Smooth Positioning Trajectory
Smooth positioning is needed by many control system applications such as auto steering systems. A smooth positioning solution refers to GPS/GNSS data that has been run through a special filter or algorithm to create a smooth trajectory without any sudden position jumps due to changing GNSS signal conditions.
In addition to providing a smooth trajectory, smoothing of GPS or GNSS based epoch to epoch data also provides greater solution availability. Smooth positioning solutions are used in:
- Unmanned Ground Vehicles (UGV)
Trajectory determination applications
- Real time and post-mission processed solutions
- Minimizes position solution jumps often associated with satellite geometry changes
- Bridges through short periods of partial or even complete GPS or GNSS signal outages
- Utilizes more observations in position computation allowing better observation error detection
- Output available in different formats
Real Time GPS or GNSS Smooth Positioning:
Utilizing both Pseudorange and Delta-Phase (PDP) GPS or GNSS measurements, our PDP filtered position and velocity solution is computed based on assumed satellite signal observations. The advantage of this approach is smoother solution output and greater solution availability.
The PDP filter solution optimizes the absolute positioning accuracy of the GPS code observation and leverages the excellent relative stability of the GPS carrier phase and Doppler observations. By optimally combining these satellite signal observations, the solution stability improves over traditional code only positioning algorithms.
In addition to our PDP filter, our GLIDE® positioning filter is optimized for applications that operate under open sky conditions and where smooth and consistent outputs are required. The GLIDE filter produces a very smooth consistent relative solution rather than absolute position accuracy. Market segments like agriculture value this repeatable accuracy for their pass-to-pass boundary sensitive operations.
NovAtel’s STEADYLINE technology reduces position jumps that can occur when a GNSS receiver changes positioning modes. This effect is especially evident when a receiver transitions from a high accuracy RTK position solution to a lower accuracy solution such as PPP, DGPS, SBAS+GLIDE or even autonomous GLIDE. Smooth transitions are extremely important for precision agricultural steering applications where sudden jumps are disruptive.
Real Time SPAN® Positioning:
NovAtel's SPAN technology tightly couples GPS or GNSS measurements with Inertial Measurement Unit (IMU) data to prove a smooth, reliable, continuously available 3D position, velocity and attitude solution-even when satellite signals are blocked or unavailable for short periods of time, such as in urban canyons or under heavy foliage. SPAN solutions can be output up to 200 Hz (based on the IMU data rate).
Post-processed Smoothed Trajectory:
Inertial Explorer® post-processing software takes advantage of both forward and backward data computations to generate the most accurate combined solution. This is especially useful for increasing solution accuracy, availability and providing quality assessment of data collected under challenging environments.
In addition, combined soluton smoothing can be used to provide an optimal trajectory. While this feature is aimed primarily at datasets suffering from GNSS outages, it can be used in virtually any circumstance with large position errors. Inertial Explorer provides a continuous smoothed trajectory, ideal for the demands of ground and airborne laser scanning and other imaging sensor applications.
When choosing a smooth positioning solution, consider the following needs of your application:
- Solution accuracy
- Signal availability
- Solution rate
- Continuity of solution updates
- System dynamics
- System exportability
- System price
- System installation constraints
- Real time versus post-processed solution