Coordinates: A resource on positioning, navigation and beyond: "Unconventional applications with single frequency DGPS
RAJNEESH GUPTA, VIVEK BANSAL, BRIG M C DHAMIJA (RETD)
CURRENTLY the trend is that more and more project authorities are mandating use of GPS for control work and private surveyors have to comply with this requirement. Dual frequency DGPS have been beyond the financial reach of these surveyors as such most prefer to invest in single frequency DGPS, which cost almost one third the cost of dual frequency DGPS.
Conventionally DGPS have been used so far for horizontal control. Recently however there have been a number of articles on using GPS for leveling. All the authors have used a dual frequency DGPS. These authors belong to national mapping agencies or academic institutions as such had access to leveling Bench Marks (BMs) of their countries. However, India being a very price sensitive market compounded with the fact, that private surveyors have no access to spirit level height BMs. Even if they work for govt. agencies, obtaining height data involves lot of hassles, security implications, takes unviable time frames and is quite expensive. Finally, when height data is made available, there is no certainty that the BM’s would be found intact on ground. Therefore, the general practice by private surveyors is to make do with alternatives such as commencing leveling from an arbitrary p"
No comments:
Post a Comment