METHOD AND GENERATOR FOR GENERATING A SPREAD-SPECTRUM SIGNAL
A method of generating a spread-spectrum signal in a navigation system comprises the steps of providing a carrier wave and a modulation waveform and modulating the carrier wave with the modulation waveform. The modulation waveform comprises a so-called anti-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform, expressible as α·BOC(1,1)−β·BOC(m,1), where m represents an even integer number, α and β are non-zero coefficients of the same sign, indicating the relative power split between the BOC(1,1) waveform and the BOC(m,1) waveform.
1 . A spread-spectrum signal generator providing a carrier wave and a modulation waveform, wherein said modulation waveform comprises an anti-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform, m representing an even integer number, said anti-phase linear combination being expressible as α·BOC(1,1)−β·BOC(m,1), wherein α and β are non-zero coefficients indicating the relative power split between said BOC(1,1) waveform and said BOC(m,1) waveform and wherein α and β are of same sign; and
modulating said carrier wave with said modulation waveform.
2 . A satellite comprising a spread-spectrum signal generator as claimed in claim 1 and a transmitter broadcasting said modulated carrier wave.
3 . A pseudolite comprising a spread-spectrum signal generator as claimed in claim 1 and a transmitter broadcasting said modulated carrier wave.
4 . The spread-spectrum signal generator as claimed in claim 1 , wherein said modulation waveform includes a pilot signal and a data signal, wherein one of said pilot signal and data signal comprises said anti-phase linear combination and wherein the other of said pilot and data signal comprises a BOC(1,1) waveform.
5 . The spread-spectrum signal generator as claimed in claim 1 , wherein said modulation waveform includes a pilot signal and a data signal, wherein one of said pilot signal and data signal comprises said anti-phase linear combination and wherein the other of said pilot signal and data signal comprises an in-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform, said in-phase linear combination being expressible as α·BOC(1,1)+β·BOC(m,1).
6 . The spread-spectrum signal generator as claimed in claim 5 , wherein said said pilot signal comprises said anti-phase linear combination and wherein said data signal comprises said in-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform.
7 . The spread-spectrum signal generator as claimed in claim 1 , wherein m=6.
8 . A spread-spectrum signal generator configured and arranged to
provide a carrier wave and a modulation waveform, wherein said modulation waveform comprises an anti-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform, m representing an even integer number, said anti-phase linear combination being expressible as α·BOC(1,1)−β·BOC(m,1), wherein α and β are non-zero coefficients indicating the relative power split between said BOC(1,1) waveform and said BOC(m,1) waveform and wherein α and β are of same sign; and
to modulate said carrier wave with said modulation waveform.
9 . A satellite comprising a spread-spectrum signal generator as claimed in claim 7 and a transmitter broadcasting said modulated carrier wave.
10 . A pseudolite comprising a spread-spectrum signal generator as claimed in claim 7 and a transmitter broadcasting said modulated carrier wave.
11 . The spread-spectrum signal generator as claimed in claim 7 , wherein said modulation waveform includes a pilot signal and a data signal, wherein one of said pilot signal and data signal comprises said anti-phase linear combination and wherein the other of said pilot and data signal comprises a BOC(1,1) waveform.
12 . The spread-spectrum signal generator as claimed in claim 7 , wherein said modulation waveform includes a pilot signal and a data signal, wherein one of said pilot signal and data signal comprises said anti-phase linear combination and wherein the other of said pilot signal and data signal comprises an in-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform, said in-phase linear combination being expressible as α·BOC(1,1)+β·BOC(m,1).
13 . The spread-spectrum signal generator as claimed in claim 12 , wherein said said pilot signal comprises said anti-phase linear combination and wherein said data signal comprises said in-phase linear combination of a BOC(1,1) waveform and a BOC(m,1) waveform.
14 . The spread-spectrum signal generator as claimed in claim 7 , wherein m=6.