Sygic is a standalone app, i.e., it doesn't need cell connection to work. Cell is needed only for updates and real time info like construction activities and accident alerts. In fact I use Sygic with my WiFi only Samsung tablet. I'm not familiar with Genius but I would think it would be the same as Sygic in that respect.I like to have both. More than once I’ve found myself without a cell signal and the phone using best guess reckoning as to where I am
I agree with IdahoMtnSpyder. Your phone does not need a cell connection to work as a gps. In fact it may be more accurate and faster than a inexpensive stand alone GPS. Whether you need a cell connection or wifi, depends on the app you are using. For example, a free app like Google Waze must have a cell connection. Google maps is also free and can be used without cell connection, but you have to prepare and download maps ahead of time. In general standalone gps apps are not free.
I'm a stand alone Garmin guy, but agree on their latest routing being somewhat substandard. Always willing to learn though, so help me out a bit. So my smart phone has a GPS receiver in it and will get direction without cell service. Cool. With the phone connections in the front and rear trunks you will have to make some kind of power plug modifications so the phone has a line of sight on the sky, right? You'll at very minimum have to get the phone mounted on the dash or bars for the phone GPS receiver to work I would think.
Smartphones for the past few years have included a very good GPS receiver. At least Samsung has. You can keep it in the glove box, trunk, frunk, coat pocket, or most anywhere and it will pick up the satellite signals very well. I've had my tablet in the trunk during rain storms and listened to the voice instructions. Since I don't have the new cluster I use a Bluetooth receiver to feed the tablet audio via BT into the GPS input of the radio.So my smart phone has a GPS receiver in it and will get direction without cell service. Cool. With the phone connections in the front and rear trunks you will have to make some kind of power plug modifications so the phone has a line of sight on the sky, right? You'll at very minimum have to get the phone mounted on the dash or bars for the phone GPS receiver to work I would think.