The future for GPS , WAAS and EGNOS and Galileo looks promising
The future for GLONASS is harder to assess but could also match expectations
In the worst case if only the GPS satellites and all of those GPS satellites launched after 2005 will have significantly enhanced capabilities However it will take some time before there are sufficient satellites with enhanced capabilities for the new resources is also hard to assess but it is certain that they will and we should except our speed of survey production and capability in difficult environments to improve significantly
It is less likely that prices for geodetic survey receivers will fall significantly because of the overall limited volume of the market
When Galileo is operational then the possibilities for combined GPS , GLONASS and Galileo receivers mean that the enhanced coverage will permit satellite survey in some previously very difficult environments
However , geodetic survey receivers using GPS , Galileo and GLONASS will most likely command a high premium
Undoubtedly there will be many different and varied applications of satellite technology and the survey market will only have a very small share of the total applications market
It seems likely that equipment manufacturers select signals based on :
Purpose of product -
Chipset a availability -
Satellites and signals currently available and their limitations -
Satellites and signals excepted to be available in the next 2-4 years -
Manufacturing cost -
Expected market -
Competitor activity -
However it is likely that manufacturers will also be making their current products more attractive by future proofing them i . e making existing products capable of using new signals and codes when they become available
Applications
The previous pages have already indicated the basic application of GPS in engineering surveying such as in control surveys topographic surveys and setting out on site
Indeed much three dimensional spatial data normally captured using conventional surveying techniques with a total station can be captured by GPS even during the night provided sufficient satellites are visible
However GPS is not the solution for all survey data capture problems
Where GPS works i,e in an open skies environment it works very well
However once the skies become obstructed as they often are on the construction site then conventional survey techniques may be more appropriate
, GPS does not at present work well or at all close to buildings , indoors underground or underwater
On a national scale horizontal and to a certain extent vertical control used for mapping purposes and previously established by classical triangulation with all its built in scale error are being replaced by three dimensional GPS networks
In relation to Great Britain and the Ordnance Survey this has been dealt with in previous pages
The great advantage of this to the engineering surveyor is that when using GPS at the local level there is no requirement for coordinate transformations
Kinematic methods can be used for rapid detailing and Real -Time Kinematic ( RTK ) for setting out
Whilst the above constitutes the main area of interest for the engineering surveyor other applications will be briefly mentioned to illustrate the power and versatility of GPS
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