It appears that the majority of devices tested do not perform as stated by thedesigner/manufacturer in a bench test environment. The largest discrepancy of “advertised specifications” versus “actual observation” involves the use of GNSS constellations enabled andused. This is important to note because a higher number of satellites observed and used could lead to a better position estimate.
When choosing a GNSS receiver for your autopilot, mission critical applications could also
from factors including:
- data communication type
- redundant communication capability
- actual real-world performance (i.e. how the device reports position data when subjectedto structural or environmental interference)
- how the device performs given EMI produced by neighboring equipment
- data refresh rate
- additional sensors that improve the accuracy of data being processed by the autopilot (i.e.barometric pressure sensor or magnetometer)It appears that each manufacturer’s published product data focuses on the uBlox chipset installedon the receiver, however the capabilities of the particular chipset must be realized in design and configuration (i.e. if a uBlox chipset states that it can concurrently track 3 satellite constellations, the manufacturer/designer should actually enable those constellations for the benefit of the end user).Since this document is not a comprehensive analysis, it is important to validate these observations in your actual working environment and consider the maximum limitation of each device before use. When selecting the best receiver for your application, if a trial-and-error approach is impractical, consider the observations from this report when purchasing a select receiver (or receivers). Environmental conditions and related hardware in your end-product ecosystem will impact the actual performance of each GNSS receiver. The observations made in this document have been acquired either from public-facing manufacturer/designer resources or from uBlox U-Center log reports (available to download in Table 5 and 9).