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andycruce

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  1. As I understand it, if I set up a coordinates call back method with a call back time less than 100ms it will be automatically called whenever there are new gps data available. Does this mean that all the other gps data other than coordinates is also updated? In the coordinate call back method could I then use the get methods to retrieve things like motion, status, fix, etc and would these have the same time stamp as the coordinate call back results? The alternate would be to have multiple call back methods which would be messy. Andy Cruce
  2. I believe I got the firmware with the SBAS disabled and ran some of my test software again. I used the call back method with the rate set to 100ms and some of the call backs were at the 100 ms rate. A lot weren't. I assume this is because the GPS is stationary and sometimes there isn't a noise error in the gps position from one call back to the next to trigger the call back. Hope to get the gps in the plane sometime this week to check how it operates in the air. In my actual data collection system I am using direct calls to the device to collect the data. Shouldn't be a problem since there isn't much else going on so there isn't an issue with through put. However, it does allow me to synchronize the gps data collection with the IMU and Baro collection. One question I have is when I query the gps how old is the position information that is returned? A 140 mph translates into 205 ft/sec or about 20 ft/100ms. Is the the uncertainty or when I query the gps will I get a position close to the time I actually query the device? Also, how much does the SBAS improve the position accuracy? Andy
  3. Thanks for looking into this. I'll await your reply. Andy Cruce
  4. andycruce

    GPS2 Operation

    I am using a GPS2 in conjunction with an IMU brick and a Baro bricklet to record aerobatic aircraft performance. GPU2 has a specified mimnium update period of 100ms. When I record data it appears that the GPS doesn't update at that rate. When flying at 150 kts there are periods of up to 1 sec where the GPS output doesn't change. I created a test case for only the GPS using both the callback method and the direct access method (getcoordinates). The direct access method is driven by a high accuracy timing system with resolution in the microsecod range. Testing the device in a car moving at about 40 mph I found that if I set the update period to 1,000 ms the system mostly recorded a new position every update. However at a 500ms update there were many updates where the sensed lat long were the same even though the car was traveling at 40 mph. As the update rate was increased the problem got worse. Is there something I should be doing differently? If you want to look into the problem I can share the test software via dropbox. You will have to have access to VS 2015 to run the software. Andy Cruce
  5. The IMU2 Brick is connected to my computer via a usb cable. I have the brick viewer active and am in the Updates/Flashing screen. I selected the Brick tab and in the Serial Port text box the only option is COM1- Communications Port (COM1). In the firmware text box is IMU2.0 (2.0.. Selecting the Refresh button does not add any other selections to the Serial Port text box drop down menu. Selecting the Save button results in the error Could not connect to Brick: No Brick in Bootloader found. In the documentation it looks like for Windows 10 there should be a Serial Port selection of either Bossa Program Port or GPS Camera Detect. Neither of these show up. I still have the IMU2 Brick connected to the Baro bricklet and the GPS2 bricklet. Is this the problem? Andy
  6. I have the wrong firmware version. However when I go into updates/flashing and select brick I only have a COM1-Communications Port(COM!) in the serial port drop down. When I try to save the firmware, version 2.0.8, I get the message "Could not connect to Brick: No Brick in Bootloader Found. I am not using a master brick. Could this be the problem? Andy Cruce
  7. I got the versions incorrect. The Daemon version is 2.3.0.0 and the viewer version is 2.3.9.0. I believe these are the latest versions. Andy Cruce
  8. I have a GPS2 bricklet connected to a master brick. I have downloaded new daemon and viewer software. The daemon software is brickd.exe, version 2.3.9.0.0. The viewer software is brickv.exe, version 2.3.0.0. I start brickd by double clicking on the .exe file. I then start brickv by double clicking on the brickv icon. The view comes up and recognizes the IMU2 and Baro brick and bricklets installed in the system. However, it doesn't recognize the new GPS2 bricklet. What am I missing? Andy Cruce
  9. When do you expect the new GPS bricklet to be available. I would like to order 4 of them as soon as they area available as well as some other hardware as soon as they are available.
  10. I tested the IMU data collection in my airplane today and have a question. I show the calibration level for the Accelerometer, Gyroscope, Magnetometer and System continuously. Prior to flying I did the calibration procedure, moving the device to various positions until I had a lever 3 calibration on all the internal devices. However, once I started flying the Accelerometer and Gyroscope showed a continuous level 3 calibration but the Magnetometer calibration dropped to 1 or 2 and the System calibration dropped to 0. I believe that part of this showed up by the heading euler angle being off by about 30 degrees by the rest of the flight. Am I missing something on how to calibrate the system? Also I notice there is a new firmware version for the IMU. I can't find the documentation on how to load the updated firmware into the device. Would you please point me to the documentation. Finally, what is the status of the new GPS bricklet? Thanks, Andy Cruce
  11. I must be missing something. I checked the URL you listed and the only description of code I found was to subtract gravity from an accelerometer output. The IMU 2 brick does this automatically when it provides linear accelerations. Where did you find any discussion of the complementary filter code?
  12. I have been looking at the code from the github reference that combines the imu and baro data to provide a more accurate and stable altitude estimate. The comments say it is a complementary filter. However, I can't reconcile the code with a complementary filter that consists of a high and low pass filter in parallel. I'd like to be able to contact the person who generated the code to try to understand what he did. Is that possible? Also, I'm still looking for someone who has fused the GPS and IMU sensors to provide more accurate and stable horizontal position information. Thanks, Andy Cruce Andy Cruce
  13. Based on your question about getting covariance values for the GPS errors, it sounds like you are working on a Kalman filter to fuse GPS and IMU data. Is this the case? I am interested in the same thing but need someone to talk to about the actual kalman filter implementation. If you are working on the kalman filter I'd like to converse with you. My email is andycruce@comcast.net.
  14. I am impressed with the video showing the result of fusing the IMU/Baro sensor data to get an accurate/smooth altitude estimate. Is it possible to get the algorithm used in this fusion process? I don't need the code just the filter algorithm. Andy Cruce
  15. Since you changed the connector on the bricklet does that mean that it will no longer be cable compatible with the old master brick? I'm hoping that I can use the existing hardware and cables to interface the GPS bricklet.
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