The presence or absence of a preamble is detected with accuracy in a reception apparatus that receives a signal including a preamble. A reception section receives a subframe including a subframe preamble and a message and a frame including a frame preamble. A processing section performs a process of detecting the presence or absence of the subframe preamble according to whether or not a given relation holds between a reception timing of the subframe preamble and a reception timing of the frame preamble. A message decoding section extracts the message from the subframe and decodes the message in a case where the presence of the subframe preamble is detected.

Apparatus and methods permit the use of a microelectromechanical systems (MEMS) oscillator in a satellite positioning system receiver, such as a Global Positioning System (GPS) receiver. Techniques to ameliorate jitter or phase noise disadvantages associated with MEMS oscillators are disclosed. For example, a receiver can use one or more of the following techniques: (a) use another source of information to retrieve ephemeris information, (2) perform advanced tight coupling, and/or (3) use a phase-locked loop to clean up the jitter or phase noise of the MEMS oscillator. With respect to advanced tight coupling, an advanced tight coupling processor can include nonlinear discriminators which transform I and Q data into linear residual measurements corrupted by unbiased, additive, and white noise. It also includes an amplitude estimator configured to operate in rapidly changing, high power noise; a measurement noise variance estimator; and a linear residual smoothing filter for input to the navigation filter.

Apparatus and methods permit the use of a microelectromechanical systems (MEMS) oscillator in a satellite positioning system receiver, such as a Global Positioning System (GPS) receiver. Techniques to ameliorate jitter or phase noise disadvantages associated with MEMS oscillators are disclosed. For example, a receiver can use one or more of the following techniques: (a) use another source of information to retrieve ephemeris information, (2) perform advanced tight coupling, and/or (3) use a phase-locked loop to clean up the jitter or phase noise of the MEMS oscillator. With respect to advanced tight coupling, an advanced tight coupling processor can include nonlinear discriminators which transform I and Q data into linear residual measurements corrupted by unbiased, additive, and white noise. It also includes an amplitude estimator configured to operate in rapidly changing, high power noise; a measurement noise variance estimator; and a linear residual smoothing filter for input to the navigation filter.

Enhancing search capacity of Global Navigation Satellite System (GNSS) receivers. A method for searching satellite signals in a receiver includes performing a plurality of searches sequentially. The method also includes storing a result from each search of the plurality of searches in a consecutive section of a memory. Further, the method includes detecting free sections in the memory. The method also includes concatenating the free sections in the memory to yield a concatenated free section. Moreover, the method includes allocating the concatenated free section for performing an additional search.

Enhancing search capacity of Global Navigation Satellite System (GNSS) receivers. A method for searching satellite signals in a receiver includes performing a plurality of searches sequentially. The method also includes storing a result from each search of the plurality of searches in a consecutive section of a memory. Further, the method includes detecting free sections in the memory. The method also includes concatenating the free sections in the memory to yield a concatenated free section. Moreover, the method includes allocating the concatenated free section for performing an additional search.

A non-systematic convolutional decoder of a convolutionally encoded multi-level data stream includes a shift register and two or more paths of exclusive-OR (XOR) gates, arranged to reconstruct an original input information stream, each path having a quantiser arranged to quantise the signal to two levels, and a set of XOR gates arranged to match an encoding path in an associated convolutional encoder, and a selector arranged to feed an output from each path to a single input of the shift register. If the paths have differing values at their output, the selector may choose the value from the path based upon a function of the multi-level signals associated with each path, such as the path with the largest absolute signal level. The decoder provides a simple means for decoding signals while allowing the signal to also or instead be decoded using e.g. a Viterbi decoder if higher performance is required.

A non-systematic convolutional decoder of a convolutionally encoded multi-level data stream includes a shift register and two or more paths of exclusive-OR (XOR) gates, arranged to reconstruct an original input information stream, each path having a quantiser arranged to quantise the signal to two levels, and a set of XOR gates arranged to match an encoding path in an associated convolutional encoder, and a selector arranged to feed an output from each path to a single input of the shift register. If the paths have differing values at their output, the selector may choose the value from the path based upon a function of the multi-level signals associated with each path, such as the path with the largest absolute signal level. The decoder provides a simple means for decoding signals while allowing the signal to also or instead be decoded using e.g. a Viterbi decoder if higher performance is required.

An integrated GNSS signal having a plurality of signal components with arbitrary power allocation may be processed. In an embodiment, an integrated signal processing unit of a GNSS receiver may generate in parallel complex rotated samples for a sample of the integrated signal. The complex rotated samples (e.g., early and late complex rotated samples) may be accumulated in parallel in a window that spans any arbitrary width that is less than or equal to a number of code chips in a PRN code sequence. In an embodiment, the integrated signal processing unit may sequentially generate complex rotated samples for the sample. The complex rotated samples (e.g., early, punctual, and late complex rotated samples) may be sequentially accumulated in the window. The GNSS receiver may utilize the accumulated complex rotated samples to perform correlation techniques, perform multipath mitigation techniques, and/or track the integrated signal.

An integrated GNSS signal having a plurality of signal components with arbitrary power allocation may be processed. In an embodiment, an integrated signal processing unit of a GNSS receiver may generate in parallel complex rotated samples for a sample of the integrated signal. The complex rotated samples (e.g., early and late complex rotated samples) may be accumulated in parallel in a window that spans any arbitrary width that is less than or equal to a number of code chips in a PRN code sequence. In an embodiment, the integrated signal processing unit may sequentially generate complex rotated samples for the sample. The complex rotated samples (e.g., early, punctual, and late complex rotated samples) may be sequentially accumulated in the window. The GNSS receiver may utilize the accumulated complex rotated samples to perform correlation techniques, perform multipath mitigation techniques, and/or track the integrated signal.

A positioning system including a satellite signal receiver 20 that receives satellite signals from a plurality of positioning satellites; a plurality of indoor pseudo satellite stations that transmit pseudo satellite signals; and a pseudo station control device that selects the positioning satellites to be allocated to the plurality of pseudo satellite stations based on the received satellite signals, allocates a PRN code corresponding to each of the selected positioning satellites to each of the plurality of pseudo satellite stations one by one, determines a delay time of the PRN code allocated to the plurality of pseudo satellite stations, and transmits a plurality of pseudo satellite signals generated using the PRN code corresponding to each of the plurality of pseudo satellite stations and the delay time to each of the plurality of pseudo satellite stations.