Docs: Add HAS/E6 corrections

Author: nseidle

docs/correction_sources.md

@@ -50,4 +50,15 @@ Not all companies providing correction services use the same type of corrections
 
 **State Space Representation** (SSR) covers huge areas, sometimes entire continents. SSR combines the readings from a handful of base stations and creates a model for the region. This model extrapolates the needed corrections for a given area. These corrections are 'good enough' for many applications. Because SSR requires far fewer base stations, they are often a much lower-cost service. The RTK Fix accuracy is lower (20mm is possible but 30-60mm is common), and the convergence time increases considerably. Convergence time for an SSR can be 180 seconds or more.
 
-The [PointPerfect](https://www.u-blox.com/en/pointperfect-service-coverage) and [Skylark Cx](https://www.swiftnav.com/products/skylark) are examples of an SSR. 
+The [PointPerfect](https://www.u-blox.com/en/pointperfect-service-coverage) and [Skylark Cx](https://www.swiftnav.com/products/skylark) are examples of an SSR. 
+
+## Galileo HAS
+
+Torch: ![Feature Supported](img/Icons/GreenDot.png)
+
+The European Union launched a free correction service called [High Accuracy Service](https://www.gsc-europa.eu/galileo/services/galileo-high-accuracy-service-has) or **HAS** starting in 2023. The service is delivered over the E6 frequency. In general, this service will greatly improve accuracy to receivers but is lower accuracy than an OSR or SSR-based RTK Fix. Additionally, a receiver can take up to 5 minutes to benefit from these corrections (convergence time is larger), as opposed to OSR (seconds) or SSR (~180 seconds) to achieve maximum accuracy. But HAS is free! And available with very little additional configuration.
+
+Various SparkFun RTK products support this new GNSS band (E6). In general, the RTK Torch will need UM980 firmware 118333 or newer. See how to [Update the UM980 Firmware](firmware_update#updating-um980-firmware) for instructions. HAS/E6 is enabled by default and can be disabled in the [GNSS Menu](menu_gnss.md#galileo-e6-corrections) if desired.
+
+
+

docs/img/Terminal/SparkFun RTK Everywhere - GNSS Menu Constellations.png

@@ -44,13 +44,17 @@ A minimum C/N0 is set in dB. If a satellite is detected that is below this signa
 
 The GNSS receiver is capable of tracking multiple channels across four constellations, each producing their own GNSS signals (ie, L1C/A, L1C, L2P, L2C, L5, E1, E5a, E5b, E6, B1I, B2I, B3I, B1C, B2a, B2b, etc). The supported constellations include GPS (USA), Galileo (EU), BeiDou (China), and GLONASS (Russia). SBAS (satellite-based augmentation system) is also supported. By default, all constellations are used. Some users may want to study, log, or monitor a subset. Disabling a constellation will cause the GNSS receiver to ignore those signals when calculating a location fix.
 
+### Galileo E6 Corrections
+
+If supported by hardware, Galileo E6 corrections are enabled by default to support High Accuracy Service. They can be disabled if desired. For detailed information see [High Accuracy Service corrections](correction_sources.md#galileo-has).
+
 ## NTRIP Client
 
 ![NTRIP Client enabled showing settings](<img/Terminal/SparkFun RTK Everywhere - GNSS Receiver.png>)
 
 *NTRIP Client enabled showing settings*
 
-The SparkFun RTK Everywhere devices can obtain their correction data over a few different methods. For detailed information see [Correction Sources](correction_sources.md).
+The SparkFun RTK Everywhere devices can obtain their correction data over a few different methods. 
 
 * Bluetooth - This is the most common. An app running on a tablet or phone has an NTRIP client built into it. Once the phone is connected over Bluetooth SPP, the RTCM is pushed from the phone to the RTK device. No NTRIP Client needs to be setup on the RTK device.
 * WiFi - The rover uses WiFi to be an NTRIP Client and connect to an NTRIP Caster. WiFi and Bluetooth can run simultaneously. This is helpful in situations where a GIS software does not have an NTRIP Client; a cellular hotspot can be used to provide WiFi to the RTK device setup to use NTRIP Client an obtain RTK Fix, while Bluetooth is used to connect to the GIS software for data mapping and collection.