Review of code and phase biases in multi-GNSS positioning

A review of the research conducted until present on the subject of Global Navigation Satellite System (GNSS) hardware-induced phase and code biases is here provided. Biases in GNSS positioning occur because of imperfections and/or physical limitations in the GNSS hardware. The biases are a result of small delays between events that ideally should be simultaneous in the transmission of the signal from a satellite or in the reception of the signal in a GNSS receiver. Consequently, these biases will also be present in the GNSS code and phase measurements and may there affect the accuracy of positions and other quantities derived from the observations. For instance, biases affect the ability to resolve the integer ambiguities in Precise Point Positioning (PPP), and in relative carrier phase positioning when measurements from multiple GNSSs are used. In addition, code biases affect ionospheric modeling when the Total Electron Content is estimated from GNSS measurements. The paper illustrates how satellite phase biases inhibit the resolution of the phase ambiguity to an integer in PPP, while receiver phase biases affect multi-GNSS positioning. It is also discussed how biases in the receiver channels affect relative GLONASS positioning with baselines of mixed receiver types. In addition, the importance of code biases between signals modulated onto different carriers as is required for modeling the ionosphere from GNSS measurements is discussed. The origin of biases is discussed along with their effect on GNSS positioning, and descriptions of how biases can be estimated or in other ways handled in the positioning process are provided.QC 20170922</p

EU Foreign and Security Policy in a Mediatized Age

This chapter provides a critical discussion of the mediatization of policy in general, and of EU foreign and security policy in particular. A common argument in public debate and research is that the media logic is increasingly affecting how policy is formulated. Brommesson and Ekengren are critical of this (as they see it) oversimplified perspective, and they analyse EU foreign and security policy from the opposite point of view in this chapter. Foreign policy is usually described as a conservative policy area, in as much as it is informed by a long-term perspective, and foreign policy is not the subject of public debate to the same extent as other policy areas. Based on this reverse perspective, the authors ask whether policy actors are actually taking advantage of the opportunities provided by mediatization to strengthen long-term policy objectives. The chapter sheds light on the relationship between policy and mediatization through a comparative analysis of two important strategy documents of EU foreign and security policy: the European security strategy of 2003 and the EU global strategy of 2016. The authors discuss the overarching question of whether the formulation of EU foreign and security policy is dominated by media logic, in other words, whether this policy has been mediatized