SSCM: An Unambiguous Acquisition Algorithm for CBOC Modulated Signal

Abstract EN

Composite binary offset carrier (CBOC) signal has been widely researched in GNSS.

The main ingredient of CBOC signal is BOC(1,1) signal.

Usually, the acquisition method for BOC(1,1) signal is used to capture CBOC signal, while the research of special acquisition method for CBOC signal is rare.

In this letter, according to the principle and characteristics of CBOC signal, a special side-peak cancellation method (SSCM) is proposed and simulated.

In this method, two special auxiliary signals are introduced.

And the local reference signals are obtained by multiplying the data channel signal and pilot channel signal by the auxiliary signals.

The cross-correlation results from the received pilot signal and the two local pilot signals with different auxiliary signals will subtract from one another.

Then, side peaks of correlation function and in-band noise of pilot channel are suppressed, while the data channel has the same operation results.

At last the outputs of pilot channel and data channel will be added up to make full use of the received signal power.

By this way, the acquisition efficiency, accuracy, and adaptability to low signal-to-noise ratio (SNR) conditions for CBOC signal have been improved, alongside possible solution when the GNSS receiver works in a critical environment.