The GPS signals are considered to be in the "Microwave" end of the radio spectrum.
Microwaves are blocked by water, for example a heavy rain. Anyone with satellite television has experienced "rain fade" during heavy rains.
Cooking in a microwave oven, shows that the microwaves pass through the glass cookware and are absorbed by the water molecules.
I often use a hand held GPS when hiking in the forest. When I am walking under a particularly heavy canopy of leaves I will lose the signal because the water in the leaves will absorb the signal.
time when cloud cover was completely blocking GPS Satellite reception. Happened to me in South Carolina -- had Satellite lock when i started out but lost it for about 10 minutes. Finally got a lock as I was floundering around looking for an address that I was unfamiliar with and got there just a little late.
My older Etrex units are pretty much water proof and have withstood some pretty heavy down pours without any damage. However they do not have the high sensitive receiver that my Venture HC has and so heavy rain and cloud cover does affect their ability to acquire satellites sometimes.
The Venture HC is also water proof and does a lot better at satellite acquisition during adverse weather conditions.
My Vehicle type Garmins are not water resistant so I don't let them get rained on. Also they seem to handle cloudy skies pretty well.
I have never had my GPS affected by the weather and I have been through some pretty heavy rain. The only thing I have noticed is if it is blocked by terrain, then the signal will be lost. (Which is a given.)
-- With God, all things are possible.
——State motto of the Great State of Ohio
I often use a hand held GPS when hiking in the forest. When I am walking under a particularly heavy canopy of leaves I will lose the signal because the water in the leaves will absorb the signal.
Seems to me that you lost the signal because of the trees blocking your view of the sky. I've had 4 Nuvi GPS and 2 TomTom and have never lost signal do to weather conditions. Those same devices will loss signal on a walking trail in the woods when there isn't a cloud in the sky.
We have had a satellite dish for over 10 years and have lost signal several times during particularly heavy thunderstorms. My GPS has never lost it's signal although the TV is out.
Seems to me that you lost the signal because of the trees blocking your view of the sky. I've had 4 Nuvi GPS and 2 TomTom and have never lost signal do to weather conditions. Those same devices will loss signal on a walking trail in the woods when there isn't a cloud in the sky.
I didn't mean that I lost the signal due to rain, but rather the large volume of water contained in the overhead leaves.
t923347 wrote:
We have had a satellite dish for over 10 years and have lost signal several times during particularly heavy thunderstorms. My GPS has never lost it's signal although the TV is out.
The frequency of my Bell Satellite TV is about 12GHz while the GPS satellites are between 1-2 GHz. The higher frequencies of the TV satellites are more susceptible to rain fade than the GPS frequencies, but I can assure you that the strength of GPS signals are also reduced by heavy rains.
In your case , you may have been in a location receiving very high signal strengths and the attenuation due to the rain was not enough to affect navigation.
Also remember that if you lose your Satellite TV signal for a second it becomes noticeable, but if you lose the signal on your GPS (for example bring it indoors) it can take up to 30 seconds or more before it complains to you.
More or less, weather will affect the signal, even smog will have some affect as well.
If you have a good GPS receiver and a good antenna, you will not see the difference. But, if you have a design that is few generations old, you probably will be on the mercy of the weather.
Modern units are not affected by weather just line of sight. Most GPS brands do not work in concrete jungles like downtown Chicago.
10 years ago I had a GPS connected to my laptop and that would not worked on stormy days.
The GPS chips are a lot better in this era.
Modern units are not affected by weather just line of sight. Most GPS brands do not work in concrete jungles like downtown Chicago.
10 years ago I had a GPS connected to my laptop and that would not worked on stormy days.
The GPS chips are a lot better in this era.
What you said is mostly true, because you chose your words carefully.
To be entirely correct, GPS signals become attenuated by rain. That hasn't changed in the last 10 years and never will. As you have said the receivers are more sensitive than they were 10 years ago, and therefore often continue working with the weaker GPS signals.
But consider that the more satellites you are locked onto the better your positional accuracy. A heavy rain may cause the weaker satellite signals to be lost all together. This will reduce the accuracy of your position.
When using an automotive GPS this often isn't noticeable because it will always snap you on to the nearest street. However if you are using a hiking GPS and your accuracy is reduced, it could show you somewhere entirely different.
I have noticed that I'm unable to get a signal in my office building even though several stories up.
Maybe the concrete and steel in the walls contributing to the blockage.
I've been in bad storms at sea where we've had a hard time maintaining a fix/position with GPSr's and I've been backcountry snowmobiling or x-country skiing in white-out conditions where it was very difficult to get a fix. But I'd have to say that only extreme weather conditions seem to effect the signal---then again I've been in areas of armed conflict where the U.S. Gov has intentionally hindered GPS accuracy...
NP
-- In times of profound change, the learners will inherit the earth while the "learned" find themselves beautifully equipped to deal with a world that no longer exists...
Well I just took my 665 out for a test on Sunday night. Seems that the big green spot on the weather is indeed RAIN ! !!
Worked quite well and kept telling me that it was rain in the area.
N o kiddin. What a gully washer. Rode north out of green spot and air dried on the ole scoot.
Not the same equipment and other requirements are in place
The GPS equipment required for IFR navigation is much more sensitive and has better antenna system than the units we use in our vehicles and on the trail.
Even with the more advanced equipment the FAA has this to say about GPS navigation:
“In summary, be careful not to rely on GPS to solve all your VFR navigational problems. Unless an IFR receiver is installed in accordance with IFR requirements, no standard of accuracy or integrity has been assured. While the practicality of GPS is compelling, the fact remains that only the pilot can navigate the aircraft, and GPS is just one of the pilot's tools to do the job.”
Under IFR (night and bad weather) this is stated:
Authorization to conduct any GPS operation under IFR requires that:
(a) GPS navigation equipment used must be approved in accordance with the requirements specified in Technical Standard Order (TSO) TSO-C129, or equivalent, and the installation must be done in accordance with Advisory Circular AC 20-138, Airworthiness Approval of Global Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR Supplemental Navigation System, or Advisory Circular AC 20-130A, Airworthiness Approval of Navigation or Flight Management Systems Integrating Multiple Navigation Sensors, or equivalent. Equipment approved in accordance with TSO-C115a does not meet the requirements of TSO-C129. Visual flight rules (VFR) and hand-held GPS systems are not authorized for IFR navigation, instrument approaches, or as a principal instrument flight reference. During IFR operations they may be considered only an aid to situational awareness.
(b) Aircraft using GPS navigation equipment under IFR must be equipped with an approved and operational alternate means of navigation appropriate to the flight. Active monitoring of alternative navigation equipment is not required if the GPS receiver uses RAIM for integrity monitoring. Active monitoring of an alternate means of navigation is required when the RAIM capability of the GPS equipment is lost.
(c) Procedures must be established for use in the event that the loss of RAIM capability is predicted to occur. In situations where this is encountered, the flight must rely on other approved equipment, delay departure, or cancel the flight.
(d) The GPS operation must be conducted in accordance with the FAA-approved aircraft flight manual (AFM) or flight manual supplement. Flight crew members must be thoroughly familiar with the particular GPS equipment installed in the aircraft, the receiver operation manual, and the AFM or flight manual supplement. Unlike ILS and VOR, the basic operation, receiver presentation to the pilot, and some capabilities of the equipment can vary greatly. Due to these differences, operation of different brands, or even models of the same brand, of GPS receiver under IFR should not be attempted without thorough study of the operation of that particular receiver and installation. Most receivers have a built-in simulator mode which will allow the pilot to become familiar with operation prior to attempting operation in the aircraft. Using the equipment in flight under VFR conditions prior to attempting IFR operation will allow further familiarization.
(e) Aircraft navigating by IFR approved GPS are considered to be area navigation (RNAV) aircraft and have special equipment suffixes. File the appropriate equipment suffix in accordance with TBL 5-1-2, on the ATC flight plan. If GPS avionics become inoperative, the pilot should advise ATC and amend the equipment suffix.
(f) Prior to any GPS IFR operation, the pilot must review appropriate NOTAMs and aeronautical information. (See GPS NOTAMs/Aeronautical Information.)
(g) Air carrier and commercial operators must meet the appropriate provisions of their approved operations specifications.
e. Use of GPS for IFR Oceanic, Domestic En Route, and Terminal Area Operations
1. GPS IFR operations in oceanic areas can be conducted as soon as the proper avionics systems are installed, provided all general requirements are met. A GPS installation with TSO-C129 authorization in class A1, A2, B1, B2, C1, or C2 may be used to replace one of the other approved means of long-range navigation, such as dual INS. (See TBL 1-1-5 and TBL 1-1-6.) A single GPS installation with these classes of equipment which provide RAIM for integrity monitoring may also be used on short oceanic routes which have only required one means of long-range navigation.
2. GPS domestic en route and terminal IFR operations can be conducted as soon as proper avionics systems are installed, provided all general requirements are met. The avionics necessary to receive all of the ground-based facilities appropriate for the route to the destination airport and any required alternate airport must be installed and operational. Ground-based facilities necessary for these routes must also be operational.
(a) GPS en route IFR RNAV operations may be conducted in Alaska outside the operational service volume of ground-based navigation aids when a TSO-C145a or TSO-C146a GPS/WAAS system is installed and operating. Ground-based navigation equipment is not required to be installed and operating for en route IFR RNAV operations when using GPS WAAS navigation systems. All operators should ensure that an alternate means of navigation is available in the unlikely event the GPS WAAS navigation system becomes inoperative.
My Nuvi does get lost it seems to only happen when it's fogy and rainy. I get lost signal I think. So I start Google nav and it can't find me either. So I'm thinking it's not Nuvi, but instead week GPS antennas.
GPS signals can be affected by conditions in the ionosphere. For example, a solar wind will change the number of electrons in the ionosphere, in turn this will change the speed of the GPS signal and thus affect the accuracy. So far as is known, solar winds do not affect the local weather conditions.
-- nuvi 855.
Life is not fair. I don't care who told you it is.
It's been so nasty outside
It's been so nasty outside that I haven't wanted to drive anywhere!!!
Couldn't resist.
Fred
.
GPS is not affected by weather conditions.
Blocked By Water
The GPS signals are considered to be in the "Microwave" end of the radio spectrum.
Microwaves are blocked by water, for example a heavy rain. Anyone with satellite television has experienced "rain fade" during heavy rains.
Cooking in a microwave oven, shows that the microwaves pass through the glass cookware and are absorbed by the water molecules.
I often use a hand held GPS when hiking in the forest. When I am walking under a particularly heavy canopy of leaves I will lose the signal because the water in the leaves will absorb the signal.
I have had one
time when cloud cover was completely blocking GPS Satellite reception. Happened to me in South Carolina -- had Satellite lock when i started out but lost it for about 10 minutes. Finally got a lock as I was floundering around looking for an address that I was unfamiliar with and got there just a little late.
Expect nothing!, appreciate benignity!
Never
I've never seen weather affect the performance of my GPS, in particular accuracy.
When you are dead, you don’t know that you are dead. It is only difficult for the others. It is the same when you are stupid.
It depends on type
My older Etrex units are pretty much water proof and have withstood some pretty heavy down pours without any damage. However they do not have the high sensitive receiver that my Venture HC has and so heavy rain and cloud cover does affect their ability to acquire satellites sometimes.
The Venture HC is also water proof and does a lot better at satellite acquisition during adverse weather conditions.
My Vehicle type Garmins are not water resistant so I don't let them get rained on. Also they seem to handle cloudy skies pretty well.
I have never
I have never had my GPS affected by the weather and I have been through some pretty heavy rain. The only thing I have noticed is if it is blocked by terrain, then the signal will be lost. (Which is a given.)
With God, all things are possible. ——State motto of the Great State of Ohio
Interesting
I'll check this out next month during our monsoons
I have had mine drop out
I have had mine drop out during severe thunderstorms. It does seem better than satellite radio though.
John B - Garmin 765T
Seems
I often use a hand held GPS when hiking in the forest. When I am walking under a particularly heavy canopy of leaves I will lose the signal because the water in the leaves will absorb the signal.
Seems to me that you lost the signal because of the trees blocking your view of the sky. I've had 4 Nuvi GPS and 2 TomTom and have never lost signal do to weather conditions. Those same devices will loss signal on a walking trail in the woods when there isn't a cloud in the sky.
We have had a satellite dish for over 10 years and have lost signal several times during particularly heavy thunderstorms. My GPS has never lost it's signal although the TV is out.
Nuvi 350, 760, 1695LM, 3790LMT, 2460LMT, 3597LMTHD, DriveLuxe 50LMTHD, DriveSmart 61, Garmin Drive 52, Garmin Backup Camera 40 and TomTom XXL540s.
Weather
I think the garmin traffic signal is affected by the weather. The gps signal doesn't seem to be affected.
Rain Fade
Seems to me that you lost the signal because of the trees blocking your view of the sky. I've had 4 Nuvi GPS and 2 TomTom and have never lost signal do to weather conditions. Those same devices will loss signal on a walking trail in the woods when there isn't a cloud in the sky.
I didn't mean that I lost the signal due to rain, but rather the large volume of water contained in the overhead leaves.
We have had a satellite dish for over 10 years and have lost signal several times during particularly heavy thunderstorms. My GPS has never lost it's signal although the TV is out.
The frequency of my Bell Satellite TV is about 12GHz while the GPS satellites are between 1-2 GHz. The higher frequencies of the TV satellites are more susceptible to rain fade than the GPS frequencies, but I can assure you that the strength of GPS signals are also reduced by heavy rains.
In your case , you may have been in a location receiving very high signal strengths and the attenuation due to the rain was not enough to affect navigation.
Also remember that if you lose your Satellite TV signal for a second it becomes noticeable, but if you lose the signal on your GPS (for example bring it indoors) it can take up to 30 seconds or more before it complains to you.
depends on your GPS receiver
More or less, weather will affect the signal, even smog will have some affect as well.
If you have a good GPS receiver and a good antenna, you will not see the difference. But, if you have a design that is few generations old, you probably will be on the mercy of the weather.
Modern units are not
Modern units are not affected by weather just line of sight. Most GPS brands do not work in concrete jungles like downtown Chicago.
10 years ago I had a GPS connected to my laptop and that would not worked on stormy days.
The GPS chips are a lot better in this era.
Weather -
I haven't noticed any difference. Guess I'll have to pay more attention to it in the future.
Interesting...
You Are Correct
Modern units are not affected by weather just line of sight. Most GPS brands do not work in concrete jungles like downtown Chicago.
10 years ago I had a GPS connected to my laptop and that would not worked on stormy days.
The GPS chips are a lot better in this era.
What you said is mostly true, because you chose your words carefully.
To be entirely correct, GPS signals become attenuated by rain. That hasn't changed in the last 10 years and never will. As you have said the receivers are more sensitive than they were 10 years ago, and therefore often continue working with the weaker GPS signals.
But consider that the more satellites you are locked onto the better your positional accuracy. A heavy rain may cause the weaker satellite signals to be lost all together. This will reduce the accuracy of your position.
When using an automotive GPS this often isn't noticeable because it will always snap you on to the nearest street. However if you are using a hiking GPS and your accuracy is reduced, it could show you somewhere entirely different.
I have noticed that I'm
I have noticed that I'm unable to get a signal in my office building even though several stories up.
Maybe the concrete and steel in the walls contributing to the blockage.
Depends....
I've been in bad storms at sea where we've had a hard time maintaining a fix/position with GPSr's and I've been backcountry snowmobiling or x-country skiing in white-out conditions where it was very difficult to get a fix. But I'd have to say that only extreme weather conditions seem to effect the signal---then again I've been in areas of armed conflict where the U.S. Gov has intentionally hindered GPS accuracy...
NP
In times of profound change, the learners will inherit the earth while the "learned" find themselves beautifully equipped to deal with a world that no longer exists...
water does affect the civilian GPS frequency
Heavy rain can absolutely impact GPS signals, reducing accuracy and on rare occasions it can be enough to lose navigation capability.
Real life experienced
Well I just took my 665 out for a test on Sunday night. Seems that the big green spot on the weather is indeed RAIN ! !!
Worked quite well and kept telling me that it was rain in the area.
N o kiddin. What a gully washer. Rode north out of green spot and air dried on the ole scoot.
GPS should not be affected
GPS should not be affected by ANY weather or more air craft would miss there mark more often than we know about.
not the same
GPS should not be affected by ANY weather or more air craft would miss there mark more often than we know about.
don't assume the airline industry(commercial/military/private) buys the same quality of equipment consumers do.
Not the same equipment and other requirements are in place
The GPS equipment required for IFR navigation is much more sensitive and has better antenna system than the units we use in our vehicles and on the trail.
Even with the more advanced equipment the FAA has this to say about GPS navigation:
Ref: http://www.faa.gov/air_traffic/publications/atpubs/aim/Chap1...
1-1-19. Global Positioning System (GPS)
Under VFR conditions (nice weather):
“In summary, be careful not to rely on GPS to solve all your VFR navigational problems. Unless an IFR receiver is installed in accordance with IFR requirements, no standard of accuracy or integrity has been assured. While the practicality of GPS is compelling, the fact remains that only the pilot can navigate the aircraft, and GPS is just one of the pilot's tools to do the job.”
Under IFR (night and bad weather) this is stated:
Authorization to conduct any GPS operation under IFR requires that:
(a) GPS navigation equipment used must be approved in accordance with the requirements specified in Technical Standard Order (TSO) TSO-C129, or equivalent, and the installation must be done in accordance with Advisory Circular AC 20-138, Airworthiness Approval of Global Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR Supplemental Navigation System, or Advisory Circular AC 20-130A, Airworthiness Approval of Navigation or Flight Management Systems Integrating Multiple Navigation Sensors, or equivalent. Equipment approved in accordance with TSO-C115a does not meet the requirements of TSO-C129. Visual flight rules (VFR) and hand-held GPS systems are not authorized for IFR navigation, instrument approaches, or as a principal instrument flight reference. During IFR operations they may be considered only an aid to situational awareness.
(b) Aircraft using GPS navigation equipment under IFR must be equipped with an approved and operational alternate means of navigation appropriate to the flight. Active monitoring of alternative navigation equipment is not required if the GPS receiver uses RAIM for integrity monitoring. Active monitoring of an alternate means of navigation is required when the RAIM capability of the GPS equipment is lost.
(c) Procedures must be established for use in the event that the loss of RAIM capability is predicted to occur. In situations where this is encountered, the flight must rely on other approved equipment, delay departure, or cancel the flight.
(d) The GPS operation must be conducted in accordance with the FAA-approved aircraft flight manual (AFM) or flight manual supplement. Flight crew members must be thoroughly familiar with the particular GPS equipment installed in the aircraft, the receiver operation manual, and the AFM or flight manual supplement. Unlike ILS and VOR, the basic operation, receiver presentation to the pilot, and some capabilities of the equipment can vary greatly. Due to these differences, operation of different brands, or even models of the same brand, of GPS receiver under IFR should not be attempted without thorough study of the operation of that particular receiver and installation. Most receivers have a built-in simulator mode which will allow the pilot to become familiar with operation prior to attempting operation in the aircraft. Using the equipment in flight under VFR conditions prior to attempting IFR operation will allow further familiarization.
(e) Aircraft navigating by IFR approved GPS are considered to be area navigation (RNAV) aircraft and have special equipment suffixes. File the appropriate equipment suffix in accordance with TBL 5-1-2, on the ATC flight plan. If GPS avionics become inoperative, the pilot should advise ATC and amend the equipment suffix.
(f) Prior to any GPS IFR operation, the pilot must review appropriate NOTAMs and aeronautical information. (See GPS NOTAMs/Aeronautical Information.)
(g) Air carrier and commercial operators must meet the appropriate provisions of their approved operations specifications.
e. Use of GPS for IFR Oceanic, Domestic En Route, and Terminal Area Operations
1. GPS IFR operations in oceanic areas can be conducted as soon as the proper avionics systems are installed, provided all general requirements are met. A GPS installation with TSO-C129 authorization in class A1, A2, B1, B2, C1, or C2 may be used to replace one of the other approved means of long-range navigation, such as dual INS. (See TBL 1-1-5 and TBL 1-1-6.) A single GPS installation with these classes of equipment which provide RAIM for integrity monitoring may also be used on short oceanic routes which have only required one means of long-range navigation.
2. GPS domestic en route and terminal IFR operations can be conducted as soon as proper avionics systems are installed, provided all general requirements are met. The avionics necessary to receive all of the ground-based facilities appropriate for the route to the destination airport and any required alternate airport must be installed and operational. Ground-based facilities necessary for these routes must also be operational.
(a) GPS en route IFR RNAV operations may be conducted in Alaska outside the operational service volume of ground-based navigation aids when a TSO-C145a or TSO-C146a GPS/WAAS system is installed and operating. Ground-based navigation equipment is not required to be installed and operating for en route IFR RNAV operations when using GPS WAAS navigation systems. All operators should ensure that an alternate means of navigation is available in the unlikely event the GPS WAAS navigation system becomes inoperative.
My Nuvi does get lost it
My Nuvi does get lost it seems to only happen when it's fogy and rainy. I get lost signal I think. So I start Google nav and it can't find me either. So I'm thinking it's not Nuvi, but instead week GPS antennas.
GPS & Weather
GPS is not affected by weather conditions.
You're correct.
GPS signals can be affected by conditions in the ionosphere. For example, a solar wind will change the number of electrons in the ionosphere, in turn this will change the speed of the GPS signal and thus affect the accuracy. So far as is known, solar winds do not affect the local weather conditions.
nuvi 855. Life is not fair. I don't care who told you it is.