Decrease calculation load by simplifying NMEA sentences

Overview
BONAV One Sentence Output shrinks the standard lengthy NMEA sentence into a shorter and more manageable $PGTOP proprietary sentence. In addition, $PGTOP also contains pre-calculated value typically not found NMEA sentences such as distances between two output data.

This ultimately allows the host processor to perform a more efficient data processing and is perfect for mobile devices where calculation power is a major concern.

Background
In the world today where mobile devices dominate, "battery power" and "processing efficiency" are two important requirements that are imprinted into designer's mind. Most handheld devices are being driven by one processing unit that is already preoccupied with its designated function and has little processing cycle to spare in processing the lengthy NMEA.

The general idea behind BONAV's One Sentence customization service is that processing cycle and power consumption can be saved by taking out parts of NMEA that is not used by the host device and combining the remaining NMEA items into one single short sentence.

In addition, the processor inside the GPS module can share a part of processing load by calculating information not found in NMEA standard. Items such as distances between two location points can all be calculated internally before passing it off to host processor.

Solution
By informing us which NMEA items are desired, we can combine them into a single $PGTOP sentence output format.

For example, the typical NMEA contain the following sentences where the desired items are underlined.

Standard GGA sentence format
$GPGGA,064951.000,2307.1256,N,12016.4438,E,1,8, 0.95,39.9,M,17.8,M,,*65
Standard RMC sentence format
$GPRMC,064951.000,A,2307.1256,N,12016.4438,E, 0.03,165.48,260406,,,A*55
Standard VTG sentence format
$GPVTG,165.48,T,,M,0.03,N,0.06,K,A*37

By Combining the items desired in each of the three sentences in to a single sentence, the result is:
One Sentence Format
$PGTOP, 064951.000,2307.1256,N,12016.4438,E, A,0.03,165.480.03,N,0.06,K * checksum