Simplified estimation of ray-path mirroring height for HF radiowaves reflected from the ionospheric F-region

From Milsom's equations, which describe the geometry of ray-path hops reflected from the ionospheric F-layer, algorithms for the simplified estimation of mirror-reflection height are developed. These allow for hop length and the effects of variations in underlying ionisation (via the ratio of the F2- and E-layer critical frequencies) and F2-layer peak height (via the M(3000)F2-factor). Separate algorithms are presented which are applicable to a range of signal frequencies about the FOT and to propagation at the MUF. The accuracies and complexities of the algorithms are compared with those inherent in the use of a procedure based on an equation developed by Shimazaki.

Body-centric modelling, identification, and acceleration tracking control of a quadrotor UAV

This paper presents the mathematical development of a body-centric nonlinear dynamic model of a quadrotor UAV that is suitable for the development of biologically inspired navigation strategies. Analytical approximations are used to find an initial guess of the parameters of the nonlinear model, then parameter estimation methods are used to refine the model parameters using the data obtained from onboard sensors during flight. Due to the unstable nature of the quadrotor model, the identification process is performed with the system in closed-loop control of attitude angles. The obtained model parameters are validated using real unseen experimental data. Based on the identified model, a Linear-Quadratic (LQ) optimal tracker is designed to stabilize the quadrotor and facilitate its translational control by tracking body accelerations. The LQ tracker is tested on an experimental quadrotor UAV and the obtained results are a further means to validate the quality of the estimated model. The unique formulation of the control problem in the body frame makes the controller better suited for bio-inspired navigation and guidance strategies than conventional attitude or position based control systems that can be found in the existing literature.

Re-evaluating the place of urban planning history

This commentary seeks to prompt new discussion about the place of urban planning history in the era of contemporary globalisation. Given the deep historic engagement of urban planning thought and practice with ‘place’ shaping and thus with the constitution of society, culture and politics, we ask how relevant is planning's legacy to the shaping of present day cities. Late twentieth century urban sociology, cultural and economic geography have demonstrated the increasing significance of intercity relations and the functional porosity of metropolitan boundaries in the network society, however statutory urban planning systems remain tied to the administrative geographies of states. This ‘territorial fixing’ of practice constrains the operational space of planning and, we argue, also limits its vision to geopolitical scales and agendas that have receding relevance for emerging urban relations. We propose that a re-evaluation of planning history could have an important part to play in addressing this spatial conundrum.

Financial viability appraisals for site-specific planning decisions in England

In England, appraisals of the financial viability of development schemes have become an integral part of planning policy-making, initially in determining the amount of planning obligations that might be obtained via legal agreements (known as Section 106 agreements) and latterly as a basis for establishing charging schedules for the Community Infrastructure Levy (CIL). Local planning authorities set these policies on an area-wide basis but ultimately development proposals require consent on a site-by-site basis. It is at this site-specific level that issues of viability are hotly contested. This paper examines case documents, proofs of evidence and decisions from a sample of planning disputes in order to address major issues within development viability, the application of the models and the distribution of the development gain between the developer, landowner and community. The results have specific application to viability assessment in England and should impact on future policy and practice guidance in this field. They also have relevance to other countries that incorporate assessments of economic viability in their planning systems.

The new localism, anti-political development machines, and the role of planning consultants: lessons from London's South Bank

This paper draws on a study of the politics of development planning in London’s South Bank to examine wider trends in the governance of contemporary cities. It assesses the impacts and outcomes of so-called new localist reforms and argues that we are witnessing two principal trends. First, governance processes are increasingly dominated by anti-democratic development machines, characterized by new assemblages of public- and private-sector experts. These machines reflect and reproduce a type of development politics in which there is a greater emphasis on a pragmatic realism and a politics of delivery. Second, the presence of these machines is having a significant impact on the politics of planning. Democratic engagement is not seen as the basis for new forms of localism and community control. Instead, it is presented as a potentially disruptive force that needs to be managed by a new breed of skilled private-sector consultant. The paper examines these wider shifts in urban politics before focusing on the connections between emerging development machines and local residential and business communities. It ends by highlighting some of the wider implications of change for democratic modes of engagement and nodes of resistance in urban politics.

Governing calculative practices: An investigation of development viability modelling in the English planning system

Over the last decade the English planning system has placed greater emphasis on the financial viability of development. ‘Calculative’ practices have been used to quantify and capture land value uplifts. Development viability appraisal (DVA) has become a key part of the evidence base used in planning decision-making and informs both ‘site-specific’ negotiations about the level of land value capture for individual schemes and ‘area-wide’ planning policy formation. This paper investigates how implementation of DVA is governed in planning policy formation. It is argued that the increased use of DVA raises important questions about how planning decisions are made and operationalised, not least because DVA is often poorly understood by some key stakeholders. The paper uses the concept of governance to thematically analyse semi-structured interviews conducted with the producers of DVAs and considers key procedural issues including (in)consistencies in appraisal practices, levels of stakeholder consultation and the potential for client and producer bias. Whilst stakeholder consultation is shown to be integral to the appraisal process in order to improve the quality of the appraisals and to legitimise the outputs, participation is restricted to industry experts and excludes some interest groups, including local communities. It is concluded that, largely because of its recent adoption and knowledge asymmetries between local planning authorities and appraisers, DVA is a weakly governed process characterised by emerging and contested guidance and is therefore ‘up for grabs’.

Sticking to the script? The co-production of Neighbourhood Planning in England

Efforts to engage with communities in spatial planning have been criticised as being tokenistic, vehicles for co-option or designed to promote neo-liberal agendas. The introduction of neighbourhood planning (NP) in England under the Localism Act (2011) is claimed by proponents to be a step change in the way that local communities are involved in planning their own areas. However, little empirical evidence has yet emerged to substantiate such claims, or provide details about the practices and experiences of NP. The paper highlights that there are numerous parties involved in the co-production of Neighbourhood Development Plans and there are numerous instances where ideas, policies and priorities that emerge from within neighbourhoods are being ‘rescripted’ to ensure conformity to a bounded form of collaboration.

The take-up of Neighbourhood Planning in England 2011-2015

Exploration of how neighbourhoods and others have responded to the UK government’s localism agenda in England, and specifically towards Neighbourhood Planning (NP), is important given that NP is a prominent part of that policy agenda. It is also of interest as the ramifications emerge for planning practice in the formal introduction of statutory plans which are ostensibly led by communities (Parker et al, 2015; Gallent, 2013). There is a necessary task to provide critical commentary on the socio-economic impact of localist policy. The paper explores the issues arising from experience thus far and highlights the take-up of Neighbourhood Planning since 2011. This assessment shows how a vast majority of those active have been in parished areas and in less-deprived areas. This indicates that government needs to do more to ensure that NP is accessible and worthwhile for a wider range of communities.