YuriT

Yes, nothing new, agree with you. It's more terminology issue than technical one. Of course, special receiver is used which outputs raw data along with the NMEA, the pseudo-ranges and carrier phase. Regards, Yuri

Yo, you compile data on the ground reading raw file from flash disk and then "see" the formation. Google lists the most common terms to describe diff positioning (DGPS), but there's many other techniques to get the same result. Timing errors are the same, but we want to know relative distances between divers not the absolute ones. The abs position comes from standard NMEA stream.

It's a DGPS but in bit different matter which you can find on Google. One just logs (raw) data from all receivers in formation and then you can get relative distance between divers much better than absolute one and draw nice 3D OpenGL picctures. You don't need any ref station, another receiver is this base station. Yuri

Receivers are differential only relatively to each other, so to log formation you need at least 2 skydivers in this formation. In formation of 1 person it will not work :)

Planning 2 versions of the device, simple the NMEA-only and full-blown raw/DGPS one. Sampling rate for non-DGPS version is 5 Hz, for DGPS could be as high as 1 KHz since raw receiver data (pseudo-ranges) is stored on flash disk and then processed offline on the ground workstation. Actual altitude is fused from pressure sensor and GPS data. Obviously, it's not well suited for the BASE jumps for the reason you've just mentioned. Kind regards, Yuri

Actually, will appriciate very much your help. Please, contact me via email. This page is more memo/spec than an actual commercial site, just to get an idea is such GPS thing in demand or not. Thank you, Yuri

Kiitos, Sir ! Will ask you for a good photo later ! Yuri

Terve, Ahti ! Just have removed the photo. No any questions, totally agree with you, sorry for that. I did show this info (with photo) to your guys in Hanko previous summer, it was OK. People involved in project are Julian F (testing) Ossi L (club) Zoltan B (collision alarm idea) and me (design) kiitos/spasibo, Yuri

19 April, 2007 Dear friends, For your reference, There's a research project going on at The Parachute Club of Finland at the moment. We evaluate the possibility to create a highly dedicated GPS for the skydiver community, combining GPS receiver, short-range radio, altimeter, 3D accelerometer, microprocessor with large storage capacity and USB interface. The GPS will feature practically zero acquisition time since it stores the raw receiver data, along with the NMEA one, for further processing (satellite fix) on the ground. The collected data (tracks) could be then viewed on standard computer using built-in device keypad similar to a TV remote control, so one does not even need to touch PC mouse or keyboard. If interested, please visit the project site at www.DropZoneGPS.com Briefly, the main features of the device: * High Resolution Differential GPS (DGPS) * Zero Acquisition Time * Collision Warning Alarm * Formation Recorder (incl. orientation) * G-Meter * Standard Logbook * Built-in Flash Memory (no card required) * USB / Wireless Operation * Track Browser Keypad * FREE 3D Graphical Viewer Preliminary specifications: Resolution 0.5 m (differential) Frequency band 2.4 GHz Output power 1 mW Range approx. 100 meters Memory capacity 8 MB Data format NMEA / raw Interface USB / IEEE 802.15.4 (uses one device as a dongle) Battery 3 x AA type Size 10 x 40 x 60 mm Weight 50 g (w/batteries) Target price 95 EU Kind nordic regards, Yuri Tregubov / FINLAND Team Leader www.DropZoneGPS.com