Article 47383 of sci.geo.satellite-nav: Path: matra.meer.net!news1.best.com!newsxfer3.itd.umich.edu!news-peer.sprintlink.net!news.sprintlink.net!Sprint!vixen.cso.uiuc.edu!newsrelay.iastate.edu!news.msy.bellsouth.net!news.mem.bellsouth.net!news.clt.bellsouth.net!news.mco.bellsouth.net!not-for-mail From: Joe Mehaffey Newsgroups: sci.geo.satellite-nav Subject: Garmin GPS-III Map Internal GPS Receiver: Product Review Date: Mon, 29 Sep 1997 00:08:58 -0400 Lines: 574 Message-ID: <342F29DA.7B92@mehaffey.com> NNTP-Posting-Host: host-207-53-41-21.atl.bellsouth.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; name="g3review.web" Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.03Gold (Win95; U) CC: joem@hi-s.com Content-Disposition: inline; filename="g3review.web" Xref: matra.meer.net sci.geo.satellite-nav:47383 Garmin's GPS-III Road Map GPS Product Review By Joe Mehaffey and Jack Yeazel Release 1> September 24, 1997 When most people get their first GPS receiver, they ask, "Where's the MAP?" Garmin answers that question with their GPS- III receiver. The GPS-III (G3) is Garmin's new handheld 12 channel PARALLEL GPS with built-in maps. The G3 comes in several variants, an Americas road map version and an International version and a "pilot" model with aviation features in both road map versions. This review will focus on the Americas (includes USA) road map edition. While the G3 is perhaps not a revolutionary product, It IS the only unit we know of with extensive (but not nearly exhaustive) road maps of the USA and Canada INCLUDED in the basic unit. The display is much smaller than the map display on a laptop or even a palmtop, but we find the maps both accurate and useful. GPS-III Feature Highlights The G3 is packaged in the same case as the GPS-II+. However, the differences between the two units are substantial. The G3 provides the usual Garmin G-II+ features as a base, but the user interface has been extensively redesigned and for the better. In addition, the G3 has major enhancements including an overview map of the world plus maps of USA interstate, national, primary and secondary state highways, cities, larger towns, waterways, rivers, and coastlines. (Note: See text at the end of this review for more information on map content vs areas.) ALL maps are included in its internal memory. There is no provision for users to upload maps into the GPS. Additional features beyond the G-II+ include: A [100x160] high resolution 4 gray scale display, a world overview map display, road map display, trip computer (includes maximum speed, average speed, trip timer, odometers, etc.) Almost all numeric displays fields are user selectable. A "3D" highway page is another new and innovative feature to provide steering directions along routes or toward waypoints. Roads curve to the right or left as appropriate and "waypoint signs" show directions and progress along a route. Forty six ICONS are available in the G3 to identify waypoints and mark routes. A large diameter calibrated compass rose page provides bearing, course and other information. The battery meter can be set to alkaline, lithium, or NiCad types. Alkaline battery life in the G3 is about 9.5 hours compared with about 24 hours for the G-II+. (Garmin specifies 8 to 10 hours on alkaline cells.) An automatically reset battery use timer is provided so the user can easily compare battery lifetimes. Eleven independ- ent track logs can be used to store an assortment of user tracks. Street pricing of the G3 is about US$360 for the Americas version. One UK vendor's price for the International version is UKP449 inc VAT. Current Garmin plans are for USA dealers NOT to be able to sell the G3 International version apparently to protect their International dealers. Features and Operation Basic functions in the G3 mimic those in the earlier G-II+, but many functions are implemented with enhanced features and users may customize almost every data display field. The G3 incorpo- rates the same 12 channel PARALLEL GPS receiver design used in the G-12XL and G-II+ products. Like these, the G3 locks on to the SV signals quickly. "Warm starts" are typical in 12 seconds. "Cold Starts" after 3 hours off time take 50 to 70 seconds. In Autolocate after a 1000 mile UPS trip, the G3 locked on in less than five minutes. Specifications are "warm start" , 15 seconds, "cold start" 45 seconds, "Autolocate" 5 minutes. These times are typical of 12 channel parallel receivers in the clear and not moving. This is significantly faster than any of the single channel scanning type receivers such as the G-45XL and the M-4000XL (dual channel version) but a bit slower than the G-II+ in our measurements. If the G3 is shielded from SVs (and thus unable to lock) for a time, the unit will request initialization. With Garmin's "Initialize by Map" feature, you do not need your approximate lon/lat to speed up the initial lock when you move more than 300 miles with the unit off. Simply point at your approximate location on the map and press "enter". The G3's specification for position accuracy is 100 meters with SA, 15 meters exclusive of SA and 5 meters with suitable DGPS correction signals. These are the same as the G-12XL and the G- II+. This specification is considerably better than the DGPS specs available with the Eagle Explorer and most low cost single and dual channel multiplexing systems. For instance, the DGPS error specification for the G-45XL is 10 meters. For the EE it is 22 meters. The G3 appears to have enhanced position and velocity filtering as compared with the G-12xl/G-II+ as a result of improved the data filtering algorithms. We notice more directional stability in the compass display when walking as well as somewhat less variation of indicated velocity. The G3 has Garmin's "dead reckoning" feature which, upon loss of SV signals, will project a course for 30 seconds along the last valid heading. This reduces the impact of momentary loss of GPS signals at underpasses, tree cover, and city buildings. Position averaging is available in the G3 to improve the accuracy of individual waypoints. The G3, like the G-12 (and others) uses an over determined solution when more than 4 SVs are locked. This produces somewhat higher accuracy than units which use only the best four SVs. Garmin uses an algorithm that gives varying "authority" to measurements from SVs depending on their geometry, and other factors. This may be responsible for the relatively good accuracy of Garmin's 12 channel parallel receivers. The G3 operates from 4 AA batteries or from external power in the range of 10 to 32 volts DC. External current draw at 12 volts input on my unit is about 65ma (light off). Battery drain is about 150ma (light off). Memory backup power drawn from batteries when the unit is off is about 100 microamps. Eight to ten hours is specified as the AA battery life with Duracell or similar batteries. We got about 9.5 hours of operation with Toshiba AA alkaline cells. This battery life is about 40% of the battery life of the G-II+. Garmin says shorter battery life is a result of the higher power requirements of the components used to support the high resolution display and mapping functions of the unit. The Electroluminescent display lighting has a rated design life of 100,000 hours. The G3 shuts down when the internal battery voltage goes below 4.50vdc. The data/power cable used is the same as the Garmin G-45/12/II+ units. The external antenna connector, a BNC coax jack, is located on the right-rear of the unit just behind the keys. The BNC jack is powered and has a current limit rated at 50ma to protect the unit from shorts on the antenna cable. (Note: We measured 90ma short circuit current on our unit.) However, the standard antenna is passive. We measured 5.54 volts on the connector with antenna load =30ma and battery voltage measuring 5.71vdc on the G3's voltage monitor. The Garmin GA-26 amplified antenna and the MAGELLAN M-4000 amplified antenna both work with the G3. We believe most other amplified GPS antennas, including the Lowe unit, will work as well. The G3 puts out only the NMEA protocol NMEA-0183 ver 2.0 and accepts RTCM-0104. Other proprietary (GARM/GARM) sentences are input/output as well. There is STILL no way to switch from NMEA to up/download without manual intervention. DGPS signals in the RTCM-104 format are accepted. Anytime NMEA output is selected, the baud rate of both the input and output serial port is set to 4800 baud. RTCM (DGPS) alone can use baud rates of 300 to 9600. A setup screen permits selection of the I/O combination needed by a particular application. Operating temperature range is specified as -15C to +70C. Unique in their class, the G3, G-II+, and the G-12XL are rated submersible to one meter per IEC529 IPX(7). The maximum altitude rating is 60,000ft and speed maximum is 999 knots. Feature Details The G3 has a number of features and displays that are useful. These include: (&= Feature essentially identical in the G-II+.) (#= New (or significantly modified) Feature not in the G-II+.) #a) A unique "3D" highway display screen shows the highway ahead including coming curves and turns. A tape compass provides heading. Four digital data fields may have user selectable displays including: altitude, avg. speed, bearing, course, dist to destination, dist to next waypoint, ETA at dest., ETA at next waypoint, max speed, off course distance, course pointer, speed, time of day, time to destination, time to next waypoint, steer to course, track, trip odom, trip timer, turn indicator, user timer, VMG, and destination waypoint. A GOTO waypoint is displayed in a separate field on the highway display. #b) A compass rose display screen shows direction of travel and has an arrow pointing to the next waypoint. This screen provides four user selectable numeric data fields which may display any four of the following: altitude, avg speed, bearing, course, dist to destination, dist to next waypoint, ETA at dest, ETA at next, max speed, off course distance, speed, sunrise time, sunset time, time of day, time to dest, time to next, bearing to course, track, trip odom, trip timer, turn indicator, user timer, VMG, Destination (waypoint), Next (waypoint). The display can show a LARGE letter data fields and a small compass rose OR a LARGE compass rose and smaller data fields. #c) A moving map display is provided to plot your course over ground. (These comments apply to the G3 Americas version.) The detail of the map is the best we have seen in any low cost GPS. Map data includes an overview map of the world plus maps of USA interstate, national, primary and secondary state highways, cities, larger towns, waterways, rivers, and coastlines in its internal memory. Outside of Canada, Mexico and the USA, maps have the same features, but are generally less detailed. In addition, four optional fields on the map display can display four of the following user selectable fields: altitude, avg speed, bearing, course, dist to destination, dist to next waypoint, ETA at dest, ETA at next, max speed, off course, bearing pointer, speed, time of day, time to dest, time to next waypoint, steer to course, track, trip odom, trip timer, turn indicator, user timer, VMG, destination waypoint, next waypoint. Waypoints saved in the machine are displayed on the moving map page as they come within range of the map scale selected. Note: The map detail is quite impressive, but it does NOT show residential streets or (in general) city streets excepting numbered highways and major roads. It is NOT a replacement for Street Atlas 4 or similar. The map screen has pan and zoom and scales from 500 feet to 3000 miles (screen width). Map operation is quite intuitive. You can "point" at any point on the map with the cursor, and the distance and bearing to that waypoint from your present position will be displayed. You can also "mark" and store a new waypoint by moving the cursor to the desired position on the map and pressing the MARK key. You can generate ROUTES directly from the map by either "clicking" on a series of existing waypoints OR by just sequentially "clicking" on a series of map locations. Routes can also be generated from a series of cataloged waypoints as in the G- II+. There appear to be 7 layers of map detail. The map may be set to north up, or current track up. The map display provides an array of user customize features such as map orientation, autozoom, land data (off/on), map line width selection, text size selection, city size selection, and similar. The map screen also supports zoom and pan and "measure distance" features. On the G3, waypoints can have one of 46 symbols such as boat, house, gas pump, etc. When you are moving, an "arrow" pointer shows your direction and leaves a "cookie trail" showing your track. Map accuracy appears to be good. #d) The G3 has a TRIP COMPUTER feature page. This page has a trip odometer, trip timer, maximum speed, odometer, and average speed displays. These displays may be independently or simultaneously reset. &e) A simulator feature provides display of simulated motion and simultaneously outputs simulated tracking data to your computer for test of mapping software, data gathering simulations and such. However, the simulated present position cannot be changed as in the G-II+. If you are in simulator mode and turn off power, a power ON automatically restores normal mode operation. #f) A screen back lighting timer permits setting the backlight to None, 15, 30, 60, 120, and 240 seconds. Backlighting is adjustable in three steps on the G3. The backlighting is uniform and tinted green and the display at night is easy to read. The display has four shades of gray with 100x160 pixel resolution. &g) There is no audible warning tone for alarms or warnings on the G3. &h) A message screen pops up to show system warnings and messages. These include such things as approaching waypoint, no DGPS position, poor gps coverage, and battery is low. The total number of such advisory messages is 26. #i) When the unit is powered ON, a Garmin introductory screen comes on followed by a "land data is provided only as a general reference to your surroundings" page. Then, (no manual intervention necessary), the usual satellite status page comes up. It displays a "fuel" or battery gauge showing battery remaining, and a "compass" display of satellite numbers (1 to 32) in view along with signal strength bars for each satellite potentially in view (up to 12). If the unit is powered from an external source, the "fuel" gauge bar disappears. The signal strength bars are hollow if the GPS has found the SV and has not yet download- ed ephemeris data and changes to solid black when data is received from each satellite in turn. Each signal strength bar is marked with the associated satellite number. On the polar plot, SV numbers are black on white when not locked and white on black when locked. When LOCK occurs, the G3 automatically goes to the map page. #j) Waypoints may be named with a six character name plus a symbol (boat, gas pump, house, etc.) which may be selected from a library of 46 symbols. If you have a "mysterious" waypoint in your list, select it, hit menu, select SHOW MAP and the map will jump to that waypoint location so you can identify it. &k) The G3 has a new track log system. One ACTIVE track log with 1900 log points where track log points are initially recorded and Ten additional "compressed" track logs are provided in the G3. The compressed logs have a maximum of 250 log points and the active track is compressed into a save file. Saved logs are similar to routes in the method in which they are stored AND these saved logs can be used in TracBack when desired. Each saved log can be named with up to 13 characters. By default, the log will be named with the date it was saved. Each saved log can be individually deleted, or TracBacked. &l) TracBack is a feature shared with the G-12XL and the G-II+. If a user goes out along a random track and then wants to return to his point of origin, he may select, TRACBACK, and the G3 will compute up to 30 "best" waypoints for a return path and store them as a Route. When TRACBACK is activated, the unit will route using the computed informa- tion in the Route. In the G3, you can TracBack using any of the eleven compressed track logs. Jack tested the compression algorithm and found it quite accurate. It will duplicate even a small circle in the uncompressed track. &m) The G-II+ accepts the RTCM-104 version 2.0 DGPS correction format. The GPS can control the frequency of the Garmin GBR-21 or other Starlink compatible DGPS receivers when it is set to the RTCM/NMEA mode. (For the Garmin GBR-21 DGPS receiver, you must connect the NMEA output to the DGPS Rx, but you can also use the G3's serial output for your computer's serial port input. In such case, you cannot upload/download data to the G3.) DGPS beacon frequency and signal strength will display on the G3 when DGPS activity is present on the RTCM input. Note: The NMEA I/O baud rate is ALWAYS 4800 baud on the G3 EXCEPT that in RTCM-104 only mode, (no NMEA output), 9600, 4800, 2400, 1200, 600, and 300 baud are selectable. This could be a problem for simultaneous DGPS/NMEA operation since some DGPS receivers will not output at 4800 baud, which is the only speed you can get with RTCM/NMEA. Garmin says that all of Garmin's DGPS ready GPS receivers are compatible with all DGPS receivers which output RTCM SC104 version 2.0 data streams within the above limitation. Alert messages (but no beeps on the G3) alarm DGPS signal failure after about 15 seconds when that mode is enabled. &n) External I/O signal modes available are: NMEA/NONE, RTCM/NMEA, GRMN/GRMN, and RTCM/NONE. If NMEA is one of the selections, the baud rate is automatically 4800 baud. NMEA $GP sentence output list for the G3 is: BOD, GGA, GLL, GSA, GSU, RMB, RMC, RTE, and WPL. BOD and GLL are in addition to those in the G-12xl. &o) No Waypoint Proximity Alarm feature is provided on the G3 (as is present on the G-12XL) as the G3 has no alarm beeper. System setup has an ALARM CLOCK, ARRIVAL ALARM, and OFF COURSE ALARM, but these alarms only produce screen messages and so are of limited value. &p) The user may select a Magnetic heading reference or true north or User Selectable reference as required. &q) The G-3 has 107 built in map datums plus the capability for users to set in their own datum settings. &r) USER GRIDS are NOT currently supported in the G3, but USER DATUMS are. #s) If the ENTER key is pressed and held when the unit is turned ON, an undocumented test screen is activated which inciden- tally measures battery voltage. In addition, Battery voltage and an AUTOMATICALLY RESETTING battery timer may be configured in the user optional data fields on the position page. The "TIMERS" page under system setup provides readouts for the USER TIMER, BATTERY USAGE TIMER, USAGE SINCE MIDNIGHT TIMER and SINCE FACTORY RESET TIMER. &t) The G3 provides 500 user waypoints. These waypoints may be organized into twenty ROUTES (plus one TracBack route) with 30 waypoints each. The G3 has a ROUTE function similar to the G12xl and the G-II+. Twenty routes of up to 30 waypoints each may be input by the user. The G3 does NOT have the feature of being able to add a new waypoint to a route during the input of a new waypoint as was provided in the G-12xl and G-II+. When navigating a ROUTE, as each waypoint is passed, the G3 automatically switches to the next waypoint in the route list. Routes may be inverted to return along a path in the reverse direction. A route may be copied to a new route and renamed. If a route is activated when your location is somewhere in the middle, the nearest waypoint will be selected as the starting point of the route. If you are on a route and do a GoTo, the G3 will take you to the GoTo waypoint and then resume navigat- ing along an active route. &u) The G3 has dedicated ZOOM in/out buttons on the front panel. This permits easy expansion or contraction of the map display with a single keystroke. #v) The G3 offers a waypoint symbol feature for pictorially identifying waypoints. This feature permits the user to show such objects as anchors, boats, gas pumps, houses, cars, fish, etc. (forty six different icons) to further identify waypoints on the map display. &y) A "Delete By Symbol" feature permits deleting all waypoints of a class. TracBack waypoints may be deleted in the G3 as a "class". &z) The G3 offers the ability (like the G-II/II+) of being able to operate its display in the horizontal or vertical format. This is convenient for automobile dash operation. Other: We note that the G3 draws only about 100 microamps from the AA battery in OFF mode whether or not the external power is connected. In storage, this small drain will not deplete the batteries for years. Subjective Observations of Performance Jack Yeazel and I have tested the G3 on the road and in the field. Our G3 has worked without a flaw that either of us could find. We uploaded and downloaded waypoints, tracks and routes using Waypoint+(W95), and G7to..(DOS). We tried it out on SA4, Delorme MapExpert 2, Precision Mapping 3, Vista, AutoRoute 5. No problems found. (Some upload/download programs will require later releases for all of the new G3 functions to upload/download properly. Examples: 46 icons, the Active Route and the 10 compressed track logs in the G3 require updated versions of upload/download software.) Note: We do not suggest that we have tried all features of all programs with the G3. All map programs which specified a NMEA-0183 ver 2.0 data stream as input worked properly with the G3. We compared the G3 with the G-12XL and the G-II+. The G3 performed on a par with the G-12XL and the EE in every test for lock stability, multipath performance, re-lock after an underpass, and ability to suddenly change direction without loss of lock. As with the G-II+, G-12XL and the EE, we were very impressed at the speed the G3 responded to changes in direction. At about 4mph, the G3 would complete a change of direction in about 20 feet. Previously we found with the G-II+, about 15 feet, G-45 about 50ft, and the M-4000, about 60ft. We noted better low (and high) speed stability of the displayed speed. At low speeds, the compass display was noticeably more stable than the G-II+ and the G-12xl's similar displays and the slightly more sluggish response in low speed turns results from the added filtering in the G3. The G3 laid down smooth tracks on our highway maps during all tests. No gaps, jumps, etc., (The G3 has data smoothing like the G-12xl and the G-II+.) Our G3 included the vibration fix Garmin previously installed in the G- II+. We noted that both the G3 (along with the G-12XL and the G-II+) have a form of "dead reckoning" for moments when signal dropouts occur. For instance, if the G-II+ is tracking along and just before a sharp turn you invert it and block its antenna, it will continue to track straight for about 30 seconds. It also provides a very good data smoothing filter to throw out random fixes that are way off track. This results in an exceptionally smooth track on a moving map display even when multipath is present. Even with this filter, there was no overshoot apparent during quick stops, sharp turns, and similar maneuvers when normal continuous tracking was taking place. Performance under tree cover was about the same as the G-II+, G- 12XL and the EE and we rate that as very good. We noted that the G-3 and G-II+ were considerably less sensitive to interference from the Eagle Explorer than is the G-12XL. However, all three units show reduced sensitivity when placed within a few feet of Jack's cellular telephone. We found the display controls easy to learn and use. The menu system and arrangement is considerably improved over the *good* arrangement in the G-II+. The G3 has many additional features as compared with the G-II+, but the reorganization of menus and functions make it (we think) easier and more intuitive to use than the G-II+. Our overall impressions are that the G3 is a substantial improvement in features and performance beyond the G-12XL and the G-II+ even discounting the new built in map features. We used two Toshiba 430CDT laptop computers running moving map software during our tests. The comparison gps units were operated on the dash in front of the driver (G3) and with the G- II+ on the dash in front of the passenger. The laptops with Moving Map Software were used to log tracks, "cookie trails", and operation for comparison. Since the G3, G-12XL and the G-II+ use the same receiver and exhibited essentially identical tracking performance in our tests, we did not perform the extensive field trials we made with the G-12XL, EE, and others. For more information on tracking results with our testing of the G-12XL, and the G-II+ see our reviews at: http://www.bridge.de/~tom/garmin.htm If anyone has any additions, questions, suggestions, error corrections other comments, please feel free to Email Jack or Joe. Joe Mehaffey and Jack Yeazel ================================================================ Other information: ================================================================ WHAT MAPS ARE TO BE INCLUDED IN THE Garmin GPS-III GPS III, AMERICAS Model 010-00126-00 The GPS III, Americas version, includes the United States, Alaska, Canada, Mexico, Central and South America, and covers an area from W180 to W30 Longitude, S60 to N75 Latitude. Also included is a high-level worldwide map with political boundaries and major cities. The standard map coverage for the Americas version includes: 1) Oceans, rivers and lakes (greater than 30 sq. miles) 2) Principal cities and a small number of smaller cities and towns 3) Major interstates and principal highways 4) Political boundaries (state and international borders) A. United States: In addition to the standard map coverage, USA coverage also includes: 1) Small lakes, major streams and rivers 2) Principal urban areas (including Alaska and Hawaii) 3) Railroads 4) National and State level roads, plus some local roads in or near urban areas 5) More detailed coastline 6) Small cities and towns B. Alaska: In addition to the standard map coverage, Alaska coverage also includes: 1) National and State level roads, plus some local roads in or near urban areas 2) Lakes greater than 5 square miles 3) Small cities and towns 4) Railroads C. Canada: In addition to the standard map coverage, Canadian coverage also includes: 1) Lakes greater than 5 square miles-Southern Canada 2) Lakes greater than 10 square miles-Central Canada 3) Railroads D. Mexico, Central and South America: 1) Standard Map Coverage GPS III, INTERNATIONAL 010-00126-01 The GPS III, International version, includes Europe, Asia, Africa, Australia, and Oceania, and covers an area from W30 to E180 Longitude, S60 to N75 Latitude. Also included is a high-level worldwide map with political boundaries and major cities and a portion of the South Pacific. The standard map coverage for the Interna- tional basemap includes: 1) Oceans, rivers and lakes (greater than 30 sq. miles) 2) Principal cities and a small amount of smaller cities and towns 3) Major motorways and/or interstates and principal highways 4) Political boundaries (state and international borders) A. Western Europe, South Africa, Australia, and Oceania: In addition to the standard map coverage, it also includes: 1) Small lakes, major streams and rivers 2) Urban areas 3) Railroads 4) Regional arterial roadways 5) Small cities and towns B. Southeast Asia, China and Japan: In addition to the standard map coverage, it also includes: 1) Lakes greater than 10 square miles 2) Large urban areas 3) Small cities and towns Note: The GPS-III-Pilot versions (Americas and International) have the same map data as is furnished on the standard G3 versions, but the features are not identical. In the AMERICAS version, we noted that the maps in South America are not as complete as in North America particularly as to road maps. Garmin's Statement on the reason that this is true follows: Quote from Garmin follows: * Map data on the G3 for areas outside the USA will almost always be of less detail than in the USA. This is because electronic map data for the USA and to a lesser extent for Canada and Mexico is readily available and free or very low cost. Virtually all other countries around the world charge for this type of data if you can get it at all. Garmin had difficult decisions to make as far as what data to purchase, what to digitize our selves, and what to leave out. We did the best we could given the cost, and potential customer base to pay for our efforts. End of Garmin Quote ================================================================= Features we found "missing" in the G-III receiver and ver 2.00 firmware as compared with the G-II+ are as follows: 1. Changing the present position Lat/Long or UTM in the Simulator mode is not possible. 2. The Pan Keys are disabled after jumping map to a Waypoint. It requires panning across the US to get near a distant Waypoint. (The Pan keys are enabled after jumping map to a Routepoint.) 3. Automatic Route creation with the "Mark" key is not available. Marked waypoints must be selected by "spelling" the waypoint name for each waypoint to be included in a Route. (A work-around is to use the New Route selection and click on map waypoints to create a Route.) 4. The G-III battery life is 10 hours as compared to 24 hours in the G-II+.