Accuracy, iPhone SOS, updated videos and Andy’s top tips
Currently in Orbit
GPS – 31 with 24 operational 95% of the time – Dual Frequency L1 & L5
In March 2021, about 52% of GPS satellites had L5. By 2023, we expect about 71%
GLONASS – 23 Operational – Single Frequency L1
GALILEO – 30 with 24 operational – Dual Frequency E1 & E5
We tend to find using GPS & Galileo we achieve approx.. 10ft (3m) Glonass similar
We have seen with GPS & Galileo / WASS & EGNOS on with a high sensitive antenna GPS Device e.g. GPSMap 65,66,86 Montana 700 Series accuracy down to approx. 8ft (2.5m)
We tend to find with Multi Band + GNSS using a GPSMap65s or 66sr unit accuracy approx. – 7ft (2M) we have seen this down as low as 5ft (1.5m)
Things that affect accuracy – How are you holding the device, view of sky, tall buildings cliffs etc.
A handheld Device needs to lock onto 4 x Satellites locked to determine both your location and GPS height data.
Etrex 10,22x,32x, Touch 25 & 35 use GPS or GPS & Glonass + Waas / Egnoss
Oregon 700– use GPS or GPS & Glonass + Waas / Egnoss
GPSMap66s uses GPS or GPS & Glonass or GPS & Galileo + Wass / Egnoss
GPSMap66i uses GPS or GPS & Galileo + Wass Egnoss
Montana 700 uses GPS or GPS & Glonass or GPS & Galileo + Wass / Egnoss
Montana 700i / 750i uses GPS or GPS & Galileo + Wass / Egnoss
GPSMap65s & 66sr – GPS or Multi GNSS or Multi GNSS + Multi Band
Multi GNSS Picks up GPS, GLONASS & Galileo
Multi GNSS + Multi Band (Dual Frequency) – GPS, GLONASS & Galileo L1 (e1) & GPS & Galileo L5 (e5)
When the 65 or 66sr receives multi-band from a satellite, it can use those multiple signals to do quality analysis and correction, reducing the error introduced by bouncing signals (multi-path error) and the earth’s atmosphere.
What Advantages Do Multi-Band Devices Have Over Other Models?
More consistent tracklogs and improved positioning when using the device in challenging environments (e.g. around tall buildings in urban canyons as well as tree cover).
Can achieve accuracy within about +/- 2 meters or 6 feet under ideal conditions versus the +/- 3 meters or 10 feet accuracy of other models.
Detect (and reject) reflected satellite signals better than a single frequency receiver which improves accuracy.
Better equipped to account for and correct errors that can be introduced by atmospheric effects (e.g. ionosphere errors).
WAAS – Wide Area Augmentation System
WAAS consists of multiple ground reference stations positioned across the U.S. that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through 1 of 2 geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.
Who benefits from WAAS?
Currently, WAAS satellite coverage is only available in North America. There are no ground reference stations in South America, so even though GPS users there can receive WAAS, the signal has not been corrected and thus would not improve the accuracy of their unit. For some users in the U.S., the position of the satellites over the equator makes it difficult to receive the signals when trees or mountains obstruct the view of the horizon. WAAS signal reception is ideal for open land and marine applications. WAAS provides extended coverage both inland and offshore
EGNOS – European Geostationary Navigation Overlay Service
The European Geostationary Navigation Overlay Service (EGNOS) is Europe’s regional satellite-based augmentation system (SBAS) that is used to improve the performance of global navigation satellite systems (GNSSs), such as GPS and Galileo. It has been deployed to provide safety of life navigation services to aviation, maritime and land-based users over most of Europe.
The services will be progressively extended to the European Neighbourhood countries. Funding has already been allocated by the European Commission through the European Neighbourhood Instrument for infrastructure and technology development. Learn more about the EGNOS extension to the Eastern European Neighbourhood here.
EGNOS uses GNSS measurements taken by accurately located reference stations deployed across Europe. All measured GNSS errors are transferred to a central computing centre, where differential corrections and integrity messages are calculated. These calculations are then broadcast over the covered area using geostationary satellites that serve as an augmentation, or overlay, to the original GNSS message.
As a result, EGNOS improves the accuracy and reliability of GNSS positioning information, while also providing a crucial integrity message regarding the continuity and availability of a signal. In addition, EGNOS also transmits an extremely accurate universal time signal.
What new videos have you added over the past few months?
Discount code landing page – https://mailchi.mp/gpstraining/youtubeoffer
To find out more about our GPS Training online resource please go to our website – GPSTraining.co.uk > then click on ‘online resource’ on the top menu bar
AND you will find a link to the discount code in the Podcast show notes – https://mailchi.mp/gpstraining/youtubeoffer
In mid-September 2022 at the launch of the iPhone 14 the world was introduced to the function of sending a SOS signal via satellites from your iPhone in the very near future.
Initially, this was just going to be in the US, but on the 13th December 2022 this was also rolled out for UK users, at the same time it was rolled out for France, Germany and Ireland.
How did we first discover this was in place?
The first question we need to ask listeners, has anybody in the UK used it?
So, the big question must be, is this a replacement for those using a current outdoor satellite communicator, such as a Spot, Garmin inReach or Zoleo user?
Globalstar – Traditionally been the ‘budget’ option but with a massive cash injection from Apple will this change?
According to Reuters, Apple will pay for 95% of the approved capital expenditure for the new satellites needed to support the service.
In the world we are in I have heard the phrase ‘Apple have literally bought Globalstar out’, but with Apple being the 6th richest company in the world in 2022, why not?
Iridium – Garmin inReach (inReach messenger, mini 1+ 2, GPSMAP66i, Montana 700i, 750i) and Zoleo
Used a lot by SatPhones etc but more expensive technology
BUT, these are automatically routed to local emergency services via text.
If you are outside the UK or it ends up at an emergency responder centre that does not receive emergency text messages these messages are routed through one of Apples Emergency relay centres. Apple have over 300 members of staff in these call centres and they will also deal with those requests that it may be unsure who the emergency messages should be routed to.
Once you press the SOS button on any of these products the signal goes to the Garmin IERCC centre (Garmin InReach Emergency Response Coordination Centre), it’s interesting that this is owned by Garmin but both Spot and Zoleo users also use the same facility.
To find out more about this subject there is a new article online which has x 10 videos taking you through the whole subject. Just go to GPStraining.co.uk > Product Reviews > iPhone 14 SOS and tracking v Garmin inReach, Zoleo and Spot Outdoor trackers
We talked about satellite accuracy – using the Satellite page on your home screen – this will also display your grid reference.
Setup – System – Position format for GB BNG or research for country you are going to.
If Satellite not on homepage touch screens add page or push button press menu button once from home screen – select change item order – move cursor to add page – application – satellite.
To find more top tips please do sign up for the GPS Training online resource, this is packed full of video top tips. Go to our website – gpstraining.co.uk and click on the – Online resource – on the top menu bar
Tel: 01669 621044