Interesting Uses For Gps

[Trail&Stream]

I hear stories and read posts about what everybody does with their GPS units. I figured I'd post a story of my own. My speedometer has been slowly dying this past month or so. Now, I think it's dead. I was driving through Mammoth Cave National Park, when an NPS buddy informed me that the visitor protection rangers were giving tickets at 1-2 miles over. They do have a reputation as jerks at that park. Anyway, that was reason 1. School is now in session. The local motorcycle cops and cruisers are running laser near school zones. Reason 2. The answer: I am now using my GPS as a speedometer. It's mounted on my windshield next to the left windshield post. That screen is large and easy to read, and with the light on, it's great at night. With accuracy such as 20.1 mph, it's especially handy to set my cruise control to. I go RVing with some guys who are addicted to geocaching. I'm not doing that yet, but my little "free" GPS is turning into a lot of fun to play with, and has saved me a repair I can't afford right now, plus I'm sure it's saved me from tickets.

[+IVxIV]

I always thought it was Geocaching itself that was the "alternate use of a GPS"

 

The initial uses of these wonderboxes were for boating/hunting/aviation/etc. And yep I used mine as a speedo too, especially handy when I stuck larger tires on my Jeep causing the dash speedo to read wrong lol

 

I'm flying across the country this weekend & love bringing the gadget on the plane so as to see exactly where I am, how fast the plane is going, etc etc.. great way to fill up some boring hours

 

I've heard of people "hiding" their GPSr in the family car just before their son/daughter borrows it, so as to see where they've been and perhaps how fast they've been driving

[tholt4]

I've already reported to the service department where I purchased my new car that I wanted them to check the speedometor accuarcy when I bring it in for next service because my gpsr shows the speed shown on the car's speedometer is 3 mph too slow.

[+tflight]

Although a more traditional use I've frequently used mine to build maps of hiking, mountain biking, and snowshoeing trails around my area. Turn on track logging, go play, download data, build maps.

[Neo_Geo]

I've already reported to the service department where I purchased my new car that I wanted them to check the speedometor accuarcy when I bring it in for next service because my gpsr shows the speed shown on the car's speedometer is 3 mph too slow.

So it's my understandint that the GPSr will tell you that you're going 30 M.P.H. and your speedo shows 27? As a safety measure, auto manufacturers typically do the reverse - set speedos to report a a few miles FASTER than accurate speed.

[+Couparangus]

As a safety measure, auto manufacturers typically do the reverse - set speedos to report a a few miles FASTER than accurate speed.

 

Agreed. Most every car I've driven is like this. The exception is my new Pontiac Montana which appears to be bang-on. As the tires wear I suspect it will start to show a little faster than what I'm travelling. Conversely my Acura read about 8% too high. I did a speed run at 100MPH and had to go well past that on the speedometer to net it on the GPS "max speed".

 

I use my GPS for work where I'm involved in terrestrial microwave radio planning. It comes in very handy when visiting prospective radio sites and establishing the viability of radio paths. I use it in conjunction with other solftware which generates outputs like this.

The jagged line in the grey area is the elevation along the path above sea level. The red line is the optical line-of-sight. The bottom blue line represents what's known as the 1st Fresnel Zone. In microwave radio you need to keep the 1st Fresnel Zone 60% in the clear to have a reliable path, this represented by the upper blue line. In this case the path isn't obstructed by the land so we know the path to be a good one.

 

Much more information here if anyone is interested. Its always fun to combine a hobby with work.

 

Cheers!

C-A

Edited August 17, 2005 by Couparangus

[+MtnRubi]

I purchased a display-less, "mouse" type GPS unit, and attached it to our companies mail server. I use it only for the purpose of keeping the clock accurate.

 

$69 bucks vs the $1400 they wanted for a commercial GPS based time standard. [8D]

[+tflight]

I purchased a display-less, "mouse" type GPS unit, and attached it to our companies mail server.

Why not just use time synchronization software?

[tholt4]

Neo Geo,

To clarify, the speedometer indicates I am going 3 MPH faster than what the GPSr indicates. I was wondering why more than the usual amount of cars were passing me when I first got the vehicle. I don't agree that auto manufactuers set their speedometers to intentionally show a faster speed than actual speed. My previous 3 vehicle have all been right on with the GPSr when equipped with the original specified tire sizes.

[+A.T.Hiker]

It's probably a good thing some set the speedo's 3-4 MPH faster especially with the way people drive around here. Some people can't handle 3-4 MPH, period!

 

Anyway, I use mine alot for other than geocaching uses. I use it all the time hiking to track distance and make sure I don't become lost. It bailed us out while hiking a remote island in Maine. The fog had gotten so thick that we could not visually see our way back to the dock to catch our ride back to the mainland. Visability had suddenly dropped to about 100 feet, a rather common condition on this island apparently. Fourtunately, I had captured a waypoint before we set off and when I realized we were not in the right spot, I navigated the 0.4 miles to that waypoint and made it back just in time for the 3:00 departure back to the mainland.

 

I also have City Select loaded on both my Legend C and 60C. My big complaint is that A) City Select is a memory hog, making only small areas of map detail possible and The map data is often wrong. Still, the "Find Address" feature has helped me more than hurt, and it's nice when you are vacationing and really don't know where much is in relation to where you are staying. You can navigate to restaurants, address, attractions, even Dunkin Donuts when you have a craving and aren't sure where one is.

[+Greymane]

Well, I fall into that category as well. I have discovered the car speedo is about 3 mph too fast (which is ok with me).

 

I have also heard of tons of other uses for GPSrs. Some are listed below:

• Real estate agents use them to mark property boundaries
  
• Marking gas / power lines
  
• Search and rescue
  
• Finding your way to the still (just kidding)
  
• Some people walk/drive over large areas and create pictures from the track they produce
  
• Kayakers marking danger / caution spots on a river
  
• Hunters marking locations for animal tracks / signs
  

That is just a small sample of some of the things people do with these little gems.

[Neo_Geo]

Neo Geo,

To clarify, the speedometer indicates I am going 3 MPH faster than what the GPSr indicates. I was wondering why more than the usual amount of cars were passing me when I first got the vehicle. I don't agree that auto manufactuers set their speedometers to intentionally show a faster speed than actual speed. My previous 3 vehicle have all been right on with the GPSr when equipped with the original specified tire sizes.

I've read several threads here regarding GPSrs and speedos, and just regurgitating what I read.

 

Gps Miles Per Hour Accuracy, Something seems fishy...

Gpsr Speed Accuracy, How fast can I go?

Your GPS versus your Speedometer - need your input.

[+overtaxed1]

I've used mine as a speedo for my Jeep too - however, my max speed is shown as 117 MPH and I've never driven that fast so I'm skeptical on the accuracy.

 

Must have been some freak satelite error or something .

[Neo_Geo]

Must have been some freak satelite error or something .

 

That happens!

 

I was standing on a street corner in Washington, DC doing 1,084 MPH! CLICK HERE

[marty621]

The jagged line in the grey area is the elevation along the path above sea level. The red line is the optical line-of-sight. The bottom blue line represents what's known as the 1st Fresnel Zone. In microwave radio you need to keep the 1st Fresnel Zone 60% in the clear to have a reliable path, this represented by the upper blue line. In this case the path isn't obstructed by the land so we know the path to be a good one.

 

So to a non-electrical engineer, can we assume that the microwave signals almost sag like a clothesline, a catenary? How wide would the microwave beam be? Or is it a question of signal reflections off the ground terrain? This might explain some weird readings we get on our GPS when near mountains or sheer rock walls.

[marty621]

[*]Some people walk/drive over large areas and create pictures from the track they produce

Check out "Blackjack in the Blackness" , GCH772, cache for this idea.

[JDMC]

I'm adding the capability to USAPhotoMaps for ham radio operators with "TNC" signal converter boxes to receive other ham radio operators with GPSs and "TNC" signal converter boxes, and show their location. This would be good for search-and-rescue (okay, there are already a few other highly-developed programs out there that do this, but...).

[+Couparangus]

microwave signals almost sag like a clothesline, a catenary?

Sorta kinda, but not really.

Or is it a question of signal reflections off the ground terrain?

This is more the reason for it. The wavefront expands as it travels in concentric rings. Think pebble thrown in pond here. There are an infinite number of Fresnel zones but in microwave planning we're normally only concerned with the 1st Fresnel zone, which is calculated based on distance from source and frequency of operation. As you go up in frequency the Fresnel zone becomes smaller. Encroachment on this FZ will impact the wave much as a stick in the water would distort the ring pattern of the pebble if close enough to where it was dropped in the water.

weird readings we get on our GPS when near mountains or sheer rock walls.

Okay, a couple of things are happening here. All RF (radio freq) signals exhibit polarity. Usually they are linear (like a line) and either vertical or horizontally polarized. For any transmission system the Rx (receive) antenna must be polarized in the same manner as the Tx (transmit). If they are opposite, there is (typ) 25-35dB of attenuation (30dB = 1/1000th of original signal). Here are some examples of polarities:

 

Television - H

Two-way radio - V

AM broadcast - V

 

So if you took your TV antenna (assuming you weren't on cable) and flipped it vertically you'd probably lose your picture.

 

GPS signals are different. They are left-hand circularly polarized (LHCP). If you tried to pick them up with a linear antenna there would be 3dB of attenuation (not much), but if you were to try and pick them up with a right-hand circ pol antenna there would be a LOT of attenuation - more than 30dB (typ). That said, the antenna on your GPS is LHCP. The reason for this is simple. When a LHCP polarized signal is reflected off anything (like a rock wall in a cavern) it becomes RHCP and the GPS won't even "see" it. This will cause the recieve to ignore that signal and not give you an erroneous reading. Of course it is hoped that the GPS can still see enough LHCP signals from other satellites to determine where it is. Where the confusion comes in is if the signal is bounced twice, thus becoming LHCP again. Because this can happen in the matter of moving only a few inches (no kidding) the software in the GPS gets confused. Its programmed to ignore the odd bogus signal, but when it starts getting a lot of them then it basically gives up.

 

Another problem is caused by diffraction. Radio signals get bent over sharp obstructions. In the case of a chasm, the GPS may receive a signal that has been bent over the top edge of the cliff. What happens in this case is the actually distance it has travelled is much longer than it would normally be and the GPS therefore thinks that you are lower in elevation that you really are (and also not exactly in the same lat/lon depending upon the geometry). This combined with the above, the weaker signals and receiving fewer satellites pretty much assures you of miserable performance in this type of situation.

 

Cheers!

C-A

[+Rubberhead]

I've used mine as a speedo for my Jeep too - however, my max speed is shown as 117 MPH and I've never driven that fast so I'm skeptical on the accuracy.

 

Must have been some freak satelite error or something .

Reset the max speed after you get a good satellite lock and you won't have a problem.

 

The max speed problems occur most often when a GPS is first getting a lock and the error goes from 200 feet to 17 feet in a second. (200 - 17)/1 = 183 feet per second which is roughly 125 miles per hour.

 

I travel to hunt and fish alot so I've been using my GPSmap 60CS as an alarm clock that always has the right time. I've never had it let me down.

[Neo_Geo]

I travel to hunt and fish alot so I've been using my GPSmap 60CS as an alarm clock that always has the right time. I've never had it let me down.

Yep - I've used the alarm clock feature many times, especially while traveling. I've been known to use the calculator a couple of times as well.

[+wornout]

I pass out real estate flyers for a friend every once in a while. While walking the route, I turn on track log. When I get back to the office, I load the track into mapsource, print the map and it shows where I walked. They loved it....

[+gdeas]

I use my Garmin Map 60 to plot flight plans for aerial photos. On occasion, I will have as many as 20 buildings to photograph from a helicopter. It can be very difficult to identify a specific building from the air. This allows me to locate the facilities easily from the air and keeps my charter time to a minimum by having my pilot simply follow the gps!

[+2Wheel'in]

I use a Garmin Foretrex as a replacement for the "cyclocomputer" on my mountain bike. The Foretrex gives all the basic bike computer functions: speed, average speed, max speed, distance, trip time, etc.. Plus I download the tracklog on National Geographic software to overlay my rides on topographic maps (shows the route plus the elevation profile). The maps can be used/shared with other riders as "cue sheets"....pretty cool actually.

Regards,

Bill

[Mittellegi]

I've heard of people strapping a GPS to their dog's collar. It's surprising where they get to at night...

[+overtaxed1]

I use a Garmin Foretrex as a replacement for the "cyclocomputer" on my mountain bike.  The Foretrex gives all the basic bike computer functions: speed, average speed, max speed, distance, trip time, etc.. Plus I download the tracklog on National Geographic software to overlay my rides on topographic maps (shows the route plus the elevation profile).  The maps can be used/shared with other riders as "cue sheets"....pretty cool actually.

Regards,

  Bill

I've done this before too - it sure beats using the ol' Avecet (spelling?) that I had when I first got into Mtn Biking. I keep thinking I'm gonna take my track logs and make some website with my favorite trails - sigh - there's never enough time to do it all.

[+MtnRubi]

(MtnRubi @ Aug 17 2005, 07:05 AM)

I purchased a display-less, "mouse" type GPS unit, and attached it to our companies mail server.

 

Why not just use time synchronization software?

 

Without it turning into a WAAYYY too long story, lets just say our engineering staff had some major concerns during a time when our T1 was less than reliable, and they required our time server to be 'stratum 1'

 

Yeah, I know....

[Difficult Run]

I've attached the gps to my riding lawnmower. You would be surprised to see just how far you traveled.

 

Also, I've seen higher end gps units being incorporated into commercial farming equipment, i.e., tractors and combines. Saw it on the History Channel a few months ago.

 

Even truckers have gps units installed on the big rigs. I guess management uses the data to micromanage the lonely trucker.

 

The possibilities are really endless.

[+Rubberhead]

In the old days it took days to locate areas where ducks were feeding in the twisted coastal marshes that don't have much in the way of trees or other landmarks.

 

Even if I could draw a bearing with a compass by the time I rode through the winding creeks, I'd be lost.

 

Anyway, now I use sight-n-go and draw two bearings to where I'm seeing ducks in the air. Right were the lines cross - the ducks.

 

It's easy as pie.

[+Crystal Sound]

I"m always finding new uses for my GPS, particularly work related.

 

The most recent comes from last weekend...

 

I do sound & lighting work for a wide variety of events. Last weekend, I was asked to provide sound coverage over a multiple-city-block-area. This meant, I had to run ALOT of wire to the different locations where speakers would be located.

 

Using my handy GPS as a (long) tape measure, I was able to easily approximate how far cables would run, where speakers would be placed, coverage areas, and more.

[OuttaHand]

This is related to you folks who use it as a speedo.

 

I used to work in an auto shop as the shop manager. Had a customer come in who had gotten a speeding ticket. He honestly believed his speedo was off and was trying to get the ticket reduced from speeding to 'defective equipment' or some such. He wanted us to test his speede.

 

So I ran home, got my GPS, and took the car for a leisurely ride. I found his speed to be about 3mph off and noted it on the work card for him.

 

Weather or not he actually got the ticket reduced, I don't know.

[+AZBuckeye04]

Also, I've seen higher end gps units being incorporated into commercial farming equipment, i.e., tractors and combines.  Saw it on the History Channel a few months ago.

You couldn't be MORE right. GPS units have been used by farmers for YEARS (in some form or another)! I actually can remember my high school Agriculture teacher talking to us about how they will someday be almost commonplace for farmers (granted that was only like 7 years ago, but still). One of the most impressive displays of farmers using this technology is in Corn Mazes. Below is a picture from a corn maze that's located just north (like .15 mi) from my parents house:

A GPS unit in a combine, that's all you need! Kinda cool. If you want to see more photos check out MazePlay.com

 

Ohh, and a quick note on that speedometer issue. Keep in mind that changing your wheel/tire size can also have an effect on your actual speed. Don't ask me to explain how, cause I don't remember, just google it!

 

Take Care,

Jared of AZBliss02

[+RJFerret]

From a car forum I frequent, apparently US DOT requires speedos to read 0-5 mph high. (That's FAR better than being a little low.)

 

I've used it to find Lat/Long settings for astronomical observations and tide tables.

 

The speedo thing (nearly 70 mph on skis, 12 mph on swingset, I forget on lawn tractor).

 

Verify speedo variance when installed different sized tires.

 

Locate property boundaries... Used as compass to see above ground where a cave went underneath.

 

Weather forecasting: used the barometer to determine weather trend (deciding to camp or not before sunset)--'twas right thankfully.

 

I've also used it as yellow pages (phone numbers from POI data).

 

Hah! Just (an hour ago) used autorouting to calculate driving mileage for IRS tax deduction purposes!

 

Enjoy,

 

Randy

[+Cornix]

Interesting Uses For Gps, Alternate uses for GPS ...

Just listen to Radio K.A.O.S., or read the transcript.

 

Cornix

[WH]

Ohh, and a quick note on that speedometer issue. Keep in mind that changing your wheel/tire size can also have an effect on your actual speed. Don't ask me to explain how, cause I don't remember, just google it!

 

Larger tires have a larger circumference so for each turn of the axle, your car travels further than with a smaller tire.

 

Thus a bigger tire will make you travel slightly faster than a smaller one.

Edited August 19, 2005 by WH

[+AZBuckeye04]

Ohh, and a quick note on that speedometer issue. Keep in mind that changing your wheel/tire size can also have an effect on your actual speed. Don't ask me to explain how, cause I don't remember, just google it!

 

Larger tires have a larger circumference so for each turn of the axle, your car travels further than with a smaller tire.

 

Thus a bigger tire will make you travel slightly faster than a smaller one.

Exactly! DUH!!! Thanks WH, I knew it was something like that. My dad was looking into plus sizing his wheels and found that going up an inch doesn't even add 1mph extra, so the effect is pretty minimal.

[mudhuggers]

ALTERNATE USES FOR GPS:

- In the Boat for Duck Hunting to go back to a good hunting spot on the lake at 3 am in the early morning fog/mist.

- 4x4ing cross country at night with night vision goggles trying to find lost people giving you the coordinates on the radio....I would not recommend this at home............

[rooster97]

I deer hunt once a year. Distance from your stand to your maximum effective range can be really important to make a good shot. Add to that the difficulty in estimating over varied terrian. 100 yrds over changes in elevation does not equate to true line of sight (which all a bullet cares about) I used to spend a lot of time pacing the distances in each direction and marking with a flag. Guess how I do it now?

[Overland1]

I've attached the gps to my riding lawnmower.  You would be surprised to see just how far you traveled.

 

Also, I've seen higher end gps units being incorporated into commercial farming equipment, i.e., tractors and combines.  Saw it on the History Channel a few months ago.

 

Even truckers have gps units installed on the big rigs.  I guess management uses the data to micromanage the lonely trucker. 

 

The possibilities are really endless.

I did that (geomowing?) once when I first got my eTrex Vista...... it showed some fairly accurate paths for the ol' Dixon ZTR, and it also showed this one path to a point across the streetand back.... everybody asked why I went across the street (was I visiting the neighbor?).

 

Many cars have speedometers that read a bit high because they come equipped with a "standard" sized tire. The optional sized tire is often slightly larger and the speedometer is then corrected. Several years ago, my 1998 Jeep GC had 225/75-15's as OEM tires; when I upgraded to 235/75-15's, the speedometer was dead on.

 

My current Jeep speedometer is quite accurate, but my motorcycle speedometer reads 3-4% high .

 

By the way, I have used the GPS for locating a Landing Zone on Rescue/EMS calls - works like a charm every time.

Edited August 22, 2005 by Overland1

[+doggity]

Okay - here's a good (bad) one . . . !

 

I heard that taxi cabs in major cities use gps to coordinate those TV-type advertising monitors on their roofs, for "location sensitive" marketing.

 

For example when you get withing a certain radius, the advertising will change content and say something like "You are only 1 block from McDonalds"

 

I suppose its handy if you are lost in a city and in need to pick up some cache swag . . .

 

Carry On!

doggity