FME AGPS Evaluation Hints Version /AFF

Transcription

1 Page 1 of 22 FME AGPS Evaluation Hints Version /AFF 1 STARTING THE EVALUATION KIT 2 2 PREPARATION OF ASSISTED DATA RUN IN ASSISTED MODE ASSISTED DATA ACQUISITION TIME ASSISTED DATA REQUESTED FROM THE SERVER (YELLOW LED) ASSISTED DATA TRANSMITTING FROM SERVER TO RECEIVER (BLINKING ORANGE) ASSISTED DATA RECEIVED (GREEN LED) 4 3 MEASUREMENT METHOD STARTING MEASUREMENT STOPPING MEASUREMENT 6 4 TEST AUTOMATION TESTNAME AUTOMATED RUNS AND TIME OUT STATISTICS ERROR CALCULATIONS 9 5 CONFIGURATION FOR COLD/WARM/HOT IN UE-BASED (ASSISTED) AND STAND-ALONE MODE ASSISTED MODE STAND-ALONE MODE COLD/WARM/HOT START COLD START SETTINGS HOT START SETTINGS DETAILED CONFIGURATION OPTIONS ASSISTED MODE COLD ASSISTED MODE HOT AUTONOMOUS COLD AUTONOMOUS HOT TIPS AND TRICKS 22 6 SUPPORT 22

2 Page 2 of 22 1 Starting the Evaluation Kit Double-click this icon on your desktop to start the Evaluation Kit. Documentation of the Evaluation Kit s/w can be found in the installation directory or via the Windows Start menu:

3 Page 3 of 22 2 Preparation of Assisted Data The Evaluation Kit allows the configuration of the Assistance Data. In the Advanced option tab you can specify the various assisted options. Checking Server in the Data Source box enables the assisted mode. In the Server Settings box you will see the IP address and port of the server available for evaluation. In the Server column in Data Sources box, you find several options what kind of assisted data you want to use. Init Position Position estimate provided by the server (please uncheck this option). Time Current time will be provided by the server. Satellite models Checking this box will download the current Almanac from the server. Accurate Models This downloads the current ephemeris of all satellites into the receiver. Long Term Models Download of a proprietary satellite model. GPS -> Options -> Aiding Data tab

4 Page 4 of Run in Assisted Mode If you select assisted mode and start the receiver by clicking the Start button in the main window, the tool will try to open a connection to the server. If this fails, the receiver will be stopped. If the tool can download the assisted information, it will update the receiver and you will see the respective columns in the main window filled with the downloaded information. After this initial update the assistance server is no longer needed. 2.2 Assisted Data Acquisition Time In assisted mode, the Evaluation Kit retrieves assisted information from a server via the TCP/IP protocol. The Evaluation Kit provides a graphical way to show the transmission of the assisted data Assisted Data Requested from the Server (yellow LED) When assisted data is requested from the server, the Srvr Connection LED goes yellow Assisted Data Transmitting from Server to Receiver (blinking orange) While assisted data transmission is in progress, the Srvr Connection LED blinks orange Assisted Data Received (green LED) When the first packet of the assisted information is received, the Srvr Connection LED goes green and the respective columns are filled with the values from the server.

5 Page 5 of 22 The Evaluation Kit does not provide data when the update of the assisted information is finished. It simply depends on the network connection speed. Experimental tests show that with a connection speed of 56.6 kbps, this time is about 8-10 seconds. Obviously the higher the connection speed, the lower the assisted data completion time. This time can be calculated using several methods: 1) Displaying the properties of the internet connection and monitoring transmitted and received bytes. When the assisted data collection begins, these values will begin to increase, until the assisted data collection is complete. 2) Using a packet sniffer tool to monitor the packets transmission between the PC and the eride server ( :37433).

6 Page 6 of 22 3 Measurement Method 3.1 Starting Measurement The Evaluation Kit starts a measurement by clicking on the Start button or pressing CTRL+G on the keyboard. 3.2 Stopping Measurement A measurement can be stopped by clicking on the Stop button or pressing CTRL+S on the keyboard. 4 Test Automation The Evaluation Kit s/w allows the automatic execution of multiple test runs. The following steps need to be taken: 1. Specification of a testname. 2. Settings for automated runs like number of runs, timeout value, etc. 3. Results in the GUI. 4.1 Testname In the Advanced option tab, you can enter the testname for the all data files which belong to the same test run. GPS -> Options -> Advanced tab

7 Page 7 of 22

8 Page 8 of Automated Runs and Time Out In the Automated Runs option tab, you can define the settings for repeated start and stops of the receiver. Unchecking Manual run only allows you to fill in the data for the automated settings. The setting allows to define a Time out which can be useful for test setups with low signal power levels. GPS -> Options -> Automated Runs tab 4.3 Statistics During automated runs, you can see the Statistics window by clicking Stats in the lower right corner of the Sky Plot display. This window provides you with the number of fixes in the completed runs and the minimum, maximum and average TTFF values.

9 Page 9 of Error Calculations If the true position is known, the Evaluation Kit can calculate CEP and 2DRMS. You need to enter the true position in the Initialization option tab. GPS -> Options -> Initialization

10 Page 10 of 22 During the automated runs, Hoz./Alt. Error shows the current error, CEP and 2DRMS calculate error statistic over all valid position fixes.

11 Page 11 of 22 5 Configuration for Cold/Warm/Hot in UE-Based (Assisted) and Stand-Alone Mode 5.1 Assisted Mode This mode requests assisted data from the server, gets measurements from satellites signals and uses this data to calculate a position fix 5.2 Stand-Alone Mode This mode does not use assisted information from a server, it only gets measurements from satellite signals. Therefore the Server check box in the Aiding options tab must be unchecked. 5.3 Cold/Warm/Hot start Three start conditions are usually specified where cold and hot are more strict in their definitions. In Cold Start the receiver basically has no aiding information at all, it only uses an inbuilt Almanac. In Hot Start the receiver has the most current information on Ephemeris, Almanac, Time and Last Position. In Warm Start the receiver usually has only the Almanac. For all the possible aiding information the Evaluation Kit allows their combination in the following ways Cold Start Settings In the cold start settings only the system s Satellite Models check box is checked. This is the in-built default almanac which was installed with the Evaluation Kit.

12 Page 12 of Hot Start Settings In the hot start settings the Previous Run data is kept. It depends on the quality of the previous run data how much this data helps for the current measurement. The following data could be available Ephemeris o Ephemeris of the satellites seen in the previous run are available. o Time difference between previous and current run should not be more than 4 hours, otherwise the data is invalid and might affect TTFF. Almanac o Almanac collected in the previous run might be incomplete depending on the duration of the previous run. It should be ensured that the Full Almanac LED is green.

13 Page 13 of 22 Position o Make sure that previous run data are stored when the receivers is stopped by checking the Save At Shutdown check box. o The position of the previous run is only available if the previous run had a position fix. Time from RTC o RTC keeps only running if the Power Mode is set correctly and power is not put off during runs. o After initial power-up, RTC needs one run with a position fix to be set. If all of the above is set, the receiver starts in hot mode.

14 Page 14 of Detailed Configuration Options Assisted Mode Cold 1) Aiding data tab Only the Server data source is checked (only time and satellite models, but not initial position). Satellite models (default in-built almanac) are provided by the system as well. 2) Shutdown Save data for next run is checked (it will not use it as the previous data checkbox is not checked in the aiding tab) Keep real-time clock running is not checked so no previous information about time will be used.

15 Page 15 of 22 3) Automated runs Please ensure that the 30 seconds value is enough time to have a fix in your testing environment. Otherwise, a higher value should be filled in, or the Stop run if no fix within 30 seconds box should be unchecked. 4) Advanced

16 Page 16 of Assisted Mode Hot 1) Aiding data tab Previous run and Server data source (only time and satellite models, but not initial position) are checked. Satellite models (default in-built almanac) are provided by the system. Initial manual position aiding can also be checked. The initial position estimate can be manually entered by the user or loaded from a previous position solution (by clicking the Load Position button). 2) Shutdown Save data for next run is checked (it will not use it as the previous data checkbox is not checked in the aiding tab) Keep real-time clock running is checked so previous information about time will be used for the next run. Note: prior to use RTC time as an aiding data source, it is necessary to do a manual run first, and wait for a fix. This is because the RTC time is synchronized to GPS time just after a fix is achieved. It will keep on running after the run is finished if the box is checked and the receiver is powered through the USB port.

17 Page 17 of 22 3) Automated runs Please ensure that the 30 seconds value is enough time to have a fix in your testing environment. Otherwise, a higher value should be filled in, or the Stop run if no fix within 30 seconds box should be unchecked.

18 Page 18 of 22 4) Advanced Autonomous Cold 1) Aiding data tab Nothing is checked except Satellite models (default in-built almanac), provided by the system.

19 Page 19 of 22 2) Shutdown Save data for next run is checked (it will not use it as the previous data checkbox is not checked in the aiding tab) Keep real-time clock running is not checked so no previous information about time will be used. 3) Automated runs Please ensure that the 30 seconds value is enough time to have a fix in your testing environment. Otherwise, a higher value should be filled in, or the Stop run if no fix within 30 seconds box should be unchecked.

20 Page 20 of 22 4) Advanced Autonomous Hot 1) Aiding data tab Previous run is checked. Satellite models (default almanac, not updated) are provided by the system. Initial position is checked as well. Server data source is unchecked.

21 Page 21 of 22 2) Shutdown Save data for next run is checked. Keep real-time clock running is checked so previous information about time will be used for the next run. Note: prior to use RTC time as an aiding data source, it is necessary to do a manual run first, and wait for a fix. This is because the RTC time is synchronized to GPS time just after a fix is achieved. 3) Automated runs

22 Page 22 of 22 Please ensure that the 30 seconds value is enough time to have a fix in your testing environment. Otherwise, a higher value should be filled in, or the Stop run if no fix within 30 seconds box should be unchecked. 4) Advanced Tips and tricks When switching from cold to hot mode, and before doing the automated runs, it is desirable to do a manual hot run first and wait for a fix (RTC will synchronize with GPS time in the fix, and initial position, almanac and ephemeris will be updated for the next run), to ensure that the very first run of the automated process will be able to use the aiding information coming from RTC and the previous run. In the same way, when switching from hot to cold mode, the first run will use time information because the RTC was running meanwhile. It is desirable then to do a manual cold run first, and at the end of this run the RTC will not keep on running. Then, the very first run of the automated process will not use any timing information coming from the RTC. 6 Support If you have any questions or comments regarding the Evaluation Kit, please send an to: gps.support@fme.fujitsu.com