U.S. patent application number 13/755914 was filed with the patent office on 2014-03-20 for method and system for utilizing reduced functionality processing channels in a gnss receiver.
This patent application is currently assigned to Broadcom Corporation. The applicant listed for this patent is Broadcom Corporation. Invention is credited to Charles ABRAHAM.
Application Number | 20140077990 13/755914 |
Document ID | / |
Family ID | 44353277 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140077990 |
Kind Code |
A1 |
ABRAHAM; Charles |
March 20, 2014 |
Method and System for Utilizing Reduced Functionality Processing
Channels in a GNSS Receiver
Abstract
A global navigation satellite system (GNSS) receiver comprising
one or more regular channel circuits and one or more sniff channel
circuits may be operable, utilizing the sniff channel circuits, to
monitor power levels of currently visible GNSS satellites which are
not being utilized by the regular channel circuits. An alternative
GNSS satellite from the currently monitored GNSS satellites may be
selected by the GNSS receiver based on the monitored power levels.
GNSS signals received from the selected alternative GNSS satellite
may be processed by a regular channel circuit. The GNSS receiver
may be operable to detect, for example, signal-to-noise ratios
(SNRs) or carrier-to-noise density ratios (C/N0s) of the currently
visible GNSS satellites utilizing the sniff channel circuits. The
sniff channel circuits may not be utilized to generate GNSS
measurements so that functionality of each of the sniff channel
circuits may be reduced.
Inventors: |
ABRAHAM; Charles; (Los
Gatos, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Broadcom Corporation; |
|
|
US |
|
|
Assignee: |
Broadcom Corporation
Irvine
CA
|
Family ID: |
44353277 |
Appl. No.: |
13/755914 |
Filed: |
January 31, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12702786 |
Feb 9, 2010 |
8395545 |
|
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13755914 |
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Current U.S.
Class: |
342/357.22 ;
342/357.67 |
Current CPC
Class: |
G01S 19/39 20130101;
G01S 19/28 20130101; G01S 19/30 20130101 |
Class at
Publication: |
342/357.22 ;
342/357.67 |
International
Class: |
G01S 19/28 20060101
G01S019/28; G01S 19/39 20060101 G01S019/39 |
Claims
1. A method of communication using a global navigation satellite
system (GNSS) receiver, comprising: generating a GNSS measurement
utilizing a regular channel circuit; monitoring attributes of a
plurality of GNSS satellites using a sniff channel circuit having
reduced functionality with respect to the regular channel circuit;
selecting an alternative GNSS satellite from the plurality of GNSS
satellites based on its monitored attribute; and processing a
signal received from the selected alternative GNSS satellite
utilizing the regular channel circuit.
2. The method of claim 1, wherein the plurality of GNSS satellites
comprises visible GNSS satellites that are not being used by the
regular channel circuit.
3. The method of claim 1, further comprising detecting a loss of a
lock on a GNSS satellite currently tracked by the regular channel
circuit.
4. The method of claim 3, wherein selecting an alternative GNSS
satellite is performed in response to detecting the loss of the
lock.
5. The method of claim 1, wherein monitoring attributes comprises
at least one of monitoring power levels, monitoring signal-to-noise
ratios, and monitoring carrier-to-noise density ratios.
6. The method of claim 1, wherein the processing comprises
generating GNSS measurements for calculating a navigation
solution.
7. The method of claim 1, further comprising generating a second
GNSS measurement utilizing a second regular channel circuit.
8. The method of claim 1, wherein a second sniff channel circuit is
also used to monitor attributes of the plurality of GNSS
satellites.
9. The method of claim 1, wherein the regular channel circuit
comprises a multi-tap correlator.
10. The method of claim 1, wherein the sniff channel circuit
comprises a single-tap correlator.
11. A global navigation satellite system (GNSS) receiver,
comprising: a regular channel circuit configured to generate a GNSS
measurement; a sniff channel circuit configured to monitor
attributes of a plurality of GNSS satellites, wherein the sniff
channel circuit has reduced functionality with respect to the
regular channel circuit; and a baseband processor configured to
select an alternative GNSS satellite from the plurality of GNSS
satellites based on its monitored attribute, wherein the regular
channel circuit is further configured to process a signal received
from the selected alternative GNSS satellite.
12. The receiver of claim 11, wherein the sniff channel circuit is
configured to monitor the attributes of the plurality of GNSS
satellites by monitoring visible GNSS satellites that are not being
used by the regular channel circuit.
13. The receiver of claim 11, wherein the regular channel circuit
is further configured to detect a loss of a lock on a GNSS
satellite it is currently tracking.
14. The receiver of claim 13, wherein the baseband processor is
further configured to select the alternative GNSS satellite in
response to detecting the loss of the lock.
15. The receiver of claim 11, wherein the sniff channel circuit is
configured to monitor attributes by monitoring at least one of
power levels, signal-to-noise ratios, and carrier-to-noise density
ratios.
16. The receiver of claim 11, wherein the regular channel circuit
is configured process the signal received from the alternative GNSS
satellite by generating GNSS measurements for calculating a
navigation solution.
17. The receiver of claim 11, further comprising a second regular
channel circuit configured to generate a second GNSS
measurement.
18. The receiver of claim 11, further comprising a second sniff
channel circuit configured to monitor attributes of the plurality
of GNSS satellites.
19. The receiver of claim 11, wherein the regular channel circuit
comprises a multi-tap correlator.
20. The receiver of claim 11, wherein the sniff channel circuit
comprises a single-tap correlator.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY
REFERENCE
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 12/702,786 filed Jul. 9, 2010, which is hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] Certain embodiments of the invention relate to communication
systems. More specifically, certain embodiments of the invention
relate to a method and system for utilizing reduced functionality
processing channels in a GNSS receiver.
BACKGROUND OF THE INVENTION
[0003] A global navigation satellite system (GNSS) utilizes an
earth-orbiting constellation of a plurality of satellites each
broadcasting GNSS signals which indicates its precise location and
ranging information. From particular locations on or near the
earth, GNSS receivers may detect valid GNSS signals and take
various GNSS measurements such as pseudorange, carrier phase,
and/or Doppler to calculate navigation information or solution such
as GNSS receiver position, velocity, and time. The American global
positioning system (GPS), the Russian global orbiting navigation
satellite system (GLONASS), the European Galileo positioning system
and the Chinese Compass navigation system are examples of
GNSSs.
[0004] A GNSS receiver is often described by its number of
channels. In a GNSS receiver, a channel is a path for an electronic
signal that is reserved for a specific GNSS satellite and used for
various functions. The number of channels in a GNSS receiver
signifies how many GNSS satellites the GNSS receiver can monitor
simultaneously. Originally limited to four or five, the number of
channels in, a GNSS receiver has progressively increased over the
years so that a GNSS receiver may typically have a large number of
channels for processing signals from many GNSS satellites.
[0005] Further limitations and disadvantages of conventional and
traditional approaches will become apparent to one of skill in the
art, through comparison of such systems with the present invention
as set forth in the remainder of the present application with
reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0006] A system and/or method for utilizing reduced functionality
processing channels in a GNSS receiver, substantially as shown in
and/or described in connection with at least one of the figures, as
set forth more completely in the claims.
[0007] Various advantages, aspects and novel features of the
present invention, as well as details of an illustrated embodiment
thereof, will be more fully understood from the following
description and drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0008] FI block diagram illustrating an exemplary communication
operable to provide utilization of reduced functionality processing
channels in a GNSS receiver, in accordance with an embodiment of
the invention.
[0009] FIG. 2 is a block diagram illustrating an exemplary GNSS
receiver that is operable to utilize reduced functionality
processing channels, in accordance with an embodiment of the
invention.
[0010] FIG. 3 is a block diagram illustrating an exemplary regular
channel and an exemplary sniff channel of the GNSS receiver, in
accordance with an embodiment of the invention.
[0011] FIG. 4 is a flow chart illustrating exemplary steps for
utilizing reduced functionality processing channels in a GNSS
receiver, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Certain embodiments of the invention can be found in a
method and system for utilizing reduced functionality processing
channels in a GNSS receiver. In various embodiments of the
invention, a global navigation satellite system (GNSS) receiver,
which comprises one or more regular channel circuits and one or
more sniff channel circuits, may be operable to monitor power
levels of currently visible GNSS satellites utilizing one or more
of the sniff channel circuits. In this regard, the currently
monitored visible GNSS satellites are not being utilized by the
regular channel circuits. An alternative GNSS satellite from the
currently monitored GNSS satellites that are not being utilized may
be selected by the GNSS receiver based on the monitored power
levels. GNSS signals received from the selected alternative GNSS
satellite may be processed by the GNSS receiver utilizing one of
the regular channel circuits. In this regard, the GNSS receiver may
be operable to detect, for example, signal-to-noise ratios (SNRs)
or carrier-to-noise density ratios (C/N0s) of the currently visible
GNSS satellites utilizing the sniff channel circuits. Each of the
regular channel circuits may be utilized to generate GNSS
measurements for calculating a navigation solution of the GNSS
receiver. Each of the regular channel circuits may comprise a
plurality of multi-tap correlators and each of the multi-tap
correlators may comprise a delay-locked loop (DLL). An early
correlator tap, a late correlator tap and the delay-locked loop
(DLL) may be utilized by each of the multi-tap correlators to
produce a punctual correlator tap during a correlation process.
[0013] The sniff channel circuits may not be utilized by the GNSS
receiver to generate GNSS measurements so that functionality of
each of the sniff channel circuits may be reduced. In other words,
the sniff channel circuits do not handle all the channel processing
that is handled by the regular channel circuits. The sniff channel
circuits only handle a subset of the channel processing that is
handled by the regular channel circuits. Each of the sniff channel
circuits may comprise a single-tap correlator. A navigation
solution of the GNSS receiver may be utilized by the single-tap
correlator to produce a punctual correlator tap during a
correlation process.
[0014] The GNSS receiver may comprise, for example, a global
positioning system (GPS) receiver, a global orbiting navigation
satellite system (GLONASS) receiver, a Galileo receiver and/or a
Compass receiver.
[0015] FIG. 1 is a block diagram illustrating an exemplary
communication system that is operable to provide utilization of
reduced functionality processing channels in a GNSS receiver, in
accordance with an embodiment of the invention. Referring to FIG.
1, there is shown a communication system 100. The communication
system 100 comprises a plurality of GNSS receivers 110 of which
GNSS receivers 110a-110c are illustrated, and a GNSS infrastructure
120. The GNSS infrastructure 120 comprises a plurality of GNSS
satellites such as GNSS satellites 120a through 120c.
[0016] The GNSS receiver such as the GNSS receiver 110a may
comprise suitable logic, circuitry, interfaces and/or code that may
be operable to receive GNSS broadcast signals from a plurality of
visible GNSS satellites such as GNSS satellites 120a through 120c
in the GNSS infrastructure 120. The GNSS receiver 110a may
comprise, for example, a GPS receiver, a GLONASS receiver, a
Galileo receiver and/or a Compass receiver.
[0017] The advent of multiple satellite constellations has placed
great demand on GNSS receivers 110 to provide a large number of
channels for utilizing signals from many GNSS satellites 120.
However, it may not be necessary to produce or generate GNSS
measurements from all channels. Having so many GNSS measurements
could overburden a CPU or baseband processor of the GNSS receiver
110a.
[0018] In an exemplary embodiment of the invention, the GNSS
receiver 110a may comprise one or more regular channel circuits and
one or more sniff channel circuits. The regular channel circuit is
a full functionality processing channel circuit while the sniff
channel circuit is a simplified and reduced functionality
processing channel circuit with respect to the regular channel
circuit. The GNSS receiver 110a may be operable to monitor power
levels of currently visible GNSS satellites such as, for example,
the GNSS satellites 120b, 120c utilizing the sniff channel
circuits, while these monitored GNSS satellites 120b, 120c are not
being utilized by the regular channel circuits. In this regard, for
example, the GNSS receiver 110a may be operable to detect
signal-to-noise ratios (SNRs) or carrier-to-noise density ratios
(C/N0s) of the currently visible GNSS satellites 120b, 120c
utilizing the sniff channel circuits. The SNR is the ratio of the
signal power to the noise power as measured in dB. The C/N0 is the
ratio of the power level of a signal carrier to the noise power in
a 1-Hz bandwidth as measured in dB-Hz. In instances when the GNSS
receiver 110a loses lock on a currently utilized GNSS satellite
such as, for example, the GNSS satellite 120a an alternative GNSS
satellite from the currently monitored GNSS satellites 120b, 120c
may be selected by the GNSS receiver 110a based on the monitored
power levels of the currently monitored GNSS satellites 120b, 120c.
The selected alternative GNSS satellite such as, for example, the
GNSS satellite 120b may be utilized by one of the regular channel
circuits for processing. Accordingly, the GNSS receiver 110a may be
able to promptly select alternative GNSS satellites to track.
[0019] Each of the regular channel circuits may be utilized to
generate GNSS measurements for calculating a navigation solution of
the GNSS receiver 110a. Each of the sniff channel circuits may not
be utilized to generate GNSS measurements so that functionality of
each of the sniff channel circuits may be reduced.
[0020] The GNSS satellite such as the GNSS satellite 120a may
comprise suitable logic, circuitry, interfaces and/or code that may
be operable to provide satellite navigational information or data
to various GNSS receivers on earth such as, for example, the GNSS
receiver 110a through 110c. The GNSS satellite 120a may be operable
to broadcast its own ephemeris periodically, for example, once
every 30 seconds. The broadcast ephemeris may be utilized to
calculate navigation information or solution such as, for example,
position, velocity, and clock information of the GNSS receivers
110. The GNSS satellite 120a may be operable to update ephemeris,
for example, every two hours. The broadcast ephemeris may be valid
for a limited time period such as, for example, 2 to 4 hours into
the future from the time of broadcast.
[0021] In operation, a GNSS receiver such as the GNSS receiver 110a
may be operable to detect and/or receive GNSS signals from, for
example, the GNSS satellites 120a-120c. The GNSS receiver 110a may
be operable, utilizing the sniff channel circuits, to monitor power
levels of the currently visible GNSS satellites 120b, 120c while
these GNSS satellites 120b, 120c are not being utilized by the
regular channel circuits. An alternative GNSS satellite such as,
for example, the GNSS satellite 120b from the currently monitored
GNSS satellites 120b, 120c may be selected by the GNSS receiver
110a based on the monitored power levels. The GNSS receiver 110a
may be operable to detect, for example, signal-to-noise ratios
(SNRs) or carrier-to-noise density ratios (C/N0s) of the currently
visible GNSS satellites 120b, 120c utilizing the sniff channel
circuits. Each of regular channel circuits may be utilized to
generate GNSS measurements for, calculating a navigation solution
of the GNSS receiver 110a. Each of the sniff channel circuits may
not be utilized to generate GNSS measurements, and as a result, the
functionality of each of the sniff channel circuits and the
corresponding processing may be reduced.
[0022] FIG. 2 is a block diagram illustrating an exemplary GNSS
receiver that is operable to utilize reduced functionality
processing channels, in accordance with an embodiment of the
invention. Referring to FIG. 2, there is shown a GNSS receiver 200.
The GNSS receiver 200 may comprise an antenna 201, a GNSS front-end
202, a plurality of regular channel circuits 204, a plurality of
sniff channel circuits, a memory 208 and a baseband processor
210.
[0023] The antenna 201 may comprise suitable logic, circuitry,
interfaces and/or code that may be operable to receive GNSS signals
from a plurality of visible or available GNSS satellites such as
the GNSS satellites 120a through 120c. The antenna 201 may be
operable to communicate the received GNSS signals to the GNSS
front-end 202 for further processing.
[0024] The GNSS front-end 202 may comprise suitable logic,
circuitry, interfaces and/or code that may be operable to convert
the received GNSS signals to GNSS baseband signals, which may be
suitable for further processing in the regular channel circuits
204, the sniff channel circuits 206 and or the baseband processor
210.
[0025] Each of the regular channel circuits 204 may comprise
suitable logic, circuitry, interfaces and or code that may be
operable to process or correlate GNSS baseband signals from many
GNSS satellites 120. The regular channel circuits 204 are full
functionality processing channel circuits. Each of the regular
channel circuits 204 ma generate GNSS measurements for calculating
a navigation solution of the GNSS receiver 200. Each of the regular
channel circuits 204 may comprise a plurality of multi-tap
correlators and each of the multi-tap correlators may comprise a
delay-locked loop (DLL). An early correlator tap, a late correlator
tap and the delay-locked loop (DLL) may be utilized by the
multi-tap correlators to produce a punctual correlator tap during a
correlation process.
[0026] Each of the sniff channel circuits 206 may comprise suitable
logic, circuitry, interfaces and/or code that may be operable to
monitor power levels of currently visible GNSS satellites 120b,
120c. For example, the sniff channel circuits 206 may be operable
to detect signal-to-noise ratios (SNRs) or carrier-to-noise density
ratios (C/N0s) of the currently visible GNSS satellites 120b, 120c.
The sniff channel circuits 206 are simplified and reduced
functionality processing channel circuits. Each of the sniff
channel circuits 206 may not generate GNSS measurements so that
functionality of each of the sniff channel circuits 206 may be
reduced. In other words, the sniff channel circuits 206 only handle
a subset of the channel processing that is handled by the regular
channel circuits 204. Each of the sniff channel circuits 206 may
comprise a single-tap correlator. A navigation solution of the GNSS
receiver 200 may be utilized by the single-tap correlator to
produce a punctual correlator tap during a correlation process.
[0027] The memory 208 may comprise suitable logic, circuitry,
interfaces and/or code that may be operable to store information
such as executable instructions, data and/or database that may be
utilized by the regular channel circuits 204, the sniff channel
circuits 206 and the baseband processor 210. The memory 208 may
comprise RAM, ROM, low latency nonvolatile memory such as flash
memory and/or other suitable electronic data storage.
[0028] The baseband processor 210 may comprise suitable logic,
circuitry, interfaces and/or code that may be operable to process
GNSS baseband signals from the GNSS front-end 202, the regular
channel circuits 204, and/or the sniff channel circuits 206. The
baseband processor 210 may be operable to calculate navigation
information or solution for various navigation applications.
[0029] In an exemplary embodiment of the invention, the baseband
processor 210 may be operable to select an alternative GNSS
satellite such as, for example, the GNSS satellite 120b from the
currently visible GNSS satellites 120b, 120c based on the power
levels of the GNSS satellites 120b, 120c which may be monitored and
detected by the sniff channel circuits 206.
[0030] In operation, the GNSS front-end 202 may be operable to
process the received GNSS signals via the antenna 201 and convert
into GNSS baseband signals. Each of the regular channel circuits
204 may be operable to process or correlate GNSS baseband signals
from many GNSS satellites 120. Each of the regular channel circuits
204 may generate GNSS measurements for calculating a navigation
solution of the GNSS receiver 200. Each of the regular channel
circuits 204 may comprise a plurality of multi-tap correlators and
each of the multi-tap correlators may, comprise a delay-locked loop
(DLL). An early correlator tap, a late correlator tap and the
delay-locked loop (DLL) may be utilized by the multi-tap
correlators to produce a punctual correlator tap during a
correlation process. Each of the sniff channel circuits 206 may be
operable to monitor power levels of currently visible GNSS
satellites 120b, 120c such as, for example, the signal-to-noise
ratios (SNRs) or the carrier-to-noise density ratios (C/N0s). Each
of the sniff channel circuits 200 may comprise one single-tap
correlator. A navigation solution of the GNSS receiver 200 may be
utilized by the single-tap correlator to produce a punctual
correlator tap during a correlation process. The baseband processor
210 may be operable to calculate navigation solution for various
navigation applications. The baseband processor 210 may be operable
to select an alternative GNSS satellite such as, for example, the
GNSS satellite 120b among the currently monitored GNSS satellites
120b, 120c based on the power levels of the GNSS satellites 120b,
120c which may be monitored and detected by the sniff channel
circuits 206. The selected alternative GNSS satellite 120b may be
utilized by one of the regular channel circuit 204 for
processing.
[0031] FIG. 3 is a block diagram illustrating an exemplary regular
channel circuit and an exemplary sniff channel circuit of the GNSS
receiver, in accordance with an embodiment of the invention.
Referring to FIG. 3, there is shown a regular channel circuit 301
and a sniff channel circuit 302. The regular channel circuit 301,
which is a full functionality processing channel circuit, may
comprise a plurality of multi-tap correlators 301a, 301b for
searching for satellite signals in time. Each of the multi-tap
correlators 301a, 301b may comprise a DLL such as the DLL 312a or
the DLL 312b. The sniff channel circuit 302, which is a simplified
and reduced functionality processing channel circuit with respect
to the regular channel circuit 301, may comprise a single-tap
correlator 320.
[0032] The multi-tap correlator such as the multi-tap correlator
310a may comprise suitable logic, circuitry, interfaces and/or code
that may be operable to perform correlation function of the regular
channel circuit 301 for generating GNSS measurements. The multi-tap
correlator 310a may employ the DLL 312a and utilize an early
correlator tap and a late correlator tap to drive the DLL 312a for
producing a punctual correlator tap. The produced punctual
correlator tap may be used to lock and/or track a visible GNSS
satellite such as, for example, the GNSS satellite 120a for
generating GNSS measurements.
[0033] The single-tap correlator 320 may comprise suitable logic,
circuitry, interfaces and/or code that may be operable to perform
correlation function of the sniff channel circuit 302 for
monitoring or detecting power levels of available GNSS satellites
120. The single-tap correlator 320 does not employ a DLL. Instead,
the timing location of the single punctual correlator tap is guided
by a navigation solution of the GNSS receiver 110a. The navigation
solution provides information such as current position of the GNSS
receiver 110a GNSS time, satellite orbit data (ephemeris) and
satellite clock data. Accordingly, the time delay at which a
punctual signal, should be centered may be calculated from the
navigation solution and the punctual correlator tap may be placed
at the right timing location. In an exemplary embodiment of the
invention, only one single tap correlator 320 may be utilized for
each sniff channel circuit 302 since knowledge of the location of
the satellite signals can be determined or derived based on the
navigation solution. Accordingly, for each of the sniff channel
circuits 302, there is no need to search for satellite signals as
with the regular channel circuits 301
[0034] In operation, the regular channel circuit 301 may comprise a
plurality of multi-tap correlators 310a, 310b. The multi-tap
correlator 310a may be operable to perform correlation function of
the regular channel circuit 301 for generating GNSS measurements.
The multi-tap correlator 310a may employ the DLL 312a and utilize
an early correlator tap and a late correlator tap to drive the DLL
312a for producing a punctual correlator tap. The produced punctual
correlator tap may be used to lock and/or track a visible GNSS
satellite 120a for generating GNSS measurements.
[0035] The sniff channel circuit 302 may comprise a single-tap
correlator 320. The single-tap correlator 320 may be operable to
correlate GNSS signals for the sniff channel circuit 302 to enable
monitoring and/or detecting power levels of available GNSS
satellites 120. The single-tap correlator 320 does not employ a
DLL. A navigation solution of the GNSS receiver 110a, which
provides information such as current position of the GNSS receiver
110a, GNSS time, satellite orbit data (ephemeris) and satellite
clock data, may be utilized by the single-tap correlator 320 to
produce a single punctual correlator tap. The timing location of
the punctual correlator tap may be guided by the navigation
solution of the GNSS receiver 110a. The time delay at which a
punctual signal should be centered may be calculated from the
navigation solution and the punctual correlator tap may be placed
at the right timing location.
[0036] FIG. 4 is a flow chart illustrating exemplary steps for
utilizing reduced functionality processing channels in a GNSS
receiver, in accordance with an embodiment of the invention.
Referring to FIG. 4, the exemplary steps start at step 401. In step
402, one or more regular channel circuits 204 in the GNSS receiver
200 may be utilized to generate GNSS measurements for calculating a
navigation solution in time. In step 403, one or more sniff channel
circuits 206 in the GNSS receiver 200 may be utilized to monitor
power levels of currently visible GNSS satellites 120b, 120c which
are not being utilized by the regular channel circuits 204. In step
404, the GNSS receiver 200 may lose lock on one of currently
tracked GNSS satellites 120a which is being utilized by one of the
regular channel circuits 204. In step 405, the GNSS receiver 200
may be operable to select an alternative GNSS satellite 120b from
the currently monitored GNSS satellites 120b, 120c based on the
monitored power levels of the currently monitored GNSS satellites
120b, 120c. In step 406, one of the regular channel circuits 204 in
the GNSS receiver 200 may be utilized to process GNSS signals
received from the selected alternative GNSS satellite 120b. The
exemplary steps may proceed to the end step 407.
[0037] In various embodiments of the invention, a GNSS receiver
110a, which comprises one or more regular channel circuits 204 and
one or more sniff channel circuits 206, may be operable to monitor
power levels of currently visible GNSS satellites 120b, 120c
utilizing one or more of the sniff channel circuits 206. In this
regard, the currently monitored visible GNSS satellites 120b, 120c
are not being utilized by the regular channel circuits 204. The
GNSS receiver 110a may comprise, for example, a GPS receiver, a
GLONASS receiver, a Galileo receiver and/or a Compass receiver. An
alternative GNSS satellite 120b from the currently monitored GNSS
satellites 120b, 120c may be selected by the GNSS receiver 110a
based on the monitored power levels. GNSS signals received from the
selected alternative GNSS satellite 120b may be processed by the
GNSS receiver 110a utilizing one of the regular channel circuits
204. In this regard, the GNSS receiver 110a may be operable to
detect, for example, SNRs or C/N0s of the currently visible GNSS
satellites 120b, 120c utilizing the sniff channel circuits 206.
Each of the regular channel circuits 204 may be utilized to
generate GNSS measurements for calculating a navigation solution of
the GNSS receiver 110a. Each of the regular channel circuits 301
may comprise a plurality of multi-tap correlators 310a, 310b and
each of the multi-tap correlators 310a, may comprise a DLL 312a. An
early correlator tap, a late correlator tap and the DLL 312a may be
utilized by the multi-tap correlators 310a to produce a punctual
correlator tap during a correlation, process.
[0038] Each of the sniff channel circuits 206 may not be utilized
to generate GNSS measurements so that functionality of each of the
sniff channel circuits 206 may be reduced. Each of the sniff
channel circuits 302 may comprise a single-tap correlator 320. A
navigation solution of the GNSS receiver 110a may be utilized by
the single-tap correlator 320 to produce a punctual correlator tap
during a correlation process.
[0039] Another embodiment of the invention may provide a machine
and/or computer readable storage and/or medium, having stored
thereon, a machine code and/or a computer program having at least
one code section executable by a machine and/or a computer, thereby
causing the machine and/or computer to perform the steps as
described herein for utilizing reduced functionality processing
channel in a GNSS receiver.
[0040] Accordingly, the present invention may be realized in
hardware, software, or a combination of hardware and software. The
present invention may be realized in a centralized fashion in at
least one computer system or in a distributed fashion where
different elements are spread across several interconnected
computer systems. Any kind of computer system or other apparatus
adapted for carrying out the methods described herein is suited. A
typical combination of hardware and software may be a
general-purpose computer system with a computer program that, when
being loaded and executed, controls the computer system such that
it carries out the methods described herein.
[0041] The present invention may also be embedded in a computer
program product, which comprises all the features enabling the
implementation of the methods described herein, and which when
loaded in a computer system is able to carry out these methods.
Computer program in the present context means any expression, in
any language, code or notation, of a set of instructions intended
to cause a system having an information processing capability to
perform, a particular function either directly or after either or
both of the following: a) conversion to another language, code or
notation; b) reproduction in a different material form.
[0042] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
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