EP0501829B1
Expired / Lapsed
EP
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System and method for a digital navigation satellite receiver
Assignee: Texas Instruments Inc
•
Filing: 1992-02-28
•
Granted: 1999-06-16
•
Expires: 2012-02-28
Abstract
No abstract record available.
Inventors
- 👤 John P. Volpi
- 👤 Chyi H. Lu
- 👤 Mitchel B. Stiles
- 👤 Leonard J. Lapadula, Iii
- 👤 Hugh L. Scott
- 👤 George W. Pawlowski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 14:08
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/01; G01S19/13; G01S19/32; G01S19/21; G01S19/24; G01S19/35; G01S19/37
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
289 words
A receiver (20) for acquiring and tracking a plurality of
analog spread spectrum signals from a satellite, said analog
spread spectrum signals having analog carrier signals with
data and pseudo-random noise codes modulated thereon, which
receiver (20) comprising; a down-conversion circuit (103) for down-converting the
acquired analog spread spectrum signals to analog down-converted
spread spectrum signals; a local clock generation circuit (107,108) coupled to
said down-conversion circuit (103) for generating a sample
clock frequency to produce the analog down-converted spread
spectrum signals and for providing control signals for said
receiver (20); a sampling circuit (201) for converting the analog down-converted
spread spectrum signals to digital spread spectrum
signals; a plurality of channel processing circuits (202, 203,
204) for demodulating the digital spread spectrum signals to
obtain actual code and carrier phase information, each channel
processing circuit (202, 203, 204) generating an estimated
code and carrier phase and comparing said estimated code and
carrier phase to said actual code and carrier phase, each
channel processing circuit (202, 203, 204) including
correlators (813) for generating predetection integration data
in response to said comparison; a search processor (823) coupled to each of said channel
processing circuits (202, 203, 204); a general purpose processor (21) for overall receiver
control; and characterised in that said search processor (823) is
capable of autonomously and simultaneously controlling each of
said plurality of channel processing circuits (202, 203, 204),
each of said channel processing circuits (202, 203, 204) being
arranged for simultaneously acquiring and tracking each of
said plurality of analog spread spectrum signals associated
with said satellite, and each of said channel processing
circuits (202, 203, 204) further being capable of
simultaneously processing each of said pseudo-random noise
codes associated with said analog spread spectrum signals.
Claim 2
Dependent Claim
40 words
The receiver set forth in Claim 1, wherein each channel
processing circuit (202, 203, 204) is capable of generating an
estimated code and carrier phase, and predetection integration
data for analog spread spectrum signals acquired from more
than one satellite.
Claim 3
Dependent Claim
47 words
The receiver set forth in Claim 2, wherein each channel
processing circuit (202, 203, 204) comprises sufficient
correlators (813) for generating predetection integration data
in response to comparison of said estimated code and carrier
phase and said actual code and carrier phase for more than one
satellite.
Claim 4
Dependent Claim
33 words
The receiver set forth in any preceding claim, wherein a single
sampling circuit (201) is capable of digitising both the in
phase (I) and quadrature components of a received
downconverted spread spectrum signal.
Claim 5
Dependent Claim
20 words
The receiver set forth in any preceding claim, wherein the
sampling circuit (201) generates a multi-level digital spread
spectrum signal.
Claim 6
Dependent Claim
27 words
The receiver set forth in any preceding claim, wherein each
channel processing circuit is capable of establishing
simultaneous steady-state precision-code (P(Y)-code) tracking
and coarse-acquisition (C/A) code tracking.
Claim 7
Dependent Claim
29 words
The receiver set forth in any preceding claim, wherein the
receiver employs a fast multiplexing technique between the
high frequency (L1) band signals and low frequency (L2) band
signals.
Claim 8
Dependent Claim
43 words
The receiver set forth in claim 7, wherein the receiver
is capable of establishing a single signal path for L1 and L2
band signals such that interchannel bias between the L1 and L2
band signals, and interchannel bias between channels is
substantially eliminated.
Claim 9
Dependent Claim
28 words
The receiver set forth in any preceding claim, wherein said
analogue carrier signal comprises L1 and L2 carrier signals
modulated with the data and the pseudorandom noise codes.
Claim 10
Dependent Claim
31 words
The receiver set forth in any preceding claim, wherein
said search processor employs a Tong detection algorithm for
determining signal acquisition at a particular code state for
a predetermined search threshold.
Claim 11
Dependent Claim
60 words
The receiver set forth in any preceding claim, further
comprising a fourier transform circuit (824) for generating
frequency bins (B 0 , B 2 , B 4 , B 6 , B 8 , B 10 , B 12 ) from said
predetection integration data in order to extend a Doppler
frequency range of search for said analog carrier signal.
Claim 12
Dependent Claim
25 words
The receiver set forth in claim 11, wherein said fourier
transform circuit (824) is a discrete fourier transform
approximation circuit (824) using two-bit complex vectors.
Claim 13
Dependent Claim
27 words
The receiver set forth in claim 11 or claim 12, wherein
said search processor implements a Robertson approximation for
generating envelopes for each of said frequency bins.
Claim 14
Dependent Claim
31 words
The receiver set forth in any of claims 11 to 13, wherein
said search processor includes circuitry for interpolating new
frequency bins from said frequency bins of said fourier
transform circuit.
Claim 15
Dependent Claim
24 words
The receiver set forth in any of claims 10 to 13, further
comprising a noise meter (819) for dynamic setting of said
search threshold.
Claim 16
Dependent Claim
15 words
The receiver set forth in claim 15, wherein said noise
meter has a programmable bandwidth.
Claim 17
Dependent Claim
32 words
The receiver set forth in claim 15 or claim 16, wherein
said search processor includes a threshold calculator that
adjusts said search threshold in response to an output from
said noise meter.
Claim 18
Dependent Claim
53 words
The receiver set forth in any of claims 15 to 17, wherein
said search processor further includes a second threshold
calculator corresponding to said interpolated fourier
transform frequency bins, said second threshold calculator
generating a second threshold which is the square root of two
greater than said search threshold of said threshold
calculator.
Claim 19
Dependent Claim
20 words
The receiver of any of claims 15 to 18, wherein said
noise meter measures gaussian, continuous wave or pulse noise.
Claim 20
Dependent Claim
21 words
The receiver of any of claims 15 to 19, wherein said
noise meter is programmable to a desired pseudorandom noise
bandwidth.
Claim 21
Dependent Claim
55 words
The receiver set forth in any of claims 10 to 20, wherein
said search processor includes a first counter for limiting a
number of passes through said Tong detection algorithm and
forces signal acquisition to continue at a new code state
after a specific number of passes have been performed at said
particular code state.
Claim 22
Dependent Claim
44 words
The receiver set forth in any of claims 10 to 20, wherein
said search processor includes a first counter for limiting a
number of passes through said Tong detection and forces signal
acquisition to stop after a specific number of passes have
been performed.
Claim 23
Dependent Claim
20 words
The receiver of any of claims 20 to 22, wherein said
search processor processes a plurality of code states
simultaneously.
Claim 24
Dependent Claim
46 words
The receiver set forth in any preceding claim, wherein
said search processor includes a second counter for aiding in
determination of the adequacy of a predetermined search
threshold by counting the number of signal samples which
exceed said predetermined search threshold for a given search
duration.
Claim 25
Dependent Claim
31 words
The receiver set forth in any preceding claim, wherein
said search processor includes circuitry for suspending signal
acquisition in response to a period of time of known
conditions of bad signal.
Claim 26
Dependent Claim
27 words
The receiver set forth in any preceding claim, wherein
said search processor circuitry is embedded with said
plurality of channel processing circuits on a single
monolithic circuit.
Claim 27
Dependent Claim
108 words
The receiver set forth in any preceding claim, further
comprising a plurality of rover channel processing circuits
for demodulating said digital spread spectrum signals to
obtain actual code and carrier phase information, each rover
channel processing circuit generating an estimated code and
carrier phase and comparing said estimated code and carrier
phase to said actual code and carrier phase, each rover
channel circuit roves one L-band signal received from a
plurality of satellites while each continuous channel
processing circuit continuously tracks the other L-band signal
of a specific satellite; and said general purpose processor for controlling said
continuous and rover channel processing circuits during signal
acquisition and tracking.
References Cited (Backward Citations)
No citation records indexed.
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