Manuel d'utilisation / d'entretien du produit GPS du fabricant Garmin
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GPS Field guide © WHO 2002.
09/25/02 GPS_field_guide 8:19 A9/P9 2 CONTENTS CHAPTER 1: I NTRODUCT ION TO GPS 1.1 What is GPS ?…………………………………………………………...2 1.2 How does GPS work ?…………………………………………………..3 1.
09/25/02 GPS_field_guide 8:19 A9/P9 3 CHAPTER 1: INTRODUCTION TO GPS 1.1 What is GPS? The Global Positioning System (GPS) is a syst e m allowi ng to precise ly identi fy loc ations on the earth 's surface. The GPS system has 3 parts (Figure 1): · The Spac e segment : a network of 24 satellites placed into orb it (Figure 2).
09/25/02 GPS_field_guide 8:19 A9/P9 4 1.2 How does GPS work? GPS satellites circle the Earth twice a day in a very precise orbit at an altitude of around 19 000 Kilo metr es ( Fig ure 2) . T his co nste llatio n al lows a ny u ser to acc ess be twee n fi ve and eight sate llites from any point on the Earth .
09/25/02 GPS_field_guide 8:19 A9/P9 5 The receiver: 1. Calculates the distance to the first satellite he is able to catch. Let's suppose that the receiver calculates a di stance of 17 '000 km between this first satellite and the receive r.
09/25/02 GPS_field_guide 8:19 A9/P9 6 3. Repeats the operation mentioned under point 2 with a third satellite. In our ex ample the receiver finds out that it is 20,000 km from the third satellite whic.
09/25/02 GPS_field_guide 8:19 A9/P9 7 1.3 Sources of GPS signal errors Even if today's GPS receivers a re ext remely accurate, c ertain atmosphe ric factors and other sources of error c an affect the accura cy of GPS recei vers.
09/25/02 GPS_field_guide 8:19 A9/P9 8 There m a y also be so urces o f si gnal mult ipath ( i.e on Fi gure 8) occur ring whe n the GPS signal is reflect ed off these o bj ects before r eaching th e rece iver. This incre ases the travel time of the sign al and c reat es erro rs of d ista nce es timatio n be twee n the satelli te and the receiver.
09/25/02 GPS_field_guide 8:19 A9/P9 9 CHAPTER 2: WHY USING GPS IN THE CONTEXT OF THE WHO WHS ? The fir st reason for using GPS in the WHS context is the added value it gives to the survey by allowing .
09/25/02 GPS_field_guide 8:19 A9/P9 10 CHAPTER 3: THE GARMIN ETREX UNIT The Garm in eT rex G PS re ceive r h as be en chos en fo r t he WH O W HS b ecaus e i t i s eas y to use and inexpensive. Its utilisation in the c ontext of diffe rent survey s operated in the field has proven its suitability for this kind of work.
09/25/02 GPS_field_guide 8:19 A9/P9 11 Figure 10 - Back view of the G armin eTrex device Table 1 describes the elements report ed on the Figures 9 and 10 Inside the waterproo f case are located a set .
09/25/02 GPS_field_guide 8:19 A9/P9 12 1. Intern al GPS Antenna This antenna a llows the receiver to tr ack satellites sig nals. Thus, when using the GPS, the unit should be parallel to the ground and facing upwards. Apart from the cover of the hol ster nothing should be put on this part of the unit as this may stop satellite signal.
09/25/02 GPS_field_guide 8:19 A9/P9 13 3.2 Utilisati on of the eT rex unit This se ction presents th e major elements th at will be used in the contex t of the WHO W HS. It introduces you to the basic features of th e eTrex as well as some b asic definitions of terms in a more detailed way tha n presented on the Quic k Reference guide.
09/25/02 GPS_field_guide 8:19 A9/P9 14 3.2.3 The Garmin eTrex Pages Th e eTr ex op erat ing s yst em i s c omp osed o f dif fer ent pa ges or ganise d i n a hi era rchic al wa y starti ng fro m 4 m ain pa ges (Fi gure 12 ). Th e 'NOR MAL S KYV IEW SATELLIT E' p age is one of them.
09/25/02 GPS_field_guide 8:19 A9/P9 15 This information concerns: - The Status of the device. Two t ype of messages can appear: a) "WAIT… LOCATING SATELLITES" indicat ing that the r eceiver is tracking satellite sig nals.
09/25/02 GPS_field_guide 8:19 A9/P9 16 You can access to these two pa ges by pressing the ENTER button from the 'NORMAL SKYVIEW SATELLITE' page in order to open the 'OPTIONS' w indow. From there you can use the UP and DOWN but tons to h ighli ght the pa ge you want to acces s and press the ENTER button.
09/25/02 GPS_field_guide 8:19 A9/P9 17 The 'ADVANCED SKYVIEW SATELLITE' page Thi s page con tain s the sam e eleme nts as the ' NORM AL SKYV IEW S ATELLI TE ' page but presented in a different graphical way (Figure 16).
09/25/02 GPS_field_guide 8:19 A9/P9 18 Figure 17 - The ' MENU' page There are two options of interest for the W HS on the 'MENU' page: the 'MARK' and 'SETUP' ones. The Figure 18 allows you to visualise how to access to the structure of these two options.
09/25/02 GPS_field_guide 8:19 A9/P9 19 The 'MARK WAYPOINT' option page Once the GPS receiver has be en set-up and that the user has found an op en area for the reading, this pag e will allow the user to visualise his location (Figure 19). Th e other information or options re ported on this pag e will not be used in the context of the WHS.
09/25/02 GPS_field_guide 8:19 A9/P9 20 The 'UNITS' se tup page This page (Figure 21) allows the user to set up the units of the differ ent parameters. I t is important to make sur e that this pag e contains the setting specific to the WHS as indicated in t he Figure 21 a) and in the Quick R eference Gui de.
09/25/02 GPS_field_guide 8:19 A9/P9 21 CHAPTER 4: TROUBLESHOOTING 4. 1 eTrex do es not turn on: 1. Check to see if the batter ies a re installe d correctly and if the battery te rminals are clean.
09/25/02 GPS_field_guide 8:19 A9/P9 22 - eTrex then asks: 'IS TODAY dd-mmm-yy?'. Two possibilities: a) The date indicated matches the curr ent date : · Press UP/ DOWN buttons · Highlight 'YES' and press the ENTER button, the eTRe x will conti nue tr acki ng satellite s and sw itch to the Satellite page.
09/25/02 GPS_field_guide 8:19 A9/P9 23 4.6 eTrex does n ot disp lay the lo cal time in th e 'SE TUP' pa ge The eTrex operate s on universal time (or GMT, Gree nwich Mean Time ). It is not necessary to have your local time display e d. Do not worry about a wron g display ed time.
09/25/02 GPS_field_guide 8:19 A9/P9 24 GLOSSARY Accuracy : How close to t he real valu e a measur ement is. Backlight: Se lectable on/off illumination that lig hts the display f or enhanced screen a t night and in low lig ht. Contrast: The di fference betw een the li ghtest and darkest a reas on a displa y screen.
09/25/02 GPS_field_guide 8:19 A9/P9 25 Variance: In this context correspond to the errors in magnetic compass re adings caused b y variance in the earth 's magne tic field at different locations on the planet. Waypoint: Current location on the face of the Earth, in terms of the specific latitude/long itude coordinates.
Un point important après l'achat de l'appareil (ou même avant l'achat) est de lire le manuel d'utilisation. Nous devons le faire pour quelques raisons simples:
Si vous n'avez pas encore acheté Garmin GPS c'est un bon moment pour vous familiariser avec les données de base sur le produit. Consulter d'abord les pages initiales du manuel d'utilisation, que vous trouverez ci-dessus. Vous devriez y trouver les données techniques les plus importants du Garmin GPS - de cette manière, vous pouvez vérifier si l'équipement répond à vos besoins. Explorant les pages suivantes du manuel d'utilisation Garmin GPS, vous apprendrez toutes les caractéristiques du produit et des informations sur son fonctionnement. Les informations sur le Garmin GPS va certainement vous aider à prendre une décision concernant l'achat.
Dans une situation où vous avez déjà le Garmin GPS, mais vous avez pas encore lu le manuel d'utilisation, vous devez le faire pour les raisons décrites ci-dessus,. Vous saurez alors si vous avez correctement utilisé les fonctions disponibles, et si vous avez commis des erreurs qui peuvent réduire la durée de vie du Garmin GPS.
Cependant, l'un des rôles les plus importants pour l'utilisateur joués par les manuels d'utilisateur est d'aider à résoudre les problèmes concernant le Garmin GPS. Presque toujours, vous y trouverez Troubleshooting, soit les pannes et les défaillances les plus fréquentes de l'apparei Garmin GPS ainsi que les instructions sur la façon de les résoudre. Même si vous ne parvenez pas à résoudre le problème, le manuel d‘utilisation va vous montrer le chemin d'une nouvelle procédure – le contact avec le centre de service à la clientèle ou le service le plus proche.
