GNSS receivers face the same old challenges (extremely weak received signal, orbit and satellite clock errors, ionospheric and tropospheric delays, multipath, dilution of precision, urban canyons, etc.) and new ones (increased interference). However, compared with just a few years ago, they benefit from new signals, many more satellites, a panoply of options for corrections, and improved integration with inertial navigation systems (INS).
For example, pole-tilt compensation is quickly becoming standard. This feature enables users to locate dangerous or hard-to-reach points by measuring them at an angle with just the tip of the pole to which the receiver is attached.
Pole-tilt compensation also makes surveying and mapping easier by removing, in many situations, the need to use total stations or offsets. Together with improvements in work processes, this makes GNSS receivers more user friendly. This is particularly welcome now that more surveyors are retiring than there are new surveyors entering the profession.
The greater accuracy of GNSS receivers enabled by the increase in the number and quality of satellites, signals, corrections services and integration of GNSS with other sensors is also increasing the number of use cases, especially at the high end of the accuracy requirements, such as lane-level vehicle navigation. (Next month’s cover story will center on this year’s Google Smartphone Decimeter Challenge contest, in which competing teams aim to bring smartphone location down to the decimeter or even centimeter resolution using raw location measurements from Android smartphones. This could enable services that require lane-level accuracy, such as estimated time of arrival when using a high-occupancy vehicle lane.)
This month’s cover story highlights what has changed “inside the box” to improve the accuracy and resilience of GNSS receivers for surveying, mapping and a variety of other applications. Read the success stories from five different companies below.
Swift Navigation: Driving safety for consumers
CHC Navigation: Making receivers user-friendly
Trimble: Positioning engine optimized for fusion