diff --git a/README.md b/README.md index 6c8773727..1c8622065 100644 --- a/README.md +++ b/README.md @@ -1156,7 +1156,7 @@ More documentation at the [Channels page](https://gnss-sdr.org/docs/sp-blocks/ch #### Acquisition -The first task of a GNSS receiver is to detect the presence or absence of in-view satellites. This is done by the acquisition system process, which also provides a coarse estimation of two signal parameters: the frequency shift with respect to the nominal IF frequency, and a delay term which allows the receiver to create a local code aligned with the incoming code. [AcquisitionInterface](./src/core/interfaces/acquisition_interface.h) is the common interface for all the acquisition algorithms and their corresponding implementations. Algorithms' interface, that may vary depending on the use of information external to the receiver, such as in Assisted GNSS, is defined in classes referred to as *adapters*. These adapters wrap the GNU Radio blocks interface into a compatible interface expected by AcquisitionInterface. This allows the use of existing GNU Radio blocks derived from ```gr::block```, and ensures that newly developed implementations will also be reusable in other GNU Radio-based applications. Moreover, it adds still another layer of abstraction, since each given acquisition algorithm can have different implementations (for instance using different numerical libraries). In such a way, implementations can be continuously improved without having any impact neither on the algorithm interface nor the general acquisition interface. +The first task of a GNSS receiver is to detect the presence or absence of in-view satellites. This is done by the acquisition system process, which also provides a coarse estimation of two signal parameters: the frequency shift with respect to the nominal frequency, and a delay term which allows the receiver to create a local code aligned with the incoming code. [AcquisitionInterface](./src/core/interfaces/acquisition_interface.h) is the common interface for all the acquisition algorithms and their corresponding implementations. Algorithms' interface, that may vary depending on the use of information external to the receiver, such as in Assisted GNSS, is defined in classes referred to as *adapters*. These adapters wrap the GNU Radio blocks interface into a compatible interface expected by AcquisitionInterface. This allows the use of existing GNU Radio blocks derived from ```gr::block```, and ensures that newly developed implementations will also be reusable in other GNU Radio-based applications. Moreover, it adds still another layer of abstraction, since each given acquisition algorithm can have different implementations (for instance using different numerical libraries). In such a way, implementations can be continuously improved without having any impact neither on the algorithm interface nor the general acquisition interface. Check [GpsL1CaPcpsAcquisition](./src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.h) and [GalileoE1PcpsAmbiguousAcquisition](./src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.h) for examples of adapters from a Parallel Code Phase Search (PCPS) acquisition block, and [pcps_acquisition_cc](./src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition_cc.h) for an example of a block implementation. The source code of all the available acquisition algorithms is located at: @@ -1169,14 +1169,13 @@ Check [GpsL1CaPcpsAcquisition](./src/algorithms/acquisition/adapters/gps_l1_ca_p |---------gnuradio_blocks <- Signal processing blocks implementation ~~~~~~ -The user can select a given implementation for the algorithm to be used in each receiver channel, as well as their parameters, in the configuration file. For a GPS l1 C/A receiver: +The user can select a given implementation for the algorithm to be used in each receiver channel, as well as their parameters, in the configuration file. For a GPS L1 C/A receiver: ~~~~~~ ;######### ACQUISITION GLOBAL CONFIG ############ Acquisition_1C.implementation=GPS_L1_CA_PCPS_Acquisition ; Acquisition algorithm selection for this channel Acquisition_1C.item_type=gr_complex -Acquisition_1C.if=0 ; Signal intermediate frequency in [Hz] -Acquisition_1C.sampled_ms=1 ; Signal block duration for the acquisition signal detection [ms] +Acquisition_1C.coherent_integration_time_ms=1 ; Signal block duration for the acquisition signal detection [ms] Acquisition_1C.threshold=0.005 ; Acquisition threshold Acquisition_1C.pfa=0.0001 ; Acquisition false alarm probability. This option overrides the threshold option. ; Only use with implementations: [GPS_L1_CA_PCPS_Acquisition] or [Galileo_E1_PCPS_Ambiguous_Acquisition] @@ -1192,8 +1191,7 @@ and, for Galileo E1B channels: ;######### GALILEO ACQUISITION CONFIG ############ Acquisition_1B.implementation=Galileo_E1_PCPS_Ambiguous_Acquisition Acquisition_1B.item_type=gr_complex -Acquisition_1B.if=0 -Acquisition_1B.sampled_ms=4 +Acquisition_1B.coherent_integration_time_ms=4 Acquisition_1B.pfa=0.0000008 Acquisition_1B.doppler_max=15000 Acquisition_1B.doppler_step=125