GPS

This library has been deprecated and its functionality is now made available in as two separate libraries: GPSParser and GPSUARTDriver.

This library is a driver for GPS modules that can be interfaced over UART. It does not support all data types received by GPS. It supports VTG, RMC, GLL, GGA, GSV and GSA. For information on these formats and other satellite data packets, please see this page.

You can view the library’s source code on GitHub. Click here to see information on the available versions of this library.

To add this library to your project, add #require "GPS.device.lib.nut:0.1.0" to the top of your device code.

Class Usage

Constructor: GPS(uart, fixCallback[, baudrate])

The class constructor takes two required parameters and one optional parameter. The first required parameter, uart, is an imp UART bus which need not have been previously configured.

The second required parameter, fixCallback, is a callback function that should take two arguments: a boolean indicating whether the GPS currently has a fix, and a table containing the most recent GPS data. The table contains the key type, which indicates which type of data the table contains. The table’s remaining keys will depend upon the data type, and are listed in the tables below.

The third parameter, which is optional, is the baudrate of the GPS. This defaults to 9600 baud.

VTG

Key	Description
type	GPS_VTG
trackt	True track made good (degrees)
speedkmh	Speed in kilometers per hour
checkSum	Checksum, used to check the validity of the data

RMC

Key	Description
type	GPS_RMC
time	The timestamp of received data (minutes, hours, seconds)
latitude	The latitude received
longitude	The longitude received
status	The status of the satellite, `"A"` for active, `"V"` for void
checkSum	Checksum, used to check the validity of the data

GLL

Key	Description
type	GPS_GLL
time	The timestamp of received data (minutes, hours, seconds)
latitude	The latitude received
longitude	The longitude received
status	The status of the satellite, `"A"` for active, `"V"` for void
checkSum	Checksum, used to check the validity of the data

GGA

Key	Description
type	GPS_GGA
time	The timestamp of received data (minutes, hours, seconds)
latitude	The latitude received
longitude	The longitude received
status	The status of the satellite, `"A"` for active, `"V"` for void
fixQuality	The quality of the satellite fix
numSatellites	The number of satellites being tracked
altitude	Altitude, meters, above mean sea level
checkSum	Checksum, used to check the validity of the data

GSV

Key	Description
type	GPS_GSV
numSatellites	The number of satellites in view
checkSum	Checksum, used to check the validity of the data

GSA

Key	Description
type	GPS_GSA
threeDFix	3D fix. Values: 1 = no fix, 2 = 2D fix, 3 = 3D fix
PDOP	Dilution of precision
HDOP	Horizontal dilution of precision
PDOP	Vertical dilution of precision
checkSum	Checksum, used to check the validity of the data

Example

function myCallback(gotFix, data) {
    if (gotFix) {
        server.log(format("I have valid %s data!", data.type));
        switch(data.type) {
            case GPS_RMC:
                // Do something with RMC data
            break;
            case GPS_VTG:
                // Do something with VTG data
            break;
            case GPS_GLL:
                // Do something with GLL data
            break;
            case GPS_GGA:
                // Do something with GGA data
            break;
            case GPS_GSV:
                // Do something with GSV data
            break;
            case GPS_GSA:
                // Do something with GSA data
        }
    }
}

myGPS <- GPS(hardware.uart1, myCallback);

getLastLocation()

The getLastLocation() method will return a table containing the last detected latitude and longitude, and a table containing the time the co-ordinates were received.

local last = myGPS.getLastLocation();
server.log(format("Last lat: %f, last long: %f. Received @%d:%d:%d", last.latitude,
    last.longitude, last.time.hours, last.time.minutes, last.time.seconds));

Release History

The Electric Imp Dev Center documents the latest version of the library. For past versions, please see the Electric Imp public GitHub repos listed below.

Version	Source Code	Notes
0.1.0	GitHub	Beta release

License

The GPS library is licensed under the MIT License.

Deprecated