Cost Effective Sunlight Readable GPS

Sunlight Readable PNA for Soaring

There are several excellent sunlight readable moving map systems on the market if you are in the position of installing a new panel or completely upgrading your system but these are all very pricey. What if you want a good soaring moving map capability without ripping your panel apart, obsoleting perfectly good equipment, and don’t have $5000 to spend in the process?

Based on personal experience there are several criteria that moving map soaring instruments need to meet to be useful.

1         they are bright enough to see when looking into the sun (ie sun dead ahead)

2         they do not reflect so much ambient light that the screen visibility is below threshold for normal human viewing

3         they are not washed out by direct sun (ie sun from behind)

4         they are bright enough to use in strong light while wearing sunglasses, and not affected by polaroids.

5         they are large enough that key information is easily visible in turbulent flight without excessive squinting.

Finding a PDA or PNA with a screen that works well when the sun is behind you  (transflective screen required) and that is both bright enough to give enough contrast for the human eye when looking into the sun, and without massive reflections  in either of these cases, has been very difficult.

The PNA/PDA format device is very compelling from a cost effective perspective but has suffered from real visibility limitations due to the nature of the screens used.

The unit I am testing has all the processing power of a late model pocket PC combined with built in GPS and 4GB of flash storage . It runs Windows Mobile 6.0 and has the ubiquitous SiRF GPS engine. In direct sun the visibility is as good as or better than iPaq PDA’s as they share a common trnsflective screen technology. Into the sun, and in dealing with reflections, the unit is far better than the iPaq or the Mio PNA’s I’ve also been playing with.

Comparison of various levels and costs of moving map soaring instruments

Device Specs

            5” Sunlight readable LCD  (Good backlight, TFT, high contrast ratio, anti-reflective coating)

800*480 pixel touch screen  ~ 600nits TFT with anti-reflection coating – suitable for all soaring s/w.

Win CE 6.0

SiRF GPS built-in

MicroSD external memory slot

Mini-USB data and charging port

Internal GPS on COM1, External (including FLARM and flight computer input) on COM4

All comparison pictures are taken at full brightness. The camera image sensors are more sensitive than the eye in high contrast situations – in real life the sunlight readable unit looks significantly better than the iPaq – also the viewing angle of the sunlight readable device is  better than the iPaq and way better than the Mio PNA so relections are much easier to deal with.

Indoors, Full Brightness

Outdoors Full Bright sun Directly onto Screen

Outdoor  - Directly into Full Bright Sunlight

What I'm trying to achieve with this

• Provide access to cost effective sunlight readable GPS navigation hardware
• Avoiding artificial barriers to progress and costs through over customized solutions
• Software agnostic, not tied to any one commercial soaring software package
• Some support and help – provided by help sheet (readme installed on unit)
• Enable ANY soaring pilot (club, juniors, recreational X-C to contest pilots) to have a full feature low cost GPS nav capability without breaking the bank. Money is better spent on tows.

This device will probably not appeal to tech geeks and early adopters of new OS's and device formats - but it should appeal to anyone who wants flexibility and value for money. This low cost unit that doesn't double-up as a personal phone is cheaper and better suited to club or FBO type operations - install it and leave it in the glider.

The number and type of available units for soaring moving map displays is pretty dynamic right now - Wndows CE devices are good for current legacy software and only ONE soaring software package is currently available on Android (XCSoar) however it is not as configurable as LK8000 (which is based on XCSoar open source code) or SeeYou Mobile. 

Android tablet and smart phone devices are sophisticated sensor platforms these days (specifically GPS & barometric pressure to come...) but the focus has not been on outdoor use. Useful size of soaring cockpit displays maxes out at around 5inches - much bigger than this and panel space can become a real problem. 7" tablets will be too big. Upcoming Pixel-Qi displays are monochrome mode for outdoor use - at least for now.

Additionally, many pilots have existing panels and instruments sets that work perfectly fine, converting to an expensive moving map flight computer (like a LX9000 or ClearNav or Ultimate) These are all great units for new panel installs but are too expensive for the average pilot.

Installed Picture

Here is the initial install in my LS8. My USB power cable requires an elbow but thats easy to do. The RAM arms and hardware are available from folks like Craggy Aero and Cumulus Soaring

One key is to be able to drive the Soaring PNA with Flarm and/or other flight recorder and/or your flight computer output. This typically  means converting RS232 type outputs to 3V quasi-differential data for the mini-USB port and converting onboard 12V supply to 5V for the USB power supply. Multiple sources are available for hardware and signal conversion from 12V RS232 signals to USB format PNA unit -  a good looking option is here..

http://www.glidertools.com/products/converter-rs232-to-usb-for-pna-with-switching-power-supply-5v/

I am planning on using this cable as the interface between my FLARM driven SN10 nmea output (Dave Nadler kindly reflects all nmea input on the SN10 output so FLARM is output as well as wind information from the SN10) - So,  one interface gives wind, Flarm, barometric info directly into the PNA - LK8000 is already set up to accept all these nmea packets from the SN10.

When I get my FLARM brick I'll post the setup here as part of the blog. I'll be putting the Butterfly display front and center in place of the Cambridge GPS-NAV, driving the SN10 with the FLARM and driving the combined SN10 output into the Soaring PNA through the glidertools cable.