Introduction
For most purposes, the GPS receivers built into modern phones, along with wireless location services, are more or less adaquit; However, if you are a blind traveler navigating erban canyon, bad weather conditions and unfamiliar areas via walking GPS, adaquit may not cut it for you. The Duel electronics xGPS150A is a 64 channel receiver capable of retrieving 5 locations per second and operating at altitudes of 10,000 Feet. It's rock solid pluetooth connection, incredible speed and accuracy, make it a superb choice for detaled proxibate navigation. Nearby Explorer (the premierre GPS navigation app for the blind), supports external gps receivers including the xgps150A. This tutorial describes how I went about seting it all up.
For this tutorial, I'm using the following:
Mock Locations
Unlike IPhones where you can connect a compatible receiver and go, android forces you to take some extra steps to get things running.
First, you need to turn on developer options. Then, you need to enable mock locations. In lollypop, the steps to do this are as follows:
- tap settings, about phone.
- Scroll down to the bottom and find the build number.
- In the sighted world, you would touch the build number seven times quickly. With talkback on, each of these is a double tap of course. Just flail away until it unlocks the developer options. There's a bit of a countdown that the device goes through before it enables and you'll probably interupt talkback's speaking of the announcement that the countdown is started.
- hit back or navigate up to back out of the about screen.
- Under system you now have a new settings panel called developer.
- Tap developer. Then tap allow mock locations to switch it on.
paring the receiver
First, make sure the receiver is fully charged. On the top face of the receiver, there is a plastic cap which you leaver up with a thumbnail or some other flat object. Under the cap is the usb charging port and a tiny switch.
For connecting to android devices and updating the firmware, the switch needs to be set towards the usb jack and away from the hinge of the cover. The other position is for connecting to apple devices.
To power on the receiver, locate the circle on the front face of the receiver. The quarter of the circle nearest the usb charging port is the on off button. Press and hold for about 6 seconds to turn the receiver on.
On the android device:
- Tap settings.
- Tap bluetooth.
- Tap the switch to turn on bluetooth if it is off.
- Your XGPS shows up as a random sequence of letters and numbers. Tap this to add the device.
- the XGPS does not require a bluetooth pin.
Once connected, the name of your receiver changes to Duel XGPS150 and a list of numbers and letters. It also moves from the searching section to the pared devices section. Note that if the switch is in the wrong position, the receiver will still appear to be connected, but will not in fact be connected.
To complete the instalation, download the Duel Bluetooth status tool. The status tool shows the connection status, battery level, furmware status and other important aspects of using your receiver. Now then, I'm an idiot and didn't fully read the directions. Duel status tool says that it automatically pares the gps for use as long as mock locations is enabled. Try this first, and then if it doesn't work, go through the rest of the steps here.
bluetooth GPS
XGPS 150A users should not need this section of the tutorial. I didn't read all the way through and so I set it all up anyhow. Most receivers require a third party utility to help them take advantage of androids mock locations feature. As I have this tool installed already, I may just pare up my iblue 737 and see if it flies. The utility interface is more or less accessible. Once you have it installed turn on your receiver and tap start. Most likely you would see a connection refused error. In that case:
- tap more options
- tap settings.
- Under connection problems, there are three checkboxes and a com port setting. Test various combinations, restarting the service after each change until you find the one that works for you
The table below shows a list of devices and the combinations users reported working. Please add your device commbination and settings to help other users.
| Device | android version | GPS receiver | checkbox1 security | checkbox2 workaround | Com port setting | Checkbox 3 workaround | Notes |
|---|---|---|---|---|---|---|---|
| Motorola Moto G | Lollypop 5.0.1 | Duel XGPS150A | unchecked | checked | Com1 default | checked | This receiver apparently does not require third party paring software, but works with it regardless. |
Nearby explorer
Nearby explorer supports the use of third party GPS receivers. Apparently, it checks to see if an external receiver is paired by default and uses the internal AGPS only if it fails to find an external receiver. It does not have any way to varify which receiver you are actually using though. I can always tell if my receiver is paired in a couple of ways. My accuracy is consistanly hanging out between 1 and 3 metres on the xGPS while it bobs between 3 and 15 metres on the AGPS. My phone is quiet with the external receiver in use. With the internal receiver in use, the sat connection is constantly dropping and reconnecting. When it does this, Nearby explorer makes an obnoctious boinking sound for each acquisition or loss and when on network with the GPS disconnected the speech rattles off five or ten of the streets near me in loo of providing my actual location. An info item to show the receiver in use might be handy for some users and if not, a user could always uncheck it.
