Notes on GPS Modernization

The next generation Global Navigation Satellite Systems (GNSS), such as Galileo and Global Positioning System (GPS) modernization, will use signals with equal code and bit periods, resulting in a potential bit sign transition in each primary code period of the received signal segments. A bit sign transition occurring within an integration period usually causes a splitting of the Cross Ambiguity Function (CAF) main peak into two smaller side lobes along the Doppler shift axis in the search space and it may lead to an incorrect Doppler shift estimate, which results in a serious performance degradation of the acquisition system. This paper proposes a novel two steps based bit sign transition cancellation method which can overcome the bit sign transition problem and remove or mitigate the CAF peak splitting impairments. The performance of the proposed technique has been comprehensively evaluated with Monte Carlo simulations in terms of detection and false alarm probabilities, which are presented by Receiver Operating Characteristic (ROC) and Signal-to-Noise-Ratio (SNR) curves. The test results show that the proposed acquisition technique can provide improved performance in comparison with the state-of-the-art acquisition approaches.

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GPS, GALILEO and GLONASS satellite navigation systems & amp; GPS modernization

Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005. ◽

10.1109/rast.2005.1512598 ◽

2006 ◽

Cited By ~ 14

Author(s):

R.M. Alkan ◽

H. Karaman ◽

M. Sahin

Keyword(s):

Satellite Navigation ◽

Navigation Systems ◽

Gps Modernization ◽

Glonass Satellite ◽

Satellite Navigation Systems

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Triple-Frequency Method for High-Order Ionospheric Refractive Error Modelling in GPS Modernization

Journal of Global Positioning Systems ◽

10.5081/jgps.4.1.291 ◽

2005 ◽

Vol 4 (1&2) ◽

pp. 291-295 ◽

Cited By ~ 28

Author(s):

Zemin Wang ◽

Yue Wu ◽

Kefei Zhang ◽

Yang Meng

Keyword(s):

Refractive Error ◽

High Order ◽

Frequency Method ◽

Triple Frequency ◽

Gps Modernization

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Combined Acquisition and Tracking Methods for GPS L1 C/A and L1C Signals

International Journal of Navigation and Observation ◽

10.1155/2010/190465 ◽

2010 ◽

Vol 2010 ◽

pp. 1-19 ◽

Cited By ~ 6

Author(s):

Florence Macchi-Gernot ◽

Mark G. Petovello ◽

Gérard Lachapelle

Keyword(s):

Kalman Filter ◽

Data Channel ◽

Signal Simulator ◽

Gps Modernization ◽

First Time ◽

Acquisition Method

As part of the GPS modernization, the GPS L1 C/A signal will be augmented by the L1C signal. With this improvement, for the first time, several signals from the same constellation will be available at the same frequency. In this paper, an acquisition method is implemented to combine the GPS L1 C/A and L1C signals before correlation. The combined acquisition succeeds to acquire the signal at low C/N0, whereas the acquisition of the L1C data channel alone fails. Concerning the tracking, a method to combine the GPS L1 C/A and L1C signals before the discriminator is developed. This method shows better performance than the traditional tracking using only one signal. Finally, a Kalman filter to combine the signals in the tracking is developed. It shows better performance than the traditional tracking in all conditions. Since the L1C signal will not be broadcast before 2013, these methods are tested using a software signal simulator.

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