One of the most critical hardware parts of any GPS receiver and better GPS receivers use better (more expensive) antennas.

Distance between rover (i.e.. RTK Pathfinder) and the correction Base Station. For RTK less distance the better and maximum is 15 miles.

A base station is comprised of a GPS antenna and receiver positioned on a known location specifically to collect data for RTK corrections.

A code modulated onto the L1 carrier signal which helps the GPS receiver to compute the distance from each satellite (and therefore location).

Less is better, the time it takes a GPS receiver to sort through all the satellite signals and correction data.

A network of GPS RTK base stations coordinated by the National Geodetic Survey.

A term used to describe the features and attributes of assets that will be located in the field (ie. pipeline ID and classification).

The Earth is not round so a datum is used to compensate for this, a long/lat captured using different datum’s will yield offset positions (see WGS84).

Describes type and quality of RTK connection – you want Fix mode.

Is the Horizontal Accuracy number we display to show position accuracy.

Also called Urban Canyon Effect. Occurs when GPS signal/s reflect off of buildings and arrive at an antenna after traversing different paths. Causes errors and is common in downtown areas.

An indicator of the quality of a GPS position and the distribution (spread) of satellites in the sky, a low DOP value indicates a higher probability of accuracy. With today’s abundance of satellite networks DOP is generally not an issue (1 to 2 is very good, above 4 not so).

A real-time differential GPS method that uses carrier phase measurements for greater accuracy. RTK measurements can yield horizontal accuracy of approximately one centimeter but require connection to a local (10km) base station and near perfect conditions to obtain this.

VRS RTK uses a sophisticated nationwide math model to provide highly accurate GPS location information by creating Virtual Reference Stations (as opposed to standard RTK where users must connect to a local (15km) physical base stations). VRS accuracy is generally 10cm or 4”.

Is the most common reference coordinate system (datum).