Logger (GNSS)
A GNSS logger ( GNSS : Global Navigation Satellite System; English to log: to record) is a data logger that receives and automatically records GNSS position data . The term GPS logger is also in use , as GPS is the most widely used global navigation system .
In the simplest case, such a device only has an on / off switch and possibly a button for marking particular waypoints . The adjustment of the settings, for example the number of positions recorded per minute, and the reading out of the data is then carried out via a computer connection . Many commercially available receivers or navigation devices also have the option of recording route data.
Since the altitude data supplied by GNSS have comparatively high errors (± 10–20 m), the recording of measured values is supplemented by a barometric altimeter , especially in air sports .
Logger in gliding
In the sport of gliding , loggers are used to document cross-country flights. The logger means a considerable simplification of the sport of gliding: Before, a comparatively cumbersome procedure with photographed forms, sports witnesses, turning points photographed from the air and flight altitude documentation using barographs was necessary. The evaluation was correspondingly (time) consuming. At the end of the 1990s, the logger replaced this process. It is now the only approved documentation system.
Due to the ease of use and the rapid distribution of the logger, the number of documented glider kilometers rose by leaps and bounds, in Germany from 2.3 million kilometers (1991) to 13.0 million (2008).
The International Gliding Commission (IGC) developed a specification that all recognized loggers must comply with.
Loggers record the GNSS data and the air pressure at intervals of 1–15 seconds. The data is stored in a flash memory . During the normal flight phase , the interval is 5–15 seconds, near turning points it is 1–2 seconds.
The pressure measurement system must be calibrated according to the ICAO ISA ( International Civil Aviation Organization International Standard Atmosphere) before take-off. The logger creates a file for every flight in which the respective position and altitude is recorded every few seconds. In order to protect the data from forgery, it is provided with a digital signature . For sailplanes with retractable engine the logger records the motor runtime to ensure that the Counting distance was actually covered without power. This file with the suffix can be transferred to a computer after landing so that the flight can be evaluated in detail with the appropriate programs.
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The most popular models are the Volkslogger and the Colibri . The FLARM collision warning system , which has now become quite widespread, has also been approved as a logger since spring 2008 , so that it may not be necessary to carry a separate logger with the FLARM installed.
Web links
- IGC - Approvals for GNSS Flight Recorders. (PDF) FAI / IGC , accessed on January 25, 2011 (English, overview of the logger models officially approved for use in gliding, with a brief history).
Individual evidence
- ↑ Technical Specification For GNSS Flight Recorders. Second Edition - December 2010 with Amendment 1 - 31 May 2011. (PDF) (No longer available online.) IGC, May 2011, archived from the original on May 4, 2013 ; accessed on April 7, 2013 .
- ↑ Volkslogger, Garrecht Avionics GmbH
- ↑ Colibri. ( Memento of February 20, 2007 in the Internet Archive ) LX Navigation