GPS Accuracy

[+cobreadbasket]

First time we went out alone, downloaded 5 caches and couldn't find any of them. Is there a quick way to test the accuracy of our GPS's coordinates? We have a DeLorme PN 40.

[Motorcycle_Mama]

Your GPS unit is likely very accurate.

 

Here are some tips when first starting out.

 

1. Stick with Regular and Large size Traditional caches at first.

2. Stick with Difficulty and Terrain ratings of 1 and 1.5.

3. Read the whole cache page before you go including the previous logs.

4. Check out the cache on Google Maps to get a sense of the approximate area.

5. If you are loading the coordinates manually, be sure that you are using the correct coordinate format and be absolutely sure that you have entered the correctly.

6. Use the GPS unit to get you to the general area (20 - 30 feet) and then put it away and use your senses.

7. Look for hiding places. Think like a hider. Look for things out of place like piles of rocks and sticks. Look for cracks and crevices.

8. Do expect your GPS unit to take to the "exact" location.

9. If you don't find the cache after a thorough search, just move on to the next one.

10. Most of all, don't get discouraged and have fun.

[+dfx]

8. Do NOT expect your GPS unit to take to the "exact" location.

fixed that for ya

[Motorcycle_Mama]

Whoops! Thanks!

[+jaydeadheader]

there are so many caches i have missed, and researched more, went back, looked and couldnt find it again, looked again and again and again everytime getting wiser and closer to my goal

 

trust me, move on to the next one, and come back with a clear head, if its there, u will find it eventually

 

dont get discouraged

[+briansnat]

Your GPS has a a data field called GPS Accuracy (it's also know as EPE or estimated position error). It is an estimate of its accuracy at that moment. Being an estimate take it with a grain of salt.

[+Z_Statman]

So correct briansnat

 

Once I am in the area I switch to Compass where I have 4 data fields: Lat/Long, Dist to Dest, Battery level and GPS accuracy

 

I find that the Lat/Long & D to D turn out to be very reliable, within a few feet. Battery level is noted because I have found that when it shows 1-2 bars the "accuracy" degrades dramatically.

 

HTH

[dwlover]

i didnt know battery affected accuracy. is that true on iphones as well as regular gpses?

[+Team Cotati]

i didnt know battery affected accuracy. is that true on iphones as well as regular gpses?

 

It doesn't.

[+randco]

First time we went out alone, downloaded 5 caches and couldn't find any of them. Is there a quick way to test the accuracy of our GPS's coordinates? We have a DeLorme PN 40.

 

A quick way is to stand in a place outdoors and "mark" your current location and place a marker or something you can identify in the location. Your marked location is now a waypoint in your GPS'r.

 

Now walk about 100 feet in any direction away from the marked location. On your GPS'r select the waypoint that you marked and let you GPS'r lead you to that location. If you are really really lucky your GPS'r will take you directly to the location. If your GPS'r indicates that your are at your marked location but you are really 10 or more feet from the actual location, your accuracy in not so good. Accuracy <=10 feet is normal.

[+Z_Statman]

Not so fast Team Cotati, it could particularly regarding WAAS and sat refreshing. There is a lot of battery drain here and a low level can affect that refresh.

[+Team Cotati]

Not so fast Team Cotati, it could particularly regarding WAAS and sat refreshing. There is a lot of battery drain here and a low level can affect that refresh.

 

OK, you win.

[Ed and Cindy]

First time we went out alone, downloaded 5 caches and couldn't find any of them. Is there a quick way to test the accuracy of our GPS's coordinates? We have a DeLorme PN 40.

 

A quick way is to stand in a place outdoors and "mark" your current location and place a marker or something you can identify in the location. Your marked location is now a waypoint in your GPS'r.

 

Now walk about 100 feet in any direction away from the marked location. On your GPS'r select the waypoint that you marked and let you GPS'r lead you to that location. If you are really really lucky your GPS'r will take you directly to the location. If your GPS'r indicates that your are at your marked location but you are really 10 or more feet from the actual location, your accuracy in not so good. Accuracy <=10 feet is normal.

 

I actually have another question and this is the only way I can figure out to ask it...lol When hiding a cache, do you make the coordinates right where you place it? Im asking because we used the coordinates where we parked our car, then used clues to get you to the find. Please advise. Thanks, Ed and Cindy

[+smithdk]

First time we went out alone, downloaded 5 caches and couldn't find any of them. Is there a quick way to test the accuracy of our GPS's coordinates? We have a DeLorme PN 40.

 

A quick way is to stand in a place outdoors and "mark" your current location and place a marker or something you can identify in the location. Your marked location is now a waypoint in your GPS'r.

 

Now walk about 100 feet in any direction away from the marked location. On your GPS'r select the waypoint that you marked and let you GPS'r lead you to that location. If you are really really lucky your GPS'r will take you directly to the location. If your GPS'r indicates that your are at your marked location but you are really 10 or more feet from the actual location, your accuracy in not so good. Accuracy <=10 feet is normal.

 

I actually have another question and this is the only way I can figure out to ask it...lol When hiding a cache, do you make the coordinates right where you place it? Im asking because we used the coordinates where we parked our car, then used clues to get you to the find. Please advise. Thanks, Ed and Cindy

 

Use the coordinates where you hid the cache.

[+randco]

I actually have another question and this is the only way I can figure out to ask it...lol When hiding a cache, do you make the coordinates right where you place it? I'm asking because we used the coordinates where we parked our car, then used clues to get you to the find. Please advise. Thanks, Ed and Cindy

 

Mark the coordinates where you place the cache.

 

If you want to do something like you have mentioned you did, create a multi-cache. The first part of the multi would be the parking lot. Make up some type of puzzle, for example. Count the number of parking spaces on the North, South East and West side of the parking lot.

 

North spaces = A

South spaces = B

East spaces = C

West spaces = D

 

N27 (A+12).(714-(B*2)) W082 ((A+D).(214+B+C)-D)

 

The result of the formula will be the actual location of the cache.

 

Or find intersting ways to mix things up. Like count the number of steel sign posts or the number of a particular type of tree.

[hoosier guy]

So correct briansnat

 

Once I am in the area I switch to Compass where I have 4 data fields: Lat/Long, Dist to Dest, Battery level and GPS accuracy

 

I find that the Lat/Long & D to D turn out to be very reliable, within a few feet. Battery level is noted because I have found that when it shows 1-2 bars the "accuracy" degrades dramatically.

 

HTH

 

Had not thought of doing that, what a good idea.

[+Prime Suspect]

Not so fast Team Cotati, it could particularly regarding WAAS and sat refreshing. There is a lot of battery drain here and a low level can affect that refresh.

Modern units work just fine with the 2.5v of NiMH batteries, compared with the full 3v of alkalines. An electronic compass is affected by a voltage change from the time is was calibrated. But the GPS is either going to work correctly, or it's going to shut off before it starts giving inaccurate data. And any additional WAAS drain on modern units is not that significant. SiRF Star III and its ilk are all low power consumption chipsets. The bit about WAAS being a big power drain goes back to before the days of the high performance chips. It was true for the chipsets of that era. Today? Not so much.

 

For example, a Colorado, running with all the features turned off (in standard mode), uses about 134mA. Turning WAAS on full time only adds about 7mA to the total power consumption. By comparison, turning the back-light on at 100% brightness will add about 31mA to the power consumption.

[+CacheADoodleDo]

Not so fast Team Cotati, it could particularly regarding WAAS and sat refreshing. There is a lot of battery drain here and a low level can affect that refresh.

Modern units work just fine with the 2.5v of NiMH batteries, compared with the full 3v of alkalines. An electronic compass is affected by a voltage change from the time is was calibrated. But the GPS is either going to work correctly, or it's going to shut off before it starts giving inaccurate data. And any additional WAAS drain on modern units is not that significant. SiRF Star III and its ilk are all low power consumption chipsets. The bit about WAAS being a big power drain goes back to before the days of the high performance chips. It was true for the chipsets of that era. Today? Not so much.

 

For example, a Colorado, running with all the features turned off (in standard mode), uses about 134mA. Turning WAAS on full time only adds about 7mA to the total power consumption. By comparison, turning the back-light on at 100% brightness will add about 31mA to the power consumption.

Say whaaaat??!? It's all Greek to me - lol.

Edited August 18, 2010 by CacheADoodleDo