What’s E6 HAS? – Information

A dive into Galileo’s free corrections service, which places the “quad” in “quadband.”

A few of our latest merchandise have been described as able to quadband reception, just like the RTK Postcard and LG290P Breakout board. What units these aside from our different multiband recievers? Like our different high-precision PNT merchandise, they’re able to L1/L2/L5 reception. Nevertheless, they take it a step additional by having the ability to obtain information from the Galileo constellation’s E6b band.

The E6 frequency lies between L1 and L2.

In 2018, the European Area Company started a undertaking known as “Excessive Accuracy Service” (HAS). The aim of this undertaking was to make elevated accuracy GNSS accessible globally by broadcasting corrections straight from every satellite tv for pc in real-time. Since then, new GNSS receivers have been designed which might be able to receiving and using these corrections, such because the Unicore UM980 and the Quectel LG290P.

Galileo HAS structure. Supply: ESA

Regular GNSS has a peak accuracy of round 1.5 meters, primarily because of the uncertainty of modifications to the service part as alerts propagate via the ionosphere. With the intention to get higher accuracy than this, the GNSS alerts must be augmented by “corrections”. HAS gives corrections by transmitting them on the E6b band alongside their commonplace GNSS alerts.

So, how does HAS work?

HAS corrections are designed to be used in a Exact Level Positioning (PPP) algorithm; a typical use case for PPP could be establishing a really excessive accuracy place for a Everlasting Base Station. Conventional PPP works by having a community of floor stations monitoring satellite tv for pc broadcasts, computing the error in GNSS satellite tv for pc broadcasts (and different parameters), and creating corrections for these errors. To compute a corrected place utilizing PPP, a sequential estimation algorithm is used, equivalent to an Prolonged Kalman Filter, with the objective of discovering the next output values:

• Receiver place (ECEF X, Y, Z)
• Receiver clock offset
• Tropospheric zenith delay
• Service-phase ambiguities

There are a variety of parameters that must be corrected for after the bottom station community has noticed the GNSS alerts:

• Satellite tv for pc orbit corrections: These refine the published ephemeris information to offer extra correct satellite tv for pc positions.
• Satellite tv for pc clock corrections: These enhance the accuracy of satellite tv for pc clock offset info.
• Satellite tv for pc biases: These embody code and part biases for supported Galileo alerts.
• Atmospheric corrections: Not presently accessible; the complete service will embody atmospheric (at the least ionospheric) corrections, significantly for the European Protection Space.

Define of PPP algorithm. It will get a bit difficult. Supply

The drawbacks of PPP are the period of time and infrastructure it requires. The very best high quality PPP consequence is just accessible 12-16 days after the only level information has been collected. The CSRS Fast PPP has centimeter stage accuracy just like RTK, however just isn’t accessible till 12 hours after the top of the day the only level information was captured on. For actual time, excessive accuracy operations, RTK continues to be your best option.

Supply

A singular function of HAS is that these correction messages are computed for every satellite tv for pc within the Galileo constellation by a floor station, then uploaded to every respective satellite tv for pc the place they’re then broadcast alongside the usual GNSS alerts. This permits receivers to run the PPP algorithm in real-time, so long as they’re able to receiving the HAS E6b band, and so they have the flexibility to run the PPP algorithm. Along with HAS E6-B satellite tv for pc broadcast, HAS PPP corrections will be obtained via their Web Information Distribution channel; this distribution channel capabilities very like NTRIP; you present credentials, and PPP corrections are piped to your machine over the web utilizing NTRIP.

HAS is an incredible achievement on this manner; corrections accessible practically worldwide, no base station or NTRIP community required. However, there are some downsides; the accuracy is comparatively unhealthy in comparison with RTK (however nonetheless adequate for a lot of use-cases), the method is considerably gradual (5-Quarter-hour for PPP convergence), and it’s delicate to sudden velocity fluctuations.

What {hardware} is suitable with Galileo E6b-HAS?

SparkFun sells just a few merchandise which might be in a position to obtain HAS corrections.

Beneath is an inventory of HAS enabled receivers.

Producer	Mannequin	Section or Purposes	HAS channel/s
ANAVS	Multi-Sensor RTK/PPP Module	Automotive, robotics, maritime, railway, mining and surveying	E6b
ANAVS	AROX-PPP	Autonomous automobiles, Robots, UAVs and Vessels	E6b / IDD
Past Gravity	PODRIX	Area navigation, Exact Orbit Dedication (POD)	E6b
Past Gravity	NavRIX PinPoint	Area navigation, Exact Orbit Dedication (POD)	E6b
EOS Positioning	Arrow Gold+™	Surveying and mapping	E6b
Hemisphere	Vega	Agriculture, building & mining, machine management, marine	E6b
Hemisphere	Phantom	Agriculture, building & mining, machine management, marine	E6b
Hello-Goal	iRTK5	Surveying	E6b
Hello-Goal	VRTK	Surveying	E6b
Kongsberg	Seapath® 385	Maritime / hydrographic surveying	E6b
Quectel	LG290P	Surveying	E6b
Rokubun	SPEAR (SDK)	Street navigation, robotics engineering, location-based providers, sensible agriculture, IoT	–
SinoGNSS	K803 GNSS OEM module	Surveying	E6b
South	Perception V2	Surveying	E6b
South	INNO7 (1598)	Surveying	E6b
South	Galaxy G3	Surveying	E6b
Spaceopal	HAUT	HAS validation, surveying, maritime, machine management, aviation	E6b / IDD
SparkFun Electronics	RTK Torch	Surveying and mapping, exact agriculture	E6b
Unicore Communications	UM980	Surveying and mapping, exact agriculture	E6b
Unicore Communications	UM981	Surveying and mapping, exact agriculture, clever driving	E6b
Unicore Communications	UM982	UAV and precision agriculture	E6b