Abstract: A Global Positioning System receiver includes an intermediate frequency (IF) processor configured to downconvert broadcast signal to generate a first channel signal which is further downconverted to recover a PRN signal by an angle rotator. The receiver further includes a signal generator configured to generate N gated PRN signals. The N gated PRN signals are generated based on a local replica PRN signal time-divided by M intervals within a chip period of the local replica PRN signal. N and M are positive integers. A number of correlators is also provided. Each of which the correlators are configured to multiply a respective one of N gated PRN signals with the PRN signal to generate a number of correlation values. The correlation values are utilized to monitor distortions in the broadcast signal and/or to track the carrier frequency signal. Further, a corresponding method is also provided.

Abstract: A communication device includes a transmitter and receiver. The transmitter includes an M-ary encoder configured to generate an M−1 number of distinctive symbols each comprising k bits. M is equal to 2k and k is a positive integer. The transmitter also includes a code generator configured to produce spread spectrum codeword sequences based on the symbols generated by the M-ary encoder and based on a first and a second Gold code polynomials. The transmitter sends a radio signal based on the spread spectrum codeword sequences. The receiver is configured to receive the radio signal. The receiver includes a first shift register configured to receive an input signal generated based on the received radio signal and a second shift register configured to receive and circularly shift a locally generated codeword sequence that is identical to the codeword sequence used to encode the symbols.

Abstract: A Global Positioning System receiver includes an intermediate frequency (IF) processor configured to downconvert broadcast signal to generate a first channel signal which is further downconverted to recover a PRN signal by an angle rotator. The receiver further includes a signal generator configured to generate N gated PRN signals. The N gated PRN signals are generated based on a local replica PRN signal time-divided by M intervals within a chip period of the local replica PRN signal. N and M are positive integers. A number of correlators is also provided. Each of which the correlators are configured to multiply a respective one of N gated PRN signals with the PRN signal to generate a number of correlation values. The correlation values are utilized to monitor distortions in the broadcast signal and/or to track the PRN signal with the local replica PRN signal. Further, methods of monitoring and/or tracking the PRN signal with the local replica PRN signal by utilizing the correlation values are also provided.

Abstract: A circularly polarized multifrequency antenna is described. The antenna includes a reflector having a first side and a second side, a first crossed dipole pair having a first resonant frequency and a second crossed dipole pair having a second resonant frequency. The first and second dipole pair are symmetrically disposed on the first side of the reflector and configured to be fed with equal power in a relative phase rotation of 0°, 90°, 180° and 270°.

Abstract: A global positioning system receiver includes an inbound signal terminal to receive an inbound global positioning system signal having an inbound PRN code from a global positing system signal source. A local PRN code generator is configured to generate a local PRN code. A discriminator is coupled to the inbound signal terminal and to the local PRN code generator and configured to compare the inbound signal and the local PRN code and to generate a discriminator signal containing a positive portion and a negative portion. A processor is coupled to the discriminator and configured to receive the discriminator signal to process the discriminator signal to determine a bit code and to determine a distance from the global positing system signal source based on said bit code.

Abstract: A GPS receiver uses the energy of the L1 and L2 GPS satellite signals to track the phase of the L1 and L2 P-code and the carrier phase of the L2 signal. The in-phase channel of the L1 signal, after L1 carrier demodulation with the aid of the publicly known C/A code, is first correlated with the P-code from a P-code generator in the L1 channel of the receiver. The correlation output is filtered over two W-bit periods, using an integrate-and-dump (I&D) filter, to determine whether a polarity change has occurred. Similarly the in-phase and quadrature channels of the received L2 Y-code signal are correlated with the P-code from the P-code generator in the receiver L2 channel and I&D filtered over the corresponding period of two W-bits. Polarity transitions between the two W-bits over the I&D integration period are detected by a threshold comparison with the I&D output of the L1 punctual P-code correlation signal.