GEOG 862
GPS and GNSS for Geospatial Professionals

Surveying Receivers

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Generalized Values for Survey Receivers
Survey Receivers Autonomous
Horizontal
Precision
Real-time
Corrected
Horizontal
Network
Accuracy
Post-processed
Horizontal
Network
Accuracy
Survey 2 - 10 m > 1 m > 0.1 m
Source: GPS for Land Surveyors

Surveying Receivers

Survey grade receivers are designed for the achievement of consistent network accuracy in the static or real-time mode. Positions determined by these receivers will generally provide the best accuracy of the categories listed. The components of these receivers can usually be configured in a variety of ways. The receivers are typically dual frequency, code and carrier receivers.  Many are GNSS receivers (GPS+GLONASS). They generally provide more options for setting the observational parameters than recreational or mapping receivers. Surveying receivers are typically capable of observing the civilian code and carrier phase of all frequencies and are appropriate for collecting positions on long base lines. Survey grade receivers are capable of producing network accuracies of better than 1m with real-time differential correction and better than 0.1m with post-processing.

Most share some practical characteristics: they have multiple independent channels that track the satellites continuously, and they begin acquiring satellites’ signals from a few seconds to less than a minute from the moment they are switched on. Most acquire all the satellites above their mask angle in a very few minutes, with the time usually lessened by a warm start, and most provide some sort of alert to the user that data is being recorded, and so forth. About three-quarters of them can have their sessions preprogrammed in the office before going to their field sites. Nearly all allow the user to select the logging rate, also known as epoch interval and also known as sampling interval. While a 1 second interval is often used, faster rates of 0.1 second (10 Hz) and more increments of tenths of a second are often available. This feature allows the user to stipulate the short period of time between each of the microprocessor's downloads to storage. The faster the data-sampling rate, the larger the volume of data a receiver collects, and the larger the amount of storage it needs. A fast rate is helpful in cycle slip detection, and that improves the receiver’s performance on baselines longer than 50 km, where the detection and repair of cycle slips can be particularly difficult.