JP3294384B2 - GLONASS multi-channel receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a GLONASS (Glob)
al Orbiting Navigation Satellite System) GLONA that receives signals from satellites through multiple reception channels
The present invention relates to an SS multi-channel receiver.

[0002]

2. Description of the Related Art In recent years, various satellite navigation systems have been developed for measuring (positioning) the position of a moving body such as a vehicle, a ship, or an aircraft. Among these types of satellite navigation systems, those developed by CIS include GLONA.
There is a system called SS. GLONASS is a system that receives a signal transmitted from a satellite in an orbit around the earth by a receiver mounted on a mobile body on the earth and performs positioning of the mobile body. These satellites, GLO
The NASS satellite transmits data including orbital information of the satellite to a receiving device on the earth using a carrier modulated by a pseudo noise (PN) code. The receiving device receives a signal transmitted from the GLONASS satellite and demodulates data. From the data and the like received in this way, the receiving device obtains the position and the like of each GLONASS satellite. On the other hand, the receiving device calculates the distance (pseudo distance) from the GLONASS satellite based on the propagation time of the radio wave from the satellite to the receiving device. The receiving device calculates its own position based on the position of the satellite and the pseudorange. Since the pseudorange includes a clock error and the like, it is necessary to receive signals from at least four satellites in order to three-dimensionally determine the position of the moving object on which the receiving device is mounted.

[0003] The concept of configuring such a receiving apparatus can be roughly divided into a concept of receiving signals from all GLONASS satellites through a single receiving channel and a concept of receiving signals shared by a plurality of receiving channels. There is a way of thinking. In the case of a receiving device configured according to the former concept, that is, a single channel receiving device, a plurality of GLs are used.
In order to receive a signal from an ONASS satellite, it is necessary to switch and use a single reception channel in a time-division manner.
On the other hand, a receiving device configured based on the latter concept,
That is, according to the multi-channel receiving device, such time division allocation is unnecessary.

FIG. 2 shows a GLONAS according to a first conventional example.
The configuration of the S multi-channel receiver is shown. The device shown in this figure has a configuration for receiving a signal transmitted from a GLONASS satellite through a plurality of reception channels.
It has the simplest circuit configuration. In other words, a single circuit system is used from when a signal is received to when it is converted to a digital signal, and a plurality of circuit systems thereafter (a number corresponding to the number of GLONASS satellites to be received) are used. It is.

The device shown in FIG. 1 includes an antenna 10, an RF unit 12, a mixer 14, a reference signal generator 16, and a local oscillator 18. The antenna 10 is GL
An antenna for receiving a signal from an ONASS satellite, which is installed at a location of the best view on a mounted mobile object. The RF unit 12 amplifies a signal received by the antenna 10 at a high frequency, and amplifies the amplified signal to a mixer 14.
To supply. Reference signal generator 16 provides a local oscillator 18 with a reference signal. The local oscillator 18 generates a local oscillation signal having a predetermined frequency in synchronization with the reference signal supplied from the reference signal generator 16. The mixer 14 has an RF
The output of the section 12 and the local oscillation signal output from the local oscillator 18 are mixed, thereby converting the signal output from the RF section 12 to an intermediate frequency.

This conventional example further includes an IF section 20 and an A
A / D converter 22 is provided. The IF unit 20 amplifies the received signal converted to the intermediate frequency and supplies the signal to the A / D converter 22. The A / D converter 22 converts the analog signal into a digital signal by sampling the signal amplified by the IF unit 20. The digital signal output from the A / D converter 22 is a GLONA to be received.
It is supplied to a plurality of correlators 24 provided according to the number of SS satellites.

[0007] A plurality of correlators 24 and 26, a code generator 28 and a carrier generator 30 are provided according to the number of GLONASS satellites to be received. The code generator 28 is a P-code used in the GLONASS satellite.
The same code as the N code is generated and supplied to the correlator 24. The carrier generator 30 generates a synchronization carrier having a frequency corresponding to the carrier of the signal transmitted from the GLONASS satellite, and supplies it to the correlator 26. The output of the correlator 24 is supplied to the correlator 26, and the correlator 26
Are supplied to the signal processing unit 32. The signal processing unit 32 controls the phases of the PN code and the synchronization carrier in the code generator 28 and the carrier generator 30.

In other words, the code generator 28, the correlator 24, and the signal processing unit 32 form a code synchronous loop. That is, the signal transmitted from each GLONASS satellite and received by the antenna 10 is a predetermined P
Modulated by N code. Therefore, the digital signal output from the A / D converter 22 is also subjected to the phase modulation by the PN code. The correlator 24 calculates A
The digital signal output from the / D converter 22 and the PN code output from the code generator 28 are digitally processed, and the correlation between the two is detected. More specifically, the digital signal is despread modulated by the PN code output from the code generator 28, and the resulting signal is supplied to the correlator 26. The output of the correlator 26 is provided to a signal processing unit 32, which outputs a code generator 28 so that the correlation can be detected by the correlator 24.
The generation phase of the PN code is controlled. In this way, code synchronization with the signal transmitted from each GLONASS satellite is ensured.

Further, the carrier generator 30, the correlator 26, and the signal processing unit 32 form a carrier locked loop. That is, in GLONASS, each G
The carrier frequency of the signal transmitted from lonass differs for each satellite. Each carrier generator 30 is used in association with one of the GLONASS satellites, and generates a synchronization carrier at a frequency corresponding to the carrier frequency of the corresponding GLONASS satellite. This synchronization carrier is supplied to the corresponding correlator 26.
The correlator 26 digitally processes the signal output from the correlator 24 and the synchronization carrier generated by the carrier generator 30, and detects a correlation between the two. The signal processing unit 32 controls the phase of the synchronization carrier in the carrier generator 30 so that the correlation is detected by the correlator 26. In this way, carrier synchronization for the signal from the GLONASS satellite is ensured.

[0010] The signal processing unit 32 thus operates
Based on codes provided in a plurality of systems corresponding to the LONASS satellites and outputs from the carrier synchronization loop, predetermined positioning calculation and the like are executed. That is, the position, speed, and the like of the mounted moving body are calculated and output to a display device or the like (not shown).

FIG. 3 shows a GLONAS according to a second conventional example.
The configuration of the S multi-channel receiver is shown. The device shown in this figure differs from the first conventional example in that the RF unit 12
The following circuit configuration has a configuration in which a plurality of systems are provided corresponding to the GLONASS satellite. That is, the signal received by the antenna 10 is distributed to the plurality of RF units 12 related to each system.

[0012]

However, the conventional GLONASS multi-channel receiver having such a configuration has a problem in that high-speed sampling is required or the configuration of the device becomes large.

First, a first conventional example shown in FIG.
Since the configuration from the unit 12 to the A / D converter is a single system, there is an advantage that it can be realized with relatively simple hardware. However, in the case of this conventional example, the sampling of the intermediate frequency signal must be performed by the single A / D converter 22. As mentioned earlier, GLONA
In the SS satellite, since the carrier frequency is different for each GLONASS satellite, the bandwidth of the intermediate frequency is 13
MHz. Generally, in order to perform sufficient digital processing, sampling must be performed at a frequency several times that of the original signal. For example, if sampling is performed at three times the frequency, in the case of this conventional example, about 40 MHz
Such a high sampling frequency is required. This is significantly higher than the operating frequency of about 14 MHz, which is a general CMOS operation frequency, so that a special element must be required as an element constituting the A / D converter 22. In addition, this leads to an increase in power consumption, resulting in a decrease in reliability.

Next, in the second conventional example shown in FIG. 3, since A / D conversion is performed for each GLONASS satellite, high-speed sampling as in the first conventional example is not necessary. However, in the case of this conventional example, since the configuration after the RF unit 12 is provided in a plurality of systems in accordance with the number of satellites, the configuration of the apparatus becomes extremely complicated and bloated. Furthermore, since the local oscillation frequency differs for each system, interference between the systems becomes a problem. Countermeasures against this interference cause an increase in cost in realizing the device.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and realizes a GLONASS multi-channel receiving apparatus having a relatively simple configuration without causing a problem such as high-speed sampling. The purpose is to:

[0016]

In order to achieve the above object, the present invention provides at least a plurality of analog / digital conversion means so that a plurality of GLONASS satellites are shared by a plurality of GLONASS satellites. The sampling frequency of the conversion means is set relatively low.

[0017]

In the present invention, a plurality of GLONASS satellites are shared by each analog / digital conversion means. Therefore, the sampling frequency can be set lower than in the case where conversion into a digital signal is performed by a single analog / digital converter. In addition, the analog / digital conversion means is replaced with each GLONASS.
The device configuration is simpler than when provided corresponding to a satellite.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The same components as those of the conventional example shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows a GLON according to an embodiment of the present invention.
The configuration of the ASS multi-channel receiver is shown.
The device shown in this figure has three systems from the RF unit 12 to the code and carrier synchronization circuit.
Each system is denoted by reference numerals 34-1 to 34-3.

The signal received by antenna 10 is
It is distributed to each system 34-1 to 34-3. Each system 34-
The RF units 12 to 34-3 amplify the signal distributed from the antenna 10 at high frequency and supply it to the subsequent stage. The local oscillator 18 is supplied with a reference signal from a common reference signal generator 16. Thereby, each system 34-1-3
The local oscillator 18 of 4-3 synchronously generates a local oscillation signal.

In each of the systems 34-1 to 34-3, R
The configuration from the F section 12 to the A / D converter 22 is 1
Each system is provided. The code and carrier synchronization circuit at the subsequent stage of the A / D converter 22 are provided in the respective systems 34-1 to 34-3.
Are provided in plurality. Each system 3
The total number of codes and carrier synchronization circuits in 4-1 to 34-3 matches the number of GLONASS satellites to be received.

As described above, in this embodiment, the A / D
One converter 22 is provided for each of the systems 34-1 to 34-3. Therefore, each A / D converter 22 does not take charge of the entire 13 MHz which is the entire intermediate frequency range, and the GLON to be subjected to code and carrier synchronization by a code and carrier synchronization circuit provided at the subsequent stage.
It is sufficient to sample only the intermediate frequency related to the ASS satellite. If sampling is performed in each of the three systems 34-1 to 34-3 in this manner, the bandwidth of the shared intermediate frequency is about 4 MHz. With this bandwidth, three times the frequency (about 12 MHz)
Even if sampling is performed in z), a general element, for example, an A / D converter 22 using a CMOS element is sufficient, and a special element is not required. Further, the device configuration is simpler than that of the second conventional example shown in FIG.

In the above description, GLONA
Although reference has been made to an SS being developed by CIS, the invention is not limited to this GLONASS. That is, the present invention can be applied to any multi-channel receiving device suitable for a navigation system in which the intermediate frequency band is relatively wide.

[0024]

As described above, according to the present invention,
Since a plurality of analog / digital converters are provided so as to share a plurality of GLONASS satellites, the sampling frequency of each analog / digital converter can be relatively low. As a result, CM as an element constituting the analog / digital conversion means
A commonly used element such as an OS element can be used,
The use of a special element does not cause an increase in cost, an increase in power consumption, a decrease in reliability, or the like. Further, as compared with the case where analog / digital conversion means is provided for each satellite, the device configuration is simplified, and a highly reliable GLONASS multi-channel receiver with a relatively inexpensive configuration can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a GLONASS multi-channel receiver according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a GLONASS multi-channel receiving device according to a first conventional example.

FIG. 3 is a block diagram showing a configuration of a GLONASS multi-channel receiving device according to a second conventional example.

[Explanation of symbols]

 Reference Signs List 10 antenna 12 RF unit 14 mixer 16 reference signal generator 18 local oscillator 20 IF unit 22 A / D converter 24, 26 correlator 28 code generator 30 carrier generator 32 signal processing unit 34-1 to 34-3 system

──────────────────────────────────────────────────続 き Continuation of front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 5/00-5/14 G01C 21/00-21/24 G01C 23/00-25/00

Claims (1)

(57) [Claims] 1. A receiving means for receiving, from a plurality of GLONASS satellites, a signal carried by a carrier having a different frequency for each satellite and modulated by a predetermined code, sampling the received signal and converting the signal into a digital signal. Analog-to-digital conversion means and G to be received
A GLONASS multi-channel receiving device comprising: a plurality of synchronization means provided in correspondence with the lonass satellite and for synchronizing a code and a carrier with the digital signal obtained by the conversion, such that a plurality of the GLONASS satellites are shared. A GLONASS multi-channel receiving apparatus characterized in that at least a plurality of analog / digital conversion means are provided and a sampling frequency of each analog / digital conversion means is relatively low.