Survey Engeneering

This section relates to assistance provided to contractors, project managers, firms and public services in the areas of topographic surveys, equipment accuracy studies, methods, implementation choices, audits relating to topographic service organisation, etc.

Each study is unique. We have chosen to show just some of the projects undertaken. If you do not find specific examples corresponding to your particular needs, please contact us so we can find you a solution.

Creation of Scope Of Work for topographic work taking into account the law relating to precision classes

In 2012, Colombes Town Council (France) decided to set up a geodetic network (planimetric and altimetric) on its territory. As the Council did not have a topographic department, it appointed us to:

  • Draft the Technical Specifications for the call to tender, to ensure compliance with the obligations laid down in the law of September 16th, 2003 and its memo relating to precision classes applicable to topographic works conducted by or on behalf of the French State, local administrations and public establishment,

  • Propose a scorecard for assessing candidate responses according to the predefined criteria,
  • Perform precision checks on the network (primary and secondary, planimetric and altimetric) in accordance with the precision class law and requirements of the Special Technical Specifications.

The network, drawn up by the local registered surveyor who won the bid, can be viewed on the Colombes City Council website section "Cadre de vie / Urbanisme / Canevas topographique" or by following this link.

 

Geodetic Network Point in the town of Colombes

Creation of a Continous GNSS Reference Stations (CORS) network in Burkina Faso

The Millenium Challenge Corporation is a structure formed in 2004 by the US Senate to provide financial aid for development.

In 2009, the Senate drew up an agreement (entitled "Compact") with the Government of Burkina Faso aimed at financing four development areas, including the "Land Tenure Security" project. This project partially consisted of reinforcing the technical and institutional capabilities of the competent departments in terms of land management at all public sector levels.

The project gave rise to the creation of the BFCORS - a network of Continous GNSS Reference Stations (CORS) in Burkina Faso.

The network was installed in conjunction with the Burkina Faso Geographic Institute and Burkina Faso Millenium Challenge Account (MCA) which is the structure set up by the MCC and Burkina Faso Government to steer the "Compact" agreement.

We were appointed by MCC to assist MCA and took part in:

  • Drafting a call to tender for equipment procurement and the construction of facilities to house it,

  • GPS/GNSS equipment acceptance testing and conformity checks,
  • Facility construction work progress monitoring,
  • The Set Up of receivers, computing centres and Internet connections,
  • Monitoring training initiatives and coordinating calculations provided by the supplier,
  • Intermediate and final acceptance tests on the system.

We also took part in organising a National Forum on BFCORS Network Use in Ouagadougou in March 2014.

Network of continuously operating GPS stations (CORS) in Burkina Faso
BFCORS Network - Station BF01

Study on dazzle incurred by the installation of solar panels adjacent to an airport

Shadehouses were scheduled to be installed along with solar panels for electricity production in the car park of the Montbéliard Axone concert hall.

This project was located in the Montbéliard Courcelles airfield safety perimeter and the scheduled panels had a surface area greater than 500 m2; protection against potential dazzle for AFIS traffic control staff and pilots was therefore an obligation according to French directive 09/132/DSAC/ANA of June 25th, 2009.

We performed this study on the basis of a DGAC Technical Memo dated July 27th, 2011.

We studied the trajectory of the reflected sun rays at various times of day and year, taking into account the respective positions of the panels and their orientation, the control tower, runway protection and obstacle-free zones (OFZs) and Snell Descartes laws.

For this purpose, we used a software application describing the sun's trajectory in space according to latitude / longitude (solar diagram).

Sunpath diagram
Area of sun glare on the winter solstic

Precision analysis of area measurements performed using GPS GPS/GNSS.

This study was granted to us in 1993 by the European Commission and, more precisely, by one of the Departments of Agriculture in charge of Common Agricultural Policy-related controls.

It was conducted at a time when area measurements could only be performed using differential measurements due to GPS inaccuracy at the time (Activation of Selective Availability). The analysis aimed to model measurement uncertainty obtained using first-generation code processing receivers (positioning accuracy 2 to 5 metres after correction).

The study conclusions were used as the basis for various regulations and control methods implemented at the time. Although area measurements can now be performed in natural mode, the uncertainty modelling we performed at the time is still in use.

An article (in French) published in the XYZ magazine (n°70) describes this perimeter analysis in detail.