Telecommunications – Receiver or analog modulated signal frequency converter – Local control of receiver operation
Reexamination Certificate
2000-06-06
2003-07-29
Vo, Nguyen T. (Department: 2683)
Telecommunications
Receiver or analog modulated signal frequency converter
Local control of receiver operation
C455S314000, C342S357490
Reexamination Certificate
active
06600909
ABSTRACT:
TECHNICAL FIELDS
The invention relates to field of radio navigation can also be used in a navigational equipment of the users of satellite radio navigation systems (SRNS) and, mores specifically, in radio receiving equipment performing simultaneous reception of signals, such as SRNS “GPS” (USA) and “Glonass” (Russian Federation).
PRIOR ENGINEERING ART
It is well known (cf. <<Onboard Devices of Satellite Radio Navigation) I. V. Kudryavtsev, I. N. Mishchenko, A. I. Volynkin, et al., Ìoscow, Transport Publishers, 1988 pp. 13-15 [1], <<Network Satellite Radio Navigation Systems”, V. S. Shebshaevich, O. O. Dmitriev, N. V. Ivantsevich et al., Moscow, Radio i Svyaz Publishers, 1993, p.35 [2]. The signals, radiated by the navigational artificial satellites of the Earth (NIS
)/SRNS “GPS” are radio signals modulated by the “C/A” and “P” in-phase codes: (0, &pgr;) and (+&pgr;/2, −&pgr;/2) respectively. These signals are transmitted on two frequency bands: in a range L
1
(carrier frequency 1575.42 MHz) and in a range L
2
(carrier frequency 1227.6 MHz). Signals of the frequency band L
1
are modulated by the “C/A” and “P” codes and the signals of the frequency band L
2
are modulated by the “P” code. The first code (code “C/A”) is generated using the law of pseudo-random sequence (PRS) with a period of 1 ms and a clock frequency of 10,023 MHz; the second code (code “P”) is generated under the pseudo-random squence law with a period of about 7 days and a clock frequency of 10.23 MHz. The “C/A” code transmitted on the frequency band L
1
and known as a “standard precision” code is open for all customers of navigational information and is used in a radio navigational equipment of “standard precision”, this class including the claimed device, while the “
” code is used in a special equipment of a higher precision.
To identify the signals radiated by various NIS3 satellites, the code division of the SRNS “GPS” signals is used.
In contrast to the SRNS “GPS”, in the “Glonass” pseudo-random squence (for example, cf. [2], pages 28-30), the frequency division of signals radiated by different NIS3 is accepted. The NIS3 SRNS “Glonass” signals are identified by the nominal value of their carrier (“lettered”) frequency lying in an assigned frequency range. Two (j=1, 2) frequency band F
1
and F
2
are provided for the lettered frequencies. The nominals of the lettered frequencies are formed according to the following rule:
f
j,i
=f
j,0
+i&Dgr;f
j,
ãäå:
f
j,i
are the nominal of the lettered frequencies;
f
j,0
is the zero lettered frequency;
i are the numbers of the letters in each band;
&Dgr;f
j
is the interval between the lettered frequencies.
For the frequency F
1
(near 1600 MHz)−f
1,0
=1602 MHz, &Dgr;f
1
=0.5625 MHz; for the frequency F
2
(near 1240 MHz)−f
2,0
=1246 MHz, &Dgr;f
2
=0.4375 MHz.
The lettered frequencies among the functioning NIS3 satellites are allocated by a special almanac transmitted in the control information frame.
Similarly to the “GPS” satellite radio navigation system, each NIS3 of the “Glonass” satellite radio navigation system signals in both frequency bands F
1
and F
2
The SRNS “Glonass” signals on the frequency band F
1
are modulated by PRS codes of two types: “standard precision” (with a clock frequency of 0.511 MHz) and “high precision” (with a clock frequency of 5.11 MHz), i.e. similarly to the “C/A” and “P” code modulations by codes on the frequency band L
1
of the SRNS “GPS” signals of the “Glonass” SRNS in the frequency band F
2
and similarly to the SRNS “GPS” signals in the frequency band L
2
are modulated only by the high-precision PRS codes. The “standard precision” code transmitted in the frequency band F
1
is open for all users of the navigational information and is used in the “standard precision” radio navigational equipment whose class includes the claimed device, while the “high-accuracy” code is used, as a rule, in a special high-precision equipment.
The differences existing between the signals of the SRNS “GPS” and “Glonass” due to the code division at one carrier in the SRNS “GPS” and frequency division at several carriers defined by lettered frequencies in the SRNS “Glonass” result in differences in technical means used for the reception of the signals of satellite radio navigation systems for conversion them into such a form that enables the subsequent radio navigation measurements to be carried out.
For example, known from the “Global Positioning System (GPS) Receiver RF Front End. Analog-Digital Converter. Rockwell International Proprietary Information Order Number. May 31, 1995>>,
FIG. 1
[3] is a device used for reception of signals from the SRNS “GPS”, comprising a low-noise amplifier, a filter, a first mixer, a first intermediate frequency amplifier, a quadrature mixer two quantizers for in-phase and quadrature channels, a first heterodyne frequency oscillator (1401.51 MHz), and a divider forming of a second heterodyne frequency signal from the first heterodyne frequency signal.
This device performs the technical task of reception and conversion of the SRNS “GPS” signals to a forms permitting the customer to subsequently carry out the corresponding radio navigation measurements. The device does not allow one to receive the SRNS “Glonass” signals.
The reference book <<Satellite Radio Navigation Network Systems”, V. S. Shebshaevich, P. P. Dmitriev, H. V. Ivantsevich, et al., Ìoscow, Radio i Syaz Publishers. 1993, pp. 147-148 [2], discloses a device for reception of the SRNS “Glonass” signals (“Single-Channel Equipment for ASN-37 Customers”). The device comprises an input filter, a low-noise amplifier, a first mixer, an intermediate-frequency amplifier, a phase demodulator, a second mixer with phase suppression of the mirror channel, a limiter, a lettered-frequency synthesizer, and a local oscillator to generate signals of heterodyne frequencies. The lettered-frequency synthesizer produces its own output signals according to the lettered frequencies of the SRNS “Glonass” signals being received. The lettered frequency spacing provided by the synthesizer is 0.125 MHz. The first heterodyne frequency signal is formed as a result of multiplication of the output frequency signal of the synthesizer by a factor of 4, and the signal of the second heterodyne frequency is formed as a result of division of the synthesizer output frequency signal by 2.
This device performs the technical task of reception and conversion of the SRNS “Glonass” signals to bring them a form permitting the customer to perform the corresponding radio navigational measurements. The device does not allow one to solve the problem of reception of the SRNS “GPS” signals.
In spire of differences existing between the SRNS “GPS” and the “Glonass”, they have an identical ballistic construction of the orbital group of the NIS3 satellites and allocated frequency band allowing one to state and solve the problems associated with the creation of an integrated navigational equipment for the users of the signals of these two radio navigation systems. The achievable result consists in higher reliability, authenticity and precision of definition of the object location, in particular, due to a possibility of a choice of working constellations of the NIS3 with the best geometrical factors <<Network Satellite Radio Navigation Systems” (V. S. Shebshaevich, P. P. Dmitriev, N. V. Ivantsevich et al., Moscow, Radio i Svyaz Publishers, 1993, p. 160 [2].
Known among such devices (<<Network Satellite Radio Navigation Systems” (V. S. Shebshaevich,, P. P. Dmitriev, N. V. Ivantsevich et al., Moscow, Radio i Svyaz Publishers, 1993, pp.158-161 [2], FIG. 9.8.”) is a device performing the task of reception of the SRNS “GPS” signals in the frequency band L
1
and the “Glonass” signals in the frequency band F
1
and converting them to a form permitting one, using a digital processor (primary and navigational processors) to carry out the s
Galichina Irina Evgenievna
Nikulin Vyacheslav Stepanovich
Ly Nghi H.
Samsung Electronics Co,. Ltd.
Vo Nguyen T.
LandOfFree
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