TECHNIQUE FOR POSITION CALCULATION OF A RECEIVER VIA USE OF ENCRYPTED SIGNALS OF A PUBLIC REGULATED SERVICE

Abstract

A method for determining a position of a receiver via use of encrypted signals of a public regulated service. The method comprises transmitting PRN code chips to the receiver by an assistance server. The method further comprises storing the transmitted PRN code chips to be used before a designated time interval by the receiver. The method further comprises receiving the encrypted signals during the designated time interval by the receiver from satellites in line-of-sight to the receiver. The method further comprises determining the position of the receiver via use of the encrypted signals and the stored PRN code chips by the receiver.

Claims

1. A method for determining a position of a receiver via use of encrypted signals of a public regulated service, the method comprising: transmitting, by an assistance server, Pseudo Random Noise, PRN, code chips to the receiver; storing, by the receiver, the transmitted PRN code chips to be used for a designated time interval; receiving the encrypted signals, by the receiver, from satellites in line-of-sight to the receiver, during the designated time interval; and determining the position of the receiver, by the receiver, via use of the encrypted signals and the stored PRN code chips.

2. The method according to claim 1, wherein the PRN code chips transmitted by the assistance server are stored for a predetermined number of partial time periods of the designated time interval, wherein the partial time periods are smaller than the designated time interval.

3. The method according to claim 1, wherein the step of transmitting comprises transmitting information on the designated time interval, wherein the transmitted information is encrypted.

4. The method according to claim 1, wherein the PRN code chips transmitted by the assistance server are multiplied with encrypted navigation message symbols, wherein the encrypted navigation message symbols extend beyond a plurality of single chips of the PRN code chips.

5. The method according to claim 1, wherein the PRN code chips transmitted by the assistance server are multiplied with a binary sequence, wherein each value of the binary sequence extends beyond a plurality of single chips of the PRN code chips.

6. The method according to claim 1, wherein the encrypted signals are received by the receiver during the designated time interval from a predetermined number of satellites being smaller than the number of the satellites being in line-of-sight to the receiver.

7. The method according to claim 4, wherein at least one of the stored PRN code chips or navigation message symbols match PRN code chips or navigation message symbols included in the encrypted signals.

8. The method according to claim 1, wherein the step of determining the position of the receiver is performed during the designated time interval.

9. A non-transitory computer-readable medium having computer-executable program instructions stored thereon for implementing the method of claim 1.

10. A non-transitory storage device having stored thereon computer-executable instructions for implementing the method of claim 1.

11. A receiver for determining a position of the receiver via use of encrypted signals of a public regulated service, the receiver comprising: a first receiving unit adapted to receive Pseudo Random Noise, PRN, code chips from an assistance server; a storing unit adapted to store the transmitted PRN code chips to be used for a designated time interval; a second receiving unit adapted to receive the encrypted signals from satellites in line-of-sight to the receiver during the designated time interval; and a position determining unit adapted to determine the position of the receiver via use of the encrypted signals and the stored PRN code chips.

12. An assistance server for supporting determination of a position of a receiver via use of encrypted signals of a public regulated service, the assistance server comprising: a transmitting unit adapted to transmit Pseudo Random Noise, PRN, code chips to the receiver enabling the receiver to store the transmitted PRN code chips to be used for a designated time interval, to receive the encrypted signals from satellites in line-of-sight to the receiver during the designated time interval, and to determine the position of the receiver via use of the encrypted signals and the stored PRN code chips.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following figures show:

[0035] FIG. 1 is a schematic illustration of a method according to an embodiment of the present invention;

[0036] FIG. 2 is a schematic illustration of a scenario according to an embodiment of the present invention;

[0037] FIG. 3a is a schematic illustration of a receiver according to an embodiment of the present invention; and

[0038] FIG. 3b is a schematic illustration of an assistance server according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] FIG. 1 schematically illustrates a method according to an embodiment of the present invention. An assistance server transmits PRN code chips to a receiver in step S110. Then the receiver stores the transmitted PRN code chips to be used for a designated time interval in step S120. Then the receiver receives the encrypted signals transmitted or broadcasted from satellites in line-of-sight to the receiver during the designated time interval in step S130. Then the receiver determines its position via use of the encrypted signals and the stored PRN code chips in step S140. The method according to an embodiment of the present invention can further be illustrated in a scenario illustrated in FIG. 2.

[0040] FIG. 2 schematically illustrates a scenario according to the method illustrated in FIG. 1. The assistance server 210 transmits PRN code chips to the receiver 205. The receiver 205 receives satellite signals from a plurality of satellites 215. These satellite signals comprise encrypted signals. The receiver 205 receives the encrypted signals from the plurality of satellites 215 in line-of-sight to the receiver during a designated time interval. Therefore, the receiver 205 has stored the transmitted PRN code chips transmitted by the assistance server 210 earlier. Only the line-of-sight satellites 215 from the plurality of satellites 215 are considered for determining the position of the receiver. This is illustrated in FIG. 2 as the third satellite 215 below the horizon is not able to transmit a signal to the receiver 205. Also, the earth E is not drawn to scale for matter of illustration. As the last step, the receiver 205 determines its position via use of the encrypted signals transmitted by the satellites and the stored PRN code chips transmitted by the assistance server. This can be done during the designated time interval. Further, it is possible that the assistance server 210 transmits encrypted navigation message symbols which can be used during the step of position calculation in the correlation process for longer correlation times.

[0041] FIG. 3a schematically illustrates a receiver 305 according to an embodiment of the present invention. The receiver 305 comprises a first receiving unit 306, a storing unit 307, a second receiving unit 308 and a position determining unit 309. The first receiving unit 306 can receive PRN code chips from an assistance server. The storing unit is adapted to store the transmitted PRN code chips to be used for a designated time interval. The second receiving unit 308 is adapted to receive, from satellites in line-of-sight to the receiver, the encrypted signals during the designated time interval. The position determining unit 309 is adapted to determine the position of the receiver 305 via use of the encrypted signals and the stored PRN code chips. The first receiving unit 306 and the second receiving unit 308 can be the same receiving unit. Usually, the first receiving unit 306 and the second receiving unit 308 are not the same. This is due to the fact that the assistance server has other connection requirements via the first receiving unit 306. Further, the first receiving unit 306 and the second receiving unit 308 can be the same or different, using different frequency carriers for reception.

[0042] FIG. 3b schematically illustrates an assistance server 310 according to an embodiment of the present invention. The assistance server 310 is provided for supporting determination of a position of a receiver via use of encrypted signals of a public regulated service. The assistance server 310 comprises a transmitting unit 312 adapted to transmit PRN code chips to a receiver. The receiver then stores the transmitted PRN code chips to be used for a designated time interval. The receiver then receives the encrypted signals from satellites in line-of-sight to the receiver during the designated time interval. The receiver then determines the position of the receiver via use of the encrypted signals and the stored PRN code chips. The assistance server 310 can be part of the public regulated service. The assistance server 310 can further be adapted to communicate with the satellite. Even the satellites can be adapted to transmit encrypted signals to the assistance server, which is then able to decrypt the encrypted signals. The transmitted signals from the satellites can then further be transmitted from the assistance server 310 to the receiver.

[0043] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.