Antti Lehtinen Doppler Positioning with GPS - Matematiikan laitos

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xk xu ˆxu yu ˆyu zu ˆzu vector x estimate after k steps of an iterative algorithm user x coordinate estimated user x coordinate user y coordinate estimated user y coordinate user z coordinate estimated user z coordinate xi
Chapter 1 Introduction Satellite positioninghas received much attention duringthe last 40 years. The beginningera of satellite positioningresearch was focused on military applications. Now the focus has changed. Because of the huge commercial potential, the objective of the current research is mainly to develop equipment for personal positioning. The Global PositioningSystem (GPS) is currently the only satellite positioning system suitable for personal positioning. The GPS is funded by the United States. A new system, called Galileo, is expected to be launched by the European Union in 2008. The Galileo is very similar to the GPS. The GPS has a very good accuracy in good conditions. However, problems arise in indoors and urban areas. The standard GPS receiver needs to track at least four satellites simultaneously. In addition, it needs to demodulate the navigation message from the carrier signals. The demodulation is possible only if the signal is not too noisy. When the demodulation fails, the position cannot be solved. This is a huge drawback for use of the GPS in personal positioning. Most of the users of the positioningservices live in urban areas. Duringthe last few years much effort has been put to solve the problem. Many innovative solutions have been explored. They are mainly based on the idea of the assisted GPS. This means that the GPS measurements are combined with other data, which is available for example from cellular network. In this thesis an entirely new algorithm based on Doppler measurements is presented. Doppler positioninghas been earlier mentioned in the literature, but its value has been overlooked. The reason for the bad reputation of the GPS Doppler positioningis the fact that its accuracy is expected to be worse than that of the standard positioningmethod. This may indeed be true, but no one 1
Page 1 and 2: TAMPERE UNIVERSITY OF TECHNOLOGY De
Page 3 and 4: Contents Abstract v Tiivistelmä vi
Page 5 and 6: 5.2.3 Applications of the Doppler D
Page 7 and 8: Tiivistelmä TAMPEREEN TEKNILLINEN
Page 9 and 10: Abbreviations and Acronyms C/A coar
Page 11: σ2 variance, covariance a vector i
Page 15 and 16: Chapter 2 The Doppler Effect In thi
Page 17 and 18: in Figure 2.2. The shape of the so
Page 19 and 20: Chapter 3 The Global Positioning Sy
Page 21 and 22: sufficiently many satellites, the r
Page 23 and 24: The satellite signal is very accura
Page 25 and 26: The estimated position and time vec
Page 27 and 28: in weak signal conditions. The key
Page 29 and 30: navigation message. Here, however,
Page 31 and 32: where wi is the satellite velocity,
Page 33 and 34: the receiver clock is runningfast a
Page 35 and 36: Let us now turn into our main goal,
Page 37 and 38: Definition 3. Delta range residuals
Page 39 and 40: method [Fletcher, p. 110], [Kaleva1
Page 41 and 42: product formula a × (b × c) =(a
Page 43 and 44: Chapter 5 Positioning Performance I
Page 45 and 46: eplaced by vi −△wu. Let us rewr
Page 47 and 48: Thus, the time bias effect to the p
Page 49 and 50: Let us first calculate the expected
Page 51 and 52: • Doppler drift dilution of preci
Page 53 and 54: Let us now make the even stronger a
Page 55 and 56: Chapter 6 Numerical Results In Chap
Page 57 and 58: 6.2.2 Numerical Testing of Normalit
Page 59 and 60: 6.2.4 Magnitude of Errors The actua
Page 61 and 62: Histogram of positioning errors wit
Page 63 and 64:
used for testinghow the algorithm b
Page 65 and 66:
Chapter 7 Conclusions This thesis d
Page 67 and 68:
The positioningalgorithm was develo
Page 69 and 70:
[Hill] Hill, Jonathan. The Principl
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Antti Lehtinen Doppler Positioning with GPS - Matematiikan laitos

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