Navigation signal transmitting apparatus, navigation signal transmission method and positional information providing apparatus

• US 10,429,512 B2
• Filed: 05/11/2011
• Issued: 10/01/2019
• Est. Priority Date: 05/13/2010
• Status: Active Grant

• Current Assignee: GNSS Technologies Inc.
• Original Assignee: GNSS Technologies Inc.
• Inventors: Torimoto, Hideyuki, Okano, Kazuki
• Primary Examiner(s): Gregory, Bernarr E
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US13/697,537
• Publication Number:
  US 20130127660A1
• Time in Patent Office: 3,065 Days
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system

Abstract

A navigation signal transmitting apparatus, provided on ground, for transmitting a navigation signal to a receiver capable of positioning by receiving a spread spectrum satellite positioning signal from a satellite has first and second transmission antennas; a message generating unit that generates a message signal of positional information included in the navigation signal, and a modulating unit that modulates the message signal by a modulation process including spectrum spreading, based on spread codes of the same sequence as the satellite positioning signal allotted in advance to the navigation signal transmitting apparatus, for generating first and second navigation signals. The modulating unit executes the modulating process using either one of the first and second navigation signals as an object of demodulation at each time of reception by the receiver.

Claims

1. A navigation signal transmitting apparatus, provided on ground, for transmitting a navigation signal to a receiver capable of positioning by receiving a spread spectrum satellite positioning signal from a satellite, comprising:

first and second transmission antennas;

a memory that stores location data for specifying a location where the navigation signal transmitting apparatus is installed;

a processor that generates a message signal of positional information including the location data;

a modulator that modulates said message signal by a modulation process including spectrum spreading, using a spread code stored in advance in said navigation signal transmitting apparatus, a sequence of the spread code corresponding to a sequence of the spread codes allotted in advance to said receiver, and generates a first navigation signal based on said message signal;

an analog processor that transmits said first navigation signal from said first and second transmission antennas, the transmitter including;

a first switching circuit arranged between the modulator and the first transmission antenna; and

a second switching circuit arranged between the modulator and the second transmission antenna, and

a programmable logic circuit for outputting a first signal for controlling the first switching circuit and a second signal for controlling the second switching circuit, wherein the first signal is at an H level when the second signal is at an L level, and vice versa, the programmable logic circuit being electrically connected to the memory, the processor, and the analog processor, and the programmable logic circuit comprising the modulator,

wherein said modulator includes;

a spread code generator that generates a specific code of said spread codes of the same sequence; and

a first multiplier that performs spectrum spreading on said message signal with said specific code,

wherein the first switching circuit gates on the navigation signal to the first transmission antenna when the level of the first signal is at the H level; and

wherein the second switching circuit gates on the navigation signal to the second transmission antenna when the level of the second signal is at the H level.

2. The navigation signal transmitting apparatus according to claim 1, wherein said modulator includes:

the spread code generator that generates a specific code of said spread codes of the same sequence;

the first multiplier that performs spectrum spreading on said message signal with said specific code, to generate said first navigation signal.

3. The navigation signal transmitting apparatus according to claim 1, wherein said modulator includes:

the spread code generator that generates said specific code of said spread codes of the same sequence;

the first multiplier that performs spectrum spreading on said message signal with said specific code, to generate said first navigation signal; and

a second multiplier,

wherein the modulator delays said message signal by a prescribed time period, and

wherein the second multiplier performs spectrum spreading on said delayed message signal with said specific code, to generate a second navigational signal.

4. The navigation signal transmitting apparatus according to claim 1, wherein said positional information includes data representing at least latitude, longitude and altitude.

5. A method of transmitting a navigation signal of a transmitter provided on ground, for transmitting a navigation signal to a receiver capable of positioning by receiving a spread spectrum satellite positioning signal from a satellite, comprising:

storing, with a memory of the transmitter, location data for specifying a location where the transmitter is installed;

generating, with a processor of the transmitter, a message signal of positional information including the location data;

modulating, with a modulator of the transmitter, said message signal by a modulation process including spectrum spreading using a spread code stored in advance in the transmitter, a sequence of the spread code corresponding to a sequence of the spread code allotted in advance to said receiver, and generating a navigation signal based on said message signal;

transmitting said navigation signal from first and second transmission antennas, the transmitter comprising;

a first switching circuit arranged between the modulator and the first transmission antenna; and

a second switching circuit arranged between the modulator and the second transmission antenna;

controlling the first switching circuit with a first signal that is output from a programmable logic circuit; and

controlling the second switching circuit with a second signal that is output from the programmable logic circuit,

wherein the first signal is at an H level when the second signal is at an L level, and vice versa,

wherein modulating comprises;

generating, using a spread code generator of the modulator, a specific code of the spread codes of the same sequence; and

performing spectrum spreading, using a multiplier of the modulator, on the message signal with the specific code,

wherein transmitting comprises;

gating on the navigation signal from the first switching circuit when the first signal is at the H level; and

gating on the navigation signal from the second switching circuit when the second signal is at the H level.

6. The method of transmitting a navigation signal according to claim 5, wherein said generating said first and second navigation signals includes:

generating, with the spread code generator of the modulator, said specific code of said spread codes of the same sequence;

performing, with the multiplier of the modulator, spectrum spreading on said message signal with said specific code, to generate said first navigation signal;

delaying, with a delay device, said message signal by a prescribed time period; and

performing spectrum spreading on said delayed message signal with said specific code, to generate a second navigation signal.

7. The method of transmitting a navigation signal according to claim 5, wherein said generating said first and second navigation signals includes:

generating, with the spread code generator of the modulator, said specific code of said spread codes of the same sequence;

generating, with a sequence generator of the transmitter, a sequence of pseudo random numbers;

performing, with the multiplier, spectrum spreading on said message signal with said specific code, to generate said first navigation signal; and

performing, with the multiplier, spectrum spreading on said message signal with said specific code, to generate a second navigation signal;

wherein

said transmitting includes transmitting said first and second navigation signals successively and exclusively from either one of said first and second transmission antennas, based on said pseudo random numbers.

8. The method of transmitting a navigation signal according to claim 5, wherein said positional information includes data representing at least latitude, longitude and altitude.