positioning system according to

claim 15

, characterized in that the default position of the receiver (MS) used in the positioning of the receiver (MS) is the position of said reference point (BS), and that the positioning system also comprises:

means (3, 4) for determining the moment of transmission ({circumflex over (T)}_ToT^k) of the signals received from the satellites used in the positioning,

and means (3, 10, 11) for determining estimated time data ({circumflex over (T)}_GPS) at the moment of receiving the signal,

means (3) for determining first distances (ρ

_m^k) between the satellite (SV1-SV4) and said reference point on the basis of said signal transmission moment ({circumflex over (T)}_ToT^k) and estimated time data ({circumflex over (T)}_GPS),

means (3) for estimating second distances (ρ

_p^k) between the satellite (SV1-SV4) and said reference point by determining the position of each satellite (SV1-SV4) used in the positioning at the moment of transmission of the signal on the basis of said estimated time data ({circumflex over (T)}_GPS) and Ephemeris data, and

means (3) for calculating the position ({overscore ({circumflex over (x)})}_u) of the receiver (MS) as well as the difference between the estimated GPS time ({circumflex over (T)}_GPS) and the real GPS time (T_GPS) at least partly on the basis of said first distances (ρ

_m^k) and second distances (ρ

_p^k).

17. The positioning system according to

claim 16

, characterized in that the distances are calculated in time units at a predetermined accuracy, wherein when the value ({circumflex over (N)}_ms^k) calculated for the distance is between two values corresponding to the selected accuracy, the value ({circumflex over (N)}_ms^k) calculated for the distance is rounded to one of said two values corresponding to the accuracy.

18. The positioning system according to

claim 17

, characterized in that the code used in the modulation is formed of a set of chips, wherein a code sequence is formed of a signal modulated with said set of chips which is iterated in the code modulation, that the receiver (MS) comprises means (16) for forming a reference code, means for determining the number (N_chip^k) and code phase (Δ

chip^k) of chips received after a change in the code sequence preceding the moment of positioning on the basis of said reference code, wherein the number (N_chip^k) and code phase (Δ

chip^k) of the chips received after the change of the code phase preceding the moment of the positioning is arranged to be determined in the receiver (MS), wherein the moment of transmission ({circumflex over (T)}_ToT^k) of the signal is determined in the following way;

{circumflex over (T)}_ToT^k=T_GPS−

{circumflex over (N)}_ms^k−

N_chip^k−

Δ

chip^k.

19. The positioning system according to

claim 17

or

18

, characterized in that the accuracy to be used in determining the distance ({circumflex over (N)}_ms^k) between each satellite (SV1-SV4) and said reference point is selected to be 1 ms.

20. The positioning system according to the

claim 17

,

18

or 19, characterized in that at least one limit value (r, h) is set in the positioning means (S, MS) as the maximum distance between the receiver (MS) and said reference point (BS), wherein the positioning means (S, MS) comprises means (3, 7) for comparing the determined distance with said limit value (r, h), means (3, 7) for examining which calculated distance value ({circumflex over (N)}_ms^k) has been rounded to cause that the maximum distance is exceeded, if the position determined for the receiver (MS) is further away than said maximum distance from the reference point, wherein this distance value is arranged to be changed by rounding it to the other of said two values corresponding to the accuracy.

21. The positioning system according to any of the

claims 15

to

20

, characterized in that said reference point is a base station (BS) of a mobile communication network, and that information about the position of said reference point and Ephemeris data on the satellites (SV1-SV4) are transmitted via said base station (BS) to the positioning means (S, MS).

22. The positioning system according to

claim 21

, characterized in that the positioning means (S, MS) also comprise means for receiving propagation time data, which propagation time data are measured to determine the distances (d, d′

, d″

) in time between the receiver (MS) and at least three base stations (BS, BS′

, BS″

), means for determining the position of the receiver (MS) on the basis of said propagation time data, wherein said reference point is selected to be the position of the receiver calculated on the basis of said distances (d, d′

, d″

).

23. The positioning system according to any of the

claims 15

to

22

, characterized in that the signals transmitted by at least four satellites (SV1-SV4) are used in the positioning.

24. The positioning system according to any of the

claims 15

to

23

, characterized in that the received signals are signals transmitted by satellites of the GPS system.

25. The positioning system according to any of the

claims 15

to

24

, characterized in that it comprises means (10, 11, 12, 13, 14a, 14b, 14c) for performing mobile station functions.

26. The positioning system according to any of the

claims 15

to

25

, characterized in that the positioning means (S, MS) comprise a computing server (S), wherein a data transmission connection is arranged to be set up between the computing server (S) and the receiver (MS).

27. The positioning system according to any of the

claims 15

to

25

, characterized in that the positioning means (S, MS) are arranged in the receiver (MS).

28. An electronic device (MS) which is arranged to be used in a positioning system with positioning means, and which electronic device also comprises at least means (1, 2a-2d) for receiving a code modulated signal transmitted by satellites (SV1-SV4), the code modulated signal being formed with an individual code for each satellite (SV1-SV4), characterized in that the electronic device (MS) also comprises means (10, 11) for determining the number (N_chip^k) and code phase (Δ

chip^k) of chips received after a change in the code sequence preceding the moment of positioning on the basis of said reference code, and means for transmitting the chip number data and the code phase data to said positioning means.

29. A computing server (S) comprising at least positioning means (S, MS) for positioning a receiver (MS), the receiver (MS) comprising means (1, 2a-2d) for receiving a code modulated signal transmitted by satellites (SV1-SV4), the code modulated signal being formed with an individual code for each satellite (SV1-SV4), characterized in that the positioning means (S, MS) also comprise means (S, 10, 11) for receiving the position data of at least one selected reference point (BS) whose position is substantially known, means (S, 10, 11) for receiving Ephemeris data on the satellites (SV1-SV4), and means (S, 3) for positioning the receiver on the basis of at least said Ephemeris data and the position of said at least one reference point (BS).