The Secretary of State for Defence

John Ivor Rewbridge Owen

Anthony Richard Pratt

Techniques for processing a navigation signal are disclosed. In one particular embodiment, the techniques may be realized as a method processing a navigation signal, the method comprising the steps of: receiving, using a receiver, the navigation signal, the navigation signal comprising a carrier signal, a data signal and at least one ranging code modulated by at least one stepped subcarrier modulation signal, the at least one stepped subcarrier modulation signal comprising a number, m, of amplitude levels, where m&#x3e;2, and wherein the amplitude levels have respective magnitudes and durations arranged to influence the power spectrum of the navigation signal is constrained in a predetermined manner, processing the navigation signal to recover the modulated at least one ranging code; and processing the recovered at least one modulated ranging code to recover at least one demodulated ranging code.

Modulation signals for a satellite navigation system

A method of controlling a power spectrum of a navigation transmission signal in a navigation system is provided. The navigation transmission signal comprising a carrier signal, a navigation ranging signal, a data signal, and at least one subcarrier modulation signal. The method comprising modulating the navigation ranging signal with the at least one subcarrier modulation signal, wherein the at least one subcarrier modulation signal comprises a number, m, of amplitude levels, where m&#x3e;2, to produce a modulated ranging signal. The amplitude levels having respective magnitudes and durations arranged to influence the power spectrum of the navigation signal in a predetermined manner. Modulating the carrier with the modulated ranging signal and the data signal to generate the navigation signal.

Techniques for controlling a power spectrum of a navigation transmission signal in a navigation system are disclosed. In one particular embodiment, the techniques may be realized as a method of controlling a power spectrum of a navigation transmission signal in a navigation system, the navigation transmission signal comprising a carrier signal, a ranging code, a data signal, and at least one stepped subcarrier modulation signal. The method may comprise modulating the canier signal by the at least one stepped subcarrier modulation signal, the data signal, and the ranging code to generate the navigation transmission ranging signal, wherein the at least one stepped subcarrier modulation signal may comprise a number, m, of amplitude levels, where m&#x3e;2. The amplitude levels may be arranged to constrain the power spectrum of the navigation transmission signal in a predetermined manner.

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Farnborough, United Kingdom

John Ivor Rewbridge Owen