 Wireless communication system for adapting to frequency drift |
| OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a wireless communication system of the present ... |
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| Reduction of time to first fix in an SATPS receiver |
| The invention focuses on initial acquisition (at the time of power-up), reacquisition (after loss ... |
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| Method and circuit for achieving frequency conversion |
| The present invention was made so as to solve the above problems and has as an object thereof to ... |
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| Method and apparatus for determining time for GPS receivers |
| The present invention discloses a method and apparatus for acquiring timing signals for use in a G... |
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| Method and apparatus for tracking a communication signal in a wireless communication system |
| OF THE PREFERRED EMBODIMENT An improvement for tracking a mobile communication signal which ... |
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| Method and arrangement for antenna selection control in a radio receiver |
| Starting from this prior art, it is the object of the invention to specify a method and an ... |
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| Apparatus and method for receiving position and control signals by a mobile machine |
| I claim: 1. An apparatus for receiving position and command signals by a mobile machine, comprising:... |
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| Fixed wireless loop system that ranks non-assigned PN codes to reduce interference |
| The foregoing and other problems are overcome and the objects and advantages are realized by ... |
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| Processing a spread spectrum signal in a frequency adjustable system |
| In one aspect, the invention features processing a spread spectrum signal sampled at a selected ... |
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Single-chip GPS receiver digital signal processing and microcomputer
| Details |
Inventors: Lau, Chung Y.; Martin, Kreg A.; Lake, Gary W.;
Assignee: Trimble Navigation Limited (Sunnyvale, CA)
Primary Examiner: Park; Collin W.
Assistant Examiner:
Attorney, Agent or Firm: Law Offices of Thomas E. Schatzel
An embodiment of the present invention combines, on a single integrated circuit, an eight channel GPS receiver, a 68330-type microprocessor, a 68681-type DUART serial communications controller, an analog-to-digital converter, a real-time clock, a random access memory and a boot read-only memory. A system integration module and inter-module bus allow tri-state control of the microprocessor such that a commercially available 68332-type emulator may be used for software development. |
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG.
1 illustrates a GPS digital integrated circuit (IC) embodiment of the present invention, referred to herein by the general reference numeral 10.
The IC 10 carries out the digital processing aspects of a GPS navigation system, including GPS code correlation and position and velocity calculation, local oscillator frequency synthesis, user keyboard and display interfacing, and other digital signal processing (DSP) and input/output (I/O) functions.
IC 10 is implemented on a single semiconductor chip which may be physically laid out and fabricated on the surface of a silicon substrate, as shown in FIG.
2.
Commercial standard-cell high-performance computer-core CMOS semiconductor fabrication processes and packaging facilities available in the United States, such as provided by Motorola Semiconductor (Phoenix, Ariz.
), may be successfully used to build IC 10.
IC 10 is preferably implemented using a commercially available semiconductor fabrication technology such as advanced, triple-metal, 0.
8 micron CMOS processes directed at high performance and low power consumption.
A 144-pin thin plastic quad flat-pack (TQFP) is preferably used to package IC 10.
FIG.
1 shows that IC 10 comprises a pair of IC pin multiplexers 12 and 14, a dual universal asynchronous receiver transmitter (DUART) 16, a read only memory (ROM) 18, a random access memory (RAM) 20, a microcomputer (CPU) 22, a global channel controller 24 and a set of eight GPS receiver channels 26-33 for demodulating carrier signals simultaneously received from a plurality of orbiting GPS satellites.
IC pin multiplexers 12 and 14 make it possible for a 144-pin TQFP package to contain IC 10.
Since not all input/output signals associated with IC 10 need to be simultaneously available to the external interface, some pins are configurable to serve more than one function.
The use of standard cell devices can substantially simplify the task of implementing IC 10.
DUART 16 is preferably a standard cell device, for example the Motorola 68681 DUART
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Cell Phones 
