Glossary

• Automated calibration:

The sensors included in the imajbox^® need calibration before survey. imajbox^® takes care automatically of these operations . It allows using the imajbox^® in vehicles which are not specifically dedicated to this kind of operation and with people which are not specialists of the survey technologies.

• CCD:

Charge-coupled-device – the CCD have an electronic global shutter and takes the entire image simultaneously. It avoid deformation in the images in case of moving camera.

• Curvilinear abscissa - Linear Referencing System:

Most of the GIS software and GPS survey furnish data in XYZ, whereas the road people do use linear referencing system (curvilinear abscissa) to reference their network. A Linear Referencing Systems (LRS) is a way to define a feature or location by its linear distance from a known point on a route. With imajview you create your LRS referential based on linear data (itineraries). Once your system is created, every asset can be positioned in XY or in curvilinear abcsissa (in cumulated distance from begining of road or from last reference node).

• Dead reckoning:

Dead reckoning (DR) is the use of sensors that provide relative positioning information. DR navigation is based on the knowledge of the vehicle dynamics and an original starting point to calculate the actual vehicle position. Different sensors provide attitude rate angle and velocity measurements. These measurements are used to propagate the position estimations done on previous time instants and thus keep track of the vehicle trajectory.

Dead reckoning enables imajbox users to survey, even in bad GPS condition such as under bridge or under dense vegetation.

• Geo referenced :

Each image taken by the imajbox is related to it geographical position (longitude, lattitude and altitude)

• Hybridization of sensors:

The coupling of the different sensors of the imajbox allow an improvement in the accuracy of final position provided. Ex : data provided by the GPS and by the IMU are post processed via a Kalman filter that allows to obtain an accurate positional result even in case of non-reliable GPS data (as when received signals are affected by urban canyon phenomena).

• Inertial Measurement Unit - IMU:

Main component of an inertial guidance system, it works by using a combination of accelerometers and gyroscopes. It measures the inertial acceleration and rotational forces applied to the vehicle in which it is installed (pitch, roll, yaw).

• Photogrammetry :

Techniques that allows to position and measure objects in images.

• SBAS-Full SBAS :

The Satellite Based Augmentation systems (SBAS) is a wide-area DGPS system that provides differential GPS corrections and integrity data using geostationary (GEO) satellites. Differential GPS (DGPS) is a method to improve the positioning or timing performance of GPS using one or more reference stations at known locations, each equipped with at least one GPS receiver. Errors for the reference station pseudo range and carrier phase measurements are expected to be similar to those experienced by a nearby user. The master station proceeds to compare its known surveyed position to the position obtained from the received signals. Considering that the master station is always located in clear-sky scenarios, an estimate of the actual atmospheric and satellite-based errors can be obtained. This data is then transmitted to the user in order to enhance its positioning accuracy.