Here you can see portable GPS i think top the ranking, keeping in view the features they offer.
1. GARMIN GPSMAP 696:-
The GPSMAP 696 is one of the latest and most modren gps garmin offer its a gps a pilot could want in a portable GPS unit for the airplane. A huge 7” screen and full featured GPS is bundled with the ability to view FAA/NACO approach plate’s giving this unit Class 1/Class 2 electronic flight bag (EFB) capability, for more details check garmin website.
2. Bendix/King AV80R GPS
Bendix/King AV8OR is a feature packed GPS unit at an affordable price. It features a large 4.3” color touch screen that can be used both in the air and your car. For the air, the unit features an upgradable Jeppesen database of terrain, airspace boundaries and waypoints. The unit features WAAS capable gps technology with accuracy down to five meters and is upgradable to include XM Satellite weather. It also features the flexibility to take it in the car and use it as a full featured 3D automotive GPS with voice prompts. Bluetooth capability allows you to sync up with headsets and other Bluetooth products. For more details visit Bendix/King website
3. Garmin 496:-
The Garmin 496 packs all the power of a full multi-function display in one compact unit. The Garmin includes the ability to show XM Satellite weather including real time text and NEXRAD radar imaging as well as terrain and airspace alerts. Despite its small size the unit features a high resolution database that boasts ten times as much data as other portable units as well as an update rate that is five times faster than other portable units producing a very smooth and detailed picture. The unit comes preloaded with over 850 taxiway diagrams helping pilots navigate unfamiliar airports and taxiways on the ground. Pilots who want take it out of the airplane completely can add optional MapSource and use it in car or in sea. For details vist garmin website.
4. AvMap EKP IV
AvMap EKP IV is perfect for anyone looking for a great aviation GPS who does not want to pay the monthly subscription for XM Satellite weather service. At the heart of unit is a gigantic 7” screen that is bright and easy to read in the cockpit. The screen can be rotated to display in either landscape or portrait layout. The updatable database includes a topographic base map, instrument waypoints such as victor airways, and airport information. In addition to all of this, the unit is able to integrate with onboard avionics such as autopilots and external antennae’s. overall a nice choice