GPS receiver

The LPWA network processor supports GPS reception, if the onboard network protocol firmware supports it.

GPS receiver operation is time multiplexed with the LTE modem, and GPS and QZSS position can be received while the LTE modem is in RRC Idle mode, power saving mode (PSM), or completely deactivated.

The application processor is the system master and responsible for starting and stopping the GPS receiver. GPS can be run standalone or concurrently with QZSS. The GPS and QZSS reception can be configured through the GNSS interface API.

Note: For details regarding the GNSS API, refer to nRF Connect SDK API documentation.

Key features of the GPS receiver are as follows:

Note: There must be minimum 27dB attenuation to out of band power to avoid blocking high power RF signals to GPS receiver input. This can be achieved by using a SAW filter, for example, at the external LNA output.

Electrical specification

The following is a summary of GPS receiver performance parameters.

Table 1. Common typical conditions
Condition Value
Environment Open sky
Temperature 25°C
GPS sleep clock source TCXO

Note: Local and temporal conditions might lead to considerable variation in TTFF, positioning accuracy, 1PPS signal accuracy.

The figures in the following table assume the use of an external low-noise amplifier (LNA) with SAW filter.

Table 2. GPS electrical specification
Symbol Description Value Unit
Sensitivity, cold Acquisition sensitivity, cold start -146.5 dBm
Sensitivity, hot Acquisition sensitivity, hot start -152.5 dBm
Sensitivity, tracking Tracking sensitivity -156.5 dBm
TTFF, cold Time to first fix (TTFF), cold start 30.5 s
TTFF, hot TTFF, hot start 1.3 s
TTFF, A-GPS TTFF, A-GPS start 1.3 s
Accuracy, 2D, periodic Positioning accuracy (CEP50), periodic tracking1 3.4 m
Accuracy, 2D, periodic, A-GPS Positioning accuracy (CEP50), periodic tracking1 with A-GPS2 3.1 m
Accuracy, 2D, continuous Positioning accuracy (CEP50), continuous tracking 2.0 m
Accuracy, 2D, continuous, A-GPS Positioning accuracy (CEP50), continuous tracking with A-GPS2 1.8 m
1PPS accuracy 1PPS signal accuracy, continuous tracking ±35 ns
1 Fix interval 2 min.
2 Including NeQuick ionospheric model parameters.