Supported GPS protocols
ArcPad supports the following protocols for communicating with GPS receivers:
- National Marine Electronics Association. (NMEA) 0183, version 2.0
- Trimble Standard Interface Protocol (TSIP)
- Delorme® Earthmate®
- Rockwell PLGR Protocol
Any GPS receiver that outputs any of the above protocols should work with ArcPad, as long as the GPS receiver is correctly configured and properly connected to the device being used with ArcPad.
ESRI does not publish a list of supported GPS receivers for ArcPad. ArcPad supports the above list of GPS protocols rather than specific GPS receivers.
Selecting a GPS receiver
ESRI does not publish a list of recommended GPS receivers since there are many factors that need to be considered when selecting an appropriate GPS receiver for your specific field GIS needs. Factors that need to be considered include:
Supported protocols: Does the GPS receiver output a protocol that is supported by ArcPad?
What accuracy do you require for your GPS positions?
Is autonomous GPS with 5–15 meters accuracy sufficient, or do you require differential correction to achieve higher accuracy?
Does the GPS receiver have the ability to differentially correct the GPS positions when connected to a differential receiver or using the WAAS differential system?
How well does your GPS receiver work under a canopy or in environments that are susceptible to multipath errors?
What type of real-time differential correction is available and reliable in the area where you will be working: beacon, satellite, or WAAS?
GPS receiver functionality:
Can the GPS receiver be configured to set such factors as elevation mask, position interval, and SNR mask?
Does the GPS receiver have its own display to configure the receiver and use the receiver in a standalone mode?
How much do you want to spend on a GPS receiver? More accurate GPS receivers cost more than less accurate receivers.
Size and configuration
Do you require a compact GPS receiver or a backpack GPS receiver? Ultra-compact GPS receivers tend to be less expensive but also less accurate than larger GPS receivers. GPS receivers are available in various configurations including Compact Flash receivers, PC Card receivers, Bluetooth receivers, specialized built-in receivers, add-on expansion packs, handheld receivers, integrated receivers and mobile devices, all-in-one antennas and GPS receivers, and backpack GPS receiver systems.
Are cables an issue? Bluetooth is a good alternative for wirelessly connecting an external GPS receiver to your mobile device.
Availability and support
What GPS receivers are available in your local area, and is the local GPS vendor’s support adequate?
There is no perfect GPS receiver for use with ArcPad. You should consider all of the above factors when deciding which GPS receiver best meets your field GIS and GPS needs.
Using USB GPS
The question of USB-GPS support arises often. There is no native USB transmission/interface standard for GPS data. The most commonly used NMEA protocol was designed for RS-232 serial communication where the port is connected to one device. A USB device can have many devices connected to the port. USB also has manufacturer codes and other device descriptors associated with the device connected to the USB port.
The USB standard does not include a GPS device as part of the standard. Therefore, for a manufacturer to support a GPS with a USB interface, they must create a proprietary USB interface with that device. This involves creating a driver for the specific operating system using a proprietary interface. This type of model does not allow for third party software to function with the USB-GPS device. Some manufacturers will include an additional driver that will make their USB-GPS device look as if it is connected to a RS-232 serial port to software. This will allow for third party software like ArcPad function with that USB-GPS assuming that the protocol is using NMEA.