Camera offset survey
- Thread starter Jim Campi
- Start date
Yes. That's one reason I like it so much. I'm just using a Triumph-2 hooked up to the office router pushing out 5hz.
Matt Johnson reported a low calibration number like that using a bipod in his office to help steady the LS. I've been thinking about calibrating using my big flat screen TV. I just haven't tried it yet.
Jim Campi
Active Member
I used a seco tribod and moved the laptop to adjust position.
If you are using TCP, then can you achieve 10 hz? Of course 0.1 base transmission rate would need to be made available when configuring setup. My understanding that with narrow banding our UHF radios max at 5 hz.
Also I am using the latest version of the testing software and the base rate on the collect screen seems to either lag or report zero frequently...
If you are using TCP, then can you achieve 10 hz? Of course 0.1 base transmission rate would need to be made available when configuring setup. My understanding that with narrow banding our UHF radios max at 5 hz.
Also I am using the latest version of the testing software and the base rate on the collect screen seems to either lag or report zero frequently...
Yes 10 Hz corrections through the TCPO port can be configured in NetView. Currently J-Field doesn't have an option to connect to the GNSS board at 10 Hz (Setup>Advanced>RTK/DGPS>RTK Rate). I will request a "0.1 Sec" option be added here.
Yes the spread spectrum radio has a lot more bandwidth. The data speeds are listed in the spec sheets:
- UHF Radios - 19200 bps at 12.5 kHz
- HPT901BT Spread Spectrum Radio - 64000 bps
I've been seriously considering switching from UHF to cellular and SS. John and I have been discussing it for a while. The new high transmit rate is making this even more attractive. We have really good cell coverage in our neighborhood. The few times we haven't, the SS would allow us to keep working. It's not ideal for everyone, but I think I would prefer it.
Jim Campi
Active Member
I generally work on fairly small sites in rural environments.
I suspect spread spectrum might be viable for me as well, especially if it meant 10 hz (or higher).
I have one the older LS units. I take it none are equipped with both radios and simply require an option code to activate spread spectrum?
If not, would it be possible to add ss?
I suspect spread spectrum might be viable for me as well, especially if it meant 10 hz (or higher).
I have one the older LS units. I take it none are equipped with both radios and simply require an option code to activate spread spectrum?
If not, would it be possible to add ss?
It seems that 7 Hz seems to be about the limit for TCP corrections being received after I configured the output period to 0.1 and connected the GNSS board at 10 Hz:
The correction rate was bouncing around between 5 to 7 Hz. I'm not sure where the bottleneck was.
The correction rate was bouncing around between 5 to 7 Hz. I'm not sure where the bottleneck was.
No, there is currently a bottleneck somewhere.
The bottleneck is the GNSS CPU speed. I believe our RTK team can optimize RTK performance a lot.
Spread spectrum is an entirely different radio from UHF, so your LS would need to go back to the factory for the modem to be swapped out. Also, whatever radio modem you are using now for your base would need to be swapped out to spread spectrum.
Jim Campi
Active Member
Hi Matt,
I'm not confident about this however; it appears that my FCC license requires that I operate at 12.5 kHz or its Equivalent Efficiency.
The FCC FAQ page states:
"What does Equivalent Efficiency mean?
Any of the following meet the 12.5 kHz equivalent efficiency requirement:
- One voice path in a 12.5 kHz channel
- Two voice paths in a 25 kHz channel
- Data operations on channels greater than 12.5 KHz must employ data rates greater than 4.8 kbps per 6.25 kHz channel, such as 19.2 kbps per 25 kHz channel"
It appears that we may be operating near ar at equivalent efficiency when transmitting at 5 Hz and if not, then certainly at 10 Hz if that option were developed...
Narrowbanding is an effort to ensure more efficient use of the VHF and UHF spectrum by requiring all VHF and UHF Public Safety and Industrial/Business land mobile radio (LMR) systems to migrate to at least 12.5 kHz efficiency technology by January 1, 2013.
More specifically, all existing Part 90 radio systems operating in the 150-174 MHz and 421-512 MHz bands have until January 1, 2013 to convert those systems either to a maximum bandwidth of 12.5 kHz or to a technology that provides at least one voice path per 12.5 kHz of bandwidth or equivalent efficiency.
What does Equivalent Efficiency mean?
Any of the following meet the 12.5 kHz equivalent efficiency requirement:
- One voice path in a 12.5 kHz channel
- Two voice paths in a 25 kHz channel
- Data operations on channels greater than 12.5 KHz must employ data rates greater than 4.8 kbps per 6.25 kHz channel, such as 19.2 kbps per 25 kHz channe
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Spread spectrum is license free.
Jim Campi
Active Member
Hi Shawn,
Narrow banding requires no greater than 12.5 kHz on UHF radios in our frequ ncy range and use. The max data rate is 19.2 kb/s. My understanding is that utilizing a base transmission frequency of 5 hz is at or close to the max data rate at 12.5 kHz.
It looks like we may have the option of operating our radios at 25 kHz, doubling the max theoretical data rate to 38.4 kb/s. To do this would require we meet the "Equivelant Efficiency" standard. One way to meet that is a data rate of at least 19.2 kb/s at a 25 kHz.
So, what is the point of all this? To use our current UHF radios we can't exceed a 5 Hz base update frequency. Meeting the "Equivelant Efficiency" requirement will allow us to use our current equipment and reach a base update rate of 10 Hz, if Javad develops that technology.
Narrow banding requires no greater than 12.5 kHz on UHF radios in our frequ ncy range and use. The max data rate is 19.2 kb/s. My understanding is that utilizing a base transmission frequency of 5 hz is at or close to the max data rate at 12.5 kHz.
It looks like we may have the option of operating our radios at 25 kHz, doubling the max theoretical data rate to 38.4 kb/s. To do this would require we meet the "Equivelant Efficiency" standard. One way to meet that is a data rate of at least 19.2 kb/s at a 25 kHz.
So, what is the point of all this? To use our current UHF radios we can't exceed a 5 Hz base update frequency. Meeting the "Equivelant Efficiency" requirement will allow us to use our current equipment and reach a base update rate of 10 Hz, if Javad develops that technology.
Jim, I think you are correct that the FCC would allow us to license more than 12.5 KHz channel bandwidth if we are using 5 Hz or 10 Hz corrections. I think we should be able to get licenses with 18.75 KHz channel bandwidth for 2 Hz corrections and 24 KHz channel bandwidth for 5 Hz corrections. I'll see if Michael Glutting can inquire into this more Enterprise Wireless Alliance.
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