NovAtel Inc. has launched its new GL1DE technology, the latest enhancement to the Calgary, Alberta, Canada–based company’s high-precision OEMV GNSS product line.
GL1DE is a relative pseudorange/delta-phase filter enhancement available in the coompany’s OEMV 3.400 firmware. The new technology is targeted for agricultural guidance applications in which pass-to-pass repeatability and elimination of position “jumps” is critical.
NovAtel Inc. has launched its new GL1DE technology, the latest enhancement to the Calgary, Alberta, Canada–based company’s high-precision OEMV GNSS product line.
GL1DE is a relative pseudorange/delta-phase filter enhancement available in the coompany’s OEMV 3.400 firmware. The new technology is targeted for agricultural guidance applications in which pass-to-pass repeatability and elimination of position “jumps” is critical.
GL1DE combines GPS L1 code and L1 phase data to produce consistent positional output for developers of guidance applications, for example, those employing lightbar and autosteer systems.
The GL1DE filter uses many of the same algorithms as NovAtel’s existing PDP (Pseudorange/Delta-Phase) filter. The latter filter, however, optimizes a solution in multiple conditions, while the GL1DE design is optimized to work in clear sky conditions where users need a tight, smooth, and consistent output.
The PDP filter takes advantage of the accurate accumulated delta range (carrier phase) measurements to smooth the inherent noise in the least squares solution. It also uses a Kalman filter with a velocity and delta position model to bridge through times with less than four satellites available, thus offering an approach that follows the least squares solution, but with short term smoothing and bridging through short satellite outages.
In comparison, by making very heavy use of the carrier phase observation, the GL1DE technology emphasizes keeping the error as constant as possible over 15–20 minutes. Although GL1DE has a very smooth error, according to company field tests, it may produce an overall larger absolute error than the PDP filter.
GL1DE reportedly improves the stability of single point (autonomous), satellite-based augmentation systems such as WAAS or EGNOS, Canadian Differential GPS and OmniSTAR VBS positioning modes, and delivers pass-to-pass repeatability as good as 8 to 12 inches within a 15-minute interval.
According to NovAtel, GL1DE can be particularly helpful in improving single frequency positioning for products with limited space for a ground plane such as a small “smart” antenna. Generally, smaller smart antennas are more susceptible to multipath (reflected) signals.
The company will provide GL1DE, at no additional charge, for all NovAtel OEMV cards and OEMV-based receivers with current post-contractual support subscriptions.
For more information on GL1DE, see NovAtel’s website.
