PDF | Although this book should be classified as a book on the field of Global Positioning System (GPS), but it considerably differs from the other existing ones. This reference and handbook describes theory, algorithms and applications of the Global Positioning System (GPS/Glonass/Galileo/Compass). It is primarily. book will cover the theory, algorithms and applications of the GPS, GLONASS and Galileo systems. The equivalence of the GPS data processing algorithms and.
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This reference and handbook describes theory, algorithms and applications of the Global Positioning System (GPS/Glonass/Galileo/Compass). DRM-free; Included format: EPUB, PDF; ebooks can be used on all reading devices; Immediate. GPS. Theory, Algorithms and Applications. Authors: Xu, Guochang watermarked, DRM-free; Included format: PDF; ebooks can be used on all reading devices. book will cover the theory, algorithms and applications of the GPS, The contents of this book cover static, kinematic and dynamic GPS theory, algorithms.
Geometry-based methods are the current trend in multi-constellation development and more flexible and suitable for single-frequency receivers, but most of the existing geometry-based methods do not take the non-integer outliers into account. When non-integer outliers exist, the integer search with LAMBDA may fail, and the rounding algorithm have not applied validation process to detect them.
It can eliminate the constant integer ambiguities, inner-system bias ISB and most of the common mode errors, which vary slowly within a short period of time like 1 s [ 21 ], and obtain precise position change at the millimeter level [ 22 ]. Compared to existing geometry-based methods, this paper offers several major contributions: 1 improved local analysis method ILAM is proposed and applied in time-differenced carrier phase TDCP algorithm to detect cycle slip. The method can effectively detect the number of cycle slips and the corresponding satellites.
As the increase of the number of satellites in multi-constellation, detectable cycle slips number is more; 2 success probability and decimal test are utilized for cycle slips validation.
The non-integer outlies can be detected, which avoids the error repairs and improves the reliability. The following section first describes the TDCP algorithm and then gives a detailed description of cycle slips detection with ILAM and repair by rounding with validation.
In the subsequent section, the proposed method is verified with real receiver data and simulated cycle slips, and the conclusions follow. Methodology The principle of detection and repair is given in this section. Thereafter, we present the detection method with ILAM. Finally, we describe the validation process during repair. The TDCP measurements are the time differences of successive carrier phases to the same satellite.
Figure 6: Result of the proposed method, where the red blocks are real GPS data received from the receiver and the black crosses are the results of the proposed method. Figure 7 shows a more detailed view of the improvement in latitude and longitude values of a few points in the experiments using the proposed model. The -axis represents the data points of the experiment, and the -axis is the coordinate value second component , where the red line represents the coordinate component value of real data from the GPS receiver and the blue — line represents the data processed using the proposed method.
Figure 7: Coordinate position value improvements: a latitude and b longitude -axis is data points and -axis is coordinate value in seconds.
From the error analysis of the proposed method, we obtain an improvement of 4—10 meters while driving. We also compare the proposed method with existing recursive averaging and ARMA interpolation methods [ 1 ]. Figure 8 shows the improvement in meters of the proposed method and the recursive averaging and ARMA interpolation methods. Figure 8: Improvement of the proposed method, recursive averaging, and ARMA interpolation: a latitude values and b longitude values. We perform experiments several times in different places.
Table 2 summarizes the results of six experiments. In several different experiments, we observe that the recursive averaging method shows much improvement in positioning accuracy, but estimated waypoints are out of road because recursive averaging of latitude and longitude makes more errors in the way of curve. On the other hand, the ARMA interpolation has two coefficient parameters which affect the accuracy of new estimated points.
Overall, the proposed method outperforms other methods in terms of positioning. Table 2: Performance of the proposed method and the two state-of-the-art methods. In case of an imperfect synchronized carrier replique, the power of the satellite signal is shared between the I and Q paths.
The I as well as the Q path are split into three signal subpaths respectively. This multiplication in time space describes a convolution in frequency space.
In case of a narrowband jamming signal bandwidth of jammer is lower than 1. The signal is summed up for at least 1ms depending on the correlation time. This operation is mathematically equivalent with convoluting the signal with a rectangular impulse of the same duration. This convolution in time space describes a multiplication with the Fourier transform of the rectangular impulse in frequency space. The Fourier transform of a rectangular impulse is a sinc function with its first zero at the inverse of correlation time.
Thus the postcorrelation noise power consists only out of the small amount of power constraint within the bandwidth of the inverse of correlation time. Literature: L.
Peterson, R. Ziemer, and D. Borth, Introduction to spread-spectrum communications.
Proakis, Digital communications, 4th ed. Boston: McGraw-Hill, Richards, Fundamentals of radar signal processing, 2nd ed. It contains the antenna, the low noise distributed amplification and downconversion stages, the automatic gain control and the sampling unit. GNSS Receiver structure. In case of a perfectly synchronized carrier replique, only the I channel contains the satellite signal, whereas the Q channel only contains noise and distortions.
The results are six correlator outputs which are used by codephase and carrierphase discriminators to measure the phase error between carrier or code replique signals and the received ones. The correlation unit is executed with the IF sampling frequency. The frequency of the correlator outputs depends on the correlation time. The next stage is called the tracking stage. Inputs to the tracking stage are the discriminator outputs.
The task of the tracking stage is to generate the steering commands for carrier replique and code replique generation. There are a lot of different architectures to realize the tracking. The classic approach tracks each channel separately, where the steering commandos are generated by PID controllers.
Instead of PID controllers, optimal control strategies, incorporating Kalmanfilters, can be used. A sophisticated approach is the combined tracking of all satellite channels by using a Kalmanfilter based vector tracking filter.
In case of scalar tracking, the tracking unit outputs pseudoranges and pseudorange rates.
In case of vector tracking, the outputs can be also pseudoranges and pseudorange rates, but can even be position and velocity, mostly in ECEF coordinates. Some more supporting functions are necessary within a GNSS receiver. This includes for example the acquisition unit. The acquisition unit determines the code phase offset for the replicated CA-Code with an accuracy of at least an half CA-Code chip.
The determined offset is used by the tracking unit as initialization. The further potential lies in the fact that GNSS signals have high spatial and temporal error characteristics for not too far tens to hundreds kilometers dislocated receivers.
GNSS satellites work at an orbit height of about Signal propagation paths from the satellite to receivers are tightly related, when the receivers are operated in distances of not more than hundreds of kilometers near Earth, i. Differential GNSS.
The pseudorange error more commonly called differential correction for each satellite can be determined by a reference station at a known location for all satellites above the horizon and then be transmitted to users via radio link if real-time operation is required.
Spatial and temporal decorrelation should be considered and applied. For marine or land applications, a widely used standard format for data communication is RTCM RTCM defines the physical interface and logical data messages between reference stations and user receivers. Since aviation industry placed more stringent requirements on integrity and reliability, other augmentation schemes and systems became necessary, cf.
Parkinson, J. Spilker, P. Axelrad, and P. Enge, Global positioning system: Theory and application. Washington, D. A possible reduction of those higher effects can be obtained using reference stations and DGNSS concepts that permit a positioning with sub-meter accuracy.