Changes between Initial Version and Version 1 of Processing/IPASTC


Ignore:
Timestamp:
Feb 11, 2011 4:04:53 PM (8 years ago)
Author:
emca
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • Processing/IPASTC

    v1 v1  
     1== Leica IPAS TC navigation processing ==
     2
     3IPAS TC combines the IPAS Pro and Graftnav into one process.
     4
     5All files should be named according to the year, julian day and flight letter (where applicable) - YYYYJJJf.*
     6
     7=== Setting up the Project ===
     8
     9 1. Open IPAS TC
     10  1. Select new, navigate to the ipas folder of the relevant project, and give your project a name as above and click create
     11  1. This will create a *.itp file which will store all the parameters used
     12  1. This brings you to the Project Overview dialog box
     13 1. Select Aircraft Data File
     14  1. The Data File should point to ipas/raw/*.000 file
     15  1. The Extract Directory should be created automatically as ipas/extract, if not create it
     16  1. Click Extract Raw data. When that has finished, check the messages for any errors and click accept
     17 1. This will automatically bring you to the GNSS Base Station dialog box
     18  1. Under Options for GNSS select User Differential GNSS (for PPP see below)
     19  1. From here you can select Add Base Station or Download Service Data
     20  1. Up to 8 base stations can be added
     21  1. To add a base station select the appropriate Raw Data Folder on the Raw GNSS File tab and click convert. 
     22  1. Check the correct Co-ordinate and Antenna information have been added and accept
     23  1. When you have finished adding any additional base stations select accept
     24 1. The final stage before processing is to set the Configuration
     25  1. Click on configuration
     26  1. Enter the lever arm values under the GNSS and IMU tab
     27  1. On the GNSS tab select Processing Options (small button on the far right). Use the following settings:
     28    1. Use GLONASS if present should be ticked
     29    1. Should use L2 Carrier. Disable this if the base station is less than 10km away
     30    1. Select Engage Only
     31    1. Quality Acceptance - Q2 (99%)
     32    1. Click OK, then accept to go back to the main Project Overview
     33 1. Select Start Processing
     34    1. This will process the forwards and backwards solution, smooth the data and output the *.sol file
     35
     36=== Analysing the Data ===
     37
     38  1. Select Launch Graphical Analysis Window
     39   1. Initially you will see the trajectory of the aircraft, coloured by GPS time
     40   1. Click on Show Toolbox to plot the solution
     41
     42
     43
     44
     45
     46=== Additonal Notes: ===
     47
     48The accuracy using IPAS TC is approximately the same as using IPAS Pro and !GraftNav combined
     49IPAS TC can operate with fewer satellites and deeper turns => more reliable observations
     50
     51Leica don't recommend using recomputing the base station position as this introduces more unknown parameters into the mix.
     52
     53
     54==== Estimate Lever Arms ====
     55
     56In general you don't need to select this. However, it can be used to check the accuracy of the lever arm values. [[BR]]
     57If you have good data (3 mins flight alignment, figure of 8, good satellite data) and the lever arms values are significantly off then consider remeasuring.
     58
     59==== When Using Download Service data ====
     60
     61If you can't get a fixed solution or fixed ambiguity check the base station settings. [[BR]]
     62Some satellites need a correction file to offset to older satellites (not applicable to the Leica stations)
     63
     64==== PPP Mode ====
     65
     66- Select use Precise Point Processing from the Setup NSS Base Station window. [[BR]]
     67- Click on Check Availability to see what data are available. [[BR]]
     68- This will display all precise data that has been found, and will be default select the final orbit. [[BR]]
     69- Do not use 'Final clock (30s)' - better to use 5 or 1 second data. [[BR]]
     70
     71
     72PPP mode is not recommended for project under 90 minutes. [[BR]]
     73It is not possible to estimate the lever arm in PPP mode.
     74
     75Can process the base station data in PPP mode to get a fix on the co-ordinates.
     76
     77
     78
     79
     80== Lever arms (February 2010) ==
     81
     82Lever arm values to enter into the software from 2010 onwards are:
     83
     84|| ||X ||Y ||Z ||
     85||GNSS  ||0.019|| -0.024|| -1.692||
     86||IMU || -0.411|| 0.206|| -0.192 ||
     87||User Frame|| -0.142|| -0.001|| -0.188 ||
     88 
     89These values are entered in the flight planning software and '''should''' automatically populate in IPAS. [[BR]]
     90The GNSS and IMU values can be changed in IPAS TC if they are incorrect. The user frame values cannot. They can be checked in ipas/extract/*extract.log. If you find these values are not correct let Ops know so they can change them to what they should be.