GPS Field guide
© WHO 2002
Страница 1: ...GPS Field guide WHO 2002...
Страница 2: ...IEW SATELLITE page 17 3 2 3 2 The MENU page 17 The MARK WAYPOINT option page 19 The SETUP option page 19 The UNITS setup page 20 The SYSTEM setup page 20 CHAPTER 4 TROUBLESHOOTING 4 1 eTrex doesn t tu...
Страница 3: ...ellites was achieved in 1994 Each satellite is built to last about 10 years Replacements are constantly being built and launched into orbit The Control segment which consists of ground stations locate...
Страница 4: ...transmitted radio signal passes through clouds glass and plastic but not through most solid objects such as buildings and mountains A GPS signal contains three kinds of coded information essential for...
Страница 5: ...igure 3 Sphere indicating the potential location of the GPS receiver with one satellite signal 2 Calculates the distance to a second satellite for which it is able to catch a signal 19 000 km for exam...
Страница 6: ...e circle reported on Figure 4 corresponding to the intersection of the first two spheres Figure 5 Potential locations of the GPS receiver with 3 satellites signals b Most of the time one of these two...
Страница 7: ...e sky is called the Positional Dilution of Precision PDOP A good PDOP is obtained when the satellites are located at wide angles relative to each other Figure 6 a In the contrary a poor PDOP result fr...
Страница 8: ...mportance for the users to be located in the most open area as possible before taking the measurement There are other sources of error over which the user does not have control including Atmosphere de...
Страница 9: ...the clusters This concerns for example health facilities roads market water pumps and so on If the location of these is known the GIS tool will be used to calculate the distance to the nearest infras...
Страница 10: ...ns for approximately 22 hours on two AA alkaline batteries and can operate under dense tree canopy The present section describes the receiver as well as the operating system allowing the user to measu...
Страница 11: ...iver to perform different operations and to display the final result on the LCD screen through a specific operating system The case also contains an internal built in clock and memory that has the cap...
Страница 12: ...not want to continue 5 The Up and Down buttons These buttons are used to select options on pages and menus and to adjust the display contrast 6 The Enter button This button is used to confirm data en...
Страница 13: ...to observe the proper polarity when inserting the batteries It is very important to install the TWO batteries with the proper polarity positive and negative orientation as indicated in the unit s bat...
Страница 14: ...utton In the context of the WHS we will only need to use two of them The NORMAL SKYVIEW SATELLITE page The MENU page Figure 12 The 4 Main pages of the Garmin eTrex GPS receiver Following is the descri...
Страница 15: ...egarding its position based on the satellite s localisations The number of satellite signals that the receiver is tracking indicated by the drawing in the middle of the screen Each line between the ch...
Страница 16: ...t to setup the contrast correctly in order to insure a good reading of the information on the LCD screen When you arrive on this page the LIGHT TIMEOUT field is highlighted and you can make the scroll...
Страница 17: ...d square in black one in grey having a signal not strong enough and the last one not being read by the device the n 20 This display is very helpful to check the Positional Dilution of Precision PDOP s...
Страница 18: ...to access to the structure of these two options Figure 18 Scheme to access the MARK and SETUP option pages To access to the selected option you have to highlight it in the menu using the UP or DOWN bu...
Страница 19: ...e WHS Figure 19 the MARK WAYPOINT option page The SETUP option page The SETUP option page Figure 20 allows the user to customize the eTrex This page contains a list setup pages In the context of the W...
Страница 20: ...he GPS unit and connected with the Earth s magnetic field variation Ones all the units have been setup it is possible to keep them as default be highlighting the DEFAULTS option and pressing the ENTER...
Страница 21: ...y be large obstacles around you that stops the satellite signals move to a new location a large open area with a clear view of the sky 2 Another window with a message may appear see section 4 3 for th...
Страница 22: ...NTER eTrex then asks HAVE YOU MOVED HUNDREDS OF MILES KM SINCE LAST USE Press UP DOWN buttons Highlight YES Press ENTER eTrex will do an AUTOLOCATE and switch to the Satellite Page 4 4 I am not gettin...
Страница 23: ...get are outside the range indicated in the Country information document 1 Make sure the eTrex is configured as indicated in point 7 of the Quick Reference Guide and redo the reading correctly 2 If th...
Страница 24: ...in latitude longitude coordinates the current local time and date information obtained through the satellite signal when using the eTrex unit Map Datums Since the Earth is not flat a model needs to be...
Страница 25: ...ographic Information Into MEASURE Surveys A field Guide to GPS Data Collection Garmin Website http www garmin com Garmin GPS Guide for beginners http www garmin com manuals gps4beg pdf Eagle GPS Tutor...
