Changes between Initial Version and Version 1 of Processing/IPASTC

Timestamp:

Feb 11, 2011, 4:04:53 PM (14 years ago)

Author:

emca

Comment:

--

Processing/IPASTC

@@ +1 @@
+== Leica IPAS TC navigation processing ==
+
+IPAS TC combines the IPAS Pro and Graftnav into one process. 
+
+All files should be named according to the year, julian day and flight letter (where applicable) - YYYYJJJf.*
+
+=== Setting up the Project ===
+
+ 1. Open IPAS TC
+  1. Select new, navigate to the ipas folder of the relevant project, and give your project a name as above and click create
+  1. This will create a *.itp file which will store all the parameters used
+  1. This brings you to the Project Overview dialog box
+ 1. Select Aircraft Data File 
+  1. The Data File should point to ipas/raw/*.000 file
+  1. The Extract Directory should be created automatically as ipas/extract, if not create it
+  1. Click Extract Raw data. When that has finished, check the messages for any errors and click accept
+ 1. This will automatically bring you to the GNSS Base Station dialog box 
+  1. Under Options for GNSS select User Differential GNSS (for PPP see below)
+  1. From here you can select Add Base Station or Download Service Data
+  1. Up to 8 base stations can be added
+  1. To add a base station select the appropriate Raw Data Folder on the Raw GNSS File tab and click convert.  
+  1. Check the correct Co-ordinate and Antenna information have been added and accept
+  1. When you have finished adding any additional base stations select accept
+ 1. The final stage before processing is to set the Configuration
+  1. Click on configuration
+  1. Enter the lever arm values under the GNSS and IMU tab
+  1. On the GNSS tab select Processing Options (small button on the far right). Use the following settings:
+    1. Use GLONASS if present should be ticked
+    1. Should use L2 Carrier. Disable this if the base station is less than 10km away
+    1. Select Engage Only
+    1. Quality Acceptance - Q2 (99%) 
+    1. Click OK, then accept to go back to the main Project Overview
+ 1. Select Start Processing
+    1. This will process the forwards and backwards solution, smooth the data and output the *.sol file
+
+=== Analysing the Data ===
+
+  1. Select Launch Graphical Analysis Window
+   1. Initially you will see the trajectory of the aircraft, coloured by GPS time
+   1. Click on Show Toolbox to plot the solution
+
+
+
+
+
+=== Additonal Notes: ===
+
+The accuracy using IPAS TC is approximately the same as using IPAS Pro and !GraftNav combined
+IPAS TC can operate with fewer satellites and deeper turns => more reliable observations
+
+Leica don't recommend using recomputing the base station position as this introduces more unknown parameters into the mix. 
+
+
+==== Estimate Lever Arms ====
+
+In general you don't need to select this. However, it can be used to check the accuracy of the lever arm values. [[BR]]
+If 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. 
+
+==== When Using Download Service data ====
+
+If you can't get a fixed solution or fixed ambiguity check the base station settings. [[BR]]
+Some satellites need a correction file to offset to older satellites (not applicable to the Leica stations)
+
+==== PPP Mode ====
+
+- Select use Precise Point Processing from the Setup NSS Base Station window. [[BR]]
+- Click on Check Availability to see what data are available. [[BR]]
+- This will display all precise data that has been found, and will be default select the final orbit. [[BR]] 
+- Do not use 'Final clock (30s)' - better to use 5 or 1 second data. [[BR]]
+
+
+PPP mode is not recommended for project under 90 minutes. [[BR]]
+It is not possible to estimate the lever arm in PPP mode. 
+
+Can process the base station data in PPP mode to get a fix on the co-ordinates. 
+
+
+
+
+== Lever arms (February 2010) ==
+
+Lever arm values to enter into the software from 2010 onwards are: 
+
+|| ||X ||Y ||Z ||
+||GNSS  ||0.019|| -0.024|| -1.692||
+||IMU || -0.411|| 0.206|| -0.192 || 
+||User Frame|| -0.142|| -0.001|| -0.188 ||
+ 
+These values are entered in the flight planning software and '''should''' automatically populate in IPAS. [[BR]]
+The 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.