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Thread: which GPS?

  1. #1
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    which GPS?

    Would be for keeping my flatlander ass from getting lost on sled in the BC.


    So maybe a topo map with a you are here type shit?


    Which one would you suggest?

  2. #2
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    I have the Garmin Oregon 450 which I really like because of the ability to load my own custom maps. A topo map on its own isnt usually quite enough for you to navigate the backcountry. I use mine for biking & skiing.

    There is a larger screen version called the Montana that is even better. You will find that the handheld trail oriented GPS's a bit more expensive than the car navigation ones, but that's because of the extra features that are necessary for off-road navigation.

    Be aware that there is a learning curve invovled in using a GPS in the backcountry. You had better know how to use it properly before attempting to venture off into the unknown. Also having a GPS doesnt necessarily mean you wont get lost. You have to be proficient on its use and the pre-planning of your route.

  3. #3
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    Make sure it has the golf function also.
    Something about the wrinkle in your forehead tells me there's a fit about to get thrown
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  4. #4
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    good idea on the golf, never thought about that. Vegas had those on the carts.


    So, i guess stick with Garmin and spend tell i get the features i want?

    I've got $400 in gift certs for Cabelas, looks like i'd be into the 450 to 600 range. Maybe more if i have to buy maps.

  5. #5
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    Best and most easy to use GPS would probably be an iPhone and a Lifeproof case. Not as long of battery life compared to the dedicated units, thats about the only downside. I have buddies using iPhones for GPS on weeklong backcountry tours, and they use flexible solar panels to charge them during the day. No point is spending $600 on a GPS when you can spend half that on an iPhone, which certainly does a lot more than a dedicated GPS.

  6. #6
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    ^^Seriously? (Not being sarcastic, I just find that hard to believe).

    I mainly use a GPS to get the lat/long to place myself on the topo every once and a while to make sure I'm on the right track. Does the iPhone have the same positional accuracy as a handheld GPS?
    "Alpine rock and steep, deep powder are what I seek, and I will always find solace there." - Bean Bowers

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  7. #7
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    Just checked my Droid and it had my location off by about 7 miles? However it seemed allright when using it for driving.


    Didn't think about using my phone? Know with mine i'd have to carry extra batteries or keep it turned off. It will drain the battery when there's no signal, and maps app drains it bad also.

  8. #8
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    GPS unit choice depends on how you plan to use it. If you primarily rely on map and compass -- as you should -- it's hard to beat the Garmin 60CSX. Tried and true, great antenna and receiver, amazingly good reception in trees and canyons.

    Consider using UTM instead of lat/lon

    Learn to download waypoints from your mapping software. I use NG Topo

    ETA: I primarily rely on map and compass for navigation, using my GPS unit to verify location, get bearing + distance to stored waypoints and marking camps, stashes, etc. One set of (Eneloop) NiMH cells has powered my 60CSX for up to 9-day high routes, using the unit an average of 2+ hours per day. I carry a spare set of cells but have never needed them.

  9. #9
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    You want something with a good antena, barometric altimeter and magnetic compass all of which working together will give you much better performance than a phone, particularly in trees and narrow canyons and away from cell cervice. Most phones have tinny gps antena use cell towers to get an initial fix on your location...I've had my phone struggle for minutes to get a good fix in a remote area and still be wrong where as the latest generation of gps's are quite reliable and fast.

    Support for standard file formats for free maps and route sharing is nice too.

    I'm using and liking a garmin GPSmap 62s...I kind of wish it had a bigger screen but I think the low weight and good battery life win out for me.

    http://www.gpsfiledepot.com/ has free topo maps by state.

    I'm also working on a bunch of gps specific hillmap (my map site. posted here before) features based on what I find myself wanting on tours. You can draw a route and export it (as a gpx file) to your gps. I use this plus the slope overlays to follow safe ridges up etc. When you get back you can drag and drop the gpx outputed from your gps of your route onto hillmap when you get back and simplify and share it:

    http://www.hillmap.com/m/ag1zfmhpbGx...ZlZE1hcBiZ8REM
    (a sketchy snow day where we stayed off everything steep)

    Check it out, it is free and the ui is much better then NG Topo (since I wrote it). Also hoping to eventually figure out how to output a custom slope + topo map directly to the gps but that may take some doing.

  10. #10
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    Quote Originally Posted by hillmap View Post
    You want something with a good antena, barometric altimeter and magnetic compass. . . .
    Good antenna, certainly. But it's better to have a separate altimeter (watch okay). A traditional needle compass is essential. One with a magnetic declination setting is best. Needle compasses operate flawlessly. OTOH, digital compasses need to be recalibrated from time to time, can render goofy readings and are battery powered.

    A proper navigation kit always has two things: map and compass.

  11. #11
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    Do hand-held gps units have baro altimeters or do they give known elevation?

  12. #12
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    Quote Originally Posted by Big Steve View Post
    Good antenna, certainly. But it's better to have a separate altimeter (watch okay). A traditional needle compass is essential. One with a magnetic declination setting is best. Needle compasses operate flawlessly. OTOH, digital compasses need to be recalibrated from time to time, can render goofy readings and are battery powered.

    A proper navigation kit always has two things: map and compass.
    As I understand it, you want those features as they will help the GPS get a faster better fix in tricky conditions by giving it an initial estimate of elevation and orientation, not to replace other tools in the kit.

  13. #13
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    I've used a Garmin GPSMAP 60Cx with Garmin's TopoCanada for years. With my ATV I use a RAM mount system and a 12V cable. It shows where I am plus a track log of where I've been. Over time I've collected up the track logs on my PC and created a super track log that I compress and download into my GPS to show all the trails. Not as good as being able to edit or annotate a map file but it works. I think the altimeter and compass are a waste of time and battery power. I can wait ten seconds to aquire a signal and calculate my position.

    I use it for hiking too and since it uses AAs I can carry extra batteries for multi-day trips.

    Once the track log and way points are downloaded into my PC I can overlay the data on Google Earth. Great fun.
    If you have a problem & think that someone else is going to solve it for you then you have two problems.

  14. #14
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    Quote Originally Posted by hillmap View Post
    As I understand it, you want those features as they will help the GPS get a faster better fix in tricky conditions by giving it an initial estimate of elevation and orientation, not to replace other tools in the kit.
    Not true AFAIK. The baro-altimeter chip and compass chip are separate from the GPS chip. I’ve never heard of a handheld unit that does what you describe. Where did you hear or read that? And how would the unit’s orientation have anything to do with getting a position fix? Location fix is determined by the difference in timing of receiving signal from each satellite’s atomic clock. I don’t get how the unit’s orientation could affect that function. (Acknowledge that orientation might sometimes affect operation of antenna, but that’s a different issue.)

    Quote Originally Posted by pisteoff View Post
    Do hand-held gps units have baro altimeters or do they give known elevation?
    Some do, but IMO it’s better to have a separate baro-altimeter watch (and old fashion needle compass) so that you have navigation devices if and when the GPS until fails, battery runs out or cannot get a lock. (Better yet, rely primarily on map, compass and altimeter, and use the GPS to supplement, i.e., the safe play.) Not sure what you mean by “known elevation.” Note a handheld unit relying only on GPS satellites usually renders an unreliable elevation number. WAAS sometimes help, but don’t count on getting WAAS signals in the mountains, and you really should carry a separate baro-altimeter (and needle compass) anyway.

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    Quote Originally Posted by Big Steve View Post
    Some do, but IMO it’s better to have a separate baro-altimeter watch (and old fashion needle compass) so that you have navigation devices if and when the GPS until fails, battery runs out or cannot get a lock. (Better yet, rely primarily on map, compass and altimeter, and use the GPS to supplement, i.e., the safe play.) Not sure what you mean by “known elevation.” Note a handheld unit relying only on GPS satellites usually renders an unreliable elevation number. WAAS sometimes help, but don’t count on getting WAAS signals in the mountains, and you really should carry a separate baro-altimeter (and needle compass) anyway.
    Yeah, I'm a map and compass guy too. Don't even own a handheld GPS, and my altimeter watch is a fun toy for clocking vert, but that's about it.

    What I meant by known elevation is do the loaded maps have a data base that jives with the contour lines, so that the unit could display the mapped / surveyed elevation at your location instead of relying on barometric pressure which is less accurate due to changing weather and user error.

  16. #16
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    Some GPS units have maps, but all the maps I've seen on hand held GPS units are manifestly inferior to USGS 7.5' maps for cross country travel. I don't bother looking at the maps on my 60CSX. The better way to get to a point of known elevation is to store pre-trip waypoints that have known elevations and mark them on your paper map. When you get the spot, calibrate your altimeter.

    If you are already a map and compass guy, adding a GPS unit to your navigation kit will be easy and beneficial. It's pretty sweet to get distance and bearing to a pre-stored waypoint (e.g., key notch, saddle, stream crossing) in bad weather.

  17. #17
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    Quote Originally Posted by Big Steve View Post
    Not true AFAIK. The baro-altimeter chip and compass chip are separate from the GPS chip. I’ve never heard of a handheld unit that does what you describe. Where did you hear or read that? And how would the unit’s orientation have anything to do with getting a position fix? Location fix is determined by the difference in timing of receiving signal from each satellite’s atomic clock. I don’t get how the unit’s orientation could affect that function. (Acknowledge that orientation might sometimes affect operation of antenna, but that’s a different issue.)
    I'm extrapolating from statements from phone designers that the barometer in google's new phone is to improve gps performance:

    http://blog.gsmarena.com/google-expl...op-asking-now/

    I assume gamin does something similar but I guess they might not.

    I think you are right about the compass, I looked for the stories I was remembering (from when the iphone got a compass) and think it is only needed for turn by turn navigation in phones to establish direction of travel.

    For the record I'm mostly a map and compass guy as well.

  18. #18
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    Big Steve, thanks for the great posts. Mirrors my thought exactly, though I'm sure you're much better at navigation than I am.

    [geeking out]
    Regarding an earlier point on GPS: Depending on the GPS unit (c-code or p-code), it uses either a time or phase delay to compute position. This is done mathematically - as far as I know, the time or accuracy of the satellite fix does not depend on any other sensor (compass, barometer, etc.) Though interestingly, some companies make tiny INUs that include MEMS-based AHRS and a GPS and use a Kalman filter to integrate the GPS and attitude/heading so you have real-time position...I actually did see a cool one that had a step tracker, with the theory being you would always know EXACTLY where you were (can't seem to find the link now). But I'll keep my USGS map, compass, and altimeter for skiing/climbing/hiking. Though a GPS is extremely handy in certain situations for the reasons Big Steve described above.
    [/geeking out]
    "Alpine rock and steep, deep powder are what I seek, and I will always find solace there." - Bean Bowers

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  19. #19
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    Quote Originally Posted by hillmap View Post
    I'm extrapolating from statements from phone designers that the barometer in google's new phone is to improve gps performance
    If that's happening, I'll lay odds that the Google phone is also getting current barometric pressure from NWS or some other weather source via cell and then comparing NWS baro pressure for a certain site (e.g., SeaTac airport) to the phone's baro pressure. That comparison should give a pretty accurate elevation and could be used to self-calibrate. Fun technology, but not necessary for a mountain travel GPS unit. It would usually be worthless in the wilderness where there is no cell reception. Indeed, the cell receiver's increased battery burden might be detrimental. I don't want to clutter up my GPS unit with a cell receiver and antenna, and I certainly aint paying for cell service when most of my mountain travel lacks LOS to a cell tower.

  20. #20
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    Quote Originally Posted by auvgeek View Post
    Regarding an earlier point on GPS: Depending on the GPS unit (c-code or p-code), it uses either a time or phase delay to compute position. This is done mathematically - as far as I know, the time or accuracy of the satellite fix does not depend on any other sensor (compass, barometer, etc.) Though interestingly, some companies make tiny INUs that include MEMS-based AHRS and a GPS and use a Kalman filter to integrate the GPS and attitude/heading so you have real-time position...I actually did see a cool one that had a step tracker, with the theory being you would always know EXACTLY where you were (can't seem to find the link now).


    Quote Originally Posted by Big Steve View Post
    If that's happening, I'll lay odds that the Google phone is also getting current barometric pressure from NWS or some other weather source via cell and then comparing NWS baro pressure for a certain site (e.g., SeaTac airport) to the phone's baro pressure. That comparison should give a pretty accurate elevation and could be used to self-calibrate. Fun technology, but not necessary for a mountain travel GPS unit. It would usually be worthless in the wilderness where there is no cell reception. Indeed, the cell receiver's increased battery burden might be detrimental. I don't want to clutter up my GPS unit with a cell receiver and antenna, and I certainly aint paying for cell service when most of my mountain travel lacks LOS to a cell tower.
    I'd lay odds that you're right because an altimeter without an altimeter setting is just a barometer. Using your KSEA example, the current setting is 30.10, and the setting 24 hours ago was 29.72. If you set your altimeter yesterday morning, it would read 380 feet lower than your actual elevation today. (I won't even get into the ISA lapse rate)

    So getting this thread back on track... the handheld units don't really have quality maps? That's disappointing. Do they have a useable automated 'bread crumb' history or do you have to stop and drop a pin at strategic locations? I'm guessing that an inexpensive handheld gps won't dead reckon when signal is lost either. The LOS thing seem problematic in the mountains. The satellites are semi-synchronous so I suppose that helps a bit (or hinders depending on time of day?)

    I really want one of these things, but I envision myself standing in the woods swearing at it.

  21. #21
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    I deserved that. But the original video for that is
    "Alpine rock and steep, deep powder are what I seek, and I will always find solace there." - Bean Bowers

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  22. #22
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    I actually debated which I was going to post, and decided on the Mike Kraft version because his voice is more "Troy McClure".

  23. #23
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    Quote Originally Posted by pisteoff View Post
    So getting this thread back on track... the handheld units don't really have quality maps? That's disappointing. Do they have a useable automated 'bread crumb' history or do you have to stop and drop a pin at strategic locations? I'm guessing that an inexpensive handheld gps won't dead reckon when signal is lost either. The LOS thing seem problematic in the mountains.
    Remarkably intelligent and lucid questions for TGR : )

    To me, a “quality” map off trail in the mountains is USGS 7.5'. I can get by with a USGS 15' map in less cliffy terrain. The best handheld GPS unit maps are nothing close to 7.5'. Nonetheless, the GPS on-screen maps can be helpful if used in tandem with a real map – although I almost never bother with the screen map.

    A decent GPS unit with a good antenna and receiver does the bread crumb thing very well. The “manual” mode involves pushing the “mark” button at logical waypoints while on the fly. It will assign the spot with a waypoint number (001, 002, 003, et. seq.) or you can take a bit of time and punch in a name for the waypoint. The “auto” breadcrumb mode involves continuous tracking, but that requires the unit to be on while you are traveling. I prefer to save battery life. If you are an experienced map and compass guy, the manual process works just fine.

    My comment about LOS was confined to WAAS satellites, which supplement the GPS sats for landing aircraft. (Marine vessels might also use WAAS – not sure about that.) My 60CSX gets a lock from 4 or more GPS sats 98%+ of the time in the mountains. Maybe that’s 99%+. Fucking amazing, even in dense trees, up against big rock walls and in canyons. (If you need a GPS in a canyon, you probably ought not be there.) Occasionally a GPS sat signal will bounce off a rock wall a half mile away and render a really whacky reading. That happens, maybe, once per year to me.

    If you get a GPS, make sure your GPS unit and map are synced in the same datum! I won’t attempt to describe that here. Research it and learn it. If your GPS unit is WGS84 and your map is NAD27, you can get your ass in a world of shit.

  24. #24
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    Big Steve FTW....again. Thanks again for all the info, particularly that last bit about syncing the data (odd way to use the word, but it is technically the plural of datum).

    Quote Originally Posted by pisteoff View Post
    I'm guessing that an inexpensive handheld gps won't dead reckon when signal is lost either. The LOS thing seem problematic in the mountains. The satellites are semi-synchronous so I suppose that helps a bit (or hinders depending on time of day?)
    Obviously dead reckoning without a GPS fix is impossible in the absence of some other sensor. This is where LOS w/ a cell tower or some other sensor (Attitude and Heading Reference Sensor -> AHRS) comes in. In fact, the point of my absurd, jargon-filled post above is that there are devices that do this, and quite well, but they're relatively expensive ($1000+) and have an awful user-interface - unless you want to carry a laptop with an RS-232 connection with you and write your own GUI. Unfortunately, I don't know of a particular device that can provide real-time dead reckoning for a human in a convenient package.

    Quote Originally Posted by Big Steve View Post
    My comment about LOS was confined to WAAS satellites, which supplement the GPS sats for landing aircraft. (Marine vessels might also use WAAS – not sure about that.)
    Actually, I don't think WAAS requires LOS - in fact, I think that's it's primary advantage of Differential GPS (DGPS). Some marine vessels may use WAAS, but it's more common of them to use DGPS if doing precision navigation (think dynamic positioning systems). DGPS isn't used for aircraft simply because RF signals can get distorted near the ground and they also require LOS, which I'm pretty sure is why the FAA went to WAAS. I believe you were thinking of Assisted GPS (AGPS), as was mentioned above. (Though, honestly, aircraft navigation is a little outside my field, so feel free to correct me if you know more than I do.)

    Okay, now I'm done making an ass out of myself. Big Steve has covered all the essential points, and I've just continued to dispute minor technicalities that are irrelevant to the major discussion of using handheld GPS for navigating the backcountry.
    "Alpine rock and steep, deep powder are what I seek, and I will always find solace there." - Bean Bowers

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  25. #25
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    Quote Originally Posted by Big Steve View Post
    A decent GPS unit with a good antenna and receiver does the bread crumb thing very well. The “manual” mode involves pushing the “mark” button at logical waypoints while on the fly. It will assign the spot with a waypoint number (001, 002, 003, et. seq.) or you can take a bit of time and punch in a name for the waypoint. The “auto” breadcrumb mode involves continuous tracking, but that requires the unit to be on while you are traveling. I prefer to save battery life. If you are an experienced map and compass guy, the manual process works just fine.
    That sounds encouraging. So it's a trade-off between battery life and annoying your friends with, "just wait guys, I'm typing as fast as I can". How many hours do you typically get on a charge?

    Quote Originally Posted by Big Steve View Post
    My comment about LOS was confined to WAAS satellites, which supplement the GPS sats for landing aircraft. (Marine vessels might also use WAAS – not sure about that.) My 60CSX gets a lock from 4 or more GPS sats 98%+ of the time in the mountains. Maybe that’s 99%+. Fucking amazing, even in dense trees, up against big rock walls and in canyons. (If you need a GPS in a canyon, you probably ought not be there.) Occasionally a GPS sat signal will bounce off a rock wall a half mile away and render a really whacky reading. That happens, maybe, once per year to me.
    I'm familiar with WAAS (it's my day job). That's amazing that you consistently get 4 sats in the mountains/forrest. Can't say that about a cell phone or VHF radio. Now I really want one.

    Oh, and like auvgeek said, thanks for the solid info

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