Kalubalen watsa bayanai masu yawa daga jirgin sama mara matuki (UAV) ko na'ura mai kwakwalwa na kasa ba sabon abu bane a aikace-aikacen zamani. Wannan labarin yana tattauna ma'auni na zaɓi na modem na broadband da matsalolin da ke da alaƙa. An rubuta labarin don UAV da masu haɓaka na'ura mai kwakwalwa.
Yanayin Zaɓuɓɓuka
Babban ma'auni don zaɓar modem mai watsa shirye-shirye don UAVs ko robotics sune:
- Kewayon sadarwa.
- Matsakaicin adadin canja wurin bayanai.
- Jinkirta a watsa bayanai.
- Ma'aunin nauyi da girma.
- Matsalolin bayanai masu goyan baya.
- Bukatun abinci mai gina jiki.
- Rarrabe iko/ tashar telemetry.
Kewayon sadarwa
Kewayon sadarwa ya dogara ba kawai akan modem ba, har ma akan eriya, igiyoyin eriya, yanayin yaɗa igiyoyin rediyo, tsangwama na waje da sauran dalilai. Don raba sigogi na modem kanta daga sauran sigogi waɗanda ke shafar kewayon sadarwa, la'akari da ma'aunin kewayon [Kalinin A.I., Cherenkova EL. Yada raƙuman rediyo da aiki na hanyoyin haɗin rediyo. Haɗin kai. Moscow. 1971]
$$ nuni$$ R=frac{3 cdot 10^8}{4 pi F}10^{frac{P_{TXdBm}+G_{TXdB}+L_{TXdB}+G_{RXdB}+L_{RXdB}+ |V|_{dB}-P_{RXdBm}}{20}},$$ nuni$$
inda
$inline$R$inline$ - kewayon sadarwar da ake buƙata a cikin mita;
$inline$F$inline $ - mita a cikin Hz;
$inline$P_{TXdBm}$inline$ - ikon watsa modem a dBm;
$inline$G_{TXdB}$inline$ - ribar eriya mai watsawa a dB;
$inline$L_{TXdB}$inline$ - hasara a cikin kebul daga modem zuwa eriyar watsawa a dB;
$inline$G_{RXdB}$inline$ - riban eriya mai karɓa a dB;
$inline$L_{RXdB}$inline $ - hasara a cikin kebul daga modem zuwa eriyar mai karɓa a dB;
$inline$P_{RXdBm}$inline$ - hankalin mai karɓar modem a dBm;
$inline$|V| _{dB}$inline$ wani abu ne na ragewa wanda ke yin la'akari da ƙarin asara saboda tasirin saman duniya, ciyayi, yanayi da sauran abubuwan da ke cikin dB.
Daga kewayon kewayon ya bayyana a sarari cewa kewayon ya dogara ne kawai akan sigogi biyu na modem: ikon watsawa $inline$P_{TXdBm}$inline$ da hankalin mai karɓar $inline$P_{RXdBm}$inline$, ko kuma akan bambancinsu. - kasafin kudin makamashi na modem
$$ nuni$$B_m=P_{TXdBm}-P_{RXdBm}.$$ nuni$$
Sauran sigogin da ke cikin kewayon kewayon suna bayyana yanayin yaduwar sigina da sigogin na'urorin ciyarwar eriya, watau. Babu ruwansu da modem.
Don haka, don haɓaka kewayon sadarwa, kuna buƙatar zaɓar modem mai ƙima mai girman $inline$B_m$inline$. Hakanan, ana iya ƙara $inline$B_m$inline$ ta ƙara $inline$P_{TXdBm}$inline$ ko ta rage $inline$P_{RXdBm}$inline$. A mafi yawan lokuta, masu haɓakawa na UAV suna neman modem tare da babban ikon watsawa kuma suna ba da hankali kaɗan ga hankalin mai karɓar, kodayake suna buƙatar yin daidai da akasin haka. Mai watsawa mai ƙarfi a kan allo na modem na broadband yana haɗa da matsaloli masu zuwa:
- yawan amfani da makamashi;
- bukatar sanyaya;
- tabarbarewar daidaituwar wutar lantarki (EMC) tare da sauran kayan aikin kan jirgin na UAV;
- ƙananan sirrin makamashi.
Matsaloli biyu na farko suna da alaƙa da cewa hanyoyin zamani na watsa bayanai masu yawa a tashar rediyo, misali OFDM, suna buƙatar. mikakke watsawa. Ingancin masu watsa rediyo na layi na zamani yayi ƙasa: 10-30%. Don haka, 70-90% na makamashi mai daraja na wutar lantarki na UAV yana canzawa zuwa zafi, wanda dole ne a cire shi da kyau daga modem, in ba haka ba zai yi kasawa ko kuma ikon fitar da shi ya ragu saboda zafi a mafi ƙarancin lokacin da bai dace ba. Misali, mai watsawa 2W zai zana 6-20 W daga wutar lantarki, wanda 4-18 W zai canza zuwa zafi.
Ƙarfin kuzarin hanyar haɗin rediyo yana da mahimmanci don aikace-aikacen musamman da na soja. Ƙarƙashin ɓoye yana nufin cewa an gano siginar modem tare da babban yuwuwar mai karɓar bincike na tashar cunkoso. Saboda haka, yuwuwar murkushe hanyar haɗin rediyo tare da ƙarancin kuzari mai ƙarfi shima yana da girma.
Hankalin mai karɓar modem yana nuna ikonsa na cire bayanai daga siginar da aka karɓa tare da ƙimar da aka ba da ita. Ma'aunin inganci na iya bambanta. Don tsarin sadarwar dijital, ana amfani da yuwuwar ɗan kuskure kaɗan (ƙididdigar kuskuren bit - BER) ko yuwuwar kuskure a cikin fakitin bayanai (kuɗin kuskuren firam - FER). A haƙiƙa, hankali shine matakin siginar da dole ne a fitar da bayanai daga gare ta. Misali, hankali na -98 dBm tare da BER = 10−6 yana nuna cewa bayanai tare da irin wannan BER za a iya fitar da su daga sigina mai matakin −98 dBm ko sama, amma bayanai tare da matakin, ka ce, -99 dBm na iya. ba za a ƙara fitar da sigina mai matakin, a ce, -1 dBm. Tabbas, raguwar inganci yayin da matakin siginar ya ragu yana faruwa a hankali, amma yana da kyau a tuna cewa yawancin modem na zamani suna da abin da ake kira. Tasirin bakin kofa wanda raguwar inganci lokacin da matakin siginar ya ragu ƙasa da hankali yana faruwa da sauri. Ya isa ya rage siginar ta 2-10 dB a ƙasa da hankali don BER ya karu zuwa 1-XNUMX, wanda ke nufin cewa ba za ku ƙara ganin bidiyo daga UAV ba. Tasirin bakin kofa sakamako ne kai tsaye na ka'idar Shannon don tashar hayaniya; ba za a iya kawar da shi ba. Rushewar bayanai lokacin da matakin siginar ya ragu ƙasa da hankali yana faruwa saboda tasirin amo da aka samu a cikin mai karɓar kanta. Ba za a iya kawar da hayaniyar cikin gida gaba ɗaya ba, amma yana yiwuwa a rage matakinsa ko koyi yadda ya kamata a fitar da bayanai daga siginar hayaniya. Masu kera modem suna amfani da waɗannan hanyoyin guda biyu, suna yin haɓakawa ga tubalan RF na mai karɓa da haɓaka algorithms sarrafa siginar dijital. Haɓaka hankali na mai karɓar modem baya haifar da irin wannan haɓaka mai ban mamaki a cikin amfani da wutar lantarki da kuma zubar da zafi kamar ƙara ƙarfin watsawa. Akwai, ba shakka, karuwa a cikin amfani da makamashi da kuma samar da zafi, amma yana da sauƙi.
Ana ba da shawarar zaɓin zaɓi na modem mai zuwa daga ra'ayi na cimma iyakar sadarwar da ake buƙata.
- Yanke shawarar adadin canja wurin bayanai.
- Zaɓi modem tare da mafi kyawun hankali don saurin da ake buƙata.
- Ƙayyade kewayon sadarwa ta lissafi ko gwaji.
- Idan kewayon sadarwar ya zama ƙasa da zama dole, to gwada amfani da matakan masu zuwa (wanda aka tsara don rage fifiko):
- rage asara a cikin igiyoyin eriya $inline$L_{TXdB}$inline$, $inline$L_{RXdB}$inline$ ta hanyar amfani da kebul tare da ƙaramar layin layi a mitar aiki da/ko rage tsayin igiyoyin;
- karuwar eriya $inline$G_{TXdB}$$inline$, $inline$G_{RXdB}$inline$;
- ƙara ƙarfin watsa modem.
Ƙimar hankali sun dogara da ƙimar canja wurin bayanai bisa ga ka'ida: mafi girma gudun - mafi muni hankali. Misali, -98 dBm hankali na 8 Mbps ya fi -95 dBm hankali na 12 Mbps. Kuna iya kwatanta modem ta fuskar hankali kawai don saurin canja wurin bayanai iri ɗaya.
Bayanai game da ikon watsawa kusan koyaushe ana samun su a cikin ƙayyadaddun modem, amma bayanan kan hankalin mai karɓar ba koyaushe ake samuwa ko kuma ba su isa ba. Aƙalla, wannan dalili ne na yin hankali, tun da kyawawan lambobi ba su da ma'ana don ɓoyewa. Bugu da kari, ta hanyar rashin buga bayanan hankali, masana'anta suna hana mabukaci damar kimanta kewayon sadarwa ta hanyar lissafi. to siyayyar modem.
Matsakaicin ƙimar baud
Zaɓin modem bisa wannan siga yana da sauƙi idan an fayyace buƙatun saurin a sarari. Amma akwai wasu nuances.
Idan matsalar da ake warwarewa tana buƙatar tabbatar da iyakar iyawar sadarwa kuma a lokaci guda yana yiwuwa a ware isasshiyar mitar mitar don hanyar haɗin rediyo, to yana da kyau a zaɓi modem ɗin da ke goyan bayan faffadan mitar mitar (bandwidth). Gaskiyar ita ce, ana iya samun saurin bayanan da ake buƙata a cikin ƙananan mitar mitar ta hanyar amfani da nau'ikan daidaitawa (16QAM, 64QAM, 256QAM, da dai sauransu), ko kuma a cikin madaidaicin mitar ta amfani da ƙananan ƙarancin ƙima (BPSK, QPSK). ). Yin amfani da ƙananan ƙarancin ƙima don irin waɗannan ayyuka ya fi dacewa saboda girman rigakafi na amo. Saboda haka, hankali na mai karɓa ya fi kyau; saboda haka, kasafin makamashi na modem yana ƙaruwa kuma, a sakamakon haka, kewayon sadarwa.
Wani lokaci masana'antun UAV suna saita saurin bayanai na hanyar haɗin rediyo fiye da saurin tushen, a zahiri sau 2 ko fiye, suna jayayya cewa tushe kamar codecs na bidiyo suna da madaidaicin bitrate kuma yakamata a zaɓi saurin modem tare da la'akari da matsakaicin ƙimar. na bitrate watsi. A wannan yanayin, kewayon sadarwa yana raguwa a zahiri. Kada ku yi amfani da wannan hanyar sai dai idan ya zama dole. Yawancin modem na zamani suna da babban buffer a cikin na'urar watsawa wanda zai iya sassauta tsintsiyar bitrate ba tare da asarar fakiti ba. Don haka, ba a buƙatar ajiyar gudun sama da kashi 25%. Idan akwai dalili don yin imani da cewa ƙarfin buffer na modem ɗin da aka siya bai isa ba kuma ana buƙatar haɓakar haɓaka mai girma, to ya fi kyau ka ƙi siyan irin wannan modem.
Jinkirin canja wurin bayanai
Lokacin kimanta wannan siga, yana da mahimmanci a ware jinkirin da ke da alaƙa da watsa bayanai akan hanyar haɗin rediyo daga jinkirin da aka ƙirƙira ta na'urar ɓoyewa/decoding na tushen bayanai, kamar codec na bidiyo. Jinkiri a cikin hanyar haɗin rediyo ya ƙunshi ƙima 3.
- Jinkiri saboda sarrafa sigina a cikin mai aikawa da karɓa.
- Jinkiri saboda yaduwar sigina daga mai aikawa zuwa mai karɓa.
- Jinkirta saboda buffer bayanai a cikin mai watsawa a cikin modem na rarraba lokaci (TDD).
Nau'in jinkiri na 1, a cikin ƙwarewar marubucin, ya bambanta daga dubun microsecond zuwa millisecond ɗaya. Nau'in jinkiri na 2 ya dogara da kewayon sadarwa, alal misali, don hanyar haɗin kilomita 100 shine 333 μs. Nau'in jinkiri na 3 ya dogara da tsayin firam na TDD kuma akan rabon tsawon lokacin sake zagayowar watsawa zuwa jimlar tsawon firam kuma yana iya bambanta daga 0 zuwa tsawon firam, watau madaidaicin bazuwar. Idan fakitin bayanan da aka watsa yana cikin shigarwar watsawa yayin da modem ɗin ke cikin zagayowar watsawa, to fakitin za a watsa shi akan iska tare da nau'in jinkiri na sifili 3. Idan fakitin ya ɗan yi latti kuma an riga an fara zagayowar liyafar, to, za a watsa fakitin akan iska tare da sifiri. za a jinkirta shi a cikin buffer na watsawa na tsawon lokacin sake zagayowar liyafar. Tsawon firam na TDD na al'ada yana daga 2 zuwa 20 ms, don haka mafi munin jinkirin Nau'in 3 ba zai wuce 20 ms ba. Don haka, jimillar jinkiri a hanyar haɗin rediyon zai kasance cikin kewayon 3-21 ms.
Hanya mafi kyau don gano jinkiri a hanyar haɗin rediyo shine cikakken gwaji ta amfani da kayan aiki don kimanta halayen cibiyar sadarwa. Ba a ba da shawarar auna jinkiri ta amfani da hanyar amsa buƙatun ba, tunda jinkirin gaba da juyawa baya zama iri ɗaya ga modem TDD.
Ma'aunin nauyi da girma
Zaɓin naúrar modem akan allo bisa ga wannan ma'auni baya buƙatar kowane sharhi na musamman: ƙarami kuma mafi sauƙi shine mafi kyau. Kar a manta kuma game da buƙatar sanyaya naúrar kan jirgin; ana iya buƙatar ƙarin radiators, sabili da haka, nauyi da girma na iya ƙaruwa. Ya kamata a ba fifiko a nan ga haske, ƙananan raka'a tare da ƙarancin wutar lantarki.
Don rukunin tushen ƙasa, ma'auni mai girma ba su da mahimmanci. Sauƙin amfani da shigarwa yana zuwa gaba. Ƙungiyar ƙasa yakamata ta zama na'urar da aka dogara da ita daga tasirin waje tare da tsarin ɗawainiya mai dacewa zuwa mast ko tripod. Kyakkyawan zaɓi shine lokacin da aka haɗa naúrar ƙasa a cikin gida ɗaya tare da eriya. Da kyau, ya kamata a haɗa naúrar ƙasa zuwa tsarin sarrafawa ta hanyar haɗin da ya dace. Wannan zai cece ku daga kalmomi masu ƙarfi lokacin da kuke buƙatar aiwatar da aikin turawa a zazzabi na -20 digiri.
Abubuwan Bukatun Abinci
Raka'a a kan jirgin, a matsayin mai mulkin, ana samar da su tare da goyon baya ga nau'i-nau'i masu yawa na samar da wutar lantarki, misali 7-30 V, wanda ke rufe yawancin zaɓuɓɓukan wutar lantarki a cikin hanyar sadarwa ta UAV. Idan kuna da damar zaɓar daga nau'ikan wutar lantarki da yawa, to, ku ba da fifiko ga ƙimar wutar lantarki mafi ƙasƙanci. A matsayinka na mai mulki, ana amfani da modem a ciki daga ƙarfin lantarki na 3.3 da 5.0 V ta hanyar samar da wutar lantarki ta biyu. Ingancin waɗannan kayan wutan lantarki na biyu ya fi girma, ƙaramin bambanci tsakanin shigarwa da ƙarfin ciki na modem. Ƙarfafa haɓaka yana nufin rage yawan amfani da makamashi da kuma samar da zafi.
Raka'o'in ƙasa, a gefe guda, dole ne su goyi bayan wuta daga tushen wutar lantarki mai girma. Wannan yana ba da damar yin amfani da kebul na wutar lantarki tare da ƙananan ɓangaren giciye, wanda ya rage nauyi kuma yana sauƙaƙe shigarwa. Duk sauran abubuwa daidai suke, ba da fifiko ga raka'a na tushen ƙasa tare da tallafin PoE (Power over Ethernet). A wannan yanayin, kebul na Ethernet ɗaya kawai ake buƙata don haɗa rukunin ƙasa zuwa tashar sarrafawa.
Rarrabe iko/ tashar telemetry
Wani muhimmin fasali a cikin lokuta inda babu sarari da ya rage akan UAV don shigar da modem na telemetry daban. Idan akwai sarari, to za a iya amfani da keɓantaccen tashar sarrafawa/ telemetry na modem na broadband azaman madadin. Lokacin zabar modem tare da wannan zaɓi, kula da gaskiyar cewa modem ɗin yana goyan bayan ƙa'idar da ake so don sadarwa tare da UAV (MAVLink ko mallakar mallaka) da ikon sarrafa tashar sarrafa bayanai / bayanan telemetry a cikin ingantacciyar hanyar sadarwa a tashar ƙasa (GS). ). Misali, an haɗa naúrar kan-board na modem na broadband zuwa autopilot ta hanyar sadarwa irin su RS232, UART ko CAN, kuma an haɗa naúrar ƙasa zuwa kwamfuta mai sarrafawa ta hanyar hanyar sadarwa ta Ethernet wanda ta inda ya zama dole don musayar umarni. , telemetry da bayanin bidiyo. A wannan yanayin, modem ɗin dole ne ya iya ninka umarni da rafi na telemetry tsakanin musaya na RS232, UART ko CAN na rukunin kan-jirgin da keɓancewar Ethernet na rukunin ƙasa.
Sauran sigogi don kula da su
Samuwar yanayin duplex. Modems na Broadband don UAVs suna goyan bayan yanayin aiki mai sauƙi ko duplex. A cikin yanayin simplex, ana ba da izinin watsa bayanai kawai a cikin shugabanci daga UAV zuwa NS, kuma a cikin yanayin duplex - a cikin duka kwatance. A matsayinka na mai mulki, simplex modems suna da ginanniyar codec na bidiyo kuma an tsara su don aiki tare da kyamarori na bidiyo waɗanda ba su da codec na bidiyo. Simplex modem bai dace da haɗawa zuwa kyamarar IP ko wasu na'urori waɗanda ke buƙatar haɗin IP ba. Akasin haka, modem duplex, a matsayin mai mulkin, an tsara shi don haɗa cibiyar sadarwar IP ta kan jirgin UAV tare da hanyar sadarwar IP na NS, watau tana goyan bayan kyamarori na IP da sauran na'urorin IP, amma ƙila ba su da ginanniyar- a cikin codec na bidiyo, tunda kyamarorin bidiyo na IP yawanci suna da codec ɗin bidiyo na ku. Taimakon haɗin haɗin Ethernet yana yiwuwa ne kawai a cikin modem ɗin duplex.
liyafar Diversity (RX diversity). Kasancewar wannan damar ya zama tilas don tabbatar da ci gaba da sadarwa cikin dukkan nisan jirgin. Lokacin yadawa a saman duniya, raƙuman rediyo suna isa wurin karɓar raƙuman katako guda biyu: tare da hanya kai tsaye kuma tare da tunani daga saman. Idan ƙarin raƙuman igiyoyin igiyoyi biyu sun faru a cikin lokaci, to, filin a wurin karɓar yana ƙarfafa, kuma idan a cikin antiphase, ya raunana. Rauni na iya zama mai ma'ana sosai - har zuwa cikakkiyar asarar sadarwa. Kasancewar eriya guda biyu akan NS, wanda yake a tsayi daban-daban, yana taimakawa wajen magance wannan matsala, domin idan a wurin daya eriya ana ƙara katako a cikin antiphase, to a wurin ɗayan ba sa. A sakamakon haka, za ku iya cimma daidaituwar haɗin gwiwa a duk tsawon nisa.
Topologies cibiyar sadarwa masu goyan baya. Yana da kyau a zabi modem wanda ke ba da tallafi ba kawai don topology point-to-point (PTP) ba, har ma don maki-zuwa-multipoint (PMP) da relay (maimaitawa) topologies. Amfani da gudun ba da sanda ta hanyar ƙarin UAV yana ba ku damar fadada yankin ɗaukar hoto na babban UAV. Tallafin PMP zai ba ku damar karɓar bayanai lokaci guda daga UAV da yawa akan NS ɗaya. Da fatan za a kuma lura cewa goyan bayan PMP da relay zai buƙaci haɓaka bandwidth na modem idan aka kwatanta da yanayin sadarwa tare da UAV guda ɗaya. Don haka, don waɗannan hanyoyin ana ba da shawarar zaɓin modem ɗin da ke goyan bayan rukunin mitar mitar (aƙalla 15-20 MHz).
Samar da hanyoyin da za a ƙara rigakafin amo. Zaɓin mai amfani, da aka ba da matsanancin tsangwama a wuraren da ake amfani da UAVs. Ana fahimtar rigakafin hayaniya a matsayin ikon tsarin sadarwa don aiwatar da aikinsa a gaban kutse na asali na wucin gadi ko na halitta a cikin tashar sadarwa. Akwai hanyoyi guda biyu don magance tsangwama. Hanyar 1: ƙirƙira mai karɓar modem ta yadda zai iya karɓar bayanai cikin aminci ko da kasancewar kutsawa a cikin tashar sadarwa, a farashin ɗan raguwar saurin watsa bayanai. Hanyar 2: Mane ko rage tsangwama a shigar da mai karɓa. Misalai na aiwatar da tsarin farko sune tsarin yada bakan, wato: mita hopping (FH), pseudo-random sequence spread spectrum (DSSS) ko gaurayawan duka biyun. Fasahar FH ta zama tartsatsi a cikin tashoshin sarrafa UAV saboda ƙarancin canja wurin bayanai da ake buƙata a cikin irin wannan tashar sadarwa. Misali, don saurin 16 kbit/s a cikin rukunin 20 MHz, ana iya tsara kusan wuraren mitar 500, wanda ke ba da damar ingantaccen kariya daga tsangwama mai kunkuntar. Yin amfani da FH don tashar sadarwa ta broadband yana da matsala saboda sakamakon mitar mitar ya yi girma da yawa. Misali, don samun matsayi na mitar 500 lokacin aiki tare da sigina tare da bandwidth na 4 MHz, kuna buƙatar 2 GHz na bandwidth kyauta! Da yawa ya zama na gaske. Amfani da DSSS don tashar sadarwa ta hanyar sadarwa tare da UAVs ya fi dacewa. A cikin wannan fasaha, kowane bit bayanin ana kwafi lokaci guda a mitoci da yawa (ko ma duka) a cikin siginar band ɗin kuma, a gaban kutse mai kunkuntar, ana iya raba shi daga sassan bakan da tsangwama ya shafa. Amfani da DSSS, da kuma FH, yana nuna cewa lokacin da tsangwama ya bayyana a tashar, za a buƙaci rage yawan watsa bayanai. Duk da haka, a bayyane yake cewa yana da kyau a karɓi bidiyo daga UAV a cikin ƙaramin ƙuduri fiye da komai. Hanyar 2 tana amfani da gaskiyar cewa tsangwama, ba kamar amo na ciki na mai karɓa ba, yana shiga hanyar haɗin rediyo daga waje kuma, idan wasu hanyoyi suna cikin modem, za'a iya kashe su. Damke tsangwama yana yiwuwa idan an gurɓata shi a cikin yanki na gani, na ɗan lokaci ko na sarari. Misali, tsangwama mai kunkuntar yana cikin yanki a cikin yanki na bakan kuma ana iya "yanke" daga bakan ta amfani da tacewa ta musamman. Hakazalika, ƙarar da aka buga tana cikin yankin lokaci; don murkushe shi, ana cire yankin da abin ya shafa daga siginar shigar da mai karɓa. Idan tsangwama ba a kunkuntar ko bugun ba, to ana iya amfani da mai hana sararin samaniya don murkushe shi, tunda. tsangwama yana shiga eriya mai karɓa daga tushe daga wata hanya. Idan sifilin sifili na ƙirar eriya mai karɓa an saita shi a cikin hanyar tushen tsangwama, za a danne tsangwama. Irin waɗannan tsarin ana kiran su adaptive beamforming & beam nulling systems.
An yi amfani da ka'idar rediyo. Masu kera modem na iya amfani da ma'auni (WiFi, DVB-T) ko ka'idar rediyo ta mallaka. Ba a cika yin nuni da wannan siga cikin ƙayyadaddun bayanai ba. Ana nuna amfani da DVB-T a kaikaice ta hanyar maɗaurin mitar da aka goyan baya 2/4/6/7/8, wani lokacin 10 MHz da ambaton a cikin rubutun ƙayyadaddun fasahar COFDM (coded OFDM) wanda ake amfani da OFDM tare da haɗin gwiwa. tare da coding mai jurewa amo. A wucewa, mun lura cewa COFDM taken talla ne zalla kuma ba shi da wani fa'ida akan OFDM, tunda OFDM ba tare da yin rikodin amo ba a taɓa amfani da shi a aikace. Daidaita COFDM da OFDM lokacin da kuka ga waɗannan gajarce a cikin ƙayyadaddun modem na rediyo.
Modems da ke amfani da madaidaicin yarjejeniya yawanci ana gina su ne bisa tushen guntu na musamman (WiFi, DVB-T) da ke aiki tare da microprocessor. Yin amfani da guntu na al'ada yana sauƙaƙawa masu kera modem yawan ciwon kai da ke da alaƙa da ƙira, ƙira, aiwatarwa, da gwada nasu ka'idojin rediyo. Ana amfani da microprocessor don baiwa modem aikin da ya dace. Irin waɗannan modem suna da fa'idodi masu zuwa.
- Priceananan farashin.
- Kyakkyawan nauyi da sigogi masu girma.
- Ƙananan amfani da wutar lantarki.
Akwai kuma rashin amfani.
- Rashin iya canza halayen mu'amalar rediyo ta hanyar canza firmware.
- Ƙananan kwanciyar hankali na kayayyaki a cikin dogon lokaci.
- Iyakance iyakoki wajen ba da ƙwararrun goyan bayan fasaha lokacin warware matsalolin da ba daidai ba.
Rashin kwanciyar hankali na kayayyaki shine saboda gaskiyar cewa masana'antun guntu sun fi mayar da hankali kan kasuwannin jama'a (TV, kwamfuta, da sauransu). Masu kera modem don UAVs ba fifiko ba ne a gare su kuma ta kowace hanya ba za su iya yin tasiri ga shawarar masana'antar guntu don dakatar da samarwa ba tare da isasshen canji da wani samfur ba. An ƙarfafa wannan fasalin ta yanayin marufi na mu'amalar rediyo zuwa ƙwararrun microcircuits kamar "tsarin kan guntu" (Tsarin kan Chip - SoC), don haka a hankali ana wanke kwakwalwan kwamfuta na rediyo na kowane mutum a hankali daga kasuwar semiconductor.
Iyakance iyakoki wajen bayar da tallafin fasaha ya samo asali ne saboda gaskiyar cewa ƙungiyoyin ci gaba na modem bisa ƙa'idar ka'idar rediyo suna da ma'aikata da ƙwararru, da farko a cikin kayan lantarki da fasahar microwave. Wataƙila babu ƙwararrun hanyoyin sadarwa na rediyo a wurin kwata-kwata, tunda babu wata matsala da za su magance. Saboda haka, masana'antun UAV masu neman mafita ga matsalolin sadarwar rediyo marasa mahimmanci na iya samun kansu cikin takaici dangane da shawarwari da taimakon fasaha.
Modems da ke amfani da ka'idar rediyo ta mallaka an gina su bisa tushen analog na duniya da kwakwalwan sarrafa siginar dijital. Kwancen kwanciyar hankali na irin waɗannan kwakwalwan kwamfuta yana da girma sosai. Gaskiya ne, farashin kuma yana da yawa. Irin waɗannan modem suna da fa'idodi masu zuwa.
- Dama mai yawa don daidaita modem ɗin zuwa buƙatun abokin ciniki, gami da daidaita yanayin rediyo ta hanyar canza firmware.
- Ƙarin damar mu'amalar rediyo wanda ke da ban sha'awa don amfani a cikin UAVs kuma ba sa nan a cikin modem waɗanda aka gina bisa ƙa'idodin ƙa'idodin rediyo.
- Babban kwanciyar hankali na kayayyaki, gami da. a cikin dogon lokaci.
- Babban matakin goyon bayan fasaha, gami da warware matsalolin da ba daidai ba.
Laifi.
- Babban farashin.
- Nauyi da girman sigogi na iya zama mafi muni fiye da na modem masu amfani da daidaitattun ka'idojin rediyo.
- Ƙara ƙarfin amfani da na'urar sarrafa siginar dijital.
Bayanan fasaha na wasu modem don UAVs
Teburin yana nuna ma'aunin fasaha na wasu modem don UAVs da ake samu akan kasuwa.
Lura cewa ko da yake 3D Link modem yana da mafi ƙasƙanci ikon watsawa idan aka kwatanta da Picoradio OEM da J11 modems (25 dBm vs. 27−30 dBm), kasafin kudin wutar lantarki na 3D ya fi waɗancan modem ɗin girma saboda ƙwarewar mai karɓa (tare da gudun canja wurin bayanai iri ɗaya don modem ɗin da ake kwatanta). Don haka, kewayon sadarwa lokacin amfani da Haɗin 3D zai kasance mafi girma tare da ingantaccen kuzari.
Tebur. Bayanan fasaha na wasu nau'ikan hanyoyin sadarwa na UAVs da robotics
Alamar
(an yi a kan module daga Microhard)
(duba kuma )
Maƙerawa, ƙasa
Geoscan, RF
Mobilicom, Isra'ila
Airborne Innovations, Kanada
DTC, UK
Redess, China
Iyakar sadarwa [km] 20-60
5
n/a*
n/a*
10-20
Saurin [Mbit/s] 0.023-64.9
1.6-6
0.78-28
0.144-31.668
1.5-6
Jinkirin watsa bayanai [ms] 1-20
25
n/a*
15-100
15-30
Girman naúrar kan allo LxWxH [mm] 77x45x25
74h54h26
40x40x10 (ba tare da gidaje ba)
67h68h22
76h48h20
Nauyin naúrar kan jirgi [gram] 89
105
17.6 (ba tare da gidaje ba)
135
88
Hanyoyin musayar bayanai
Ethernet, RS232, CAN, USB
Ethernet, RS232, USB (na zaɓi)
Ethernet, RS232/UART
HDMI, AV, RS232, USB
HDMI, Ethernet, UART
Wutar wutar lantarki ta kan jirgi [Volt/Watt] 7-30/6.7
7-26/n/a*
5-58/4.8
5.9-17.8 / 4.5-7
7-18/8
Wutar wutar lantarki ta ƙasa [Volt/Watt] 18-75 ko PoE/7
7-26/n/a*
5-58/4.8
6-16/8
7-18/5
Ikon watsawa [dBm] 25
n/a*
27-30
20
30
Hankalin mai karɓa [dBm] (don saurin [Mbit/s])
−122(0.023) −101(4.06) −95.1(12.18) −78.6(64.96)
-101 (n/a*)
−101(0.78) −96(3.00) −76(28.0)
-95 (n/a*) -104(n/a*)
−97(1.5) −94(3.0) −90(6.0)
Kasafin kudin makamashi na modem [dB] (don gudun [Mbit/sec])
147(0.023) 126(4.06) 120.1(12.18) 103.6(64.96)
n/a*
131(0.78) 126(3.00) 103(28.0)
n/a*
127 (1.5) 124 (3.0) 120 (6.0)
Ƙwayoyin mitar da aka goyan baya [MHz] 4-20
4.5. 8.5
2; 4; 8
0.625; 1.25; 2.5; 6; 7; 8
2; 4; 8
Simplex/duplex
Duplex
Duplex
Duplex
Simplex
Duplex
Taimakon bambancin
a
a
a
a
a
Rarrabe tashar don sarrafawa / telemetry
a
a
a
babu
a
Goyan bayan ka'idojin sarrafa UAV a cikin tashar sarrafawa/ telemetry
MAVLink, mallakar mallaka
MAVLink, mallakar mallaka
babu
babu
MAV Link
Multiplexing goyon bayan iko / telemetry tashar
a
a
babu
babu
n/a*
hanyoyin sadarwa topologies
PTP, PMP, relay
PTP, PMP, relay
PTP, PMP, relay
PTP
PTP, PMP, relay
Ma'ana don ƙara rigakafin amo
DSSS, kunkuntar bandeji da bugun bugun jini
n/a*
n/a*
n/a*
n/a*
Ka'idar rediyo
na mallaka
n/a*
n/a*
DVB-T
n/a*
* n/a - babu data.
Game da marubucin
Alexander Smorodinov[email kariya]] babban kwararre ne a Geoscan LLC a fagen sadarwa mara waya. Daga 2011 zuwa yanzu, yana haɓaka ka'idojin rediyo da algorithms sarrafa sigina don nau'ikan modem na rediyo don dalilai daban-daban, gami da aiwatar da algorithm ɗin da aka haɓaka bisa guntuwar dabaru masu shirye-shirye. Wuraren sha'awar marubucin sun haɗa da haɓaka algorithms aiki tare, ƙididdige kaddarorin tashoshi, daidaitawa/demodulation, coding mai jurewa amo, da kuma wasu algorithms na samun damar kafofin watsa labarai (MAC). Kafin shiga Geoscan, marubucin ya yi aiki a kungiyoyi daban-daban, yana haɓaka na'urorin sadarwar mara waya ta al'ada. Daga 2002 zuwa 2007, ya yi aiki a Proteus LLC a matsayin ƙwararrun ƙwararrun ƙwararrun ci gaban tsarin sadarwa bisa ma'aunin IEEE802.16 (WiMAX). Daga 1999 zuwa 2002, marubucin ya shiga cikin haɓaka algorithms masu juriya da surutu da ƙirar hanyoyin haɗin rediyo a Cibiyar Nazarin Cibiyar Nazarin Cibiyoyin Harkokin Kasuwanci ta Tarayya ta Tarayya "Granit". Marubucin ya sami Digiri na Digiri na Kimiyyar Fasaha daga Jami'ar St. Alexander memba ne na IEEE na yanzu da kuma IEEE Communications Society.
source: www.habr.com