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A second form of precise monitoring is called carrier-phase enhancement (CPGPS). [1] The error, which this corrects, arises because the pulse transition of the PRN is not instantaneous, and thus the correlation (satellite–receiver sequence matching) operation is imperfect. The CPGPS approach utilizes the L1 carrier wave, which has a period of
Real-time kinematic positioning (RTK) is the application of surveying to correct for common errors in current satellite navigation (GNSS) systems. [1] It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to ...
A "GNSS compass" uses a pair of antennas separated by about 50 cm to detect the phase difference in the carrier signal from a particular GNSS satellite. [8] Given the positions of the satellite, the position of the antenna, and the phase difference, the orientation of the two antennas can be computed.
The L5 consists of two carrier components that are in phase quadrature with each other. Each carrier component is bi-phase shift key (BPSK) modulated by a separate bit train. "L5, the third civil GPS signal, will eventually support safety-of-life applications for aviation and provide improved availability and accuracy." [173]
The resulting 100 symbols per second (sps) symbol stream is modulo-2 added to the I5-code only; the resultant bit-train is used to modulate the L5 in-phase (I5) carrier. This combined signal is called the L5 Data signal. The L5 quadrature-phase (Q5) carrier has no data and is called the L5 Pilot signal.
A 1 bit is encoded by inverting the phase (a 180° phase shift) of the carrier for one second. A 0 bit is transmitted with normal carrier phase. The phase shift begins 0.1 s after the corresponding UTC second, so that the transition occurs while the carrier amplitude is low. [15]: 2–4
The carrier-envelope phase (CEP) or carrier-envelope offset (CEO) phase is an important feature of an ultrashort laser pulse and gains significance with decreasing pulse duration, in a regime where the pulse consists of a few wavelengths. Physical effects depending on the carrier-envelope phase fall into the category of highly nonlinear optics.
Continuous phase modulation (CPM) is a method for modulation of data commonly used in wireless modems.In contrast to other coherent digital phase modulation techniques where the carrier phase abruptly resets to zero at the start of every symbol (e.g. M-PSK), with CPM the carrier phase is modulated in a continuous manner.