Receiving device for receiving and demodulating spread spectrum-modulated GPS wave
First Claim
Patent Images
1. A receiving device for receiving and demodulating spread spectrum-modulated GPS electromagnetic waves from GPS satellites comprising:
- C/A code generator means for generating a C/A code corresponding to that of an aimed GPS satellite on a basis of a clock signal;
frequency conversion means for converting said received GPS electromagnetic wave into at least one intermediate frequency signal by means of a local oscillation signal;
despread-demodulation means for obtaining a PSK signal by performing a despread-demodulation by multiplying said intermediate frequency signal with said C/A code;
carrier reproduction means for reproducing a carrier of the PSK signal from said PSK signal;
clock signal generator means for generating a clock signal from said reproduced carrier and said local oscillation signal and supplying said clock signal to said C/A code generator means; and
demodulation means for demodulating GPS data from a frequency of said reproduced carrier and said PSK signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A receiving device for receiving spread spectrum-modulated GPS signal transmitted from GPS (Global Positioning System) satellites to the earth. Received GPS signals are converted into IF signals which are despread-demodulated on the basis of C/A codes, resulting in demodulated PSK signals. Carriers are reproduced from the IF signals and a clock signal for C/A code generator is produced from the reproduced carrier and a local oscillation signal. The PSK signal is demodulated on the basis of a reference frequency of a PLL circuit to obtain a navigation message.
23 Citations
11 Claims
-
1. A receiving device for receiving and demodulating spread spectrum-modulated GPS electromagnetic waves from GPS satellites comprising:
-
C/A code generator means for generating a C/A code corresponding to that of an aimed GPS satellite on a basis of a clock signal; frequency conversion means for converting said received GPS electromagnetic wave into at least one intermediate frequency signal by means of a local oscillation signal; despread-demodulation means for obtaining a PSK signal by performing a despread-demodulation by multiplying said intermediate frequency signal with said C/A code; carrier reproduction means for reproducing a carrier of the PSK signal from said PSK signal; clock signal generator means for generating a clock signal from said reproduced carrier and said local oscillation signal and supplying said clock signal to said C/A code generator means; and demodulation means for demodulating GPS data from a frequency of said reproduced carrier and said PSK signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of receiving and demodulating spread spectrum-modulated GPS electromagnetic waves from GPS satellites comprising the steps of:
-
generating a C/A code corresponding to that of an aimed GPS satellite on a basis of a clock signal; converting said received GPS electromagnetic wave into at least one intermediate frequency signal by means of a local oscillation signal; obtaining a PSK signal by multiplying said intermediate frequency signal with said C/A code to perform a despread-demodulation; reproducing a carrier of the PSK signal from said PSK signal; producing a clock signal from said reproduced carrier and said local oscillation signal; and demodulating GPS data from said reproduced carrier and said PSK signal. - View Dependent Claims (11)
-
Specification