I too have historically used the five minutes PLUS a minute per kilometer as a rule of thumb, works well, you may be able to shorten that a bit with lots of clean satellite data, BUT I would probably do 10 minutes minimum and maybe add a bit for 5 km-15 km lines and try to keep ALL the lines under 15 km just to speed things up. By the time you get a target set, some notes, some photos, etc., you will burn through 10 minutes anyway.
I don't know if you watched the NGS RTN Webinar on 31-Jul-2013, but some good stuff in there even though it pertains to RTN's. In particular Mark Armstrong's presentation had some results of testing he did, 90% of his shots fell on a 13 mm MAG nail head WHEN he observed (10X) eight minutes, that drops off substantially with shorter occupations. I think this validates my minimum time of 10 minutes, sure you might be able to shorten the time, BUT as pointed out you will likely be busy anyway AND the time to return is going to be greater than the extra few minutes of occupation.
SHG
Good stuff Shelby. Looks solid to me.
One other thing I'd consider is stop and go. In this I would still occupy my points for ten minutes but leave the receiver collecting between occupations. Once you step out of the truck the software will start resolving the ambiguities. The time prepping the site before the receiver is set up could be used by the post processor. This assumes your post processing software can do this with the receivers you are using.
As Shelby and Mark suggest, you can purchase GSM SIM cards from AT&T and/or T-Mobile, both cellular carriers now offer Pay-As-You-Go plans. No more 2-year service contracts needed any more. I have x2 ATT GSM SIM cards and x2 T-Mobile GSM SIM cards for my HGNSS S320 RTK units. Query the internal GSM modems in your RTK Rover for their IMEI number. With the HGNSS S320 GNSS receiver, query the S320 internal GSM modem for $GSM,IMEI, the receiver will reply with: $>GSM,IMEI,xxxxxxxxx.
Take the $>GSM,IMEI,xxxxxxxxx reply to your local regional GSM service provider, (AT&T ad/or T-Mobile), share the IMEI information, the customer service rep can enter this information into their computer system, the will know exactly what type of GSM modem is embedded in your GNSS receiver, and exactly what type of Data/SMS texting plan to provide. Confirm which APN, (Access Point Name) they use, so you can enter the APN in your HH data collection SW.
The Pay-As-You-Go plans cost about $2 per 24hours. I put $50 on each GSM SIM card. You only get charged when the SIM card is active on the GSM Network. The SIM card may expire if you don't use it for 90-days, if the SIM card is in-active, simply call AT&T, or T-Mobile, give them the telephone number assigned to the GSM SIM, ask them to juice up your SIM card again.
I travel all over the world with my RTK gear, where ever that Delta Jet takes me, I activate my SIM cards for the regional GSM service provider, find, register for credentials on the local regional RTK Network and get busy...
-BbB B-)
You can add a device or two to your existing verizon account. It runs $20/mo. per device here. There is a $35/device activation fee. You can then suspend the device when your done. I think it suspends for 6 month period and it's always available if you need it.
I agree with Shawn. Get some static shots and check closures.
What in the world are they doing that would need to be so unusual that VRS would not be allowed, even if you tie to known control? Puzzling. Better make sure you get plenty redundancy.
Use Network RTK that supports storing Actual Baselines
VRS Networks don't allow the NTRIP RTK Rover to store actual, physical measured RTK Baselines from an actual GNSS reference station. If you have a LGS SpiderNet RTK Network near your project location, (or other RTK Network), get your credentials to access SmartNet. When downloading the NTRIP Source Table, select a Mount Point for SBL, (Single Baseline RTK), at each RTK shot, connect to Mount point #1, collect 30-RTK shots + store, Network Disconnect, change to Mount Point #2, Network Connect, Using same EXACT PT ID -> collect 30-RTK shots + store, Network Disconnect, Change to Mount Point #3,Network Connect, Using same EXACT Point ID again, -> collect 30-RTK Shots + Store.
In the field, your data collection software will display the averaged point N,E,Z Delta splits for the RTK point. If some of the RTK measurements look bad, stay there and take some additional RTK shots, toss the bad RTK shot, Redundant measurement is a good thing. Back in the office, import the RTK data and RTK Baselines, you will have 3 Independent Baselines into your RTK data point, your Post-Processing SW should be able to Least Squares Adjust the RTK Point with physical, repeatable, traceable RTK Baselines.
Can VRS do this, I don't think so, but it's Virtual Now right?
-BbB B-)
I would still think static might be a good option. setup 5+ receivers and leap frog them from control point to new point. This process would most likely leave each receiver on point for about 1 or 2 hours, more than enough time to drill the points down more than good enough. But if you want more accuracy, simply do it again making sure you don't repeat any points during the same time of the day.
Although, I would like to help your client understand the benefits of a good RTN. It's possible that their experience is with a poor quality one.
I've been working on getting set up with a GSM internet connection on my Allegro CX, and it's been really difficult to get real information from AT&T and T-Mobile.
Both have pre-paid options for phones, but the reps I've spoken with indicate that using a modem is not the same as using a phone, and insist that the modem connection won't work unless you buy a block of data dedicated for that purpose. AT&T offers a "DataConnect" pass, which is available in daily, weekly, or monthly blocks. T-mobile has a similar service.
However, blemoine's experience suggests that connection can be made using traditional prepaid SIM card. That is what I was hoping originally. $2 per day sounds great!
I purchased a gprs raven over the weekend and it arrives tomorrow. Today I obtained a sim card from AT&T with a 250mb $15 a month tablet plan. Tomorrow I'm going to put them together and see if it works.
Interestingly, I went to the AT&T shop tonight to talk to a rep.. he looked at his computer a long time, looked at my raven IMEI number and concluded they had "no data plans that would work for it."
I have no idea how that could be.. but I've got my fingers crossed. If that doesn't work I'll head to T-mobile and hope for better news.
I bought a SIM card from TMobile after I had been told by them it would work on a prepaid basis at a cost of 1-2$ per day, only on days used. Then I got the card and tried to connect, but it wouldn't work, so I called for help and they told me that modem devices need to have a data plan, so was upsold to $25 per month plan. Then, found out that TMobile service in my area is not very good, and it doesn't look like such a good deal.
Similar problems with AT&T. Good luck. I'll be interested to hear of your results.
Well no luck yet, despite the fact I've fought with it all day.
AT&T sim would not register on network.
Obtained a Tmobile sim, it registered fine.. but I can't get the modem to send the corrections. I think it has to be something in my configuration of the raven, but I can't seem to get it to work.
If anyone has a template for a raven modem to be used as a base can you please email it to me?
Thanks.
Well I got it to work.. freaking fantastic. I would highly recommend trying out this solution.
BASE outputs CMR+ to raven modem, raven sends corrections to GNSS Surfer running on a static IP server at my office, GNSS Surfer outputs corrections back out to web, rover looks at static IP to obtain corrections.
Really a slick setup and costs me $25 a month when I choose to use it thanks to Tmobile pay-as-you-go data plan.
Congratulations, that sounds awesome.
I had fiddled with getting corrections via internet using T-Mobile, and purchased the $25 monthly pass. I was able to establish internet connection, but T-Mobile's service in my area is spotty, so AT&T is preferred. In any case, I got the following message from T-Mobile just a few days ago, when my monthly pass expired, and it was a surprise to me:
>Dear Customer,
>Your broadband pass has expired and you will be charged $0.20 per MB for all data use until you buy another pass Don.t worry, you will only be charged the $0.20 per MB if you use your Mobile Broadband service without buying a weekly or monthly pass.
As far as I know, the amount of data used for sending corrections is minimal, and so you might be able to save some $$ by using the per MB rate.
I do have a couple of questions about your setup. 1) How do you get GNSS Surfer? I've looked for it on the web without success. 2) Do you have to purchase a static IP address from your internet provider. I think my internet provider, both at the office and home, provides a roaming (DHCP?) IP address.
> 1) How do you get GNSS Surfer?
From the GNSS Data Center
> 2) Do you have to purchase a static IP address from your internet provider?
Most ISP's offer a static IP for an additional monthly charge.
Jim is absolutely right on both accounts. I have AT&T Uverse for business and the static IP is an extra $15 a month and gets me a block of 5 static IP addresses.