The GNSS handheld market

Handheld (Consumer) GPS devices have been around for many years. They have been extensively used by outdoor users such as walkers and yachtsmen. GPS is now available in many mobile phones as well making it a truly ubiquitous technology. Most of these devices use Commercial Grade GPS receivers and generally give a horizontal fix accuracy of 5 to 15m, which is often all that is necessary for consumer focused leisure activity.

Professional Grade (Industrial/Scientific) handhelds are a fairly recent phenomenon. The market for industrial GPS or GNSS (GPS + Glonass or other), focuses largely on GIS mapping requirements, land surveying and construction.

Professional Grade handhelds contain professional grade GNSS receiver technology which is capable of providing horizontal fix accuracies better than 1 metre and sub half-metre accuracy is possible with the highest grade units capable of delivering 1 to 2 cm horizontal fix.

The quality and complexity of the receiver technology determines the accuracy achievable, and so price increases with accuracy. This leads to segmentation of the market depending upon application accuracy requirements so that you only pay for the accuracy you need.

GNSS handheld markets can therefore be roughly split into 4 distinct groups based upon fix accuracy requirements. Blackroc Classify these groups as Class 1 through 4 as follows:

  1. Consumer Grade Systems offering limited accuracy (2-15m), e.g. personal navigation and car satnav systems. Basic GPS offers typically 5 to 15m accuracy, and this is sufficiently accurate for basic navigation, and for low order mapping. Receivers of this class are now widespread in phones and handheld devices from all major manufacturers. These units are relatively low cost.
  2. Professional Grade Systems offering sub-metre level fix accuracy, 0.5m to 1m, are required for supporting the basic fix accuracy requirements of GIS systems and asset mapping, used increasingly by local authorities, utility companies, housing associations and many other user groups. These systems are often referred to as L1 based because they use just the L1 frequency output from GNSS satellites. Such an L1 professional grade receiver, with an SBAS correction service (free) can deliver 0.7 to 1m horizontal fix accuracy.
  3. Professional Grade Systems offering sub-halfmetre fix accuracy, 0.3 to 0.5m, are required for supporting the higher quality fix accuracy requirements of higher level GIS applications and asset mapping, used by local authorities, utility companies, housing associations and many other user groups. These systems again, just use just the L1 frequency output from GNSS satellites. Such an L1 professional grade receiver, with a national grade DGPS correction service (low cost) can deliver 30 to 50cm accuracy.
  4. Professional Grade Systems offering very high fix accuracy (typically 1cm to 2cm). GNSS is used extensively nowadays by construction companies and survey companies worldwide, where positional accuracies of 1cm are often required. This accuracy is also necessary for precision machine guidance systems for the control of major earthmoving equipment for the automated shaping of ground profiles, and agricultural equipment for automated ploughing and even weeding between individual plants. A lawnmower has even been developed which automatically mows a lawn itself with precision “striping” as the finished result!To achieve this level of accuracy both the L1 and L2 satellite carrier frequencies (often called L1/L2 or dual frequency solutions) need to be used with complex mathematical computation. A higher level of correction service is also needed (often referred to as RTK correction services where fix corrections are needed in real time).

The Procyon and Geopod range of GNSS handhelds is designed to address the needs of the 3 professional user groups as determined by required accuracy band.

Procyon & Geopod range

Product Class Class 2 Class 3 Class 4
Product Name Procyon 1-200
Geopod 1-200
Procyon 1-300
Geopod 1-300
Procyon 1-400
Geopod 1-400
Constellations supported GPS GPS + Glonass GPS + Glonass
Accuracy Band 0.5m to 0.7m 0.3 to 0.5m 1 to 2cm
SBAS Yes Yes Yes
Ground based DGNSS Yes Yes Yes
RTK correction capable No No Yes
Stated accuracy 0.7m with SBAS 0.3 to 0.5m DGNSS 1 to 2cm with dual frequency RTK

NOTE: To improve on the basic accuracy delivered by GPS (15m), some form of fix accuracy correction service is required, to correct for the system errors incurred in the GNSS process. Corrections can be delivered by satellite (Government level geo-stationary satellites such as SBAS which can be free), or commercial satellites (fee based depending upon accuracy achievable); or by ground based correction services which provide the highest level of correction accuracy. Satellite based correction is received by the GNSS receiver itself; ground based correction services need either a cellular phone connection or a separate (usually UHF) radio receiver.

Blackroc manufacture a range of professional grade GNSS solutions which enables satellite fix accuracy in real time from submetre to 1cm (RTK) .

Procyon GNSS range

Procyon

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