Presentation Example: GPS Monitoring

The use of Geographical Positioning system in monitoring the status of various architectural structures such as bridges and other infrastructure has proven to be very essential. The GPS system checks for any deflections that may arise as a result of the deformation of the structures that can result from various causes such as building entropy. Through the combination of various aspects of such as mechanical and electrical oscillations of the system, the system is able to relay in real time the various aspects of the infrastructure that require critical attention. This is achieved through the arbitrary analysis of the entire structures to detect for any flaws that may be in existence. Such flaws are usually difficult to observe under normal circumstances and therefore they may pose potential threats to the people using the structures.

The GPS monitoring system relies on the basic properties of electromagnetic waves. Just like any other waves, the waves can undergo reflection when they hit surfaces that will not absorb their energies. For the case of the GPS systems, two satellites are used for the entire process. The satellites are located at right angles to each other to ensure that the reflections take place at intervals that can be sufficiently tracked down. The GPS antenna located at a specific point in the structures, say the bridge, receive the signals from an orbiting satellite. The signals are then reflected at an angle proportional to the configuration of the orbiting satellite in respect to the terrestrial satellite here on earth to ensure that correct measurement can be made. The measurements obtained by this kind of reflection provide the technicians with vertical displacements of the structures which in this case may be bridges. To effectively process the data obtained from these measurements, the Justin Javad software is used to finalize the calculations. Various calculations based on the analysis of the data obtained are carried out to determine the degrees of displacement of the structures. Moreover, the spectral analysis of the GPS data is also conducted based on various factors to come up with a final value for quantities such as the Wavelet Basis Function.

Using the electro mechanical oscillator together with a ground mapping location known as a geodesic landmark, the amplitude and frequency of a small concrete bridge can easily be determined. This is a huge leap since without such calculations; it would be difficult to view the same defections without the landmark.

Global positioning system offers advantages over the conventional terrestrial methods, visibility between two points is not mandatory, allowing flexibility in choice selection of station locations and can be done under varying weather conditions, either day or night, the time of monitoring between two points is reduced to a few minutes. It should be known that for GPS deformation monitoring systems results, the accuracy, reliability, availability and integrity of the positioning solutions on the geometric distribution of the satellites and also the number being tracked, also in depressed areas above the ground e.g. in valleys the number of visible satellites may not be enough to effectively determine accurate coordinates. It is good to know that, the weakest components of the positions obtained by GPS is the height, this is mainly due to weakness in the geometric structure of the GPS, due to this GPS technology in determining vertical deformation has to be supported by precise leveling measurements in vertical positioning.