August 7, 2008
Base-on-Demand Service
Strata gives all its Penmap GNSS users with a Network-RTK subscription full peace of mind that they can perform their job everywhere in the country. If you face temporary difficulties with celluar coverage in one area and you can't access the OS Net service, Penmap will provide you with a GNSS base station to get your job done.
We want you to invest into future-prove and cost-effective technology, with no compromise in availability, coverage, or performance.
GNSS & PHONES – A question of coverage?
Satellite and mobile phone technology is something that almost all citizens of the UK now use in one way or another. Whether it’s simply making phone calls, using in car satellite navigation or the use of commercial positioning applications, the technology has truly changed the way we all communicate and think about where we are.
Indeed, by 2010, there should be around 80 navigational satellites in orbit, helping us all, to establish accurate positioning. The USA’s GPS (Global Positioning System) and the Russian GLONASS (Global’naya Navigatsionnaya Sputnikovaya Sistema) have been with us for some time and as Galileo (the emerging European GNSS) and Compass, (also known as Beidou 2, the developing Chinese GNSS) come on stream, it will be easier than ever, to establish accurate positions, even in traditionally satellite challenged environments.
The Construction industry has for some time been taking advantage of the technology, but the benefits of satellite positioning are increasingly understood across a wide range of industries. With the implementation of the Traffic management act, civil engineers, particularly those involved with utilities projects are adopting the technology more rapidly than any other sector. Growth in adoption is also being witnessed in the emergency services, agriculture, shipping and in air traffic safety.
Leaving aside for the moment, sea and airborne applications, there have been innovations in the provision of GNSS data that is making the technology, more affordable than ever before.
Traditionally, in order to achieve sub centimetre accuracy with GPS, the user would require an RTK (Real time Kinematic) GPS base station and rover, essentially two GPS receivers communicating to establish the error in the position of the rover and hence correct the positional accuracy of the rover.
Certainly the OS Net service has positively impacted on the affordability of RTK systems by dispensing with the requirement for a GPS base station. The Ordnance Survey have established around 90 GPS base stations located around the UK. The OS Net service is packaged and provided to end users through commercial partners, as Leica SMARTNET and The Trimble VRS now. Leica and Trimble have in turn augmented the OS network of base stations with some of their own, to increase the availability of high accuracy GPS correction data across the UK.
The system relies on the GPS receiver dialling out over the GSM data network using GPRS or 3G to establish a connection to one of the OS Net services. This relies of course on the availability of a mobile phone signal wherever the user happens to be and it is this factor that seems to concern potential users of RTK GPS coupled with the OS Net service.
This is backed up by the fact that the majority of sales of RTK GPS receivers in the UK are purchased with internal radio’s to allow communication with another GPS receiver, rather than with a GSM card which would allow connection to OS Net.
So perhaps the question should be, do the RTK GPS user community and potential users, have confidence in the satellite technology, but less faith in the guaranteed availability of mobile phone coverage.
This was reflected in discussions at the GEO-8 conference in Coventry earlier this year. One surveyor provided an account of a pipeline survey in Wales, where he had opted for a base and rover GPS solution as he didn’t “trust” the coverage of the mobile phone network. He later found the mobile network to have 100% coverage for the entire survey area and that he could have used a single GPS receiver with OS Net and saved over £10k.
The reality is that mobile phone coverage for all the major networks now covers over 99% of the UK’s population and with coverage continuing to improve, now is the time to revisit the question of using RTK GPS coupled to OS Net. We know there are enough satellites and more in the near future. We also know that the mobile phone coverage is excellent and improving all the time. So perhaps we have arrived at the point where sub centimetre positional accuracy is realistic for many more customers than before and the technology has truly changed the way we all communicate and know, with sub centimetre accuracy, where we are.
No mobile signal available for the area in which you are surveying?
Take advantage of the Penmap Base-on-Demand service.