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[gpsd-dev] [PATCH 1/4] Generalise WAAS to SBAS in documentation.
From: |
Sanjeev Gupta |
Subject: |
[gpsd-dev] [PATCH 1/4] Generalise WAAS to SBAS in documentation. |
Date: |
Fri, 24 Apr 2015 00:40:56 +0800 |
---
www/faq.html.in | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/www/faq.html.in b/www/faq.html.in
index 34fc6e6..f35e631 100644
--- a/www/faq.html.in
+++ b/www/faq.html.in
@@ -95,7 +95,7 @@ GPSD Frequently Asked Questions
<li><a href='#speed'>Why does my receiver report wildly fluctuating
speed?</a></li>
<li><a href='#accuracy'>How can I improve fix accuracy from my
GPS?</a></li>
<li><a href='#time'>How can I improve time reference accuracy from my
GPS?</a></li>
- <li><a href='#waas'>How can I tell if WAAS/EGNOS is working?</a></li>
+ <li><a href='#waas'>How can I tell if SBAS Augmentation (eg WAAS/EGNOS) is
working?</a></li>
</ul>
</li>
@@ -692,15 +692,20 @@ sensor and computer.</p>
<p>There is now a <a href="gpsd-time-service-howto.html">GPSD Time
Service HOWTO</a> that gives detailed setup instructions.</p>
-<h1 id='waas'>How can I tell if WAAS/EGNOS is working?</h1>
+<h1 id='waas'>How can I tell if SBAS Augmentation (eg WAAS/EGNOS) is
working?</h1>
+
+<p>The earliest SBAS systems were WAAS (North America) and EGNOS
+(Europe). Multiple such systems exist, covering Japan (MSAS),
+India (GAGAN), etc, with more being deployed.</p>
<p>In your skyview, look for GPS sats with numbers 120 and above;
-those are the WAAS/EGNOS birds. For U.S. users 138 is the most likely
-PRN to show up. If your GPS receiver can see them at all, it can
-probably use them for correction when you're within range of a
-WAAS/EGNOS ground station. But you can't be sure of this unless
+those are the Space Based Augmentation System (SBAS) birds. For U.S.
+users 138 is the most likely PRN to show up.
+If your GPS receiver can see them at all, it can probably use them
+for correction when you're within the coverage area of a
+SBAS. But you can't be sure of this unless
they're marked as part of the satellite set for a fix. On the other
-hand, some receivers may use them <em>without</em> marking the WAAS/EGNOS
+hand, some receivers may use them <em>without</em> marking the SBAS
satellites as part of the fix set. Vendor documentation in this area
tends to be murky or nonexistent.</p>
@@ -708,11 +713,7 @@ tends to be murky or nonexistent.</p>
after the E or W qualifier for the latitude. This is the GPS fix
quality indicator field. 2 indicates that the receiver is getting and
using differential-GPS corrections. On a consumer-grade GPS this
-usually means WAAS/EGNOS is in use.</p>
-
-<p>Note that for WAAS to work, you need to be within 500 miles of a
-WAAS ground station. At present (2013) coverage is only available
-in the U.S., Europe, and the near ocean waters of these regions.</p>
+usually means SBAS is in use.</p>
<p>Unfortunately, the mere presence of "WAAS" in your receiver's
feature list is not a guarantee that WAAS is actually supported. This
--
2.1.4
- [gpsd-dev] [PATCH 1/4] Generalise WAAS to SBAS in documentation.,
Sanjeev Gupta <=