The Global Positioning System (GPS) is a highly accurate satellite-based navigation system that has been available since the 1980s but has recently increased in popularity. This sophisticated system can be used to determine the time and location of a receiver based almost anywhere on earth, with locational accuracy between 100 and 10 yards for most equipment. Owned and operated by the United States Department of Defense, this system is available for anyone to use for free.
How does it work?
GPS satellites transmit low powered radio signals to receiving equipment on the ground.
Complex calculations are performed to determine the receiver’s position, but in layman’s terms, the position of a receiver is determined by the time it takes a signal to be transmitted from a satellite to the receiver. In order to obtain a good degree of accuracy, the receiver must receive signals from at least four satellites (although this number varies between receivers; generally, the more satellites, the higher the accuracy).
Normally, an unobstructed view of the sky is required for optimum reception, so most receivers function best outside and in non-wooded areas.
How useful is GPS in the construction industry?
GPS offers a host of useful applications for the construction industry. A few of these are summarized below.
Navigation Systems
The benefits of GPS for vehicle navigation are immense. Satellite navigation can virtually eliminate the problems of unfamiliarity with the location to be visited and bad road signage.
The benefits of using GPS as a vehicle navigation system include:
- Getting to meetings in unfamiliar locations on time
- Efficient delivery of products to unfamiliar areas
- Ability to find alternative routes in urban areas from maps
- Enabling delivery to specific geographic locations, e.g. junctions on motorways
Personnel location
GPS coordinates can be used to identify the location of personnel without ambiguity. This is of particular importance when people are traveling in remote locations. For example, if somebody has not responded appropriately, the ability to transmit a GPS coordinate of their last known location to the emergency services can be life saving.
Equipment tracking
A number of devices are starting to emerge that combine mobile phone technologies with location equipment. By adding digital and analog inputs, not only is it possible to show where an item is, but to trigger alarms and activate controls using direct dial or SMS techniques.
The investment in GPS to monitor vehicle usage and to track and recover stolen vehicles gives a rapid return when set against the losses and penalties that occur without this technology.
Location of fixed equipment
By associating a unique ID with a GPS coordinate, it is possible to allow maintenance to take place on fixed items of equipment. A GPS coordinate may take you to within three yards of a unit, or less than one yard with more sophisticated equipment.
Mapping and surveying
Techniques of mapping and surveying have changed over the years, but never so much as now. With ever-increasing sophistication, GPS is now becoming more commonplace as an element in the presentation of geographical information.
Whereas the location of cables, pipes and services has previously been estimated, data can now be gathered more quickly, and more easily.
Choosing GPS equipment
The huge number of GPS devices available on the market today can make deciding which unit to buy overwhelming.
Factors to take into consideration when purchasing a device should include:
- Your budget
- The type of receiver - whether you require a fixed, vehicle, marine or handheld device
- The main purpose of the receiver - location, navigation or guidance
- The environment the device is to be operated in - the likely weather conditions and how durable the equipment will have to be to function in them
- Your battery life requirements - availability of batteries, how easy they are to change, and cost
- The size and weight of the device
