L Band

nusouthsc

Active Member
So I’ve done some searching around and can’t get a clear answer. Can someone fill us in on what exactly JAVAD is promoting here?
 

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Eric Tweet

Active Member
PPP, or Precise Point Positioning, (the real-time version, though PPP can be a post-processing solution as well) is sort of like WAAS on steroids, providing sub-meter and in some cases a handful of cm accuracy in.
Typically this involves a bunch of ground stations grabbing GNSS signal data, and sending it to processing centers where the data/errors are modelled/computed/crunched. Then the correction info can be sent to end users via the internet or blasted up to satellites and relayed to the end user's receiver via L-Band signals.

I think there may be some free services, but from what I understand most providers of PPP services are subscription based, or similar.
This is what Trimble's CenterPoint RTX service is. They claim 2cm RMS. I'm not sure how long it takes for a solution to converge with that accuracy, but I recall that some systems require (or at least used to require) something like 10 minute occupations to get full accuracy.

All of that said, just from that image I'm not sure if Javad is advertising a Javad PPP service, or simply stating that it has receivers/radios that facilitate the use of other L-Band PPP services.

Interestingly, I believe starting with the Delta-3 receivers, Javad gear has the ability to track and decode the QZSS LEX (L6) signal, which is an L-Band signal containing PPP correction data, among other things.
 

nusouthsc

Active Member
PPP, or Precise Point Positioning, (the real-time version, though PPP can be a post-processing solution as well) is sort of like WAAS on steroids, providing sub-meter and in some cases a handful of cm accuracy in.
Typically this involves a bunch of ground stations grabbing GNSS signal data, and sending it to processing centers where the data/errors are modelled/computed/crunched. Then the correction info can be sent to end users via the internet or blasted up to satellites and relayed to the end user's receiver via L-Band signals.

I think there may be some free services, but from what I understand most providers of PPP services are subscription based, or similar.
This is what Trimble's CenterPoint RTX service is. They claim 2cm RMS. I'm not sure how long it takes for a solution to converge with that accuracy, but I recall that some systems require (or at least used to require) something like 10 minute occupations to get full accuracy.

All of that said, just from that image I'm not sure if Javad is advertising a Javad PPP service, or simply stating that it has receivers/radios that facilitate the use of other L-Band PPP services.

Interestingly, I believe starting with the Delta-3 receivers, Javad gear has the ability to track and decode the QZSS LEX (L6) signal, which is an L-Band signal containing PPP correction data, among other things.
Eric,
Thanks for the great summary! We actually have a Delta on order and a Grant G5T antenna, which is what brought up the L Band question originally. When we were trying to decide which antenna to purchase, I noticed the Grant G5-Lb antenna, which is only $150 more, tracks L Band. But based on what I’m understanding it doesn’t sound like that’s something we would utilize. We are a small local company that rarely travels more than 30 miles from our office. Plus, we have a pretty solid RTN here in SC with decent cell service.

Adam, correct me if I’m wrong and you suggest stepping up to the G5-Lb.
 

nusouthsc

Active Member
I don't think you need it on your Delta base. L band may be useful at the rover in some cases like huge remote properties or navigation in shipyards, etc
Good deal. Sam had indicated the same but I wanted to be sure this wasn’t something different. With so much out there it doesn’t take long to get over my head. Thanks guys!
 

Phillip Lancaster

Active Member
Three antennas. G5T, G5T-Lb, G5T-Lb-i. I know the Lb does the L-band and the Lb-i does the L and S-band. Will spending the extra money for the Lb/Lb-i have any future advantage for a Delta S as a base receiver or just get the G5T antenna?
 
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